Datasets:

badrex

/

royal_society_corpus_metadata

like 0

112374

3701662

Description of the Cavern of Bruniquel, and Its Organic Contents.--Part II. Equine Remains. [Abstract]

201

202

Proceedings of the Royal Society of London

Professor Owen

abs

6.0.4

proceedings

http://corpora.clarin-d.uni-saarland.de/surprisal/6.0.3/?id=112374

http://www.jstor.org/stable/112374

Anatomy 2

Biography

Anatomy

I. " Description of the Cavern of Bruniquel , and its Organic Contents.-Part II . Equine Remains . " By Professor OWEN , F.R.S. Received August 20 , 1868 . ( Abstract . ) In this paper the author has selected the fossil remains of the Equine family as the subject of the second part of his Description of the Cave of Bruniquel and its contents , which Cave , with the human remains , was described in Part I. communicated to the Royal Society , June 9 , 1864 . He premises a definition of the several parts of the grinding-surface of the upper and lower molars and premolars in the genus Equus , homologizing them with those in the corresponding teeth of ipiparion , Paloplotherium , and Palceotherium . Next , referring to the want of figures of the natural size , or of any figures of the characteristic surface of the teeth of the molar series in the known species of the existing Equines , the author gives a description thereof in the Horse ( Equus caballus ) , Ass ( E. asinus ) , Kiang ( E. hemiconus ) , Quagga ( E. quagga ) , Dauw ( E. Burchelli ) , and Zebra ( E. Zebra ) , indicating by comparison their respective characteristics . These descriptions are accompanied with drawings ( of the natural size ) of the working-surface of the dentition of each species , with lettered details of such surface in the teeth of both upper and under jaws . The Equine fossils from the Cave of Bruniquel are then described and compared with each other , with the above-named existing species of Equus , and with previously defined fossil species of Equidce . Two varieties in respect of size and some minor characters are pointed out in the Bruniquel series , of one of which figures ( of the natural size ) of the grinding-surface of the upper and lower molar series , and of the second variety , figures of the same surface of the upper molar series are given . The author , remarking that such evidences of mature and full-grown animals are rare from the Bruniquel Cave-deposits , selects evidence of certain phases of dentition in the Cave Equines which lend aid in determining their affinities ; these phases being illustrated by four drawings of the natural size . Of the various fossil teeth of Equidce with which those from Bruniquel have been compared , the author finds the closest resemblance , approaching to identity , in certain fossils from freshwater sedimentary deposits of Postpliocene or " Quaternary " age in the Department of the Puy-de-Dome , France . Of these , descriptions are given of the teeth of the upper and lower jaws from such deposits at a locality traversed by the river Allier , near the '"Tour de Juvillac . " A figure of the working-surface of the teeth of the lower jaw from this locality is given ( of the natural size ) , showing the characters of the canine and proportions of the diastema . The close conformity in the characters of the upper grinders of the Puy-de-D'me fossils of deposit with those of the Bruniquel cavern enables the author to dispense with figures of them . The sum of the several comparisons is to refer the above Equine fossils from sedimentary deposits and both varieties from the Bruniquel cave to one and the same species or well-marked race belonging to the true Horses , or restricted genus Equus of modern mammalogists ; the individuals of which race , with a small range of size , probably due to sex , were less than the average-sized horse of the present period , but larger than known existing striped or unstriped species of Asinus , Gray . Interesting testimony , confirmatory of the conclusion from the palmontological comparisons , is adduced from outlines of the heads of different individuals of the Cave Equine when alive , neatly cut on the smooth surface of a rib of the same species , discovered by the Vicomte de Lastic St. Jal in 1863 , in his cavern at Bruniquel , under circumstances which indisputably showed the work to have been done by one of the tribe of men inhabiting the cavern and slaying the wild horses of that locality and period for food . The author remarks that every bone of the Horse 's skeleton ( and such evidence had been obtained from about a hundred individuals that had been exhumed at the period of his second visit to Bruniquel , in February 1864 ) had been split or fractured to gain access to the marrow . The dental canal and roots of the teeth had been similarly exposed in every specimen of jaw .

112375

3701662

On the Mechanical Possibility of the Descent of Glaciers, by Their Weight Only. [Abstract]

202

208

Proceedings of the Royal Society of London

Henry Moseley

abs

6.0.4

proceedings

http://corpora.clarin-d.uni-saarland.de/surprisal/6.0.3/?id=112375

http://www.jstor.org/stable/112375

Measurement

Fluid Dynamics

Measurement

II . " On the Mechanical Possibility of the Descent of Glaciers , by their Weight only . " By the Rev. HENRY MOSELEY , M.A. , Canon of Bristol , F.R.S. , Instit . Imp . Sc. Paris , Corresp . Received October 21 , 1868 . ( Abstract . ) All the parts of a glacier do not descend with a common motion ; it moves faster at its surface than deeper down , and at the centre of its surface than at its edges . It does not only come down bodily , but with different motions of its different parts ; so that if a transverse section were made through it , the ice would be found to be moving differently at every point of that section . This fact* , which appears first to have been made known by M. Rendu , Bishop of Annecy , has since been confirmed by the measurements of Agassiz , Forbes , and Tyndall . There is a constant displacement of the particles of the ice over one another , and alongside one another , to which is opposed that force of resistance which is known in mechanics as shearing force . By the property of ice called regelation , when any surface of ice so sheared is brought into contact with another similar surface , it unites with it , so as to form of the two , one continuous mass . Thus a slow displacement of shearing , by which different similar surfaces were continually being brought into the presence and contact of one another , would exhibit all the phenomena of the motion of glacier'ice . Between this resistance to shearing and the force , whatever it may be , which tends to bring the glacier down , there must be a mechanical relation , so that if the shearing resistance were greater the force would be insufficient to cause the descent . The shearing force of cast iron , for instance , is so great that , although its weight is also very great , it is highly improbable a mass of cast iron would descend if it were made to fill the channel of the Mer de Glace , as the glacier does , because its weight would be found insufficient to overcome its resistance to shearing , and thus to supply the work necessary to those internal displacements , of which a glacier is the subject , or even to shear over the irregularities of the rocky channel . The same is probably true of any other metal . I can find no discussion which has for its object to determine this mechanical relation between what is assumed to be the cause of the descent of a glacier , and the effect produced , to show that the work of its weight ( supposing that alone to cause it to descend ) is equal to the works of the several resistances , internal and external , which are actually overcome in its descent . It is my object to establish such a relation . The forces which oppose themselves to the descent of a glacier are , -1st , the resistance to the sliding motion of one part of a piece of solid ice on the surface of another , which is taking place continually throughout . the mass of the glacier , by reason of the different velocities with which its different parts move . This kind of resistance will be called in this paper ( for shortness ) shear , the unit of shear being the pressure in lbs. necessary to overcome the resistance to shearing of one square inch , which may be presumed to be constant throughout the mass of the glacier . 2ndly . The friction of the superimposed laminta of the glacier ( which move with different velocities ) on one another , which is greater in the lower ones than the upper . 3rdly . The resistance to abrasion , or shearing of the ice , at the bottom of the glacier , and on the sides of its channel , caused by the roughnesses sack . " " This , " says Mr. Cowell , from whose paper read before the Alpine Club in April 1864 the above quotation is made , " is not an isolated example of the scattering that takes place in or on a glacier , for I myself saw on the Theodule Glacier the remains of the Syndic of Val Tournanche scattered over a space of several acres . " 203 of the rock , the projections of which insert themselves into its mass , and into the cavities of which it moulds itself . 4thly . The friction of the ice in contact with the bottom and sides so sheared over or abraded . If the whole mechanical work of these several resistances in a glacier could be determined , as it regards its descent , for any relatively small time , dne day for instance , and also the work of its weight in favour of its descent during that day , then , by the principle of " virtual velocities " ( supposing the glacier to descend by its weight only ) , the aggregate of the work of these resistances , opposed to its descent , would be equal to the work of its weight , in favour of it . It is , of course , impossible to represent this equality mathematically , in respect to a glacier having a variable direction and an irregular channel and slope ; but in respect to an imaginary one , having a constant direction and a uniform channel and slope , it is possible . Let such a glacier be imagined , of unlimited length , lying on an even slope , and having a uniform rectangular channel , to which it fits accurately , and which is of a uniform roughness sufficient to tear off the surface of the glacier as it advances . Such a glacier would descend with a uniform motion if it descended by its weight only , because the forces acting upon it would be uniformly distributed and constant forces* . The conditions of the descent of any one portion of it would therefore be the same as those of any other equal and similar portion . The portion , the conditions of whose descent it is sought in this paper to determine , is that which has descended through any given transverse section in a day ; or , rather , it is one half this mass of ice , for the glacier is supposed to be divided by a vertical plane , passing through the central line of its surface , it being evident that the conditions of the descent of the two halves are the same . The measurements which have been made of the velocities of the surface-ice at different distances from the sides , make it probable that the differences of the spaces described in a given time would be nearly proportional to the distances from the edge in a uniform channelt ; and the similar measurements made on the velocities at different depths on the sides that , under the same circumstances , the increments of velocity would be as the distances from the bottom . This law , which observation indicates as to the surface and the sides , is supposed to obtain throughout the mass of the glaciers . Any deviation from it , possible under the circumstances , will hereafter be shown to be such as would not sensibly affect the result . The trapezoidal mass of ice thus passing through a transverse section in a day is conceived to be divided by an infinite number of equidistant vertical planes , parallel to the central line , or axis of the glacier , and also by an infinite number of other equidistant planes parallel to the bed of the glacier . It is thus cut into rectangular prisms or strips lying side by side and above one another . If any one of these strips be supposed to be prolonged through the whole length of the glacier , every part of it will be moving with the same velocity , and it will be continually shearing over two of the similar adjacent strips , and being sheared over by two others . The position of each of these elementary prisms in the transverse section of the glacier is determined by rectangular coordinates ; and in terms of these , its length , included in the trapezoid . The work of its weight , while it passes through the transverse section into its actual position , is then determined , and the work of its shear , and the work of its friction . A double integration of each of the functions , thus representing the internal work in respect to a given elementary prism , determines the whole internal work of the trapezoid , in terms of the space traversed by the middle of the surface in one day , the spaces traversed by the upper and lower edges of the side , and a symbol representing the unit of shear . WVell-known theorems serve to determine the work of the shear and the friction of the bottom and side in terms of the same quantities . All the terms of the equation above referred to are thus arrived at in terms of known quantities , except the unit of shear , which the equation thus determines . The comparison of this unit of shear ( which is the greatest possible , in order that the glacier may descend by its weight alone ) with the actual unit of shear of glacier ice ( determined by experiment ) , shows that a glacier cannot descend by its weight only ; its shearing force is too great . The true unit of shear being then substituted for its symbol in the equation of condition , the work of the force , which must come in aid of its weight to effect the descent of the glacier , is ascertained . The imaginary case to which these computations apply , differs from that of an actual glacier in the following respects . The actual glacier is not straight , or of a uniform section and slope , and its channel is not of uniform roughness . In all these respects the resistance to the descent of the actual glacier is greater than to the supposed one . But this being the case , the resistance to shearing must be less , in order that the same force , viz. the weight , may be just sufficient to bring down the glacier in the one case , as it does in the other . The ice in the natural channel must shear more easily than that in the artificial channel , if both descend by their weight only ; so that if we determine the unit of shear necessary to the descent of the glacier in the artificial channel , we know that the unit of 205 shear necessary to its descent by its weight only in the natural channel must be less than that . A second possible difference between the case supposed and the actual case lies in this , that the velocities of the surface-ice at different distances from the edge , and at different heights from the bottom , are assumed to be proportional to those distances and heights ; so that the mass of ice at any time passing through a transverse section may be bounded by plane surfaces , and have a trapezoidal form . This may not strictly be the case . All the measurements , however , show that if the surfaces be not plane , they are convex downwards . In so far therefore as the quantity of ice passing through a given section in a day is different from what it is supposed to be , it is greater than it . A greater resistance ( other than shear ing ) is thus opposed to each day 's descent , and also a greater weight of ice favours it ; but the disproportion is so great between the work of the additional resistance to the descent , and that of the additional weight of ice in favour of it , that it is certain that any such convexity of the trapezoidal surface would necessitate a further reduction of the unit of shear , to make the weight of the actual glacier sufficient to cause it to descend . A third difference between the actual glacier and the imaginary one , to the computation of whose unit of shear the following formulae are applied , is this-that the formulae suppose the daily motion of the surface of the glacier and the daily motion of its side to have been measured at the same place , whereas there exist no measurements of the surface motion and the side motion at the same place . The surface motion used has been that of the Mer de Glace at Les Ponts , and the side motion that of the Glacier du Geant at the Tacul-both from the measurements of Prof. Tyndall . This error again , however , tends to cause the unit of shear , deduced from the case of the artificial glacier , to be greater than that in the actual one ; for the Glacier du Geant moves more slowly than the Mer de Glace . The quantity of ice which actually passes through a section at Les Ponts is therefore greater than it is assumed in the computation to be , whence it follows , as in the last case , that the computed unit of shear is greater than the actual unit of shear . To determine the actual value of It ( the unit of shear in the case of ice ) the following experiment was made . Two pieces of hard wood , each three inches thick and of the same breadth , but of which one was considerably longer than the other , were placed together , the surfaces of contact being carefiully smoothed , and a cylindrical hole , l1 inch in diameter , was pierced through the two . The longer piece was then screwed down upon a frame which carried a pulley , over which a cord passed to the middle of the shorter piece , which rested on the longer . There were lateral guides to keep the shorter piece from deviating sideways when moved on the longer . The hole in the upper piece being brought so as accurately to coincide with that in the lower , small pieces of ice were thrown in , a few at a time , and driven home by sharp blows of a mallet on a wooden cylinder . By this means a solid cylinder of ice was constructed , accurately fitting the hole . Weights were then suspended from the rope , passing over the pulley until the cylinder of ice was sheared across . As by the melting of the ice , during the experiment , the diameter of the cylinder was slightly diminished , it was carefully measured with a pair of callipers . 1st experiment.-lRadius of cylinder '65625 in . , sheared with 98 lbs. 2nd experiment.-Radius of cylinder '70312 in . , sheared with 119 lbs. By the first experiment the shear per square inch , or unit of shear , was 72-433 lbs. ; by the second experiment it was 76-619 lbs. The main unit of shear of ice , from these two experiments , is therefore 75 lbs. Now it appears by the preceding calculations , that to descend by its own weight , at the rate at which Prof. Tyndall observed the ice of the Mer de Glace to be descending at the Tacul , the unit of shearing force of the ice could not have been more than 1'3193 lb.* To determine how great a force , in addition to its weight , would be necessary to cause the descent of a glacier of uniform section and slope , such as has been supposed in the calculations , let u represent , in inch-lbs . , the work of that force in twenty-four hours . Then assuming the unit of shear ( p ) in glacier ice to be 75 lbs. , it follows , by the principle of virtual velocities , that u=94134000+1012560-2668400 =92478160 inch-lbs.= 7706513 foot-lbs.t This computation has reference to half only of the width of the glacier , and to 23'25 inches of its length . The work , in excess of its weight , required to make a mile of the imaginary glacier , 466 yards broad and 140 feet deep , descend , as it actually does descend per twenty-four hours , is represented by the horse-power of an engine , which , working constantly day and night , would yield this work , or by 2 x7706513 x 5280 x 12 23 2x 24 x 60 x 3000 =88378 h. The surface of the mass of ice , on which the work u is required to be done , in aid of its weight , to make it descend as it actually does , is 124771*5 square inches . The work required to be done on each square inch of surface , supposing it to be equally distributed over it , is therefore , 7706513.76 . in foot-lbs . , = 7G 76 . 1247715 These 61'76 foot-lbs . of work are equivalent to *0635 heat-units , or to the heat necessary to raise '0635 lb. of water by one degree of Fahrenheit . This amount of heat passing into the mass of the glacier per square inch of surface per day , and reconverted into mechanical work there , would be sufficient , together with its weight , to bring the glacier down . The following considerations may serve to disabuse some persons of the idea of an unlimited reservoir of force residing somewhere in the prolongation of a glacier backward , and in its higher slopes , from which reservoir the pressure is supposed to come which crushes the glacier over the obstacles in its way . Let a strip of ice one square inch in section , and one mile in length , in the middle of the surface of the imaginary glacier , be conceived to be separated from the rest throughout its whole length , except for the space of one inch , so that throughout its whole length , except for that one inch , its descent is not retarded either by shear or by friction . Let , moreover , this inch be conceived to be at the very end of the glacier , so that there is no glacier beyond it . Now it may easily be calculated that this strip of ice , one inch square and one mile long , lying on a slope of 4 ? ? 52 ' , without any resistance to its descent , except at its end , must press against its end , by reason of its weight , with a force of 194'42 lbs. But the cubical inch of solid ice at its extremity opposes , by the shear of its three surfaces , whose attachment to the adjacent ice is unbroken , a resistance of 3x 75 lbs. , or 225 lbs. That resistance stops therefore the descent of this strip of ice , one mile long , having no other resistance than this opposed to its descent , by reason of its detachment from the rest* . It is clear , then , that it could not have descended by its weight only when it adhered to the rest , and when its descent was opposed by the shear of its whole length ; and the same may be proved of any number of miles of strip in prolongation of this . Also , with obvious modifications , it may be shown , in the same way , to be true of any other similar strip of ice in the glacier , whether on the surface or , not , and therefore of the whole glacier . It results from this investigation that the weight of a glacier is insufficient to account for its descent ; that it is necessary to conceive , in addition to its weight , the operation of some other and much greater force , which must also be such as would produce those internal molecular displacements and those strains which are observed actually to take place in glacier ice , and must therefore be present to every part of the glacier as its weight is , but more than thirty-four times as great .

112376

3701662

Notes of a Comparison of the Granites of Cornwall and Devonshire with Those of Leinster and Mourne

209

211

Proceedings of the Royal Society of London

Samuel Haughton

fla

6.0.4

http://dx.doi.org/10.1098/rspl.1868.0029

proceedings

http://corpora.clarin-d.uni-saarland.de/surprisal/6.0.3/?id=112376

10.1098/rspl.1868.0029

http://www.jstor.org/stable/112376

Geography

Chemistry 2

Geography

III . Notes of a Comparison of the Granites of Cornwall and Devonshire with those of Leinster and Morn . " By the Iev . SAMUEL HAIJGHTON , M.D. , D.C.L. , F.R.S. , Fellow of Trinity College , Dublin . Received December 18 , 1868 . The granites of Morn are eruptive , and can be proved to contain albite as their second felspar . The granites of Leinster are also eruptive ; and although albite has never yet been actually found to occur in them , its existence can be inferred with considerable probability . During the past summer ( 1868 ) I have succeeded in proving that the second felspar that occurs in the granites of Cornwall is albite . I found this mineral as a constituent of the granite at Trewavas tHead , where it has the following composition : I. Albite , var . Cleavelandite ( Trewavas Head ) . Silica ... ... ... ... ... . 65 76 Alumina ... ... ... 21 72 Lime ... ... ... ... ... 0'89 Magnesia ... ... ... . . trace Soda ... ... ... ... ... ... 923 Potash ... ... ... ... . . 1*76 Water ... ... ... ... 040 99-76 This albite is opaque , cream-coloured , lamellar , and associated with quartz and orthoclase , which has the following composition : II . Orthoclase ( Trewavas Head ) . No. 1* . No. 2t . Silica ... ... ... ... ... ... ... . 6360 63-20 Alumina ... ... ... ... ... 21'04 21-00 Iron and manganese oxides ... . trace trace Lime ... ... ... ... ... . . 0'90 0-68 Magnesia ... ... ... ... ... ... . trace trace Soda ... ... ... ... ... ... . 3-08 2-75 Potash ... ... ... ... ... . . 991 10-30 Water ... ... ... ... ... 040 040 98-93 98'33 The granites of Cornwall and Devon contain two micas , white and black . I was fortunate enough to obtain , through my fiiend Mr. W. J. Henwood , F.R.S. , of Penzance , a sufficient quantity of white mica from Tremearne , near Trewavas Head , to determine accurately its composition , which proves to be highly interesting . It differs essentially from the white mica of Leinster and Donegal , and proves to be a variety of lepidolite . III . White 3ica , Lepidolite ( Tremearne , near Trewavas Hlead ) . Silica , SiO3 ... ... ... . . 47-60 Fluosilicon , SiF3 ... ... . . 5-68 Alumina ... ... ... . 27'20 Iron peroxide ' ... ... ... . . 5 20 Manganese protoxide ... . 1 20 Lime ... ... ... ... ... . 0-45 Magnesia ... ... ... ... . . trace Potash ... ... ... ... ... . 10-48 Soda ... ... ... ... ... . 0-72 Lithia ... ... ... ... ... . 114 99-67 This lepidolite is white , pearly , and occurs in rhombic tables of 60 ? and 120 ? . Its oxygen ratios are , reckoning for the fluorine its equivalent of oxygen , Oxygen Ratios . Silica ... ... ... ... ... 247.^ 41 ~~Silica. . -24'714L}26'461 8'9 Fluosilicon ... ... ... . 1747 Alumina ... ... ... ... 12 713 14-20 48 Iron peroxide ... ... . . 1557 Manganese protoxide. . 0-268 > Lime ... ... ... ... ... 0-127 I Magnesia ... ... ... . . 982 100 Potash..7 ... ..7 ... . 6 . Soda ... ... ... 84 j Lithia 0-627 This corresponds with a theoretical formula , in which the oxygen of the silica is to that of the bases as 3 : 2 . The Black Mica of the Cornish granites seems to be more abundant than the White Mica already described . I found a sufficient quantity of it at Coron Bosavern , near St. Just , to enable me to make the following analysis : IV . Black M/ ica , Lepidomnelane ( Coron Bosavern , near St. Just ) . Silica ( SiO3 ) ... ... ... . 3992 Fluosilicon ( SiF3 ) ... ... 304 Alumina ... ... ... ... . . 22-88 Iron peroxide ... ... ... 15-02 Iron protoxide ... ... ... . 2'32 Manganese protoxide ... . 1 40 Lime ... ... ... ... ... . 0-68 Magnesia ... ... ... ... . . 1 07 Potash ... ... ... ... ... 976 Soda ... ... ... ... . 0'99 Lithia ... ... ... ... . . 171 98-79 The Black Mica of St. Just is of a blackish-bronze colour and metallic lustre , and occurs in rhombs of 60 ? and 120 ? angles . Its oxygen ratios are , reckoning for the fluorine its equivalent of oxygen , Oxygen Ratios . Silica ... ... ... ... ... 20-727 21'645 Fluosilicon ... ... ... . 0918 j Alumina ... ... ... ... 10-692 1.0 Iron peroxide ... ... . . 4'400 Iron protoxide ... ... . . 0-514Manganese protoxide ... . 0310 Lime ... ... ... ... ... . 0192 Magnesia ... ... ... . . 0427 4292 Potash ... ... . . 1-655 Soda ... ... ... ... ... . . 0-254 Lithia ... ... ... 0'940j The oxygen ratio of this iron-potash Mica ( which is undoubtedly a lepidomelane ) for silica and bases is 216 : 194 , or 1 : 1 . The granites of Cornwall and Devon , which have been frequently examined by me during the last sixteen years , appear all to contain the two felspars and the two micas above analyzed . In a future communication I hope to describe their composition in detail , and to give a comparison of this composition with that of the granites of Ireland . The following generalizations will be found , as I believe , capable of proof . ( 1 ) The granites of Ireland may be divided into two distinct classes , marked by characters both geological and mineralogical . ( 2 ) The First Class of granites consists of Eruptive rocks , of ages varying from the Silurian to the Carboniferous periods . To this class may be referred the granites of Leinster and Morn , and the granites of Cornwall and Devon . ( 3 ) The First Class of granites is characterized by the presence of orthoclase and albite , and by the absence of all the Lime Felspars . ( 4 ) The Second Class of granites consists of Metamorphic rocks , of unknown geological age , but probably subsequent to the Laurentian period . To this class may be referred the granites of Donegal and Galway , and the granites of Scotland , Norway , and Sweden . ( 5 ) The Second Class of granites is characterized by the presence of orthoclase and oligoclase , or Labradorite , or some other of the Lime Felspars , and by the absence of albite .

112377

3701662

On the Relation of Hydrogen to Palladium

212

220

Proceedings of the Royal Society of London

Thomas Graham

fla

6.0.4

http://dx.doi.org/10.1098/rspl.1868.0030

proceedings

http://corpora.clarin-d.uni-saarland.de/surprisal/6.0.3/?id=112377

10.1098/rspl.1868.0030

http://www.jstor.org/stable/112377

Thermodynamics

Electricity

Thermodynamics

I. " On the Relation of Hydrogen to Palladium . " By THOMAS GRAHAMA , F.R.S. , Master of the Mint . Received November 23 , 1868 . It has often been maintained on chemical grounds that hydrogen gas is the vapour of a highly volatile metal . The idea forces itself upon the mind that palladium with its occluded hydrogen is simply an alloy of this volatile metal , in which the volatility of the one element is restrained by its union with the other , and which owes its metallic aspect equally to both constituents . How far such a view is borne out by the properties of the compound substance in question will appear by the following examination of the properties of what , assuming its metallic character , would have to be named Ilydroyenium . 1 . Density.-The density of palladium when charged with eight or nine hundred times its volume of hydrogen gas is perceptibly lowered ; but the change cannot be measured accurately by the ordinary method of immersion in water , owing to a continuous evolution of minute hydrogen bubbles which appears to be determined by contact with the liquid . However , the linear dimensions of the charged palladium are altered so considerably that the difference admits of easy measurement , and furnishes the required density by calculation . Palladium in the form of wire is readily charged with hydrogen by evolving that gas upon the surface of the metal in a galvanometer containing dilute sulphuric acid as usual * . The length of the wire before and after a charge is found by stretching it on both occasions by the same moderate weight , such as will not produce permanent distention , over the surface of a flat graduated measure . The measure was graduated to hundredths of an inch , and by means of a vernier , the divisions could be read to thousandths . The distance between two fine cross lines marked upon the surface of the wire near each of its extremities was observed . Expt. 1.-The wire had been drawn from welded palladium , and was hard and elastic . The diameter of the wire was 0'462 millimetre ; its specific gravity was 12-38 , as determined with care . The wire was twisted into a loop at each end and the mark made near each loop . The loops were varnished so as to limit absorption of gas by the wire to the measured length between the two marks . To straighten the wire , one loop was fixed , and the other connected with a string passing over a pulley and loaded with 1'5 kilogramme , a weight sufficient to straighten the wire without ; occasionirg any undue strain . The wire was charged with hydrogen by making it the negative electrode of a small Bunsen 's battery consisting of two cells , each of half a litre in capacity . The positive electrode was a thick platinum wire placed side by side with the palladium wire , and extending the whole length of the latter within a tall jar filled with dilute sulphuric acid . The palladium wire had , in consequence , hydrogen carried to its surface , for a period of 1hour . A longer exposure was founrd not to add sensibly to the charge of hydrogen acquired by the wire . The wire was again measured and the increase in length noted . Finally the wire , being dried with a cloth , was divided at the marks , and the charged portion heated in a long narrow glass tube kept vacuous by a Sprengel aspirator . The whole occluded hydrogen was thus collected and measured ; its volume is reduced by calculation to Bar . 760 millims. , and Therm. 0 ? C. The original length of the palladium wire exposed was 609 144 millims. ( 23'982 inches ) , and its weight 1'6832 grm. The wire received a charge of hydrogen amounting to 936 times its volume , measuring 128 cubic centims. , and therefore weighing 0-01147 grm. When the gas was ultimately expelled , the loss as ascertained by direct weighing was 0'01164 grm. The charged wire measured 618'923 millims. , showing an increase in length of 9'779 millims. ( 0'385 inch ) . The increase in linear dimensions is from 100 to 101-605 , and in cubic capacity , assuming the expansion to be equal in all directions , from 100 to 104'908 . Supposing the two metals united without any change of volume , the alloy may therefore be said to be composed of By volume . Palladium ... ... ... ... 100 or 95-32 Hydrogenium ... ... ... . 4 908 or 4*68 104-908 100 The expansion which the palladium undergoes appears enormous if viewed as a change of bulk in the metal only , due to any conceivable physical force , amounting as it does to sixteen times the dilatation of palladium when heated from 0 ? to 100 ? C. The density of the charged wire is reduced , by calculation , from 12'3 to 11'79 . Again , as 100 is to 4'91 , so the volume of the palladium , 0'1358 cubic centir . , is to the volume of the hydrogenium , 0'006714 cubic centim. Finally , dividing the weight of the hydrogenium , 0'01147 grin . , by its volume in the alloy , 0'006714 cubic centim. , we find Density of hydrogenium ... ... ... ... ... ... . . 11708 The density of hydrogenium , then , appears to approach that of magnesium , 1'743 , by this first experiment . Further , the expulsion of hydrogen from the wire , however caused , is attended with an extraordinary contraction of the latter . On expelling the hydrogen by a moderate heat , the wire not only receded to its original length , but fell as much below that zero as it had previously risen above it . The palladium wire first measuring 609'144 millims. , and which increased 9'77 millims. , was ultimately reduced to 599'444 millims. , and contracted 9'7 millims. The wire is permanently shortened . The density of the pal1869 . ] 213 ladiumn did not increase , but fell slightly at the same time , namely from 12'38 to 12 12 , proving that this contraction of the wire is in length only . The result is the converse of extension by wire-drawing . The retraction of the wire is possibly due to an effect of wire-drawing in leaving the particles of metal in a state of unequal tension , a tension which is excessive in the direction of the length of the wire . The metallic particles would seem to become mobile , and to right themselves in proportion as the hydrogen escapes ; and the wire contracts in length , expanding , as appears by its final density , in other directions at the same time . A wire so charged with hydrogen , if rubbed with the powder of magnesia ( to make the flame luminous ) , burhs like a waxed thread when ignited in the flame of a lamp . Expt. 2.-Another portion of the same palladium wire was charged with hydrogen in a similar manner . The results observed were as follows : Length of palladium wire ... ... ... ... . . 488 976 millims. The same with 8 67 15 volumes ofoccluded gas 495 656 , , Linear elongation ... ... ... ... ... ... . . 668 , Linear elongation on 100 ... ... ... . 1'3663 , , Cubic expansion on 10 ... ... ... ... ... ... 4154 , , Weight of palladium wire ... ... ... ... . 1'0667 grin . Volume of palladium wire ... ... ... ... ... 008072 cub.centim . Volume of occluded hydrogen gas ... . 752 , , Weight of same ... ... ... ... ... ... ... . 0'00684 grn. Volume of hdrogenium ... ... ... ... . . 0003601 cub. centim. From these results is calculated Density of hydrogenium ... ... ... ... 1'898 . Expt. 3.-The palladium wire was new , and on this occasion was well annealed before being charged with hydrogen . The wire was exposed at the neg-ative pole for two hours , when it had ceased to elongate . Length of palladium wire ... ... ... ... 556 185 millims. Saime with 888'303 volumes hydrogen. . 563'652 , , Linear elongatio ... ... ... ... ... ... . . 7'467 , , Linear elongation on 100 ... ... ... ... . 1324 , , Cubic expansion on 100 ... ... . . 4'025 , , Weight of palladium wire ... ... ... ... . . 11675 grm. Volume of palladium wire ... ... ... ... 0-0949 cub. centim. Volume of occluded hydrogen gas 84'3 cub. centims. Weight of same ... ... ... ... ... . . 0'007553 grm. Volume of hydrogenium ... ... ... ... ... 0'003820 cub. centim. These results give by calculation Density of hydrogenium ... ... ... ... . 1977 . It was necessary to assume in this discussion that the two metals do not 214 [ Jan. 14 , contract nor expand , but remain of their proper volume on uniting . Dr. Matthiessen has shown that in the formation of alloys generally the metals retain approximately their original densities* . In the first experiment already described , probably the maximum absorption of gas by wire , amounting to 93.5'67 volumes , is attained . The palladium may be charged with any smaller proportion of hydrogen by shortening the time of exposure to the gas ( 329 volumes of hydrogen were taken up in twenty minutes ) , and an opportunity be gained of observing if the density of the hydrogenium remains constant , or if it varies with the proportion in which hydrogen enters the alloy . In the following statement , which includes the three experiments already reported , the essential points only are produced . TABLE . Volumes Linear expansion in Density of hydrogen millimetres . of occluded . From Hydrogenium . From To 329 496-189 498-552 2-055 462 493-040 496-520 1'930 487 370-358 373-126 1'927 745 305-538 511-303 1'917 867 488-976 495-656 1'898 888 556-185 563-652 1-977 936 609-144 618-923 1-708 If the first and last experiments only are ' compared , it would appear that the hydrogenium becomes sensibly denser when the proportion of it is small , ranging from 1 708 to 2-055 . But the last experiment of the Table it perhaps exceptional ; and all the others indicate considerable uniformity of density . The mean density of hydrogenium , according to the whole experiments , excluding that last referred to , is 1*951 , or nearly 2 . This uniformity is in favour of the method followed for estimating the density of hydrogenium . On charging and discharging portions of the same palladium wire repeatedly , the curious retraction was found to continue , and seemed to be interminable . The following expansions , caused by variable charges of hydrogen , were followed on expelling the hydrogen by the retractions mentioned . Elongation . Retraction . 1st Experiment 9'77 millims ... ... ... . 970 millims. 2nd , , 5 765 , , ... ... ... . 620 , , 3rd , , 236 , , ... ... ... . 314 , , 4th , , 3482 , , ... ... ... . 495 , , 23'99 The palladium wire , which originally measured 609*144 millims. , has suffered , by four successive discharges of hydrogen from it , a permanent contraction of 23'99 millims. ; that is , a reduction of 3'9 per cent. on its original length . The contractions will be observed to exceed in amount the preceding elongations produced by the hydrogen , particularly when the charge of the latter is less considerable . With another portion of wire the contraction was carried to 15 per cent. of its length by the effect of repeated discharges . The specific gravity of the contracted wire was 12 12 , no general condensation of the metal having taken place . The wire shrinks in length only . In the preceding experiments the hydrogen was expelled by exposing the palladium placed within a glass tube to a moderate heat short of redness , and exhausting by means of a Sprengel tube ; but the gas was also withdrawn in another way , namely , by making the wire the positive electrode , and thereby evolving oxygen upon its surface . In such circumstances a slight film of oxide of palladium is formed on the wire , but it appears not to interfere with the extraction and oxidation of the hydrogen . The wire measured , Difference . Before charge ... ... 443'25 millims. With hydrogen ... ... 449-90 , , + 665 millims. After discharge ... ... 437-31 , , --594 , , The retraction of the wire therefore does not require the concurrence of a high temperature . This experiment further proved that a large charge of hydrogen may be removed in a complete manner by exposure to the positive pole ( for four hours in this case ) ; for the wire in its ultimate state gave no hydrogen on being heated in vacuo . That particular wire , which had been repeatedly charged with hydrogen , was once more exposed to a maximum charge , for the purpose of ascertaining whether or not its elongation under hydrogen might now be facilitated and become greater in consequence of the previous large retraction . No such extra elongation , however , was observed on charging the retracted wire more than once ; and the expansion continued to be in the usual proportion to the hydrogen absorbed . The final density of the wire was 12'18 . The wire retracted by heat is found to be altered in another way , which appears to indicate a molecular change . When the gas has been expelled by heat , the metal gradually loses much of its power to take up hydrogen . The last wire , after it had already been operated upon six times , was again charged with hydrogen for two hours , and was found to occlude only 320 volumes of gas , and in a repetition of the experiment , 330'5 volumes . The absorbent power of the palladium had therefore been reduced to about one-third of its maximum . The condition of the retracted wire appeared , however , to be improved by raising its temperature to full redness by sending through it an-electrical current from a battery . The absorption rose thereafter to 425 volumes of hydrogen , and in a second experiment to 422'5 volumes . The wire becomes fissured longitudinally , acquires a thready structure , and is much disintegrated on repeatedly losing hydrogen , particularly when the hydrogen has been extracted by electrolysis in an acid fluid . The palladium in the last case is dissolved by the acid to some extent . The metal appeared , however , to recover its full power to absorb hydrogen , now condensing upwards of 900 volumes of gas . The effect upon its length of simply annealing the palladium wire by exposure in a porcelain tube to a full red heat , was observed . The wire measured 556-075 millims. before , and 555-875 millims. after heating ; or a minute retraction of 0-2 millim , was indicated . In a second annealing experiment , with an equal length of new wire , no sensible change whatever of length could be discovered . There is no reason , then , to ascribe the retraction after hydrogen , in any degree , to the heat applied when the gas is expelled . Palladium wire is very slightly affected in physical properties by such annealing , retaining much of its first hardness and elasticity . 2 . Tenacity.-A new palladium wire , similar to the last , of which 100 millims. weighed 0'1987 grm. , was broken , in experiments made on two different portions of it , by a load of 10 and of 10 ' 17 kilogrammes . Two other portions of the same wire , fully charged with hydrogen , were broken by 8'18 , and by 8'27 kilogrammes . Hence we haveTenacity of palladium wire ... ... ... ... ... ... 100 Tenacity of palladium and hydrogen ... ... ... . 81 29 The tenacity of the palladium is reduced by the addition of hydrogen , but not to any great extent . It is a question whether the degree of tenacity that still remains is reconcileable with any other view than that the second element present possesses of itself a degree of tenacity such as is only found in metals . 3 . Electrical Conductivity.-Mr . Becker , who is familiar with the practice of testing the capacity of wires for conducting electricity , submitted a palladium wire , before and after being charged with hydrogen , to trial , in cor parison with a wire of German silver of equal diameter and length , at 10 ? ? 5 . The conducting-power of the several wires was found as follows , being referred to pure copper as 100:Pure copper ... ... ... .100 Palladium ... ... ... ... ... ... ... ... ... ... . . 8 10 Alloy of 80 copper+20 nickel ... ... ... ... . . 6-63 Palladium +hydrogen ... ... ... ... ... ... ... 5'99 A reduced conducting-power is generally observed in alloys , and the charged palladium wire falls 25 per cent. But the conducting-power remains still considerable , and the result may be construed to favour the metallic character of the second constituent of the wire . Dr. Matthiessen confirms these results . 4 . Magnetism.-It is given by Faraday as the result of all his experiments , that palladium is " feebly but truly magnetic ; " and this element he placed at the head of what are now called the paramagnetic metals . But the feeble magnetism of palladium did not extend to its salts . In repeating such experiments , a horseshoe electromagnet of soft iron , about 15 centims. ( 6 inches ) in height , was made use of . It was capable of supporting 60 kilogs . , when excited by four large Bunsen cells . This is an induced magnet of very moderate power . The instrument was placed with its poles directed upwards ; and each of these was provided with a small square block of soft iron terminating laterally in a point , like a small anvil . The palladium under examination was suspended between these points in a stirrup of paper attached to three fibres of cocoon silk , 3 decimetres in length , and the whole was covered by a bell glass . A filament of glass was attached to the paper , and moved as an index on a circle of paper on the glass shade divided into degrees . The metal , which was an oblong fragment of electrcdeposited palladium , about 8 millims. in length and 3 millims. in widthg being at rest in an equatorial positon ( that is , with its ends averted from the poles of the electromagnet ) , the magnet was then charged by connecting it with the electrical battery . The palladium was deflected slightly from the equatorial line by 10 ? only , the magnetism acting against the torsion of the silk suspending thread . The same palladium charged with 604*6 volumes of hydrogen was deflected by the electromagnet through 48 ? 0 when it set itself at rest . The gas being afterwards extracted , and the palladium again placed equatorially between the poles , it was not deflected in the least perceptible degree . The addition cf hydrogen adds manifestly , therefore , to the small natural magnetism of the palladium . To have some terms of comparison , the same little mass of electro-deposited palladium was steeped in a solution of nickel , of sp. gr. 1'082 , which is known to be magnetic . The deflection under the magnet was now 35 ? , or less than with hydrogen . The same palladium being afterwards washed and impregnated with a solution of protosulphate of iron of sp. gr. 1 048 , of which the metallic mass held 2'3 per cent. of its weight , the palladium gave a deflection of 50 ? , or nearly the same as with hydrogen . With a stronger solution of the same salt , of sp. gr. 1-17 , the deflection was 90 ? , and the palladium pointed axially . Palladium in the form of wire or foil gave no deflection when placed in the same apparatus , of which the moderate sensitiveness was rather an advantage in present circumstances ; but when afterwards charged with hydrogen , the palladium uniformly gave a sensible deflection of about 20 ? . A previous washing of the wire or foil with hydrochloric acid , to remove any possible traces of iron , did not modify this result . Palladium reduced from the cyanide and also precipitated by hypophosphorous acid , when placed in a small glass tube , was found to be not sensibly magnetic by our test ; but it always acquired a sensible magnetism when charged with hydrogei . 218 Mi~r . Grahamn onr the Relat~aion ? It appears to follow that hydrogenium is magnetic , a property which is confined to metals and their compounds . This magnetism is not perceptible in hydrogen gas , which was placed both by Faraday and by M. E. Becqu ! rel at the bottom of the list of diamagnetic substances . This gas is allowed to be upon the turning-point between the paramagnetic and diamagnetic classes . But magnetism is so liable to extinction under the influence of heat , that the magnetism of a metal may very possibly disappear entirely when it is fused or vaporized , as appears to be the case with hydrogen in the form of gas . As palladium stands high in the series of the paramagnetic metals , hydrogenium must be allowed to rise out of that class , and to take place in the strictly magnetic group , with iron , nickel , cobalt , chromium , and manganese . 5 . Pallatdium with ydrog , en at a high Temperature.-The ready permeability of heated palladium by hydrogen gas would imply the retenl tion of the latter element by the metal even at a bright red heat . The hydrogeniumn must in fact travel through the palladium by cementation , a molecular process which requires time . The first attempts to arrest hydrogen in its passage through the red-hot metal were made by transmitting hydrogen gas through a metal tube of palladium with a vacuum outside , rapidly followed by a stream of carbonic acid , in which the metal was allowed to cool . When the metal was afterwards examined in the usual way , no hydrogen could be found in it . The short period of exposure to the carbonic acid seems to have been sufficient to dissipate the gas . But on heating palladium foil red-hot in a flame of hydrogen gas , and suddenly cooling the metal in water , a small portion of hydrogen was found locked up in the metal . A volume of metal amounting to 0'062 cubic centim. , gave 0-080 cubic centim. of hydrogen ; or , the gas , measured cold , was 1'306 times the bulk of the metal . This measure of gas would amount to three or four times the volume of the metal at a red heat . Platinum treated in the same way appeared also to yield hydrogen , although the quantity was too small to be much relied upon , amounting only to 006 volume of the metal . The permeation of these metals by hydrogen appears therefore to depend on absorption , and not to require the assumption of anything like porosity in their structure . The highest velocity of permeation observed was in the experiment where four litres of hydrogen ( 3992 cub. centims. ) per minute passed through a plate of palladium 1 millim. in thickness , and calculated for a square metre in surface , at a bright red heat a little short of the melting-point of gold . This is a travelling movement of hydrogen through the substance of the metal with the velocity of 4 millimetres per minute . 6 . Chlemical Properties.-The chemical properties of hydrogenium also distinguish it from ordinary hydrogen . The palladium alloy precipitates mercury and calomel from a solution of the chloride of mercury without any disengagement of hydrogen , that is , hydrogenium decomposes chloride of mercury , while hydrogen does not . This explains why M. Stanislas R Meunier failed in discovering the occluded hydrogen of meteoric iron , by dissolving the latter in a solution of chloride of mercury ; for the hydrogen would be consumed , like the iron itself , in precipitating mercury . Hydrogen ( associated with palladium ) unites with chlorine and iodine in the dark , reduces a persalt of iron to the state of protosalt , converts red prussiate of potash into yellow prussiate , and has considerable deoxidizing powers . It appears to be the active form of hydrogen , as ozone is of oxygen . The general conclusions which appear to flow from this inquiry are , that in palladium fully charged with hydrogen , as in the portion of palladium wire now submitted to the Royal Society , there exists a compound of palladium and hydrogen in a proportion which may approach to equal equivalents* . That both substances are solid , metallic , and of a white aspect . That the alloy contains about 20 volumes of palladium united with a volume of hydrogeniurn ; and that the density of the latter is about 2 , a little higher than magnesium to which hydrogenium may be supposed to bear some analogy . That hydrogenium has a certain amount of tenacity , and possesses the electrical conductivity of a metal . And finally , that hydrogenium takes its place among magnetic metals . The latter fact may have its bearing upon the appearance of hydrogenium in meteoric iron , in association with certain other magnetic elements . I cannot close this paper without taking the opportunity to return my best thanks to Mr. W. C. Roberts for his valuable cooperation throughout the investigation .

112378

3701662

A Memoir on the Theory of Reciprocal Surfaces. [Abstract]

220

221

Proceedings of the Royal Society of London

Professor Cayley

abs

6.0.4

proceedings

http://corpora.clarin-d.uni-saarland.de/surprisal/6.0.3/?id=112378

http://www.jstor.org/stable/112378

Formulae

Biography

Mathematics

II . A Memoir on the Theory of Reciprocal Surfaces . " By Professor CAYLLY , F.R.S. Received November 12 , 1868 . ( Abstract . ) The present Memoir contains some extensions of Dr. Salmon 's theory of Reciprocal Surfaces . I wish to put the formulae on record , in order to be able to refer to them in a " Memoir on Cubic Surfaces , " but without at present attempting to completely develope the theory . Dr. Salmon 's fundamental formulae ( A ) , ( B ) are replaced by a(n2)= r-B+ p+2-r , 6(n-2)= p+2+ 37y+3t , c(n-2)=2cr+43 ? y+ 0 , a(n-2)(n-3)= 2(8-C ) +3(ac-3X ) +2 ( ab-2p -j ) , b(n2)(n -3)= 4k ( ab-2p-j)+3(bc-31 -y-i ) , c(n-2)(n-3)== 6+ ( ae -3o--X ) + 2(bc--3 , --y-i ) , where j , 0 , X , B , C refer to singularities not taken account of in his theory ; viz. j is the number of pinch-points on the nodal curve 0 , X , the numbers of certain singular points on the cuspidal curve , C the number of conic nodes , B the number of biplanar nodes : the reciprocal singularities j ' , 0 ' , X ' , * Proceedings of the Royal Society , 1868 , p. 425 . B , C ' , are of course also considered . An equation of Dr. Salmon 's is presented in the extended form , '--4n(n-2)-8b--1 lc-2j'3X'-2C'-4B ' ; and it is remarked that o ' denotes the order of the spinode-curve . The Memoir contains an entirely new formula giving the value of P ' , but some of the constants of the formula remain undetermined .

112379

3701662

A Memoir on Cubic Surfaces. [Abstract]

221

222

Proceedings of the Royal Society of London

Professor Cayley

abs

6.0.4

proceedings

http://corpora.clarin-d.uni-saarland.de/surprisal/6.0.3/?id=112379

http://www.jstor.org/stable/112379

Formulae

Tables

Mathematics

III . " A Memoir on Cubic Surfaces . " By Professor CAYLEY , F.R.S. Received November 12,1868 . ( Abstract . ) The present Memoir is based upon , and is in a measure supplementary to that by Professor Schlifli , " On the Distribution of Surfaces of the Third Order into Species , in reference to the presence or absence of Singular Points , and the reality of their Lines , " Phil. Trans. vol. cliii . ( 1863 ) pp. 193-241 . But the object of the Memoir is different . I disregard altogether the ultimate division depending on the reality of the lines , attending only to the division into ( twenty-two , or as I prefer to reckon it ) twenty-three cases depending on the nature of the singularities . And I attend to the question very much on account of the light to be obtained in reference to the theory of Reciprocal Surfaces . The memoir referred to furnishes in fact a store of materials for this purpose , inasmuch as it gives ( partially or completely developed ) the equations in plane-coordinates of the several cases of cubic surfaces ; or , what is the same thing , the equations in point-coordinates of the several surfaces ( orders 12 to 3 ) reciprocal to these respectively . I found by examination of the several cases , that an extension was required of Dr. Salmon 's theory of Reciprocal Surfaces in order to make it applicable to the present subject ; and the preceding " Memoir on the Theory of Reciprocal Surfaces " was written in connexion with these investigations on Cubic Surfaces . The latter part of the Memoir is divided into sections headed thus:-"Section I =12 , equation ( X , Y , Z , W)= O " &c. referring to the several cases of the cubic surface ; but the paragraphs are numbered continuously through the Memoir . The principal results are included in the following Table of singularities . The heading of each column shows the number and character of the case referred to , viz. C denotes a conic node , Ba biplanar node , and Ua uniplanar node ; these being further distinguished by subscript numbers , showing the reduction thereby caused in the class of the surface : thus XIII= 12-B3--2 C2 indicates that the case XIII is a cubic surface , the class whereof is 127 , = 5 , the reduction arising from a biplanar node , B , reducing the class by 3 , and from 2 conic nodes , C , , each reducing the class by 2 . s1869 . ] 221 I 11 360600000000000000000 12 609O Cb 361600000000000000010 10 609O Cd IC 36070000000000000000196093626000000000000000208609 ( b O37000000000000000l1O 4 ) 4 ) IO v ) 760936360000000000000306609O ' cr ? H 360800000000000000026609 ( ) 000000000000002 1 ) 5609 4 ) bb __ _~~ 00000000000000040460 9. . t ? i00000000000000124609 [ Jan. 14 , 64000 x1 33040093 01 0O000001020000000000003033640093 27 15 9733013001 216 60 18 12 30000000 45 15 630100100000000000000 27 15 9733013001000103016002 24 18 16 12 10 6840200 180 96 72 38 24 6 12 20000 30 24 42 17 24 9 32 50200 12 12 12 10 9684020000 16 0,8 0 16 000000000I0020200 54 30 18 13 63010000000 00 0000O00000 00 0000000000 00 0000000000 '00 0100130 222 na6bktqJCchr0xXcCB n ' i ? r a ' IC ' b ' k ' t ' of p j/ Ct h ' a ' 0 ' X/ V ' tr C B ' na6Kbktqpch0c B3 CB n ' a ' S ' 6 ' t ' p ' j ' C ' h ' r ' 0 ' x ' 3 ' i ' lr C ' B '

112380

3701662

On the Blue Colour of the Sky, the Polarization of Skylight, and on the Polarization of Light by Cloudy Matter Generally

223

233

Proceedings of the Royal Society of London

John Tyndall

fla

6.0.4

http://dx.doi.org/10.1098/rspl.1868.0033

proceedings

http://corpora.clarin-d.uni-saarland.de/surprisal/6.0.3/?id=112380

10.1098/rspl.1868.0033

http://www.jstor.org/stable/112380

Optics

Chemistry 1

Optics

IV . " On the Blue Colour of the Sky , the Polarization of Skylight , and on the Polarization of Light by Cloudy matter generally . " By JoHN TYNDALL , LL. D. , F.R.S. Received December 16 , 1868 . Since the communication of my brief abstract " On a new Series of Chemical Reactions produced by Light , " the experiments upon this subject have been continued , and the number of the substances thus acted on considerably augmented . New relations have also been established between mixed vapours when subjected to the action of light . I now beg to draw the attention of the Royal Society to two questions glanced at incidentally in the abstract referred to , the blue colour of the sky , and the polarization of skylight . Reserving the historic treatment of the subject for a more fitting occasion , I would merely mention now that these questions constitute , in the opinion of our most eminent authorities , the two great standing enigmas of meteorology . Indeed it was the interest manifested in them by Sir John Herschel , in a letter of singular speculative power , that caused me to enter upon the consideration of these questions so soon . The apparatus with which I work consists , as already stated to the Society , of a glass tube about a yard in length , and from 2to 3 inches internal diameter . The vapour to be examined is introduced into this tube in the manner described in my last abstract , and upon it the condensed beam of the electric lamp is permitted to act until the neutrality or the activity of the substance has been declared . It has hitherto been my aim to render the chemical action of light upon vapours visible . For this purpose substances have been chosen , one at least of whose products of decomposition under light shall have a boiling-point so high that as soon as the substance is formed it shall be precipitated . By graduating the quantity of the vapour , this precipitation may be rendered of any degree of fineness , forming particles distinguishable by the naked eye , or particles which are probably far beyond the reach of our highest microscopic powers . I have no reason to doubt that particles may be thus obtained whose diameters constitute but a very small fraction of the length of a wave of violet light . In all cases when the vapours of the liquids employed are sufficiently attenuated , no matter what the liquid may be , the visible action commences with the formation of a blue cloud . I would guard myself at the outset against all misconception as to the use of this term . The blue cloud to which I here refer is totally invisible in ordinary daylight . To be seen , it requires to be surrounded by darkness , it only being illuminated by a powerful beam of light . This blue cloud differs in many important particulars from the finest ordinary clouds , and might justly have assigned to it an interrnediate position between these clouds and true cloudless vapour . With this explanation , the term " cloud , " or " incipient cloud , " as I propose to employ it , cannot , I think , be misunderstood . I had been endeavouring to decompose carbonic acid gas by light . A faint bluish cloud , due it may be , or it mayt not be , to the residue of some vapour previously employed , was formed in the experimental tube . On looking across this cloud through a Nicol 's prism , the line of vision being horizontal , it was found that when the short diagonal of the prism was vertical , the quantity of light reaching the eye was greater than when the long diagonal was vertical . When a plate of tourmaline was held between the eye and the bluish cloud , the quantity of light reaching the eye when the axis of the prism was perpendicular to the axis of the illuminating beam , was greater than when the axes of the crystal and of the beam were parallel to each other . This was the result all round the experimental tube . Causing the crystal of tourmaline to revolve round the tube , with its axis perpendicular to the illuminating beam , the quantity of light that reached the eye was in all its positions a maximum . When the crystallographic axis was parallel to the axis of the beam , the quantity of light transmitted by the crystal was a minimum . From the illuminated bluish cloud , therefore , polarized light was discharged , the direction of maximum polarization being at right angles to the illuminating beam ; theplane of vibration of the polarized light , moieover , was that to which the beam was eperpendicular . Thin plates of selenite or of quartz , placed between the Nicol ' and the bluish cloud , displayed the colours of polarized light , these colours being most vivid when the line of vision was at right angles to the experimental tube . The plate of selenite usually employed was a circle , thinnest at the centre , and augnienting uniformly in thickness from the centre outwards . When placed in its proper position between the Nicol and the cloud , it exhibited a system of splendidly coloured rings . The cloud here referred to was the first operated upon in the manner described . It may , however , be greatly improved upon by the choice of proper substances , and by the application in proper quantities of the substances chosen . Benzol , bisulphide of carbon , nitrite of amryl , nitrite of butyl , iodide of allyl , iodide of isopropyl , and many other substances may be employed . I will take the nitrite of butyl as illustrative of the means adopted to secure the best result with reference to the present question . And here it may be mentioned that a vapour , which when alone , or mixed with air in the experimental tube , resists the action of light , or shows but a feeble result of this action , may , by placing it in proximityJ with an* I assume here that the plane of vibration is perpendicular to the plane of polarization . This is still an undecided point ; but the probabilities are so much in its favour , and it is in my opinion so much preferable to have a physical image on which the mind can rest , that I ( lo not hesitate to employ the phraseology in the text . Even should the assumption prove to be incorrect , no harm will be done by the provisional use of it . other gas or vapour , be caused to exhibit under light vigorous , if not violent action . The case is similar to that of carbonic acid gas , which diffused in the atmosphere resists the decomposing action of solar light , but when placed in contiguity with the chlorophyl in the leaves of plants , has its molecules shaken asunder . Dry air was permitted to bubble through the liquid nitrite of butyl until the experimental tube , which had been previously exhausted , was filled with the mixed air and vapour . The visible action of light upon the mixture after fifteen minutes ' exposure was slight . The tube was afterwards filled with half an atmosphere of the mixed air and vapour , and another half atmosphere of air which had been permitted to bubble through fresh commercial hydrochloric acid . On sending the beam through this mixture , the action paused barely sufficiently long to show that at the moment of commencement the tube was optically empty . But the pause amounted only to a small fraction of a second , a dense cloud being immediately precipitated upon the beam which traversed the mixture . This cloud began blue , but the advance to whiteness was so rapid as almost to justify the application of the term instantaneous . The dense cloud , looked at perpendicularly to its axis , showed scarcely any signs of polarization . Looked at obliquely the polarization was strong . The experimental tube being again cleansed and exhausted , the mixed air and nitrite-of-butyl vapour was permitted to enter it until the associated mercury column was depressed 1l of an inch . In other words , the air and vapour , united , exercised a pressure not exceeding --j of an atmosphere . Air passed through a solution of hydrochloric acid was then added till the mercury column was depressed three inches . The condensed beam of the electric light passed for some time in darkness through this mixture . There was absolutely nothing within the tube competent to scatter the light . Soon , however , a superbly blue cloud was formed along the track of the beam , and it continued blue sufficiently long to permit ofits thorough examination . The light discharged from the cloud at right angles to its own length was pe:fectly polarized . By degrees the cloud became of whitish blue , and for a time the selenite colours obtained by looking at it normally were exceedingly brilliant . The direction of maximum polarization was distinctly at right angles to the illuminating beam . This continued to be the case as long as the cloud maintained a decided blue colour , and even for some time after the pure blue had changed to whitish blue . But as the light continued to act the cloud became coarser and whiter , particularly at its centre , where it at length ceased to discharge polarized light in the direction of the perpendicular , while it continued to so at both its ends . But the cloud which had thus ceased to polarize the light emitted normally , showed vivid selenite colours when looked at obliquely . The direction of maximum polarization changed with the texture of the cloud . This point shall receive further illustration subsequently . A blue , equally rich and more durable , was obtained by employing the nitrite-of-butyl vapour in a still more attenuated condition . Now the instance here cited is representative . In all cases , and with all substances , the cloud formed at the commencement , when the precipitated particles are sufficiently fine , is blue , and it can be made to display a colour rivalling that of the purest Italian sky . In all cases , moreover , this fine blue cloud polarizes perfectly the beam which illuminates it , the direction of polarization enclosing an angle of 90 ? with the axis of the illuminating beam . It is exceedingly interesting to observe both the perfection and the decay of this polarization . For ten or fifteen minutes after its first appearance the light from a vividly illuminated incipient cloud , looked at horizontally , is absolutely quenched by a Nicol 's prism with its longer diagonal vertical . But as the sky-blue is gradually rendered impure by the introduction of particles of too large a size , in other words , as real clouds begin to be formed , the polarization begins to deteriorate , a portion of the light passing through the prism in all its positions . It is worthy of note that for some time after the cessation of perfect polarization the residual light which passes , when the Nicol is in its position of minumum transmission , is of a gorgeous blue , the whiter light of the cloud being extinguished* . When the cloud texture has become sufficiently coarse to approximate to that of ordinary clouds , the rotation of the Nicol ceases to have any sensible effect on the quality of the light discharged normally . The perfection of the polarization in a direction perpendicular to the illuminatingbeam isalso illustrated bythe following experiment . A Nicol 's prisml large enough to embrace the entire beam of the electric lamp was placed between the lamp and the experimental tube . A few bubbles of air carried through the liquid nitrite of butyl were introduced into the tube , and they were followed by about 3 inches ( measured by the mercurial gauge ) of air which had been passed through aqueous hydrochoric acid . Sending the polarized beam through the tube , I placed myself in front of it , my eye being on a level with its axis , my assistant Mr. Cottrell occupying a similar position behind the tube . The short diagonal of the large Nicol was in the first instange vertical , the plane of vibration of the emergent beam being therefore also vertical . As the light continued to act , a superb blue cloud visible to both my assistant and myself was slowly formed . But this cloud , so deep and rich when looked at from the positions mentioned , utterly disappeared when looked at vertically downwards , or vertically upwards . Reflection from the cloud was not possible in these directions . When the large Nicol was slowly turned round its axis , the eye of the observer being on the level of the beam , and the line of vision perpendicular to it , entire extinction of the light emitted horizontally occurred where the longer diagonal of the large Nicol was vertical . But now a vivid blue cloud was seen when looked at downwards or upwards . This truly fine experiment was first definitely suggested by a remark addressed to me in a letter by Prof. Stokes . Now , as regards the polarization of skylight , the greatest stumblingblock has hitherto been that , in accordance with the law of Brewster , which makes the index of refraction the tangent of the polarizing angle , the reflection which produces perfect polarization would require to be made in air upon air ; and indeed this led many of our most eminent men , Brewster himself among the number , to entertain the idea of molecular reflection . I have , however , operated upon substances of widely different refractive indices , and therefore of very different polarizing angles as ordinarily defined , but the polarization of the beam by the incipient cloud has thus far proved itself to be absolutely independent of the polarizing angle . The law of Brewster does not apply to matter in this condition , and it rests with the undulatory theory to explain why . Whenever the precipitated particles are sufficiently fine , no matter what the substance forming the particles may be , the direction of maximum polarization is at right angles to the illuminating beam , the polarizing angle for matter in this condition being invariably 45 ? . This I consider to be a point of capital importance with reference to the present question . That water-particles , if they could be obtained in this exceedingly fine state of division , would produce the same effects , does not admit of reasonable doubt . And that they must exist in this condition in the higher regions of the atmosphere is , I think , certain . At all events , no other assumption than this is necessary to completely account for the firmamental blue and the polarization of the sky t. Suppose our atmosphere surrounded by an envelope impervious to light , but with an aperture on the sunward side through which a parallel beam of solar light could enter and traverse the atmosphere . Surrounded on all sides by air not directly illuminated , the track of such a beam through the air would resemble that of the parallel beam of the electric lamp through an incipient cloud . The sunbeam would be blue , and it would discharge laterally light in precisely the same condition as that discharged by the in* The difficulty referred to above is thus expressed by Sir John Herschel:- " The cause of the polarization is evidently a reflection of the sun 's light upon something . The question is on what ? Were the angle of maximum polarization 76 ? , we should look to water or ice as the reflecting body , however inconceivable the existence in a cloudless atmosphere , and a hot summer 's day of unevaporated molecules ( particles ? ) of water . But though we were once of this opinion , careful observation has satisfied us that 90 ? , or thereabouts , is a correct angle , and that therefore whatever be the body on which the light has been reflected , ifpolarized by a single reflection , the polarizing angle must be 45 ? , and the index of refraction , which is the tangent of that angle , unity ; in other words , the reflection would require to be made in air upon air ! " ( 'Meteorology , ' par . 233 ) . t Any particles , if small enough , will produce both the colour and the polarization of the sky . But is the existence of small water-particles on a hot summer 's day in the higher regions of our atmosphere inconceivable ? It is to be remembered that the oxygen and nitrogen of the air behave as a vacuum to radiant heat , the exceedingly attenuated vapour of the higher atmosphere being therefore in practical contact with the cold of space . cipient cloud . In fact the azure revealed by such a beam would be to all intents and purposes that which I have called a " blue cloud " ~ . But , as regards the polarization of the sky , we know that not only is the direction of maximum polarization at right angles to the track of the solar beams , but that at certain angular distances , probably variable ones , from the sun , " f neutral points , " or points , of no polarization exist , on both sides of which the planes of atmospheric polarization are at right angles to each other . I have made various observations upon this subject which I reserve for the present ; but pending the more complete examination of the questiou the following facts and observations bearing upon it are submitted to the Royal Society . The parallel beam employed in these experiments tracked its way through the laboratory air exactly as sun-beams are seen to do in the dusty air of London . I have reason to believe that a great portion of the matter thus floating in the laboratory air consists of organic germs , which are capable of imparting a perceptibly bluish tint to the air . This air showed , though far less vividly , all the effects of polarization obtained with the incipient clouds . The light discharged laterally from the track of the illuminating beam was polarized , though not perfectly , the direction of maximum polarization being at right angles to the beam . The horizontal column of air thus illuminated was 18 feet long , , and could therefore be looked at very obliquely without any disturbance from a solid envelope . At all points of the beam throughout its entire length the light emitted normally was in the same state of polarization . Keeping the positions of the Nicol and the selenite constant , the same colours were observed throughout the entire beam when the line of vision was perpendicular to its length . I then placed myself near the end of the beam as it issued from the electric lamp , and looking through the Nicol and selenite more and more obliquely at the beam , observed the colours fading until they disappeared . Augmenting the obliquity the colours appeared once more , but they were now complementary to the former ones . Hrence this beam , like the sky , exhibited its neutral point , at opposite sides of which the light was polarized in planes at right angles to each other . Thinking that the action observed in the laboratory might be caused in * The opinion of Sir John Herschel , connecting the polarization and the blue colour of the sky is verified by the foregoing results . " 4 The more the subject [ the polarization of skylight ] is considered , " writes this eminent philosopher , " the more it will be found beset with difficulties , and its explanation when arrived at will probably be found to carry with it that of the blue colour of the sky itself and of the great quantity of light it actually does send down to us . " " We may observe , too , " he adds , " that it is only where the purity of the sky is most absolute that the polarization is developed in its highest degree , and that where there is the slightest perceptible tendency to cirrus it is materially impaired . " This applies word for word to the " incipient clouds . " some way by the vaporous fumes diffused in its air , I had a battery and an electric lamp carried to a room at the top of the Royal Institution . The track of the beam was seen very finely in the air of this room , a length of 14 or 15 feet being attainable . This beam exhibited all the effects observed with the beam in the laboratory . Even the uncondensed electric light falling on the floating matter showed , though faintly , the effects of polarization* . YWhen the air was so sifted as to entirely remove the visible floating matter , it no longer exerted any sensible action upon the light , but behaved like a vacuum . I had varied and confirmed in many ways those experiments on neutral points , operating upon the fumes of chloride of ammonium , the smoke of brown paper , and tobacco smoke , when my attention was drawn by Sir Charles Wheatstone to an important observation communicated to the Paris Academy in 1860 by Professor Govi , of Turint . His observations on the light of comets had led M. Govi to examine a beam of light sent through a room in which was diffused the smoke of incense . He also operated on tobacco smoke . His first brief comzmunication stated the fact of polarization by such smoke , but in his second communication he announced the ( liscovery of a neutral point in the beam , at the opposite sides of which the light was polarized in planes at right angles to each other . But unlike my observations on the laboratory air , and unlike the action of the sky , the direction of maximum polarization in M. Govi 's experiment enclosed a very small angle with the axis of the illuminating beam , The question was left in this condition , and I am not aware that M. Govi or any other investigator has pursued it further . I had noticed , as before stated , that as the clouds formed in the experimental tube became denser , the polarization of the light discharged at right angles to the beam became weaker , the direction of maximum polarization becoming oblique to the beam . Experiments on the fumes of chloride of ammonium gave me also reason to suspect that the position of the neutral point was not constant , but that it varied with the density of the illuminated fumes . The examination of these questions led to the following new and remarkable results : the laboratory being well filled with the fiumes of incense , and sufficient time being allowed for their uniform diffusion , the electric beam was sent through the smoke . From the track of the beam polarized light was discharged , but the direction of maximum polarization , instead of being along the normal , now enclosed an angle of 12 ? or 13 ? with the axis of the beam . A neutral point , with complementary effects at opposite sides of it , was also exhibited by the beam . The angle enclosed by the axis of the beam , and a line drawn from the neutral point to the observer 's eye , measured in the first instance 66 ? . The windows of the laboratory were now opened for some minutes , a portion of the incense smoke being permitted to escape . On again darkening the room and turning on the beam , the line of vision to the neutral point was found to enclose with the axis of the beam an angle of 63 ? . The windows were again opened for a few minutes , more of the smoke being permitted to escape . Measured as oefore the angle referred to was found to be 54 ? . This process was repeated three additional times ; the neutral point was found to recede lower and lower down the beam , the angle between a line drawn from the eye to the neutral point and the axis of the beam falling successively from 54 ? to 49 ? , 43 ? and 33 ? . The distances , roughly measured , of the neutral point from the lamp , corresponding to the foregoing series of observations , were these:1st observation 2 feet 2 inches . 2nd , , 2 , , 6 , , 3rd , , 2 , , 10 , , 4th , , 3 , , 2 5th , , 3 , , 7 , 6th , , 4 , , 6 , , At the end of this series of experiments the direction of maximum polarization had again become normal to the beam . The laboratory was next filled with the fumes of gunpowder . In five successive experiments , corresponding to five different densities of the gunpowder smoke , the angles enclosed between the line of vision to the neutral point and the axis of the beam were 63 ? , 50 ? , 47 ? , 42 ? , and 38 ? respectively . After the clouds of gunpowder had cleared away the laboratory was filled with the fumes of common resin , rendered so dense as to be very irritating to my lungs . The direction of maximum polarization enclosed in this case an angle of 12 ? , or thereabouts , with the axis of the beam . Looked at , as in the former instances , from a position near the electric lamp no neutral point was observed throughout the entire extent of the beam . When this beam was looked at normally through the selenite and Nicol , the ring system , though not brilliant , was distinct . Keeping the eye upon the plate of selenite and the line of vision normal , the windows were opened , the blinds remaining undrawn . The resinous fumes slowly diminished , and as they did so the ring system became paler . It finally disappeared . Continuing to look along the perpendicular , the rings revived , but now the colours were complementary to the former ones . The neutral point had passed me in its motion down the beam consequent upon the attenuation of the fiumes of resin . In the fumes of chloride of ammonium substantially the same results were obtained as those just described . Sufficient I think has been here stated to illustrate the variability of the position of the neutral point . The explanation of the results will probably give new work to the undulatory theory* . Before quitting the question of the reversal of the polarization by cloudy matter , I will make one or two additional observations . Some of the clouds formed in the experiments on the chemical action of light are astonishing as to form . The experimental tube is often divided into segments of dense cloud , separated from each other by nodes of finer matter . Looked at normally , as many as four reversals of the plane of polarization have been found in the tube in passing from node to segment , and from segment to node . With the fumes diffused in the laboratory , on the contrary , there was no change in the polarization along the normal , for here the necessary differences of cloud-texture did not exist . Further . By a puff of tobacco smoke or of condensed steam blown into the illuminated beam , the brilliancy of the colours may be greatly augmented , But with different clouds two different effects are produced . For example , let the ring system observed in the common air be brought to its maximum strength , and then let an attenuated cloud of chloride of ammonium be thrown into the beam at the point looked at ; the ring system flashes out with augmented brilliancy , and the character of the polarization remains unchanged . This is also the case when phosphorus or sulphur is burned underneath the beam , so as to cause the fine particles of phosphoric acid or of sulphur to rise into the light . With the sulphur-fumes the brilliancy of the colours is exceedingly intensified ; but in none of these cases is there any change in the character of the polarization . But when a puff of aqueous cloud , or of the fumes of hydrochloric acid , hydriodic acid , or nitric acid is thrown into the beam , there is a complete reversal of the selenite tints . Each of these clouds twists the plane of polarization 90 ? . On these and kindred points experiments are still in progresst . The idea that the colour of the sky is due to the action of finely divided matter , rendering the atmosphere a turbid medium , through which we look at the darkness of space , dates as far back as Leonardo da Vinci . Newton conceived the colour to be due to exceedingly small water particles acting as thin plates . Goethe 's experiments in connexion with this subject are well known and exceedingly instructive . One very striking ohservation of Goethe 's referred to what is technically called " chill " by painters , which is due no doubt to extremely fine varnish particles interposed between the eye and a dark background . Clausius , in two very able memoirs , endeavoured to connect the colours of the sky with suspended water-vesicles , and to show that the important observations of Forbes on condensing steam could also be thus accounted for . Brnecke 's experiments on precipitated mastic were referred to in my last abstract . Helmiholtz has ascribed the blueness of the eyes to the action of suspended particles . In an article written nearly nine years ago by myself , the colours of the peat smoke of the cabins of Killarney* and the colours of the sky were referred to one and the same cause , while a chapter of the " Glaciers of the Alps , " published in 1860 , is also devoted to this question . Roscoe , in connexion with his truly beautiful experiments on the photographic power of sky-light , has also given various instances of the production of colour by suspended particles . In the foregoing experiments the azure was produced in air , and exhibited a depth and purity far surpassing anything that I have ever seen in mote-filled liquids . Its polarization , moreover , was pelfeet . In his experiments on fluorescence Professor Stokes had continually to separate the light reflected from the motes suspended in his liquids , the action of which he named " false dispersion , " from the fluorescent light of the same liquids , which he ascribed to " true dispersion . " In fact it is hardly possible to obtain a liquid without motes , which polarize by reflection the light falling upon them , truly dispersed light being unpolarized . At p. 530 of his celebrated memoir " On the Change of the Refrangibility of Light , " Prof. Stokes adduces some significant facts , and makes some noteworthy remarks , which bear upon our present subject . He notices more particularly a specimen of plate glass which , seen by reflected light , exhibited a blue which was exceedingly like an effect of fluorescence , but which , when properly examined , was found to be an instance of false dispersion . " It often struck me , " he writes , " while engaged in these observations , that when the beam had a continuous appearance , the polarization was more nearly perfect than when it was sparkling , so as to force on the mind the conviction that it arose merely from motest . Indeed in the former case the polarization has often appeared perfect , or all but perfect . It is possible that this may in some measure have been due to the circumstance , that when a given quantity of light is diminished in a given ratio , the illumination is perceived with more difficulty when the light is diffused uniformly , than when it is spread over the same space , but collected into specks . Be this as it may , there was at least no tendency observed towards polarization in a plane perpendicular to the plane of reflection , when the suspended particles became finer , and therefore the beam more nearly continuous . " Through the courtesy of its owner , I have been permitted to see and to experiment with the piece of plate glass above referred to . Placed in front of the electric lamp , whether edgeways or transversely , it discharges bluish polarized light laterally , the colour being by no means a bad imitation of the blue of the skv . Prof. Stokes considers that this deportment may be invoked to decide the question of the direction of the vibrations of polarized light . On this point I would say , if it can be demonstrated that when the particles are small in comparison to the length of a wave of light , the vibrations of a ray reflected by such particles cannot be perpendicular to the vibrations of the incident light ; then assuredly the experiments recorded in the foregoing communication decide the question in favour of Fresnel 's assumption . As stated above , almost all liquids have motes in them sufficiently numerous to polarize sensibly the light , and very beautiful effects may be obtained by simple artificial devices . When , for example , a cell of distilled water is placed in front of the electric lamp , and a slice of the beam permitted to pass through it , scarcely any polarized light is discharged , and scarcely any colour produced with a plate of selenite . But while the beam is passing through it , if a bit of soap be agitated in the water above the beam , the moment the infinitesimal particles reach the beam the liquid sends forth laterally almost perfectly polarized light ; and if the selenite be employed , vivid colours flash into existence . A still more brilliant result is obtained with mastic dissolved in a great excess of alcohol . The selenite rings constitute an extremely delicate test as to the quantity of motes in a liquid . Commencing with distilled water , for example , a thickish beam of light is necessary to make the polarization of its motes sensible . A much thinner beam suffices for common water ; while with Briicke 's precipitated mastic , a beam too thin to produce any sensible effect with most other liquids , suffices to bring out vividly the selenite colours .

112381

3701662

On the Thermal Resistance of Liquids. [Abstract]

233

236

Proceedings of the Royal Society of London

Frederick Guthrie

abs

6.0.4

proceedings

http://corpora.clarin-d.uni-saarland.de/surprisal/6.0.3/?id=112381

http://www.jstor.org/stable/112381

Thermodynamics

Chemistry 2

Thermodynamics

I. " On the Thermal Resistance of Liquids . " By FREDERICK GUTHRIE , F.C.S. Communicated by Dr. TYNDALL . Received October 16 , 1868 . ( Abstract . ) The memoir of which the following is an abstract gives an account of some experiments made by the author with the object of determining the laws according to which heat travels by conduction through liquids . After pointing out the importance of the subject , and briefly recapitulating the methods previously used and the results obtained by other experimenters , the " I Diathermometer " is described . This instrument , which may be employed for the examination of the thermal resistance or conducting power of solids as well as liquids , has the following form . A hollow brass cone , having a platinum base , is screwed with -its apex downwards into a tripod-stand which rests upon adjusting screws . The apex of the cone is tubular , and carries a cock , through which passes a vertical glass tube graduated and dipping into water . The level of the water in the tube is nearly as high as the apex of the cone . By means of a micrometer screw , a second cone , exactly similar and equal to the first , having its apex upwards , may be brought to any required distance from the lower cone . The brass cones and their platinum faces are highly polished , and the latter are cleaned by washing successively with hot nitric acid , caustic soda , alcohol , and water . The upper surface of the lower cone is brought into an exactly horizontal position , and the upper cone is lowered to any required distance from it . There is thus formed between the platinum faces a cylindrical interval of known height or thickness and diameter , and having its opposite faces parallel and horizontal . This wall-less chamber receives the liquid whose thermal resistance has to be measured . A liquid , introduced by means of a strangulated pipette of known capacity ( equal , say , to the interstitial space when the cone-faces are 1 millim. apart ) between the cones , remains there by means of its adhesion and cohesion . A description is given of the method used to get a constant current of water of uniform and known temperature to pass through the upper cone . When such a current passes , the platinum face of the upper cone becomes heated ; it communicates its heat to the liquid in contactwith it . The heat passes downwyards through the liquid , heats the upper surface of the lower cone , expands the air therein , and depresses the level of the water in the tube attached to the lower cone . A description is given of the most prominent sources of error of this instrument , and the means which were employed to eliminate them . It is concluded , from direct experiments ( 1st , by measuring the time required for the production of the first heat-effect in the lower cone ; 2ndly , by showing the smallness of the difference caused by the introduction of athermanous disks ) , and from comparison with recent results of Magnus , that the effect of radiation , in all the cases tried is negligible if not nothing . By measuring resistance rather than conductivity , several sources of [ Jan. 21 , 234 experimental error are eliminated . If the two cones are brought into actual contact , and water of a known temperature is led for a given time through the upper cone , a certain thermal effect is produced in the lower one . If the cones be then separated , and a liquid be interposed between them , and if water of the same temperature as before be led for the same time as before through the upper cone , a less thermal effect is produced . The dif erence between the two e ects is a measure of the resistance of the liquid . Results so obtained have to be corrected for the varying pressure to which the air in the lower cone is subjected as the water in the glass tube sinks . To finds the absolute results in thermal units , we have to take into account the diameter of the surface of the lower cone , its capacity , and the specific heat of the air which is in it . The following are the chief results obtained:(1 ) The connexion in the instance of water between the thickness and the time required for the first-heat effect . ( 2 ) The connexion between the temperature and the time required for the first-heat effect . It is shown that hotter water conducts heat better than colder ; and that the hotter the conducting-water , the greater is the difference in rate . ( 3 ) The connexion between the entire quantity of heat passing in a given time and the thickness and temperature of the conducting-water . ( 4 ) The effect of the solution of various salts in altering the thermal resistance of water . Every salt tried was found , when dissolved in water , to increase its thermal resistance . The author submits that the effect of the dissolved salt is chiefly , perhaps wholly , due to the displacement of a portion of the water by a substance having greater resistance , and to the modification in the specific heat of the liquid , caused by the introduction of the salt . ( 5 ) The resistance of the liquids in the following list was examined under precisely similar circumstances . The thickness was in each case 1 millim. The initial temperature of the liquid was 2Q ? O17C . , and the temperature-difference , AT , was 10 ? C. That is , the platinum surface of te upper cone was maintained at 30 ? '17C . The duration of the experiment in each case was 1 ' . The numbers show the specific resistance under the above circumstances , that is , the ratio between the quantities of heat arrested by the several liquids and that arrested by water . Liquid Specific Li Specific Liquid . resistance . Liquid . resistance . W ater ... ... ... ... ... ... ... ... ... . . 1 ' Acetate of amyl ... ... ... ... ... ... 10-00 G-lycerine ... ... ... ... ... ... ... ... ... 3-84 Amylamin ... ... ... ... ... ... ... ... 10-14 Acetic acid ( glacial ) ... ... ... ... 8-38 Amylic alcohol ... ... ... ... ... ... 10-23 Acetone ... ... ... ... ... ... ... ... 851 Oil of turpenine ... ... ... . 1175 Oxalate of ethyl ... ... ... ... ... ... 8'85 Nitrate of butyl ... ... ... ... ... ... 1187 Sperm-oil ... ... ... ... ... ... ... ... 885 Chl oroform ... ... ... ... ... ... ... ... 12.10 Alcohol ... ... ... ... ... .9.08 ichloride of carbon ... ... ... . . 12-92 Acetate of ethyl ... ... ... ... ... ... 908 Mercury amyl ... ... ... ... ... ... ... 12-92 Nitrobenzol ... ... ... ... ... ... ... . . 9-86 Bromide of ethylen ... ... ... ... 13-16 Oxalate of amyl ... ... ... ... ... . . 1006 Iodide of amyl ... ... ... ... ... ... 1327 Butylic alcohol ... ... ... ... ... ... 10-00 Iodide of ethyl ( ? ) ... ... ... ... . ? s The more salient points of these results are pointed out , such as the preeminently small resistance of water and of bodies containing a large proportion of the elements of water ( potential water ) ; the possible connexion of this fact with the results of Magnus concerning the conductivity of hydrogen ; the increased resistance accompanying increased molecular complexity in the case of isotypic liquids , as exemplified by the alcohols and their derivatives : the great resistance shown by the liquids containing halogens . The results obtained by Tyndall in regard to relative diathermancy are shown to be in accord with the author 's results concerning resistance . A highly diather'manous liquid invariably offers great resistance to conducted heat . The relation between electrical and thermal resistance in the case of liquids is also briefly discussed .

112382

3701662

Results of a Preliminary Comparison of Certain Curves of the Kew and Stonyhurst Declination Magnetographs

236

238

Proceedings of the Royal Society of London

W. Sidgreaves|Balfour Stewart

fla

6.0.4

http://dx.doi.org/10.1098/rspl.1868.0035

proceedings

http://corpora.clarin-d.uni-saarland.de/surprisal/6.0.3/?id=112382

10.1098/rspl.1868.0035

http://www.jstor.org/stable/112382

Meteorology

Tables

Meteorology

II . " Results of a preliminary Comparison of certain Curves of the Kew and Stonyhurst Declination Magnetographs . " By the Rev. W. SIDOGEAVES and BALFOUR STEWART , LL. D. , F.R.S. Received October 28 , 1868 . The observatories of Kew and Stonyhurst are not far apart , both being in England ; the first in the county of Surrey ( Lat. 51§ 28 ' 6 " N. , Long. 0§ 18 ' 47 " W. ) , and the second in the county of Lancashire ( Lat. 53§ 50 ' 40 " N. , Long. 2§ 28 ' 10"'2 W. ) . If we bear in mind ( as a fact well proved , chiefly by the researches of General Sabine ) that magnetic disturbances are of a cosmical nature , we cannot evidently expect any considerable difference between these two stations , and it might be very naturally supposed that the magnetic variations should be precisely the same in each . This is no doubt approximately true , but nevertheless there is on certain occasions a residual difference between the indications of the two places , and one which is caught by the eye from the automatic records with very great case , inasmuch as the instrumental time-scale of these is precisely the same for both places ; and not only is the time-scale the same , butfor slow disturbazces the vertical spaces traversed by the traces are the same for both declination magnetographs . We venture to bring before the Royal Society certain results of an intercomparison of the declination curves of these two observatories , although only of a preliminary nature , because the subject is one of much interest , and because these results appear to exhibit , superposed upon a disturbance which is mainly cosmical , a comparatively small effect , which appears to be more of a local nature , but which is not iunworthy of investigation . The records which we have investigated are represented graphically in Plates III . and IV . ; and in them the disturbances which have been measured are denoted by figures attached to their extremities . The following Table exhibits the results of these measurements : Ja Y 2941J868 . ( Cf Mick hN A68 A^A1 Mkarch23 . S 2 " ' ( 2). . II ' ' & 'i I , . Ir r4 . S PLate I. Fb . 5.1868 . Mcorch 6 . 1868 . ( 1 ) ( i ) I'I8E St. 10 U. 186 8 . Mwrch 24 . ( g ) 1868 . ( 5 ) ( ; 1 ) 22z If8( ( 9 ) 6 TM . b ? Moy 20 . 0,1,868 . ( 2 ) ( I(4 ) to , -[r , 2 t2 I 1T..E-/ .[ ? : . 12 Ar T , W N ' -s1 . 2ele del . W. 'HI '4Veslev del . 5.s ( fA . Mar'ch 20 . 1868 . ( 1 ) ( 2 r\j ( B ) Macrch 20 -1868 . AM ' ' ''I '7i . ' 1 r'A Apr 41868 . 1868 . dl^ 8 ( 7 ( 0 ) ( I 5 ) l 1.4 ) -Proc . Joy . Soc. Vol. XVf . Plte IV Mach . 21 . 1868ch21 . 168 . ( l ) ( 2 ) it( ( 2 ) ( 1 ) t8f ( 2 ) ( 2 ) PM 'll PM1 3 ' f 'r 4~1F^r PM llG PM 10I I 12---AT r1 PitL 1( : , 21i AV I 7 . 8 -W West imAp , '1 _r Duration , Amount of vertical disAbruptness repreStonyhurst Date Disturbance in tuirbance in units of sented byvertical minus ( see Plate ) . measured . minutes . scale ( hundredths of disturbance at Kew Kew disturan inch . ) in one minute . bance . I~ __ 1868 . Kew . Stonyhurst . Jan. 24 . ( 1 ) to ( 2 ) 14 52 54 3-7 +2 Feb. 5 . ( 1 ) to ( 2 ) 12 51 57 4-2 +6 ( 2 ) to ( 3 ) 7 18 24 2'6 +6 Mar. 6 . ( 1 ) to ( 2 ) 17 107 115 6-3 +8 20 ( A ) . ( 1 ) to ( 2 ) long con30 31 slow and curved +1 tinued . disturbance . 20 ( B ) . ( 1 ) to ( 2 ) 4 30 40 7-5 -10 , , ( 3 ) to ( 4 ) 12 40 45 3-3 +5 21 ( B ) . ( 1 ) to ( 2 ) 11 71 73 6-4 +2 21 ( A ) . ( 1 ) to ( 2 ) long con41 40 slow and curved 1 tinned . disturbance . 21(c ) . ( 1 ) to ( 2 ) 8 30 35 3-5 +5 23 . ( 1 ) to ( 2 ) 7 61 72 8-7 +11 , , ( 3 ) to ( 4 ) ... ... ... doubtful . , , ( 5 ) to ( 6 ) 3 32 57 10.7 +25 ( 6 ) to ( 7 ) 2-5 30 40 12-0 +10 , ( 8 ) to ( 9 ) 10 70 90 7'0 +20 24 . ( 1 ) to ( 2 ) 12 40 44 3-3 +4 Apr. 1 . ( 1 ) to ( 2 ) 11 57 60 5'2 +3 ( 3 ) to ( 4 ) 10 63 70 6-3 +72 ( 1 ) to ( 2 ) 4-5 21 30 4-7 + 9 , , ( 2 ) to ( 3 ) 4 11 21 2-8 +10 , , ( 4 ) to ( 5 ) 4-5 30 51 6-6 +21 , , ( 6 ) to ( 7 ) 4 45 66 11-2 +21 , , ( 8 ) to ( 9 ) 4-5 43 65 9-6 +22 , ( 10 ) to ( 11 ) 5 39 63 7-8 +24 19 . ( 1 ) to ( 2 ) 5-5 35 50 6-4 +15 , ( 3 ) to ( 4 ) 5-5 27 38 4-9 +11 , ( 5 ) to ( 6 ) 10 74 87 7-4 +13 , ( 6 ) to ( 7 ) 23 94 99 4-1 +5 27 . ( 1 ) to ( 2 ) 16 63 60 4-0 3 , , ( 2 ) to ( 3 ) 7 22 22 3-1 0 , ( 4 ) to ( 5 ) 6 52 60 8-7 +8 May 11 . ( 1 ) to ( 2 ) 17 53 53 3-1 0 20 . ( 1 ) to ( 2 ) 7 20 24 2-9 +4 ( 3 ) to ( 4 ) 12 22 23 1-8 +1 20-21 . ( l)to(2 ) 12 90 111 7.5 +21 ( 2 ) to ( 3 ) 14 40 65 2-9 +-25 , , ( 3 ) to ( 4 ) 10 20 30 2-0 +10 ( 4 ) to ( 5 ) long con65 65 slow and curved 0 tinned . disturbance . It may be inferred from this Table that where the disturbances are slow and long continued , that is to say , where there is scarcely any abruptness , the amount of disturbance as represented by the traces is the same for both places ; and this is quite confirmed by placing the curves the one over the other , when they will be found to coincide even in their most minute features . Let us now take the excesses of Stonyhurst over Kew for the varicus disturbances , and endeavour to see if this element is in any way connected with the abruptness of the disturbance . We may for convenience sake divide these excesses into four groups . Group 1 . Excesses not exceeding 4 scale-units . IT . Excesses exceeding 4 and not exceeding 9 scale-units . III . Excesses exceeding 9 and not exceeding 19 scale-units . IV . Excesses above 19 scale-units . Goup I. Group rouII . Group III . Group IV . Excess Excess Excess Excess ( under 5 ) . ( under 10 ) . Abruptness . ( under 20 ) . ( abov Abrptness 2 3-7 6 4-2 10 75 21 7-5 2 6-4 6 2-6 10 2-0 25 2-9 -3 4-0 8 6-3 11 8-7 25 10-7 0 3'1 5 3'3 10 120 20 7-0 0 3-3 8 8-7 10 , 2-8 21 66 4 2-9 5 3-5 15 6-4 21 11'2 1]37 6.3 11 4-9 22 964 3-3 9 4-7 13 7-4 24 7-8 3 5-2 5 4-1 Means 1-5 3-7 6-6 4-9 11 6-5 22 7-9 It would appear from these groups that generally , and on an average , the excess of Stonyhurst over Kew in declination disturbances varies with the abruptness of the disturbance , being great when the disturbance is very abrupt . It is hoped that on some future occasion further results , derived from an intercomparison of these curves , may be presented to the Society .

112383

3701662

On the Reappearance of Some Periods of Declination Disturbance at Lisbon during Two, Three, or Several Days

238

239

Proceedings of the Royal Society of London

Senhor Capello

fla

6.0.4

http://dx.doi.org/10.1098/rspl.1868.0036

proceedings

http://corpora.clarin-d.uni-saarland.de/surprisal/6.0.3/?id=112383

10.1098/rspl.1868.0036

http://www.jstor.org/stable/112383

Meteorology

Nervous System

Meteorology

III . Excesses exceeding 9 and not exceeding 19 scale-units . IV . Excesses above 19 scale-units . Goup I. Group rouII . Group III . Group IV . Excess Excess Excess Excess ( under 5 ) . ( under 10 ) . Abruptness . ( under 20 ) . ( abov Abrptness 2 3-7 6 4-2 10 75 21 7-5 2 6-4 6 2-6 10 2-0 25 2-9 -3 4-0 8 6-3 11 8-7 25 10-7 0 3'1 5 3'3 10 120 20 7-0 0 3-3 8 8-7 10 , 2-8 21 66 4 2-9 5 3-5 15 6-4 21 11'2 1]37 6.3 11 4-9 22 964 3-3 9 4-7 13 7-4 24 7-8 3 5-2 5 4-1 Means 1-5 3-7 6-6 4-9 11 6-5 22 7-9 It would appear from these groups that generally , and on an average , the excess of Stonyhurst over Kew in declination disturbances varies with the abruptness of the disturbance , being great when the disturbance is very abrupt . It is hoped that on some future occasion further results , derived from an intercomparison of these curves , may be presented to the Society . III . " On the reappearance of some periods of Declination Disturbance at Lisbon during two , three , or several days . " By Senhor CAPELLO , of the Lisbon Observatory . Communicated by BALFOU : R STEWAIT , LL. D. Received October 28 , 1868 . Any one who carefully examines the magnetograph curves must often notice that there are , during periods of disturbance , synchronous movements of the needle during corresponding hours for two , three , or more days . In some cases the repetition is only in two or three parallel movements , in others there are true periods of some hours in duration . The repeated periods are not entirely similar , their phases being in general so modified that in some cases their identity can only be recognized by a very minute investigation . The same periods , when repeated , have not always the same total duration ; nor do they recommence at the same precise hour , but sometimes earlier , and sometimes later , the differences varying from a few minutes to two or three hours . There is also to be remarked in the repeateed disturbances a tendency to modify in form , or to level their peaks and hollows , or , on the contrary , to augment the angular forms . CpeiJo 14186m3 1--18 C/ h Mair 311 -Aptr 1 , , 2\ 8 1865 Ml-cr . 15 . 7 . e 16 f ' 1864'Ja , n. , 17 7_ 1864 Oct.4 --(-8 1f27 , , 10 o 10 I1I 11 if 1865 JAty 17 67,18 / / 8::^^ Proc. SoC . o y. S Xo I. VaoL . Y at : 1864 Mrtr . 11 l , , 12 13 fo 2'Nov . 2 4-4 It 25 26 1865 A ug. . 10 6789 io a6798 ' 1865 Oct. 5 , , 10 ' k , \ r'---^^ 1865 Nov. 1 . 1866 13z 4 f ? .__ , . , , 13 I866 1866 10 ' ; Nov. 214186'7 18 1867 Jcr. . 12 -i 186 ; 7 1867 16 867r . 1867 Feb.77 17 M , r 1~ A_ IrH -~--~ ? C " r 18'67 14^,1 , s0 ^^ -^1 17 , O.ept- . _ 1 ' W..H . We s ley del . Au9 . 23 4It 4 , 241868 Mar. 21 _9 17 X , 3r a < *_ Mr1868 418 Mar. 220 . 11^ 'Y^^--)--p W.est Lp . W.We rt tirp Pln1 T. We also see that the greatest number of repetitions belong to the night hours , that is to say , those hours when the movements of the needle are easterly . In the morning hours there do not appear to be any wellmarked repetitions . I append examples chosen from the five years complete ( July 1863 to June 1868 ) of the declination curves of the Observatory at Lisbon ( see Plates V. & VI . ) . A greater number of cases might be quoted , but those I have chosen are sufficient for our purpose . Meanwhile I must mention that , in the majority of instances , where no relation apparently exists between one disturbance and the disturbances of the days preceding and following , the disturbances are generally violent . There are twenty-four examples , fifteen of which show repetition on two days , eight on thiee days , and one only where the curve appears repeated for four days . In order that the identity may be easily recognized , I have placed the curves with their corresponding periods vertical , the hours being marked on each curve . It appears that all the facts exhibited in these examples agree with the cosmical theory ; the cause ( existing in the sun or in space ) appears to continue sometimes during two , three , or several days without undergoing remarkable transformations . The repetition , being sometimes earlier , sometimes later , seems also to indicate that the cause possesses a proper movement ; the cause persists , but only comes again into operation when the earth by its diurnal rotation is placed in a similar position or conjunction to that of the preceding days . It would be very curious to analyze the photographs of the sun so as to see if there were any spots in the days of the examples , and if these spots remained without sensible alteration during the days when the disturbances remained so similar . Semaarcs by B. STEWART . I have compared Senhor Capello 's curves with the corresponding traces of the declination at Kew , and it would appear that the Lisbon disturbances are almost invariably reproduced at Kew at the same time , only to a greater extent . It would fuarther appear that the same amount of similarity which the various Lisbon curves exhibit is also exhibited in the corresponding Kew curves . Opinions may differ with regard to the strength of the evidence exhibited by Senhor Capello in support of the peculiar action of the disturbing forces of which he is an advocate . It would appear to me that the strongest point in favour of the hypothesis is not so much the repetition of a single disturbance as the repetition of a complicated disturbance in most if not all of its sinuosities . Several examples of this occur in these diagrams .

112384

3701662

On the Action of Solid Nuclei in Liberating Vapour from Boiling Liquids

240

252

Proceedings of the Royal Society of London

Charles Tomlinson

fla

6.0.4

http://dx.doi.org/10.1098/rspl.1868.0037

proceedings

http://corpora.clarin-d.uni-saarland.de/surprisal/6.0.3/?id=112384

10.1098/rspl.1868.0037

http://www.jstor.org/stable/112384

Chemistry 1

Thermodynamics

Chemistry

IV . " On the Action of Solid Nuclei in liberating Vapour from Boiling Liquids . " By CHARLES TOMrIINSON , F.R.S. Received November 5 , 1868 . History.-During many years after the invention of the barometer and the consequent discovery of atmospheric pressure , the boiling-point of a liquid was defined to be the temperature at which its evaporating tendency is equal to the common pressure of the atmosphere , or the lowest temperature at which its vapour can have the elasticity of common air . About the middle of the last century it was noticed by several distinguished Fellows of this Society that the boiling-point of water under a constant pressure varies within certain limits , according to the depth to which the thermometer is plunged into the boiling liquid . In the Report on Thermometers published in the Transactions for 1777 , it was stated that the steam from boiling water fairly represents the atmospheric pressure ; and it was recommended that , in determining the boilingpoint , the water be boiled in a metal vessel constructed so as to allow the bulb , and nearly the whole of that part of the stem that contained mercury , to be surrounded by the steam . In the fine experiments undertaken by Dalton , Watt , Robison , Southern , and others for determining the pressures of saturated steam at different temperatures above and below the standard boiling-point , it was noticed that if a minute portion of soda or of some salt soluble in water , and not capable of rising in vapour with it , be allowed to ascend to the top of the mercury , the column rises , thereby indicating a diminished pressure of steam . The adhesion of the soda to the water tends to restrain the water from evaporating , and thus the steam-emitting tension of a solution of soda is measurably less than that of pure water at the same temperature . In 1785 Achard* showed by a number of experiments that the boilingpoint of water , under a constant pressure , is much more inconstant in metallic than in glass vessels . He also noticed that if , while water was boiling steadily in a glass vessel , a drachm of iron-filings or of some other insoluble solid were added to the water , the boiling-point was lowered 1 ? Reaumur or even more , and that there were considerable differences in the amount of depression , according as the same substance was in powder or in lump . In 1803 De Lucti stated , in very precise terms , that boiling is produced by the bubbles of air which the heat disengages from the liquid . If the water be completely purged of air it cannot boil , because steam can only form on free surfaces , such as the air-bubbles present . Deprived of air , water can boil only on the upper or free surface . Water in a tube from which the air had been carefully expelled was raised to 234-0 F. without boiling . Inl 1812 , and again in 181.7 , Gay-Lussac* noticed Achard 's experiments on the effect of the vessel on the boiling-point , and of metal turnings , charcoal powder , and pounded glass in lowering it . he supposed the boiling-point to vary in different vessels according to the nature of their surfaces , and that the variation depends both on the condticting-power of the material for heat and on the polish of the surfaces . When water is boiling in a glass vessel , the temperature is higher tha n in a metal one ; but if a few pinches of iron-filings be put in , the boiling goes on as in a metal vessel . Without this aid the water boils in bursts , the steam having to overcome the cohesion or viscosity of the liquid , and its resistance to change of state . The adhesion of the liquid to the vessel must also be a force analogous to its viscosity . The use of platinum is recommended for preventing sou6resauts . In 1825 Bostockt noticed that ether in a matras over a spirit-lamp boiled at 112 ? F. ; but in a test-tube put into hot water it did not begin to boil under 150 ? , and on one occasion 175 ? . Bits of cedar-wood put into the ether made it boil at 110 ? ; the wood was covered with bubbles until ( according to Bostock ) having discharged all its air , it became inactive and sank . Bits of quill , feather , wire , pounded glass , &c. also lowered the boiling-point considerably . A thermometer plunged into the ether produced bubbles many degrees below the point at which ebullition took place when the thermometer was not inserted : this effect soon ceased ; but by alternately plunging the thermometer into the ether and removing it , the bubbles were produced at each immersion . Legrand : in 1835 also referred burstinog ebullition and sou6resauts to the absence of air in the liquid . Many salts prevent soubresauts ; others , such as the neutral tartrate of potash , favour them . In 1842 Marcet ? considered that iron , zinc , and other substances tend to depress the boiling-point , because they have a less molecular adhesion for water than glass has . If the vessel be coated with a thin layer of sulphur , gum-lac , or any similar substance that has no sensible adhesion for water , the temperatures of the water and of the steam are alike . The boiling-point varies in flasks of different kinds of glass , and in the same flask at different times . In a flask used for holding sulphuric acid the boiling-point of pure water was 106 ? C. These variations are referred to molecular changes on the surface of the glass . In 1843 Donny[t referred to the powerful influence of air or gases dissolved in the liquid on the phenomena of ebullition ; but as his theory is the same as that advanced by De Luc many years before , it is not necessary to notice it further . In 1861 Dufour{[ described an experiment in which globules of water suspended in hot oil are said to have been raised to from 110 ? to 178 ? C. without boiling ; but the moment they were touched with a solid they burst into steam . Porous bodies acted best because , it is said , they carried down air to the globules . Such is a very brief notice of a few of the numerous memoirs that have been published on the subject of boiling . The writers are all more or less disposed to adopt the following conclusions:-(1 ) that liquids boil with difficulty , or produce only sudden flashes of steam , as soon as the air which had been dissolved in them is expelled by heat ; ( 2 ) that those liquids that have the weakest affinity for air , such as sulphuric acid , alcohol , ether , &c. , boil with the greatest difficulty ; ( 3 ) that the adhesion of the liquid to the vessel , and the mutual cohesion of its own molecules , cause the liquid to boil in bursts , and produce sozubre1sauts ; ( 4 ) that the action of solid substances in preventing soubresauts is by carrying down air . My object in introducing a new set of experiments on boiling is ( 1 ) to show the action of solid nuclei in liberating vapour from liquids at or near the boiling-point ; ( 2 ) to define the conditions under which soubresauts take place ; and ( 3 ) to show what is the best remedy for the same . Definition.-A liquid at or near the boiling-point is a supersaturated solution of its own vapour , constituted exactly like soda-water , Seltzer-water , champagne , and solutions of some soluble gases . Action of Nuiclei.-If the above definitior be admitted , the behaviour of solid substances in liberating vapour on some occasions , and remaining " inactive " on others , becomes clear . If the solid be chemically clean , the solution of vapour will adhere to it as a whole , and there will be no liberation of vapour . If , on the contrary , the solid be unclean , the adhesion between the vapour and the solid will remaiin the same as before , while the adhesion between the liquid and the solid will be more or less diminished , according to the nature of the impurity and the liquid operated on ; and hence there will be a separation of vapour . But not only is it necessary to distinguish bodies as chemically clean or unclean , but also as porous or compact . The same force by which one volume of charcoal absorbs 98 volumes of ammoniacal gas , enables charcoal and some other porous bodies , when thrown into a boiling liquid , to separate the vapour from it , and thus to act as most efficient nuclei , The liquids operated on were water , alcohol , ether , wood-spirit , naphtha , carbonic disulphide , benzole , paraffine oil , oil of turpentine , rosemary , and a few other essential oils . The liquids with low boiling-points are converient for illustrating the phenomena in questlon . Any one of them in a tube about one-third or onehalf filled may be raised to the boiling-point by putting the tube into hot water contained in a sixor eight-ounce German fiask standing on the ring of a retort-stand . The tube should fit loosely into the neck , and rest on the bottom of the flask . In reheating the water a small spirit-lamp flame may be applied , not directly under the tube , but on one side of it , the object being to keep the liquid in the tube at or near the boiling-point , but not actually boiling . The temperature of the liquid in the tube may be taken from time to time , and the thermometer , when not in use , may be kept in a tall narrow glass containing a little of the liquid under examination . Carbonic disulphide , from its low boiling-point , gives off vapour with facility , and is consequently well adapted to show the action of solid nuclei . When the tube was placed in the hot water , a quantity of dense white vapour ascended from the surface of the liquid to the top of the tube ; but instead of overflowing it condensed in copious tears , which fell back into the liquid and caused a strong descending current . On touching the surface of the liquid with the end of a brass wire , violent ebullition set in , the bubbles rising to near the mouth of the tube . The boiling ceased altogether as soon as the wire was removed ; but when the surface was touched with a strip of paper , . it set in as violently as before . Now in these two experiments no air could have been carried down , siiice the surface only was touched , and the boiling continued only while the solid was kept in contact with such surface . Iron wire also liberated vapour abundaintly . The end of a glass rod was active at two small points , liberating from each a rapid stream of bubbles , the remaining portions being clean , or having soon become so by the action of the hot liquid , since glass is readily cleansed by liquids near the boiling-point . But it is said that rough bodies are most favourable to the liberation of vapour . The hot carbonic disulphide was touched with a rat's-tail file , and it produced furious boiling . The file was then held in the flame of a spirit-lamp , and while hot placed in the upper part of the tube , so that it might cool down to about the temperature of the liquid , and yet be sheltered from the air . On touching the surface of the disulphide with the end of the file , there was no liberation of vapour ; and the file was slowly passed to the bottom of the liquid , but still there was no action . The file was now taken out and waved in the air ; on reinserting it into the liquid , there was a burst of vapour arising from some mote or speck of dust caught by the file from the air . The file was quickly cleaned by the liquid , and it became inactive as before . It was again taken out and wlaved in the air , and on once more putting it into the liquid boiling set in again . A tube containing ether was put into the hot-water bath ; it quickly reached the boiling-point , and two specks in the tube became active in discharging rapid streams of bubbles . Specks of this kind are often powerful as nuclei in separating gas from soda-water &c. , and in causing the sudden crystallization of supersaturated saline solutions . Such specks in the bottoms of flasks , beakers , and retorts are powerful nuclei in separating Vapour from a liquid during the boiling . The vapour seems to be generated by these poiits , and to proceed from them to the surface in rapidly enlarging bubbles . Thiese'specks consist of iron , carbon , or some other material which is not so readily cleaned as the glass , or they present a porous point to the vapour . 243 As the temperature of the water-bath fell , the ether in the tube ceased to give off bubbles of vapour . A small pellet of writing-paper was now thrown in : the liquid boiled up furiously , the paper being much agitated , when suddenly it sank as if dead , and all vapour-giving action ceased . It had become , in fact , chemically clean . The paper was removed and a brass wire passed to the bottom of the tube , when the whole liquid boiled up briskly during a few seconds ; when , the wire becoming chemically clean , all action ceased , except from a point near the bottom of the wire , which continued to pour off a fine stream of bubbles during some minutes . The wire was now taken out and filed , in order to get rid of this nucleus . On returning it to the tube the ether boiled up as before , the handling and filino having made the whole immersed surface unclean ; but the ether soon cleaned it , and it became inactive ; but the active point was not only not got rid of , but there were now two points rapidly discharging vapour . These points are probably portions of porous dross entangled with the metal . During these experiments the ether was maintained at about 96 ? , and it boiled only when a solid nucleus was introduced . Methylated spirit was raised to about 178 ? . A piece of flint that had long been exposed to the air was put into the tube ; it gave off vapour from its surface in abundance . The flint was taken out and broken , and the two fragments were returned to the spirit . The newly fractured surfaces , being chemically clean , were quite inactive , not a single bubble of vapour appearing on them , while the outer surface continued to give off vapour as before . A strip of slate gave off vapour from a number of points in both surfaces ; it was split into two strips and replaced in the hot liquid ; the old surfaces were active as before , but the fresh surfaces were perfectly inactive . Mica and selenite do not answer well for these experiments . In the specimens tried , air containing dust had been dragged in in patches between the plates ; these , when newly split and put into soda water , showed considerable portions that were chemically clean in the midst of unclean patches . The action of nuclei can be well exhibited in oils with high boiling-points , such as the essential oil of turpentine , rosemary , &c. When the oil is boiling in a tube over a spirit-lamp , a strip of slate with one new surface may be introduced before the lamp is removed , so as to prevent the oil from being chilled . If , now , the lamp be taken away , vapour will pour off from the unclean surface of the slate during some minutes , while the freshly fractured surface will be quite inactive . The behaviour of nuclei , as thus far described , is the same as for supersaturated saline and gaseous solutions . A chemically clean nucleus will not separate either the salt or the gas from solution ; a chemically unclean nucleus will do so immediately it comes in contact with the solution . If the definition I have given of a liquid at or near the boiling-point be accepted , and it be admitted that solid nuclei behave in the same manner under the same conditions in separating salt , or gas , or vapour from solution , what is the action in this respect of air and gases ? It has been maintained that air is a powerfuil nucleus in separating salt from a supersaturated solution , that it is the air alone , as carried down by the solid , that acts as a nucleus in separating gases from solution , and that if air be absent from a liquid it cannot boil , because there is nothing for the vapour to expand upon . I have shown in former experiments that , in the case of supersaturated saline solutions , air is not a nucleus ; but that when it appears to be so , it is merely acting the part of a carrier of some chemically unclean mote or speck of dust . I have also shown that masses of air may be introduced into soda-water without any separation of the gas , provided the conditions of chemical purity be observed . A wire-gauze cage , for example , full of air can be lowered into soda water without producing any discharge of gas into the cage , or any separation of gas from the surface of the cage , so long as it is chemically clean ; when unclean , there is an abundant separation of gas from the surface of the cage , but the enclosed air remains purely passive all the time . A similar result may be obtained in the case of a liquid at or near the boiling-point , if precautions be taken to raise the cage to the temperature of the liquid before introducing it . The cage used in these experiments was smaller than that used in the soda-water experiments . It was five-eighths of an inch in diameter , and an inch and a half in length , and made of fine iron-wire gauze , such as is used by millers in bolting meal . Two of these cages were prepared . One was cleaned by being put into boiling spirits of wine ; it was rinsed in clean water , and so held in the steam of pure water boiling in a test-tube , so that the cage and the enclosed air might be adjusted to the temperature of the water . The cage was gently lowered into the water the moment the spiritlamp was withdrawn . There was no escape of vapour ; there was no violent boiling up , which must have ensued had air been a nucleus . But here was a mass of air in the midst of the liquid , and yet the steam did not expand into it . The openings into the cage must have been very much larger than the diameter of the globules of air which are supposed always to be present when a liquid is boiling , and yet there was no separation of vapour . This clean cage was removed , and the other cage , just as it had left the hands of the maker , was held in the steam of the water of the same tube , and the moment the lamp was removed gently lowered into the water . It was instantly and completely covered with bubbles of steam ; but there was no expansion of s ; -arn into the cage , and no escape upwards either of steam or of air . A good result was obtained with parafline oil boiling at 320 ? . While the cage was being lowered , it became filled about one-half with the liquid , but when completely submerged there was no action whatever . But , perhaps , it may be said that the liquid was now so far below the boiling-point as to be incapable of giving off vapour to any nucleus , clean or unclean . To test this , a small pellet of paper was thrown in ; the liquid immediately 245 began to seethe audibly , and it continued to give off vapour during more than two minutes , the paper pellet resting during the latter part of the time on the top of the cage . Similar good results were also obtained with oil of turpentine . The cage was also lowered into naphtha , and some of the other low boiling liquids , and whenever there was an escape of vapour , it could always be referred to some unclean portion of the cage . Care is required in lowering the cage , so as to expand the air ; for unless this be properly done , there may be a violent burst of air when the cage is near the bottom of the tube . It really does seem to me that too much importance has been attached to the presence of air and gases in water and other liquids as a necessary condition of their boiling . Cold water dissolves only onelfiftieth of its volume of nitrogen , and one twenty-fifth of its volume of oxygen , and these small quantities must be reduced to all almost inappreciable amount in hot or boiling water ; and yet some observers represent boiling water purged of air as reabsorbing it eagerly while still boiling . The only function I should assign to air would be that of diminishing somewhat the cohesive force of the liquid molecules . If the tube be of narrow bore and chemically clean , or becomes so by the action of the liquid , adhesion has some influence in raising the boiling-point . But the mode of heating the liquid is of still greater importance in this respect , as is evident in De Luc 's experiments , and was well brought out in Bostoek 's . In the latter case ether in a mattress over a spirit-lamp , boiled at 112 ? ; but in a test-tube in hot water at 150 ? and even 175 ? F. The difference in the conditions of heating has doubtless been regarded as too evident to be insisted on ; and yet it is of great importance in studying the conditions under which the boilingpoint of a liquid becomes raised . When the vessel is placed over a flame , that part in contact with the flame is heated , or tends to become heated , much more strongly than the rest of the vessel . This produces active convective currents , the effect of which is to loosen the cohesion of the particles , and so allow vapour to form more easily . When the water once begins to assume the elastic form , it does so from the overheated part of the veessel in contact with the flame . In a clean glass vessel containing distilled water placed over a spirit-lamp , no air-bubbles form , either on the sides or on the clean thermometer . They appear on the bottom surface only , playing about and disappearing upwards until the water is at about 160 ? . At about 180 ? small steam-bubbles are given off from the bottom heated surface with a crackling noise ; they rise rapidly , expand , and disappear before reaching the surface ; and until they succeed in doing so , the convective currents are active . WNhen the bubbles reach the surface and discharge steam into the air , the whole column in broken up , cohesion is overcome , and the boiling is maintained , while the liquid gradually disappears . Such is the process of boiling in a vessel heated by a flarme from below . When , however , all that part of the vessel ( such as a test-tube ) that contains liquid is put into a hot bath , the whole column is equably heated , or rather the top of the column is a little more heated than the bottom ( since the upper layers of hot water are at a higher temperature than the lower ones ) , and the effect of this is that there are no convective currents ; cohesion is diminished by expansion , not by convection . The whole column being thus about equally heated at the same moment , vapour cannot form at one part in preference to another , except at the surface ; but the whole column of liquid goes on expanding under an increasing temperature until , becoming more and more supersaturated with its own vapour , the increasing elastic force suddenly overcoming pressure , cohesion , and adhesion , there is a sudden burst of vapour . Or before this disruption takes place , if the surface be touched with a chemically unclean solid , the vapour adhering to it and thus set free , starts the vapour-giving action , just as touching a cold supersaturated saline solution starts crystallization , and the action once begun is propagated . If , however , the tube containing the ether &c. be not chemically clean , if there be minute specks and points in the glass ( as there often are ) all but invisible to the naked eye , and these be porous or not chemically clean , vapour will streamn from them long before the temperature of disruption is attained , and there will be no disruption at all . These points and specks account for many anomalous cases of crystallization which occur in operating with supersaturated saline solutions , and which puzzled Lowel and other observers . We may have , for example , two tubes apparently precisely alike , cleaned in the same manner , containing a hot filtered solution of the same salt , of the same strength , and exposed to the same cooling influence . One of the solutions in cooling will suddenly become solid , while the other will remain liquid , and . continue so during weeks and months . On examining the solidified solution , it will be found that crystallization has been promoted by a minute speck or point at some part of the tube , no matter where , and from this point , as from a centre , proceed fine crystalline needles radiating in all directions . Soubr6esautsz.-Liquids which render the surface of the vessel in which they are boiled or distilled chemically clean , thereby favour the production of soubresauts , or jumping ebullition . This is a mechanical action which does not seem to have been sufficiently explained . Thus Gay-Lusaac says , " When the liquid is above the boiling-point , it is in a forced state : instantly a burst of vapour is formed , the liquor is thrown out , and the vessel itself raised . " But why should the vessel be raised ? The burst of vapour follows an upward motion along the line of least resistance , which , so far from raising the vessel , has a precisely contrary effect . It produces an equal reaction in a downward direction , tending to force the vessel further into the ring of the retort-stand , or other support , and it is the rebound from this that causes the vessel to rise . If proof be required of the truth of this explanation , it can easily be supplied by suspending , by means of an india-rubber line or a bit of elastic , a tube containing crystals of sodic sulphate and a 247 very little water . If the flame of a spirit-lamp be applied to the bottom of the tube , the crystals soon fuse and throw down a portion of the anhydrous salt , which is highly favourable to the production of soubresauts . If the tube be suspended against an upright surface , with a mark opposite the mouth , it will be easily seen that every burst of steam is accompanied by a violent downward jerk . In order to mitigate or prevent this bumping ebullition , it has long been the practice to introduce into the retort or other vessel , a few angular pieces of solid matter , metallic being the best-such as platinum-foil , silver , copper , or platinum-wire or filings , fragments of cork or torn cartridgepaper . Faraday names these substances " promoters of vaporization , " without explaining their action ; and he remarks that if any one of these substances be suddenly introduced , it is probable that the consequent burst of vapour would be so instantaneous and strong as to do more harm than the bumping itself " * . This is precisely the action of an unclean solid introduced into a supersaturated gaseous solution , or in the case of a liquid at or near the boiling-point , into a supersaturated vaporous solution . When sand , fragments of glass , or other non-metallic substances are used for preventing bumping , they facilitate the escape of vapour only so long as they are unclean ; but as siliceous bodies are readily cleansed by the action of boiling water and other boiling liquids , they often aggravate the evil . For example , two ounces of distilled water containing a little sand from the sand-bath , were boiled in a six-ounce German flask over a spirit-lamp . The boiling proceeded briskly without any kicking . The lamp was removed and the flask left to cool . Next morning the lamp was again put under the flask , when the water boiled with such violent kickings as to endanger the safety of the vessel . The sand had become chemically clean during the first boiling . If sand , cleaned by means of sulphuric acid and much rinsing , be addedl to water in the first instance , the kickings set in at once . Similar results were obtained with fragments of glass ; when chemically clean , they serve to enlarge the adhesion surfaces , instead of the vapour-giving surfaces , and so increase the resistance to be overcome . With respect to the action of metals , there is no advantage in making them sharp-pointed , nor in having their surfaces rough ; only , in the latter case , unclean vapour-giving substances are apt to lodge in the rough lines , or between the teeth , and so far a file or other rough body may be of advantage . Metal filings are also liable to collect dust and specks of dirt , which act as nuclei . The following experiment shows the action of clean , as compared with unclean iron-filings . A flask cleaned by means of sulphuric acid contained four ounces of distilled water , which boiled at 215 ? . Some iron-filings that had long been kept in spirits of wine were thrown in . There was a good deal of kicking , and the temperature oscillated between 213 2oand 213f- ? - ? . Some unclean filings were thrown in , and the effect C Chemical Manipulation , p. 200 . was instantaneous . Copious streams of bubbles proceeded from the filings , the soubresauts ceased , and the temperature fell to 211 . Similar results were obtained with copper-filings , and copper and brass wire , clean and unclean , and also with platinum foil and wire . An experiment with mercury may perhaps be of interest . The metal was cleaned by being repeatedly shaken up with dilute nitric acid ; and after standing some time under it , a portion was drawn off from the bottom . Five ounces of water in a clean flask boiled at 2131 7 Enough mercury was poured in to form a ring at the bottom of the flask . The water soon regained its temperature , and even rose to 214 ? , with a good deal of bumping-steam forming under the mercury and distending it into a large hemisphere , which burst with a kick . The temperature varied between 213f ? and 214 ? . It would have been dangerous to have entirely covered the bottom with the metal ; for , as it was , the bursts of vapour were of an explosive character . While this uneasy boiling was going on , a very little dirty mercury was added to the flask , and , although the quantity was not more than one-sixth of that previously added , the effect was remarkable . Instead of the uneasy , kicking , jerking bursts , the whole instantly changed into a brisk , easy , soft boiling , rapid volleys of steam-balls being given off by the metal , breaking up the mass of water , while the temperature remained steady at 212-2o ? . It will thus be seen that the vitreous and metallic bodies employed in these experiments , as also the bits of paper , shavings of cedar-wood , &c. , are efficient as nuclei only so long as they are chemically unclean . When clean they become inactive as " promoters of vaporization . " Action of Porous Bodies.-But there are certain bodies , such as charcoal , coke , &c. , that I have not been able to make inactive , either by the action of strong sulphuric or nitric acid , or by repeated boiling in water , ether , spirits of wine , naphtha , &c. The same piece of charcoal held in the flame of a spirit-lamp and then put into soda-water , or into a liquid at or near the boiling-point , will liberate gas or vapour without any apparent diminution of its powers . It may be transferred from one liquid to another , from ether to alcohol , from alcohol to water , and from water to oil of turpentine without ceasing to perform useful work in setting vapour free , making the ooiling soft and easy , and preventing soubresauts* . The same remark applies to coke . It may be cleaned in the strongest acids , washed in water and alkalies without losing any of its vigour as a liberator of vapour from a hot liquid . It is quite remarkable to see how efficiently a lump of coke acts in a vessel of boiling water in giving off vapour , promoting tranquil boiling , and preventing the jumping of the vessel . Platinum sponge is also active . A small piece of this substance at the bottom of a flask of boiling water will send up vigorous jets of steam-bubbles , raising the water far above the surface . As in the case of charcoal and coke , the liberation of vapour is confined to the solid nucleus , no part of the flask giving off visible vapour . The following data show the influence of the solid upon the temperature . Five ounces of distilled water in a clean flask boiled at 213-3 ? . A small lump of platinum sponge was held in the flame of a spirit-lamp and then put into the flask . The temperature subsided to 212-4 ? 0 , and remained so for some time . A second small piece of sponge was similarly heated and put into the flask ; it was as active as the former piece in liberating vapour , but there was no further depression of temperature . The water was now allowed to get cold ; and on again applying the spirit-lamp there was a good deal of loud explosive bumping , until the water was near 2000 , when the platinum sponge began to give off steam and the boiling became soft and regular . I have not the command of apparatus for determining the volume of vapour absorbed by platinum sponge , charcoal , &c. at given temperatures ; but it would not be difficult to do so by one or other of the contrivances made by Dalton and Gay-Lussac in determining the elasticity of the vapours of liquids at the boiling-point . It would also be interesting to study the action of nuclei on liquids heated above the pressure of one atmosphere . Meerschaum is also an active nucleus . A bit of this substance was thrown into a tube filled about one-third with newly distilled oil of turpentine which boiled at about 310 ? . The whole tube became filled with bubbles ; and long after the lamp was removed the nucleus continued to liberate numerous streams of bubbles , an effect that is common to all porous bodies tried in these experiments , but more remarkable in some cases than others * . A fine-grained pumice-stone cleaned in nitric acid , and another piece not cleaned , were both very active in giving off vapour from liquids . As in the case of charcoal and meerschaum , they soon sank to the bottom of the vessel , unless buoyed up by the steam while the lamp was burning under the flask , and continued to pour off vapour so long as the liquid was at or near the boiling-point . When the water was below 100 ? , the flask was put under the receiver of an air-pump and the air exhausted ; the water soon boiled , and the pumice was as active as before in liberating vapour . Chalk , plumbago , and platinum balls are all active promoters of vaporization . In the absorption of gases by charcoal , Saussure found that , if a piece of charcoal impregnated with one gas were introduced into another gas , a por* Illustrations were frequently afforded in these experiments of the different action of a clean as compared with an unclean surface . In the experiment in hand , in order to take the temperature of the boiling turpentine , the thermometer-bulb and part of the stem were made chemically clean ; but having on one occasion to leave the thermometer in the tube , its bulb was made to rest on the bottom , so that about an inch and a half of the stem that had not been made chemically clean became immersed . This portion was instantly covered with minute beads of vapour , so as to give it a frosted appearance , exactly distinguishing the clean from the unclean portion . 250 tion of the absorbed gas might either be driven out or further condensed . A somewhat similar action may be noticed by transferring a piece of charcoal from one boiling liquid to another . For example , a small piece of wellburnt charcoal from the centre of a lump was held in the flame of a spiritlamp until it was red-hot , and so put into boiling water . It was not very active at first , but it soon became so , and continued so as long as the heat was kept up . After about half an hour 's action the charcoal was taken out , dried in a cloth , and put into boiling turpentine ; here it was amazingly active , and continued so during some minutes after the lamp had been removed . The charcoal was dried on filtering-paper and put into spirits of wine ; it was now much less active than fresh charcoal would have been ; and in ether its activity was still more diminished . The charcoal was next put into hot water , and it at once started into activity ; it was far more vigorous than clean charcoal is in water under any of the circumstances that have come under my notice . The charcoal was doubly active , not only from its porosity , but also from its want of chemical purity . On this latter account charcoal that has been used in boiling turpentine is singularly active in boiling water . And this sufficiently accounts for the fact noticed by Dufour , that when globules of water in hot oil came into contact with the thermometer or the sides of the vessel , they at once exploded into steam ; but I believe the globules of water were in the spheroidal state in all the cases of very high temperature cited by him . The diminished activity of charcoal and other porous bodies depends on the order in which they are introduced into liquids of different boilingpoints . If transferred from a liquid with a high into one with a low boiling-point , the charcoal is more or less inactive , its absorptive powers being already satisfied ; but if transferred from a liquid with a low into one with a high boiling-point its activity is increased , not only by the expulsion of the liquid absorbed , but also by the want of chemical purity that accompanies the process . Thus meerschaum or coke that is very active in turpentine becomes inactive when transferred to spirits of wine ; but after a time a single point in the solid may become active , and produce a rapidly rising inverted cone of vapour that has a very striking effect . Oonclusions.--The conclusions to which the foregoing details seem to lead are : ( 1 ) That a liquid at or near the boiling-point is a supersaturated solution of its own vapour . ( 2 ) That a solid non-porous nucleus either is or is not efficient in liberating vapour , according as it is chemically unclean or clean . ( 3 ) That as porous bodies do not become inactive , the proper nucleus for liberating vapour in the operations of boiling and distilling liquids , and for preventing soubresauts , is charcoal , coke , or some other porous body . P.S. ( Jan. 21 , 1869).-As it seemed probable that some numerical results as to the action of porous nuclei in increasing the amount of the T2 251 distillate might be expected , I asked my friend Mr. Hatcher , late of King 's College , to perform some experiments for me . The following are selected from his results . 1 . A glass flask with a wide neck was filled about one-third with distilled water ; it was boiled over a gas-burner , rapidly weighed , and replaced over the burner . After boiling twenty minutes , it was weighed again . The flask was once more filled to the original quantity , and some bits of coke were added ; it was boiled and weighed as before , the gas-flame remaining unaltered all the time . Results.--Water boiled away in the first trial ( water only ) 995 grains , in the second trial ( with coke ) 1130 grains . Ratio of products , as 100 : 113'6 . 2 . Water was made to distil freely from a still , and the quantity collected in fifteen minutes was weighed . A few pieces of coke were then aided to the water in the still , and the distillate collected again during fifteen minutes . Results.-Distillate from water only , 293 grains ; from water with coke , 310 grains . Ratio of products , as 100 : 1058 . 3 . A similar trial was made with common wood-charcoal ; but the vessel having been made much cleaner by the action of the first boiling , the water boiled irregularly , with bumping . The addition of the charcoal made the boiling tranquil and regular . Results.-Distillate from water only , 262 grains ; from water with charcoal , 334 grains . Ratio of results , as 100 : 1274 .

112385

3701662

Researches Conducted for the Medical Department of the Privy Council, at the Pathological Laboratory of St. Thomas's Hospital

252

256

Proceedings of the Royal Society of London

J. L. W. Thudichum

fla

6.0.4

http://dx.doi.org/10.1098/rspl.1868.0038

proceedings

http://corpora.clarin-d.uni-saarland.de/surprisal/6.0.3/?id=112385

10.1098/rspl.1868.0038

http://www.jstor.org/stable/112385

Botany 2

Chemistry 2

Botany

I. " Researches conducted for the Medical Department of the Privy Council , at the Pathological Laboratory of St. Thomas 's Hospital . " ByJ . L. W. THUDICHUM , M.D. Communicated by JOHN SIMON , Esq. Third Series.-Results of Researches on Luteine and the Spectra of Yellow Organic Substances contained in Animals and Plants . Received November 11 , 1868 . 1 . Name.-Various parts of animals and plants contain a yellow crystallizable substance which has hitherto not been defined , and to which , from its prominent property , I assign the name of " luteine . " 2 . Occurrence.-It occurs normally in the corpora lutea of the ovaries of mammals , in the serum of the blood , the cells of the adipose tissue , and the yellow fat of the secretion of the mammary gland , or butter ; in mammals it occurs abnormally in ovarian tumours and cysts , and in serous effusions . It is a regular ingredient of the yelks of the eggs of oviparous animals . In the vegetable world it is observed in seeds , such as maize ; in the husks and pulps of fruits , such as anatto ; in roots , such as carrots ; in leaves , such as those of the coleus ; and in the stamina and petals of a great variety of flowers . 3 . Properties.-Luteine is easily soluble in alcohol , ether , and chloroform , but is insoluble in water . It is soluble in albuminous liquids , such as the contents of ovarian cysts and the serum of the blood . All these solutions are yellow ; but the chloroform solution when concentrated has an orange-red colour . 4 . Spectrum.-The spectrum of these solutions is distinguished by great brilliancy of the red , yellow , and green part , and by three absorption-bands , which are situated in the blue , indigo , and violet part of the spectrum . The positions of the absorption-bands vary a little with the different solvents . AaBC -c D 35 aG i ' Ovario-luteine in alcohol . Egg-luteine in ether . 5 . Crystallization.-The crystals of luteine are apparently rhombic plates , as shown in the accompanying figure , of which two or more are 253 1869 . ] always superposed in a curious mannier . Possibly these crystals may be rhombohedra imperfectly developed on four of their edges . They are microscopic , yellow when thin , orange to red when thick , and have no resemblance to any other known animal or vegetable substance . 6 . Reactionzs.-Luteine combines with few substances , mercury-acetate being perhaps the only ordinary reagent by which it is immediately and completely precipitated , as a yellow deposit . Mercury-nitrate produces a yellow precipitate , which on standing becomes white . Nitric acid poured over the crystals produces a blue colour , which immediately passes into yellow . The blue is not produced when nitric acid is added to either alcohol , chloroform , or ether solution , but appears with the solution in acetic acid and disappears again rapidly . 7 . Affinity for Fats . In the corpora lutea luteine is deposited in granules , which become the darker and larger the older the corpora grow . In the yelks of eggs it also exists in granules ; and when extracted from any of these bodies it is always mixed with a considerable amount of an oily fat which contains cerebrine , and neutral fats , amongst them a peculiar fat containing phosphorus , like cerebrine . In butter after clarification it is found dissolved . 8 . Affinity for Albumen.-On the other hand , luteine has great attraction to albumen , and can only with difficulty be extracted from serum or the fluid of ovarian cysts . 9 . Luteine in Vegetables.- In vegetable matters luteine is contained in such a form that a clear watery solution cannot easily be obtained . All vegetable matters , however , readily yield their luteine to alcohol , and form by proper treatment clear solutions . In maize , luteine is accompanied by fats which are somewhat similar to those of eggs . 10 . Type of new Spectra.--The spectrum of luteine is the type of the spectra of a series of bodies which are probably chemically identical ; but not all yellow vegetable , animal , or chemical products are identical with luteine . 11 . New Spectra like that of Luteine.-The yellow-coloured matters of the following plants present the spectrum of luteine , or one closely resembling it:-(1 ) Crocus or saffron ( stamina ) ; ( 2 ) Ilelianthus annuus ( flower ) ; the petals of the following plants-(3 ) Leontodon taraxacum , ( 4 ) Leontodon ( varietas ? ) , ( 5 ) Gazania elegans , ( 6 ) Marigold common , ( 7 ) Hypericum oblongifolium , ( 8 ) Acacia leprosa , ( 9 ) Galphimia splendens , ( 10 O ) Stigmzatophyllumi ciliatum , ( II 1 ) Lankesteria elegans , ( 12 ) Allamanda neriifolia , ( 13 ) Colutea frutescens , ( 14 ) Tagetes lucida , ( 15 ) Sehkuhria atrovirens , ( 16 ) Diplotaxis tenuifolia , ( 17 ) Virgilia sylvatica , ( 18 ) Einothera grandifgora , ( 19 ) Verbascum phlomoides , ( 20 ) Tagetes pumila , ( 21 ) Helianthus macrophyllus , ( 22 ) Chrysopsis villosa , ( 23 ) Heleniumn autumnale , ( 24 ) Obeliscaria pinnata , ( 25 ) Heliopsis leevis , ( 26 ) Linosyris vulgaris , ( 27 ) Berberis Darwinii , ( 28 ) Solidago serotina , ( 29 ) Ruta graveolens , ( 30 ) Melilotus elegans , ( 31 ) Medicago 254 elegans , ( 32 ) Allamanda Hendersonii ; ( 33 ) the root of the common carrot , Daucus carota ; ( 34 ) the seeds of Indian corn , Zea mays . The extracts of the berries of the following plants also give the luteine spectrum:-(35 ) Anatto ; ( 36 ) Asparagus ; ( 37 ) Physalis Alkekengi ( outer shell and inner berry ) ; ( 38 ) Solanum dulcamara ; ( 39 ) Solanum capsicastrum ; ( 40 ) Cyphomandra betacea ; ( 41 ) Crataegus crus-galli ; ( 42 ) Pyrus aria . 12 . Uncertainty.- In several of these matters only two absorption-bands are with certainty distinguished . The third , clearly observable e.g. in the extract from the common marigold , requires further researches with more powerful light . 13 . Yellow Bodies with one Band.-The yellow principles contained in yellow-wood or fustic , in the flowers of the Calceolaria of ornamental gardens , and in the yellow faeces of sucking infants , show but one absorption-band , in the blue . 14 . Uranium Salts.-The yellow solutions of uranium salts exhibit two absorption-bands in the blue , which are very different from any of the above bands . 15 . Spectra of Yellow Bodies with continued Absorption of Blue.-A great number of yellow substances , amongst them some of the most important dye-stuffs , show spectra with continued absorption of blue , indigo , and violet , without any bands . On dilution the absorption gradually recedes towards violet . To this class belong ( 1 ) Rhamnine , from French berries ; ( 2 ) Luteoline , from weld ; ( 3 ) Quercitrine , from extract of quercitron or fluorine ; ( 4 ) Turmeric ; ( 5 ) Picric , and ( 6 ) Purree , or Indian yellow ; the orange-coloured solution of the petals of ( 7 ) Coreopsis lanceolata , ( 8 ) Helichrysum bracteatum ; the light-yellow solution of ( 9 ) Viola lutea , ( 10 ) Acacia decurrens , ( 11 ) Helianthus macrophyllus( ? ) , ( 12 ) Berberis Darwinii ( ? ) , ( 13 ) Gnaphaliumfcetidum . 16 . Luteine not identical with Hematoidine or Cholophceine.-Luteine differs entirely from hematoidine on the one , and from cholophaeine on the other hand , and ought not , and after the elucidation of its spectral phenomena cannot , any longer be confounded with either of them . 17 . Error of Stiideler and Holm.-The bodies described by Holm and Stadeler under the name of hematoidine are not hematoidine , but luteine . 18 . Robin 's Hematoidine is Cholophaeine.-The bodies described by Valentiner , and by Robin , Rich , and Mercier , under the name of hematoidine , are not hematoidine , but cholophaeine or bilirubine . 19 . Hematoidine peculiar . Hematoidine is a useful expression for certain microscopical crystals and amorphous bodies occurring in effused blood , the substance of which has not as yet been chemically isolated or defined . 20 . Luteine leads to new morphological views.-The discovery of the identity of luteine from corpora lutea of mammals with that from yelks of eggs will probably lead to a revision of the present doctrines regarding the 1869 . ] 255 homologies of the various parts of the ova of mammals and the eggs of birds and lower animals . Chemically the corpus luteum is the homologue of the yelk , genetically it is nearly so ; but its use and destiny are totally different . Note.-The foregoing researches are technical parts of inquiries carried on by the author at the Pathological Laboratory , St. Thomas 's Hospital , for the Medical Department of the Privy Council , in continuation of researches already published in the Ninth and Tenth Reports of the Medical Officer of the Privy Council . The special thanks of the author are due to Dr. Hooker , Director of the Royal Botanical Gardens , Kew , for the kindness and liberality with which he supplied , through Mr. Smith , the Curator , most of the botanical specimens examined in the course of this research .

112386

3701662

On Hydrofluoric Acid. [Abstract]

256

260

Proceedings of the Royal Society of London

G. Gore

abs

6.0.4

proceedings

http://corpora.clarin-d.uni-saarland.de/surprisal/6.0.3/?id=112386

http://www.jstor.org/stable/112386

Chemistry 2

Thermodynamics

Chemistry

II . " On Hydrofluoric Acid . " By G. GORE , F.R.S. Received November 14 , 1868 . ( Abstract . ) A. Athydrous Hydro , luoric Acid . This paper contains a full description of the leading physical and che . mical properties of anhydrous hydrofluoric acid , and also an account of various properties of pure aqueous hydrofluoric acid . The author obtained the anhydrous acid by heating dry double fluoride of hydrogen and potassium to redness in a suitable platinum apparatus ( shown by a figure accompanying the paper ) , and states the conditions under which it may be obtained in a state of purity . The composition and purity of the anhydrous acid are shown and carefully verified by various methods of analysis , both of the double fluoride from which it was prepared and of the acid itself ; and particulars are given of all the circumstances necessary to insure reliable and accurate results . Nearly all the operations of preparing , purifying , analyzing , and examining the properties of the acid were conducted in vessels of platinum , with lutings of paraffin , sulphur , and lampblack ; articles of transparent and colourless fluor-spar were also employed in certain cases . Nearly all the manipulations with the acid were effected while the vessels containing it were immersed in a strong freezing-mixture of ice and crystallized chloride of calcium . The pure anhydrous acid is a highly dangerous substance , and requires the most extreme degree of care in its manipulation . It is a perfectly colourless and transparent liquid at 60 ? Fahr. , very thin and mobile , extremely volatile , and densely fuming in the air at ordinary temperatures , and absorbs water very greedily from the atmosphere . It was perfectly retained in platinum bottles , the bottle having a fanged mouth with a platinum plate secured with clamp-screws , and a washer of paraffin . A number of attempts were made , finally with success , to determine the molecular volume of the pure anhydrous acid in the gaseous state , the acid in these cases being prepared by heating pure anhydrous fluoride of silver with hydrogen in a suitable platinum apparatus over mercury . Particulars are given of the apparatus employed and of the manipulation . The results obtained show that one volume of hydrogen , in uniting with fluorine , produces not simply one volume of gaseous product as it does when uniting with oxygen , but two volumes , as in the case of its union with chlorine . The gaseous acid transferred to glass vessels over mercury did not corrode the glass , or render it dim in the slightest degree during several weeks , provided that noisture was entirely absent . The author concludes that the anhydrous acid he has obtained is destitute of oxygen , not only from the various analyses and experiments already referred to , but also , 1st , because the double fluoride from which it was prepared , when fused and electrolyzed with platinum electrodes , evolved abundance of inflammable gas at the cathode , but no gas at the anode , although oxides are by electrolysis decomposed before fluorides ; 2nd , because the electrolysis of the acid with platinum electrodes yielded no odour of ozone , whereas the aqueous acid of various degrees of strength evolved that odour strongly ; and , 3rd , because the properties of the acid obtained from hydrogen and fluoride of silver agree with those of the acid obtained from the double salt . He considers also that the acid obtained from pure fluor-spar and monohydrated sulphuric acid heated together in a platinum retort is free from oxygen and water . The specific gravity of the anhydrous liquid acid was several times determined , both in a specific-gravity bottle of platinum , and also by means of a platinum float submerged and weighed in the acid . Concordant and reliable results were obtained ; the specific gravity found was 0'9879 at 55 ? Fahr. , that of distilled water being1000 at the same temperature . The anhydrous acid was much more volatile than sulphuric ether . Its boiling-point was carefully determined in a special apparatus of platinum , and was found to be 67 ? Fahr. Not the slightest sign of freezing occurred on cooling the acid to -30 ? Fahr. ( = 34 ? '5 C. ) ; and it is highly probable that its solidifying temperature is a very great many degrees below this . Its vapour-tension at 60 ? Fahr. was also approximately determined , and was found to be =7'58 lbs. per square inch . On loosening the lid of a bottle of the acid at 60 ? Fahr. , the acid vapour is expelled in a jet like steam from a boiler ; this , together with the low boiling-point , the extremely dangerous and corrosive nature of the acid , and its great affinity for water , illustrates the very great difficulty of manipulating with it and retaining it in a pure state . Nevertheless , by the contrivances described , and by placing the bottles in a cool cellar ( never above a temperature of 60 ? Fahr. ) , the author has succeeded in keeping the liquid acid perfectly , without loss and unaltered , through the whole of the recent hot summer . The electrical relations of different metals &c. in the acid were found to be as follows at 0 ? Fahr.:-zinc , tin , lead , cadmium , indium , magnesium , cobalt , aluminium , iron , nickel , bismuth , thallium , copper , iridium , silver , gas-carbon , gold , platinum , palladium . Numerous experiments were made of electrolyzing the anhydrous acid with anodes of gas-carbon , carbon of lignum-vitm and of many other kinds of wood , of palladium , platinum , and gold . The gas-carbon disintegrated rapidly ; all the kinds of charcoal flew to pieces quickly ; and the anodes of palladium , platinum , and gold were corroded without evolution of gas . The acid with a platinum anode conducted electricity much more readily than pure water ; but with one of gold it scarcely conducted at all . These electrolytic experiments presented extreme difficulties , and were conducted in a platinum apparatus ( shown by a figure ) specially devised for the purpose . The particulars of the conditions and results obtained are described in the paper . Various mixtures of the anhydrous acid with monohydrated nitric acid , with sulphuric anhydride , and with monohydrated sulphuric acid were also electrolyzed by means of platinum anodes , the particulars and results of which are also described . To obtain an idea of the general chemical behaviour of the pure anhydrous acid , numerous substances ( generally anhydrous ) were immersed in separate portions of the acid in platinum cups , kept at a low temperature ( 0 ? to --200 Fahr. ) . The acid had scarcely any effect upon any of the metalloids or noble metals ; and even the base metals in a state of fine powder did not cause any evolution of hydrogen . Sodium and potassium behaved much the same as with water . Nearly all the salts of the alkali and alkaline-earth metals produced strong chemical action . Various anhydrides ( specified ) dissolved freely . Strong aqueous hydrochloric acid produced active effervescence . The alkalies and alkaline earths united strongly with the acid . Peroxides gave no effect . Numerous oxides ( specified ) produced strong chemical action , some of them dissolving . Some nitrates were not chemically affected ; others ( those of lead , barium , and potassium ) were decomposed . Fluorides generally were unchanged ; but those of the alkalimetals and of thallium produced different degrees of chemical action , those of ammonium , rubidium , and potassium uniting powerfully . Numerous chlorides were also unaffected , whilst those of phosphorus ( the solid one only ) , antimony ( the perchloride ) , titanium , and of the alkaline-earth and alkali metals , were decomposed with strong action , and generally with effervescence . The chlorates of potassium and sodium were also decomposed with evolution of chloric acid ; the bromides of the alkaline-earth and alkali metals behaved like their chlorides . Bromate of potassium rapidly set free bromine . Numerous iodides were unaffected ; but those of the alkaline-earth and alkali metals were strongly decomposed , and iodine ( in some cases only ) set free . The anhydrous acid decomposed all carbonates with effervescence , and those of the ' alkaline-earth and alkali metals with violent action . Borates of the alkalies also produced very strong action . Silico-fluorides of the alkali metals dissolved with effervescence . All sulphides , except those of the alkaline-earth and alkali metals , exhibited no change ; the latter evolved sulphuretted hydrogen violently . Bisulphite of sodium dissolved with effervescence . Sulphates were variously affected . The acid chromates of the alkali metals dissolved with violent action to blood-red liquids , with evolution of vapour of fluoride of chromium . Cyanide of potassium was violently decomposed , and hydrocyanic acid set free . Numerous organic bodies ( specified ) were also immersed in the acid ; most of the solid ones were quickiy disintegrated . The acid mixed with pyroxylic spirit , ether , and alcohol , but not with benzole ; with spirit of turpentine it exploded , and produced a blood-red liquid . Gutta percha , india-rubber , and nearly all the gums and resins were rapidly disintegrated and generally dissolved to red liquids . Spermaceti , stearic acid , and myrtle wax were but little affected , and paraffin not at all . Sponge was also but little changed . Gun-cotton , silk , paper , cotton-wool , calico , gelatine , and parchment were instantly converted into glutinous substances , and generally dissolved . The solution of gun-cotton yielded an inflammable film on evaporation to dryness . Pinewood instantly blackened . From the various physical and chemical properties of the anhydrous acid , the author concludes that it lies between hydrochloric acid and water , but is much more closely allied to the former than to the latter . It is more readily liquefied than hydrochloric acid , but less readily than steam ; like hydrochloric acid it decomposes all carbonates ; like water it unites powerfully with sulphuric and phosphoric anhydrides , with great evolution of heat . The fluorides of the alkali metals unite violently with hydrofluoric acid , as the oxides of those metals unite with water ; the hydrated fluorides of the alkali metals also , like the hydrated fixed alkalies , have a strongly alkaline reaction , and are capable of expelling ammonia from its salts . It may be further remarked that the atomic number of fluorine lies between that of oxygen and chlorine ; and the atomic number of oxygen , added to that of fluorine , nearly equals that of chlorine . B. Aqueous Hydrofluoric Acid . Under the head of the aqueous acid the author enumerates the various impurities usually contained in the commercial acid , and describes the modes he employed to detect and estimate them , and to estimate the amount of HF in it . The process employed by him for obtaining the aqueous acid in a very high degree of purity from the commercial liquid , is also fully described . It consists essentially in passing an excess of sulphuretted hydrogen through the acid , then neutralizing the sulphuric and hydrofluosilicic acids present by carbonate of potassium , decanting the liquid after subsidence of the precipitate , removing the excess of sulphuretted hydrogen by carbonate of silver , distilling the filtered liquid in a leaden retort with a condensing-tube of platinum , and , finally , rectifying . 2he effect of cold upon the aqueous acid was briefly examined , the result being that a comparatively small amount of hydrofluoric acid lowers the freezing-point of water very considerably . The chemico-electric series of metals &c. in acid of 10 per cent. and in that of 30 per cent. were determined . In the latter case it was as follows:-zinc , magnesium , aluminium , thallium , indium , cadmium , tin , lead , silicon , iron , nickel , cobalt , antimony , bismuth , mercury , silver , copper , arsenic , osinium , ruthenium , gas-carbon , platinum , rhodium , palladium , tellurium , osmi-iridium , gold , iridium . Magnesium was remarkably unacted upon in the aqueous acid . The chemico-electric relation of the aqueous acid to other acids with platinum was also determined . Various experiments of electrolysis of the aqueous acid of various degrees of strength were made with anodes of platinum . Ozone was evolved , and , with the stronger acid only , the anode was corroded at the same time . Mixtures of the aqueous acid with nitric , hydrochloric , sulphuric , selenious , and phosphoric acids were also electrolyzed with a platinum anode , and the results are described .

112387

3701662

On a Momentary Molecular Change in Iron Wire

260

265

Proceedings of the Royal Society of London

G. Gore

fla

6.0.4

http://dx.doi.org/10.1098/rspl.1868.0040

proceedings

http://corpora.clarin-d.uni-saarland.de/surprisal/6.0.3/?id=112387

10.1098/rspl.1868.0040

http://www.jstor.org/stable/112387

Measurement

Electricity

Measurement

III . " On a momentary Molecular Change in Iron Wire . " By G. GoaE , F.R.S. Received November 14 , 1868 . WVhilst making some experiments of heating a strained iron wire to redness by meatns of a current of voltaic electricity , I observed that , on disconnecting the battery and allowing the wire to cool , during the process of cooling the wire suddenly elongated , and then gradually shortened until it became quite cold . On attempting , some little time afterwards , to repeat this experiment , although a careful record of the conditions of the experiment had been kept , it was with some difficulty , and after numerous trials , that I succeeded in obtaining the same result . Having again obtained it , I next examined and determined the successfiul conditions of the experiment , and devised the following arrangement of apparatus . AA ( fig. 1 ) is a wooden base 61 centimetres long and 15'5 centimetres wide . B and C are binding-screws ; they are provided with small brass mercury-cups fixed in the heads of the screws for attachment of the wires of a voltaic battery . D is a binding-screw for holding fast the sliding wire hook E. F is a cylindrical binding-screw , fixed to the sliding wire G , which is held fast by the binding-screw B. H is the iron or other wire ( or ribbon ) to be heated : one end of this wire passes through the screw F and is tightly secured by it , whilst the other end is held fast by the cylindrical binding-screw I ; the binding-screw I has a small projecting bent piece of copper wire secured to it , which dips into a little shallow dish or cup of mercury , J ; and the mercury in this cup is connected by a screw and strip of brass to the binding-screw C. K is a stretched band of vulcanized india-rubber , attached at one end to the hook of the wire E , and Mr. G. Gore on a momentary at the other end to the hook L ( see fig , 2 ) . The cylindrical bindingscrew I has a hook by which it is attached to the loop M ( fig. 2 ) . N is an axis suspended delicately upon centres , and carrying a very light index pointer 0 . The hook L and loop M are separate pieces of metal , and move freely upon an axis , P ( fig. 2 ) . The distance from the centre of the axis N to that of P is 12*72 millimetres(=0'5 inch ) , and to the top of the index pointer 25 45 centimetres ( = 10'0 inches ) ; every movement horizontally , therefore , of the loop M3 is attended by a movement , twenty times the amount , of the top of the pointer . Q is a screw for supporting the axis N. I have found it convenient to put the zero-figure of the index towards the left-hand side of the index-plate . It is a separate piece of wood fitting into a rectangular hole in the base board ; it carries a graduated rule , 8 , for measuring the length of the wire to be heated , and is easily removed , so that the wire may , if necessary , be heated by means of a row of Bunsen 's burners . The rule T is used when measuring the amount of strain . U is a vertical stud or pin of brass ( of which there are two ) for limiting the range of movement of the pointer 0 . In using this apparatus , a straight wire or ribbon , H , of a suitable length and thickness was inserted , the index pointer brought to 0 by adjustment of the sliding-wire G , and a suitable amount of strain ( varying from less than two ounces to upwards of twenty ) put upon the wire by adjusting the sliding hooked wire E. One pole of a voltaic battery , generally consisting of six Grove 's elements , was connected with the binding-screw C , and the other pole then inserted in the mercury-cup of B. As soon as the needle O attained a maximum or stationary amount of deflection , the battery-wire was suddenly removed from B , and the wire allowed to cool . The movement of the needle O was carefully watched both during its movement to the right hand and also during its return , to see if any irregularity of motion occurred . Wires of the following metals and alloys were employed:-palladium , platinum , gold , silver , copper , iron , lead , tin , cadmium , zinc , brass , germansilver , aluminium , and magnesium ; metallic ribbon was also employed in certain cases . In these experiments the thickness and length of the conducting-wire or ribbon had to be carefully proportioned to the quantity and electromotive power of the current , so as to produce in the first experiments with each metal only a very moderate amount of heat ; thinner ( and sometimes also shorter ) wires were then successively used , so as ultimately to develope sufficient heat to make the metal closely approach its softening or fisionpoint . The battery employed consisted in each case of six Grove 's cells , each ; cell containing two zinc plates 3a inches wide , and a platinum plate 3 inches wide , each immersed about 5 inches in their respective liquids . The amount of tension imparted by the elastic band required to be carefully adjusted to the cohesive power of each metal ; if the stretching power was too weak , the phenomenon sought for was not clearly deve loped ; and if too great , the wire was overstretched or broken when it approached the softening-point . The amount of strain imparted was approximately measured by temporarily substituting the body of a small spring balance for the hooked wire F. The heated wire must be protected from currents of cold air . With wires of iron 0'65 millimetre thick ( size " No. 23 " ) and 21'5 centimetres long , strained to the extent of 10 ounces or more , and heated to full redness , the phenomenon was clearly developed . As an example , the needle of the instrument went with regularity to 18'5 of index-plate ; the current was then stopped ; the needle instantly retreated to 17'75 , then as quickly advanced to 19'75 , and then went slowly and regularly back , but not to zero . If the temperature of the wire was not sufficiently high , or the strain upon the wire not enough , the needle went directly back without exhibiting the momentary forward movement . The temperature and strain required to be sufficient to actually stretch the wire somewhat at the higher temperature . A higher temperature with a less degree of strain , or a greater degree of strain with a somewhat lower temperature , did not develope the phenomenon . The wire was found to be permanently elongated on cooling . The amount of elongation of the wire during the momentary molecular change was usually about 2 part of the length of the heated part of the wire ; but it varied in different experiments ; it was greatest in amount when the maximum degrees of strain were applied . The molecular change evidently includes a diminution of cohesion at a particular temperature during the process of cooling ; and it is interesting to notice that at the same temperature during the heating-process no such loss of cohesion ( nor any increase of cohesion ) takes place ; a certain temperature and strain are therefore not alone sufficient to produce it ; the condition of cooling must also be included . The phenomena which occur during cooling are not the exact converse of those which take place during heating . The phenomenon of elongation of iron wire during the process of cooling evidently lies within very narrow limits ; it could only be obtained ( with the particular battery employed ) with wires about 21'5 centimetres ( =8-7 inch ) long , and about 0-65 millimetre ( =Nos . 22 & 23 of ordinary wire-gauge ) thick , having a strain upon them of 10 ounces or upwards ; with a weaker battery the phenomenon could only be obtained by employing a shorter and thinner wire . The experiment may easily be verified in a simpler manner by stretching an iron wire about 1.0 millimetre diameter between two fixed supports , keeping it in a sufficient and proper degree of tension by means of an elastic band , then heating it to full redness by means of a row of Bunsen 's burners , and , as soon as it has stretched somewhat , suddenly cutting off the source of heat . In some experiments of this kind , with a row ( 42 centimetres long ) of 21 burners and a row ( 76 centimetres long ) of 43 burners , and the wire attached to a needle with index-plate , as in the figure , conspicuous effects were obtained ; but the momentary elongation was relatively much less ( in one instance g of the length of the heated part ) than when a battery was employed , apparently in consequence of the wire being less intensely heated . A large number of experiments were made with wires of palladium , platinum , gold , silver , copper , lead , tin , cadmium , zinc , brass , german-silver , aluminium , and magnesium ( wire and ribbon ) , diminishing the length and thickness of the wire in each case , and adjusting the tension until suitable temperature and strain were obtained ; but in no instance could a similar molecular change to that observed in iron be detected . Palladium and platinum wires of different lengths , thickness , and degrees of strain were examined at various temperatures , up to that of a white heat ; but no irregularity of cohesion , except that of gradual softening at the higher temperatures , was observed ; they instantly contracted with regular action on stopping the current . Several gold wires were similarly examined at different temperatures up to that of a full red heat ; no irregularity occurred either during heating or cooling ; but little tension ( about 4 ounces ) was applied , on account of the weak cohesion of this metal . Wires of silver similarly examined would only bear a strain of about 2 ounces , and a temperature of feeble red heat visible in daylight ; no irregularity of elongation or contraction occurred during heating and cooling . By employing exactly the proper temperature and strain , a very interesting phenomenon was observed ; the wire melted distinctly on its surface without fusing in its interior , although the surface was most exposed to the cooling influence of the air ; this occurred without the wire breaking , as it would have done if its interior portion had melted ; the phenomenon indicates the passage of the electricity by the surface of the wire in preference to passing by its interior . Wires of copper expanded regularly until they became red-hot ; they then contracted slightly ( notwithstanding the strain applied to them ) , probably in consequence of a cooling effect of increased radiation produced by the oxidized surface , as a similar effect occurred with brass and germansilver ' . On stopping the current the wire contracted without manifest irregularity . Wires of lead and tin were difficult to examine by this method , on account of their extremely feeble cohesion and the low temperature at which they softened : wires about 1'63 millimetre diameter , 25-5 centimetres long ( with a strain upon them of about one ounce ) , were employed ; no irregularity was detected . Wires of cadmium from 1'255 millimetre to 1 525 millimetre thick , and 24'2 centimetres long ( with a strain of two ounces ) , exhibited a slight irregularity of expansion at the lower temperatures ; they elongated , and also cooled , with extreme slowness , more slowly than those of any other metal . Wires of zinc exhibited a slight irregularity of expansion , like those of cadmium ; the most suitable ones were about 25 centimetres long and 1'2 millimetre in diameter , with a strain of 10 ounces . Wires of brass and german-silver , when heated to redness , ' This supposition does not agree with the results obtained with iron wire , which also oxidizes freely . behaved like those of copper in expanding regularly until a maximum was attained , and then contracting slightly to a definite point whilst the battery remained connected ; on stopping the current they contracted without irregularity . When examined at lower temperatures , with a greater degree of strain , no irregularity was observed . Various wires of aluminium were examined ; the most suitable was one 0'88 millimetre thick , 20'4 centimetres long , with a strain of 12 ounces ' ; no irregularity was observed at any temperature below redness ; aluminium expanded and cooled very slowly , but less so than cadmium . Various wires and ribbon of magnesium were also examined below a red heat , but no irregularity of cohesion , except that due to gradual softening by heat , was detected . All the metals examined exhibited gradual loss of cohesion at the higher temperatures if a suitable strain was applied to develope it . It is probable that if the fractions of time occupied by the needle in passing over each division of the index were noted , and the wire perfectly protected from currents of air , small irregularities of molecular or cohesive change might be detected by this method ; cadmium and zinc offer a prospect of this kind . This molecular change would probably be found to exist in large masses of wrought iron as well as in the small specimens of wire which I have examined , and would come into operation in various cases where those masses are subjected to the conjoint influence of heat and strain , as in various engineering operations , the destruction of buildings by fire , and other cases .

112388

3701662

On the Development of Electric Currents by Magnetism and Heat

265

267

Proceedings of the Royal Society of London

G. Gore

fla

6.0.4

http://dx.doi.org/10.1098/rspl.1868.0041

proceedings

http://corpora.clarin-d.uni-saarland.de/surprisal/6.0.3/?id=112388

10.1098/rspl.1868.0041

http://www.jstor.org/stable/112388

Electricity

Measurement

Electricity

IV . " On the Development of Electric Currents by Magnetism and Heat . " By G. GORE , F.R.S. Received November 14 , 1868 . I have devised the following apparatus for demonstrating a relation of current electricity to magnetism and heat . AA , fig. 3 , is a wooden base , upon which is supported , by four brass clamps , two , B , B , on each side , a coil of wire , C ; the coil is 6 inches long , 1 inch external diameter , and 3 of an inch internal diameter , lined with a thin glass tube ; it consists of 18 layers , or about 3000 turns of insulated copper wire of 0'415 millirn . diameter ( or size No. 26 of ordinary wiregauge ) ; D is a permanent bar-magnet held in its place by the screws E , E , and having upon its poles two flat armatures of soft iron , F , F , placed edgewise . Within the axis of the coil is a straight wire of soft iron , G , one end of which is held fast by the pillar-screw H , and the other by the cylindrical binding-screw I ; the latter screw has a hook , to which is attached a vulcanized india-rubber band , J , which is stretched and held secure by the hooked brass rod K and the pillar-screw L. The screw H is surmounted by a small mercury cup for making connexions with one pole of a voltaic battery , the other pole of the battery being secured to the pillar-screw M , which is also surmounted by a small mercury cup , and is connected with the cylindrical binding-screw I by a copper wire with a middle flattened portion 0 to impart to it flexibility . The two ends of the fine wire coil are soldered to two small binding-screws at the back ; those screws are but partly shown in the sketch , and are for the purpose of connexion with a suitable galvanometer . The armatures F , F are grooved on their upper edges , and the iron wire lies in these grooves in contact with them ; and to prevent the electric current passingo through the magnet , a small piece of paper or other thin non-conductor is inserted between the magnet and one of the armatures . The battery employed consisted of six Grove 's eleinents ( arranged in one series ) , with the immersed portion of platinum plates about 5 inches by 3 inches ; it was suiciently strong to heat an iron wire 1'03 millim. diameter and 20'5 centimus . long to a low red heat . By making the contacts of the battery in unison with the movements of the galvanometer-needles , a swing of about 12 degrees of the needles each way was obtained . The galvanometer was not a very sensitive one ; it contained 192 turns of wire . Similar results were obtained with a coil 8 inches long and 14 inch diameter containing 16 layers , or about 3776 turns of wire of 0'415 millinm . diameter ( or No. 26 of ordinary wire-gauge ) , and a permanent magnet 10 inches long . Less effects were obtained with a 6-inch coil consisting of 40 layers , or about 10,000 turns of wire 0'10 millim. diameter , also with several other coils . The maximum effect of 12 degrees each way with six Grove 's cells in one series was obtained when the wire became visibly red-hot , and this occurred with an iron wire 1*03 millilm . diameter ( or No. 19 of ordinary wire-gauge ) ; but when employing ten such cells as a double series of five , the maximum effect was then obtained with an iron wire ( size Nos. 17 and 18 ) 1 '28 to 1*58 millirn . diameter , the deflection being 16 degrees each way . By employing a still thicker wire and a battery of greater heating-power still greater effects were obtained . The galvanometer was placed about 8 ( and in some instances 12 ) feet distant from the coil . A reversal of the direction of the battery current did not reverse or perceptibly affect the current induced in the coil ; but by reversing the poles of the magnet , the direction of the induced current was reversed . On disconnecting the battery , and thereby cooling the iron wire , a reversed direction of induced current was produced . By substituting a wire of pure nickel 24'5 centims. long and 2'1 millims. diameter , induced currents were obtained as with the iron , but they were more feeble . No induced current occurred by heating the iron wire if the magnet was absent ; nor was any induced current obtained if the magnet was present and ' wires of palladium , platinum , gold , silver , copper , brass , or german-silver were heated to redness instead of iron wire ; nor with a rod of bismuth 3'63 millims. diameter enclosed in a glass tube and heated nearly to fusion ; it is evident , therefore , that the axial wire must be composed of a magnetic metal . No continuous current ( or only a very feeble one ) was produced in the coil by continuously heating the iron wire . In several experiments , by employing twelve similar Grove 's elements as a double series of six intensity , an iron wire 1 56 millim. diameter was made bright red-hot ; and by keeping the current continuous until the galvanometer-needles settled nearly at zero , and then suddenly disconnecting the battery , the needles remained nearly stationary during several seconds , and then went rapidly to about 10 : this slow decline of the current during the first few seconds of cooling was probably connected with the " momentary molecular change of iron wire " during cooling which I have described in the preceding paper . The irregularity of movement of the needles did not occur unless the wire was bright red-hot , a condition which was also necessary for obtaining the molecular change . The direction of the current induced by heating the iron wire was found by experiment to be the same as that which was produced by removing the magnetfrom the coil ; therefore the heat acted simply by diminishing the magnetism , and the results were in accordance with , and afford a further confirmation of , the general law , that wherever there is increasing or decreasing magnetism , there is a tendency to an electric current in a conductor at right angles to it .

112389

3701662

On Fossil Teeth of Equines from Central and South America, Referable to Equus conversidens, Equus tau, and Equus arcidens. [Abstract]

267

268

Proceedings of the Royal Society of London

Professor Owen

abs

6.0.4

proceedings

http://corpora.clarin-d.uni-saarland.de/surprisal/6.0.3/?id=112389

http://www.jstor.org/stable/112389

Anatomy 2

Biography

Anatomy

I. " On Fossil Teeth of Equines from Central and South America , referable to Equus conversidens , Equus tau , and Equus arcidens . " By Professor OWEN , F.R.S. Received November 17 , 1868 . ( Abstract . ) The author , referring to his previous paper on the Equine fossil remains from the cavern of Bruniquel , finds , in the preliminary illustrations of the dental characters of existing species of the Horse-kind , the requisite and much-needed basis of comparison for the determination of other fossils of the Solidungulate group , and he devotes the present paper to the elucidation of those which have reached him from Central and South America . He commences by referring to the type-specimens of teeth , from two localities in South America , on which he founded the species E. curvidens , describing it ( in 1840 ) " as one coexisting with the Megatherium , Toxodon , &c. in that continent , and which had become extinct at a prehistoric period . " -He then proceeds to describe more complete evidences of the dentition of an allied extinct Horse discovered by Don Antonio del Castillo , mining engineer , in newer Tertiary deposits of the Valley of Mexico . Besides repeating the originally described characters of the curvature of the grinder , with a certain resemblance of enamel-pattern to the grindingsurface of the E. curvidens , they show a greater degree of curvature of the alveolar series of the upper jaw , with corresponding greater convergence of the right and left molar series toward the fore part of the palate , than in any previously described species of Equus . Deciduous teeth of the Equus conversidens from the same deposits of the Valley of Mexico are described . Having determined these corroborative and distinctive characters of aboriginal and now extinct American horses , the author remarks , " It is unlikely , seeing the avidity with which the Indians of the Pampas have seized and subjugated the stray descendants of the European horses introduced by the Spanish 'Conquistadors ' of South America , and the able use the nomad natives make of the multitudinous progeny of those war-horses at the present day , that any such tameable Equine should have been killed off or extirpated by the ancestors of the South-American aborigines . " If , therefore , the fossil Equine teeth do belong , as the author deems that he has proved , to a species distinct from Equus caballus , Linn. , " the circumstances of their discovery , and the fact of the extinction of such ( curvident and conversident ) species of Horse would point to some other cause than that of man 's hostility to so useful an animal , and such doubt as to extinction by human means may then be extended to the contemporaries of the Equus curvidens and E. conversidens , viz. Megatherium , Mylodon , Toxodon , Nesodon , Macrauchenia , Glyptodon , Mastodon , &c. " The author next proceeds to describe fossil teeth from the upper and lower jaws , discovered by Don A. del Castillo in the same deposits of the Valley of Mexico , and referable to a third species of Equus , viz. Equus tau , Ow . Finally the author proceeds to the description of some fossil upper molar teeth from Pampas deposit , in the bed of a brook falling into the " Arroyo Negro " near Paysandi , Monte Video , showing characters more decisively distinct from any other known species of Equus than have hitherto been described . The degree of curvature of the upper molar teeth exceeds that in Equus curvidens , and equals that in Toxodon ; and the specific name " arcidens " is accordingly proposed for this aboriginal American species of Horse . It is compared with so much of the characters as have been given by Dr. Lund of his Equus neogceus and E. principalis from Brazilian caverns ; and the differences from all other Equines which these species and the E. arcidens agree in presenting lead the author to view them as having , like the liippotheritum of Kaup , formed a generic group in the Equide , for which he proposes the name Hipplidion . The fossil teeth of IH . arcidens were found associated with remains of Meyacthelrium and Glyptodon in the above-named locality ; the specimens were transmitted and presented to the British Museum ( in 1867 ) by the lion . W. G. Lettsom , Her Britannic Majesty 's Minister at Monte Video . This paper is illustrated by drawings of the specimens described .

112390

3701662

Compounds Isomeric with the Sulphocyanic Ethers.--III. Transformations of Ethylic Mustard-Oil and Sulphocyanide of Ethyl

269

276

Proceedings of the Royal Society of London

A. W. Hofmann

fla

6.0.4

http://dx.doi.org/10.1098/rspl.1868.0043

proceedings

http://corpora.clarin-d.uni-saarland.de/surprisal/6.0.3/?id=112390

10.1098/rspl.1868.0043

http://www.jstor.org/stable/112390

Chemistry 2

Thermodynamics

Chemistry

II . " Compounds Isomeric with the Sulphocyanic Ethers.--III . Transformations of Ethylic Mustard-oil and Sulphocyanide of Ethyl . " By A. W. HOPMANN , Ph. D. , M.D. , LL. D. , F.R.S. Received November 19 , 1868 . In the present paper I beg leave to communicate to the Royal Society some experiments made for the purpose of testing the views which I have lately* advanced respecting the constitution of the mustard-oils and the sulphocyanic ethers isomeric with them . These experiments were exclusively performed in the ethyl-series . Not only is ethylamine much nor readily prepared than the methyl-base , but the elucidation of the metamorphoses examined was not unfrequently facilitated by the selection of compounds for the construction of which the material had simultaneously been taken from the monocarbonand dicarbon-series . Action of Hydrogen in condicione nascendi upon Ethylic Mustard-oil . I have , in the first place , examined this reaction , because experiments performed by M. Oeserf have already supplied some information on the behaviour of allylic mustard-oil under analogous conditions . On adding zinc and hydrochloric acid to an alcoholic solution of ethylic mustard-oil an evolution of sulphuretted hydrogen becomes at once perceptible ; it soon diminishes , but continues for several days . In the several stages of this process the gas evolved was examined for carbonic acid ; but not a trace of this gas could be detected . As soon as the evolution of sulphuretted hydrogen has ceased , the liquid is found to contain a large quantity of fine white needles ; when submitted to distillation , it yields the same body , which , passing over with the vapour of water and alcohol , collects in the form of white crystals upon the water in the receiver . If the residue be now allowed to cool , an additional quantity of the crystalline compound is deposited . Analysis and examination of the properties of these crystals have identified them with the substance generated by the action of sulphuretted hydrogen upon methylic aldehyde , to which I assigned the formula C H , S , stating at the same time that a higher molecular weight might possibly be found to belong to this sulphaldehyde of the methyl-series . On adding strong soda-lye to the liquid containing chloride of zinc , from which the crystals have been separated , until the oxide at first precipitated is redissolved , a strongly alkaline layer collects on the surface of the solution , which may be considerably augmented by the intervention of a small quantity of alcohol . This layer was removed and separated from adhering , soda by distillation . When the very volatile distillate was saturated with ' Proceedings , vol. xvii . p. 67 . t Ann. Chem. Pharm. vol. cxxxiv . p. 7 . + Proceedings of the Royal Society , vol. xvi . p. 156 . x hydrochloric acid and mixed with perchloride of platinum , the well-known hexagonal tables of the ethylamine-platinum-salt were at once deposited . The mother-liquor was found to contain a second salt , much more soluble both in water and alcohol , which was precipitated by ether . By recrystallization it was obtained in magnificent orange-red needles , which on analysis exhibited the composition of the platinum-salt of methyl-ethylamine . The interpretation of these observations presents no difficulty . There are obviously two parallel reactions to be distinguished . In the first place ( and this is doubtless the principal reaction ) there are two molecules of hydrogen inserted at the place in which the two compounds of ethylic mustard-oil are joined together-this insertion giving rise to the formation , on the one hand , of ethylamine , the mother-compound of the mustard-oil , and on the other hand , of methylic sulphaldehyde , the hydrogen-derivative of bisulphide of carbon . C2 II N+ 21-1= 2 IIt }N+ CHI S. Or the substance , under the powerful influence of hydrogen , splits in another place ; three molecules of hydrogen penetrate into the fragment of the bisulphide , and the products of this secondary and subordinate transformation are methyl-ethylamine and sulphuretted hydrogen . ( P HT 1C H3 CH }N +3H 1H= 21-5 N+ 12 S. Action of Hydrogen in condicione nascendi on Sulphocyanide of Ethyl . On treating the isomeric sulphocyanide of ethyl with zinc and hydrochloric acid , sulphuretted hydrogen is also evolved ; it contains , however , so abundant an admixture of mercaptan , that the brown spot of sulphide of lead appearing upon lead-paper held over the mouth of the flask in which the reaction takes place is surrounded by a yellow ring of mercaptide of lead . In order to examine the gases evolved , they were passed in the first place through lime-water , then through hydrate of sodium , and lastly through acetate of lead and perchloride of mercury ; ultimately they were collected in a gas-holder . The lime-water remained clear ; hence the gases did not contain carbonic acid ; the liquid , however , was saturated with hydrocyanic acid . By the hydrate of sodium large quantities of sulphuretted hydrogen and ethyl-mercaptan were fixed ; the two metallic salts , lastly , retained some ethylic mercaptan and ethylic sulphide . The gas collected in the gas-holder was transmitted once more through limewater and sodic hydrate , and then passed over a layer of incandescent oxide of copper . Toether with water , large quantities of carbonic acid were thus produced , proving that the hydrogen contained a carbonated gas , which I do not hesitate to consider marsh-gas , although verification of this assumption , by transformation of the hydrocarbon into tetrachloride , has still to be adduced . On distilling the liquid , when the evolution of sulphuretted hydrogen has ceased , there are evolved , together with a small quantity of the latter gas , ethylic mercaptan , sulphide and , under certain conditions , even bisulphide of ethyl , these several compounds being easily recognized by their special reactions . The residue , when heated with hydrate of sodium , disengages abundant quantities of ammonia , and also an appreciable amount of methylamine . If these varied results be taken into consideration , the action of nascent hydrogen upon sulphocyanide of ethyl would appear to be a very complicated process . The principal transformation of the body is nevertheless extremely simple . Here , again , the point of junction of the two components of sulphocyanide of ethyl is the vulnerable part . A molecule of hydrogen entering at this point , between the sulphur and the carbon , the compound separates into hydrocyanic acid on the one hand and ethylic mercaptan on the other . C IS+HIH=IHNC+ C2 }S . All the other products belong to secondary reactions . In contact with hydrogen , hydrocyanic acid is converted into methylamine . HCN C+2H= IH N.:N C4-2HH== HI [ N 1-1 J Sulphide of ethyl , ammonia , marsh-gas , and sulphuretted hydrogen may be looked upon as resulting from a further and deeper destruction of the molecule of sulphocyanide of ethyl under the influence of hydrogen . 2[C N S]+8HIHC= I-I S +21N+2N2H , C+H S. Action of Hydrogen in condicione nascendi upon Allylic Mustard-oil . According to the experiments of M. Oeser already quoted , the mustardoil par excellence , when submitted to nascent hydrogen , would appear to undergo a transformation different from that of its ethylic congener . M. Oeser represents the metamorphosis of the allyl-compound by the following equation : C. -J }N+2Hi Oi=C }N+H2S+002 . This equation , however , obviously represents no reduction process ; the nascent hydrogen . has no share in this reaction , which is simply accomplished under the influence of the elements of water . To clear up this anomaly , the experiments above described were repeated in the allyl-series . On treating mustard-oil with zinc and hydrochloric acid , an abundant evolution of sulphuretted hydrogen was observed , but ( under the conditions , at all events , in which I repeatedly performed this experiment ) the gas did not contain a trace of carbonic acid ; on the other hand , large quantities of the sulphaidehyde of the methyl-series were inva riably obtained . If the spirit which is employed in dissolving the mustardoil to be reduced be dilute , a fine crystallization of the sulphaldehyde is frequently observed after the lapse of a few hours . Together with this compound allylamine is generated in large proportion . The principal reaction is thus seen to be exactly the same as with ethylic mustard-oil . C6 } N+2 H = 3 } N+C H S. The sulphuretted hydrogen would therefore likewise belong to a secondary reaction . Vainly , however , have I endeavoured to trace in the motherliquor of the allylamine-platinum salt the existence of the platinum compound of a second base-of methyl-allylanine for instance ; though working on a rather large scale , I was unable to detect even a trace of such a compound . The origin of the sulphuretted hydrogen , however , could not be doubtful . In the gas evolved during the reaction , a large amount of a gaseous hydrocarbon ( very probably marsh-gas ) was present , as could be easily proved by burning the gas , after an appropriate purification , with oxide of copper . c -I5 NN+4I-= C3 , HI NH , + IS . Action of Hydrogen in condicione nascendi upon Hydrosulphocyanic Acid . It would have been strange if in the course of these researches I had omitted to investigate the action of zinc and hydrochloric acid upon sulphocyanide of potassium . The result of this experiment could scarcely.be doubtful-evolution of sulphuretted hydrogen in torrents , copious separation of sulphuretted methylic aldehyde , in the residue ammonia and methylamine . The reaction is not without interest , since the hydrosulphocyanic acid liberated by the hydrochloric acid exhibits the principal metamorphosis both of mustard-oil and the isomeric sulphocyanide of ethyl . } UN +2 H= -3 N+ OC S , ]t S S+H ! I : =H CN+}t2S . C NN 2 Hydrocyanic acid , it is true , is not directly observed in this case ; but we meet with its hydrogen-derivative , methylamine . Together with the behaviour of these bodies under the influence of reducing agents , I have studied the action of water and ot acids upon the mus- . tard-oils and the ethers isomeric with them . Action of Water and lydrocdloric Acid upon EthZylic lIustard-oil . When exposed in sealed tubes together with water to a temperature of 2000 for eight or ten hours , ethylic mustard-oil splits up into ethylamine , carbonic acid , and sulphuretted hydrogen . The idea naturally suggests itself that two water-molecules act in succession . Under the influence of the first , ethylic mustard-oil would yield ethylamine and sulphoxide of carbon . CS }N+H20= I-2 N+CSO . The action of the second would transform the rather unstable sulphoxide of carbon into carbonic acid and sulphuretted hydrogen . 080 +20=0 O2+11 , S. The decomposition remains essentially the same if , instead of water , hydrochloric acid be employed . The reaction , however , is very considerably accelerated ; in fact an hour 's digestion at 100 ? is sufficient to split up the mustard-oil right off into ethylamine , carbonic acid , and sulphuretted hydrogen . Action of Wcater and Hydrochloric Acid upon Sulphocyanide of Ethyl . Water , even at rather high temperatures , acts but very slowly upon sulphocyanide of ethyl . Even at 200 ? , after several days ' digestion , very appreciable quantities of the compound had remained unaltered . The reaction , as might have been expected , proceeds much more rapidly in the presence of concentrated hydrochloric acid . The ultimate products of transformation are sulphuretted hydrogen , sulphide of ethyl , carbonic acid , and ammonia . I{ere , again , we have by no means to deal with direct products of decomposition . Probably the compound , with the cooperation of one molecule of water , changes in the first place into ethyl-mercaptan and cyanic acid . 0,51 } S+0= 02 { 5 } S+C IINO . CN f2 tt Under the influence of a second molecule of water , cyanic acid yields ammonia and carbonic acid . C HN O -+ 20 =t 1N+ 0O . Sulphide of ethyl and sulphuretted hydrogen , lastly , have to be looked upon as products of transformation of ethylic mercaptan . 2 [ C2 } s2 H=D : } 4+ 1 8 . Action of Water and HIydrochloric Acid upon Allylic Mustard-oil . Whilst engaged with these researches , I have incidentally made also some experiments upon the mustard-oil par excellence . As might have been expected , when submitted to the action of water at a high temperature , and more especially in the presence of hydrochloric acid , allylic mustard-oil splits up into allylamine , carbonic acid , and sulphuretted hydrogen . CS N+2H,20 = 03 N+C 02+I2 S ' Simultaneously , however , another reaction takes place , which up to the present moment I have not yet been able to elucidate . Together with atios of allylamine there is formed a-second liquid base having a very high boilingpoint , nvhich yields an amorphous platinum-salt . It remains behind as an oily layer , not volatilizable with the vapour of water , when the product of the action of hydrochloric acid upon mustard-oil , for the purpose of purifying the allylamine , is distilled with soda . Action of Sulphuric Acid upon Et , hylic Mustard-oil . Dilute sulphuric acid acts like water and hydrochloric acid . Highly characteristic , however , is the behaviour of ethylic mustard-oil towards concentrated sulphuric acid . The two liquids mix with considerable evolution of heat , and after a few momeents a powerful disengagement of gas takes place , which , if the reaction be promoted by the application of heat , may be increased to explosive violence . The gas evolved is inflammable , and burns with a blue fame . It has a peculiar odour , essentially different from that of bisulphide of carbon , or of sulphuretted hydrogen ; from the latter it differs , moreover , by its having no action upon lead-paper . These are the characteristics of sulphoxide of carbon , lately discovered byvonThan . The residue contains sulphate of ethylamine . C 211 N+ 1N 0 IJ 2}NC SO . In contact with water , more especially in the presence of an alkali , sulphoxide of carbon is converted into carbonic acid and sulphuretted hydrogen . Treatment of ethylic mustard-oil with concentrated sulphuric acid thus enables us to arrest halfway the transformation which is accomplished under the influence of water . Action of Sulpluric Acid lupon Sulphoocyanide of Ethyl . Dilute sulphuric acid acts but slowly upon sulphocyanide of ethyl ; concentrated acid , on the other hand , attacks the compound with great energy , powerful evolution of heat and disengagement of carbonic and sulphurous acids taking place . On distilling the liquid after addition of water , sulphuretted ethereal products are volatilized ; the deep-brown residue , when treated with lime , yields abundance of ammonia . In the presence of these observations , it appeared very probable that the action of sulphuric acid resembled that of water and of hydrochloric acid , and that in this case likewise the ethylgroup was eliminated in combination with sulphur . Interesting experiments on the action of sulphuric acid upon sulphocyanide of ethyl , lately communicated to the Chemical Society of Berlin* by Messrs. Schmitt and Glutz , have indeed verified this assumption ; but these experiments have proved , moreover , that the reaction , exactly as in the case of the transformation of ethylic mustard-oil , is capable of stopping at an intermediate stage , inasmuch as the above-named chemists have succeeded in isolating from the products of the reaction a compound isomeric with xanthic ether . Accordingly the metamorphosis of sulphocyanide of ethyl under the influence of sulphuric acid would appear to be accomplished in the following two phases:2[C } S ] +3 I2 0 cS , 0o 2H , N+CO , C2 C S2 20 5 S+ Ca 20 12 +11 C2 H5 ~ -2 It is true Messrs. Schmitt and Glntz , when submittinfg their ether to the action of water , obtained mercaptan , whilst , according to my observations , the products of decomposition of sulphocyanide of ethyl with hydrochloric acid are sulphide of ethyl and hydrosulphuric acid . But since two molecules of mercaptan contain the elements of one molecule of sulphide of ethyl and one molecule of sulphuretted hydrogen , the final products of decomposition of sulphocyanide of ethyl by water and by hydrochloric and sulphuric acids are virtually the same . Actio ? n of Sulphuric.4cid upon Allylic uetstard-oil.:Mustard-oil par excellence , when treated with sulphuric acid , as might have been expected , exactly imitates the behaviour of the ethyl-compound . Sulphoxide of carbon is evolved with effervescence ; the residue contains sulphate of allylamine . C HIN +IO=C- } N+CSO . The reaction proceeds with the utmost regularity and precision . The liquid scarcely becomes coloured ; mixed with water and distilled with hydrate of sodium , it yields abundance of perfectly pure allylamine . It would be difficult to imagine a more elegant and expeditious process for preparing this interesting base in a state of perfect purity . Allylamine thus obtained was identified by the analysis of the platinum-salts , the preparation of the terribly smelling allyl-formonitril , which I shall describe in another paper , and , lastly , by its retransformation into mustard , oil , according to the method described in my last paper* . Also phenylic and tolylic mustard-oils exhibit an analogous behaviour with sulphuric acid ; in these cases likewise sulphoxide of carbon is evolved ; the base , however , does not remain as sulphate , but in the form of an amine-sulphate in the residue . CIN+ HS C6 H } N SO +C S O. Even phenyl-sulphocarbamide , as well as its homologues and analogues , is changed in this sense . * ' Proceedings of the Royal Society , vol. xvii . p. 67 . ( CC6^-)2 r H1 CS }N942 HS O=2L 6 1t , S ) O+ 4-2 0S 0 . In the presence of an excess of sulphuric acid , the water-molecule eliminated is without influence upon sulphoxide of carbon . Action of Nitric Acid upon Ethylic IMustard-oil . I have still to say a few words respecting the behaviour of ethylic mustard-oil with nitric acid , although the experience acquired in the several experiments I have described could not possibly leave any doubt on the nature of this reaction . Here , again , the ethyl-group separates , united with nitrogen , in the form of ethylamine , from the molecule , while the carbon and sulphur of the group CS are burnt and eliminated in the form of carbonic and sulphuric acids . The same deportment is exhibited by the homologues of ethylic mustard-oil , and also by the allylcompound . The products which are generated by the action of nitric acid upon sulphocyanide of ethyl and its homologues are known . According to the experiments of Muspratt , sulphocyanide of ethyl yields with nitric acid ethyl-sulphurous acid , 2 . } SO3 . Accordingly there is also in this case elimination of the ethyl-group , in the form of a sulphur-compound . In conclusion it may be stated that I have examined the action of several other chemical agents , and more especially of the alkali-metals and their hydrates , on the two classes of isomeric compounds . Most of the experiments , however , which I have made in this direction are not yet completed , and I will here only briefly allude to the elegant transformation which sulphocyanide of ethyl suffers in contact with metallic sodium . A powerful reaction ensues , cyanide of sodium and sulphide of ethyl being formed . 2 C2 } S+NaNa=2NaCN+ C2 H } It affords me great pleasure to mention the energy and intelligence with which Dr. Bulk has assisted me during the performance of the experiments described in this paper . My best thanks are due to him .

112392

3701662

On the Structure and Development of the Skull of the Common Fowl (Gallus domesticus). [Abstract]

277

280

Proceedings of the Royal Society of London

W. Kitchen Parker

abs

6.0.4

proceedings

http://corpora.clarin-d.uni-saarland.de/surprisal/6.0.3/?id=112392

http://www.jstor.org/stable/112392

Anatomy 1

Biography

Anatomy

I. " On the Structure and Development of the Skull of the Conmmon Fowl ( Gallus domesticus ) . " By W. KITCHEN PARKER , F.R.S. Received November 25 , 1868 . ( Abstract . ) In a former paper ( Phil. Trans. 1866 , vol. clvi . part 1 , pp. 113-183 , plates 7-15 ) I described the structure and development of the skull in the Ostrich tribe , and the structure of the adult skull of the Tinamou-a bird which connects the Fowls with the Ostriches , but which has an essentially struthious skull . That paper was given as the first of a proposed series , the subsequent communications to be more special ( treating of one species at a time ) and carrying the study of the development of the cranium and face to much earlier stages than was practicable in the case of the struthious birds . Several years ago Professor HIuxley strongly advised me to concentrate my attention for some considerable time on the morphology of the skull of the Common Fowl ; that excellent advice was at length taken , and the paper now offered is the result . A full examination of the earlier conditions of the chick 's skull has cost me much anxious labour ; but my supply of embryonic birds ( through the kindness of friends)* was very copious , and in time the structure of the early conditions of the skull became manifest to me . The earliest modifications undergone by the embryonic head are not given in this paper : they are already well known to embryologists ; and my purpose is not to describe the general development of the embryo , but merely the skeletal parts of the head . These parts are fairly differentiated from the other tissues on the fourth day of incubation , when the head of the chick is a quarter of an inch ( 3 lines ) in length ; this in my paper is termed the " first stage . " The next stage is that of the chick with a head from 4 to 5 lines in length , the third 8 to 9 lines , and so on . The ripe chick characterizes the " fifth stage ; " and then I have worked out the skull of the chicken when three weeks , two months , three months , and from six to nine months old , the skull of the aged Fowl forming the " last stage . " During all this time ( from their first appearance to their highly consolidated condition in old age ) the skeletal parts are undergoing continual change , obliteration of almost all traces of the composite condition of the early skull being the result-except where there is a hinge , for there the parts retain perfect mobility . Here it may be remarked that although the Fowl is only an approach to what may be called a typical Bird , yet its skull presents a much greater degree of coalescence of primary centres than might have been expected from a type which is removed so few steps from the semistruthious Tinamou , a bird which retains so many of its cranial sutures . The multiplicity of parts in the Bird 's skull at certain stages very accurately represents what is persistent in the Fish , in the Reptile , and to some degree in certain Mammals ; but the skull at first is as simple as that of a Lamprey or a Shark , and , in the Bird above all other Vertebrates , reverts in adult age to its primordial simplicity-all , or nearly all , its metamorphic changes having vanished and left no trace behind them . Although in this memoir I have no business with the Fish , yet all along I have worked at the Fish equally with the Bird , the lower type being taken as a guide through the intricacies of the higher ; and here the Car* Dr. Murie is especially to be thanked for his most painstaking kindness in this respect . tilaginous and the Osseous Fishes are never fairly out of sight . The Reptile , and especially the Lizard , has been less helpful to me , on account of its great specialization . On the fourth day of incubation the cranial part of the notocllord is twothirds the length of the primordial skull , but it does not quite reach the pituitary body ; it lies therefore entirely in the occipito-otic region . The fore part of the skull-base extends horizontally very little in front of the pituitary space ; this arises from the fact that the " mesocephalic flexure " has turned the " horns of the trabecule " under the head . Thus at this stage the nasal , oral , and postoral clefts are all seen on the under surface of the head and neck of the chick . At this time the facial arches have begun to chondrify ; but only the quadrate , the Meckelian rod , and the lower thyro-hyal are really cartilaginous ; the other parts are merely tracts of thickened blastema or indiferent tissue . In the second stage an orbito-nasal septum has been formed ; the " horns of the trabeculem " have become the " nasal alse , " and an azygous bud of cartilage has grown downwards between them ; this is the " prenasal " . or snout cartilage ; it is the axis of the intermaxillary region . At the commencement of this second stage the primordial skull stands on the same morphological level as that of the ripe embryo of the Sea-turtle ; at the end of this stage it has become struthioius ; and now parosteal tracts ( the angular , surangular , dentary , &c. ) appear round the mandibular rod . In this abstract I shall not trace the changes of the skull any further , but conclude with a few remarks on the nomenclature of certain splints , and as to the nature of the great basicranial bones . Some years ago I found that certain birds ( for instance the Emeu ) possessed an additional maxillary bone on each side ; knowing that the socalled " turbinal " of the Lizard and Snake was one of the'maxillary series , I set myself to find the homologies of these splints . Renaming the reptilian bones " preevomers , " on account of their relation to the vomer , and supposing the feeble maxillaries of the Bird to represent them , I considered that the true maxillaries were to be found in those newly found cheekbones of the Emeu and some other birds . After discussion with Professor Huxley I have determined to drop the term " prmvomer , " and to call the supposed turbinal of the Lizard " septomaxillary , " and the additional bone in the Bird 's face " postmaxillary . " In many Birds , but not in the Fowl , the " septo-maxillary " is largely represented-not , however , as a distinct osseous piece , but as an outgrowth of the true maxillary . With regard to the basicranial bones , I have now satisfied myself that the " parasphenoid " of the Osseous Fish and the Batrachian reappears in the Bird as three osseous centres-all true " parostoses , " as in the single piece of the lower types ; these three pieces are , the " rostrumn of the basisphenoid and the two " basitemporals . " These three centres rapidly coalesce to form one piece , the exact counter part of the Ichthyic and Batrachian bone ; but just as this coalescence begins , ossification proceeds inwards from these " parostoses , " and affects the overlying cartilage , the cartilage of the basisphenoidal region having no other osseous nuclei . This process of the extension inwards of ossification from a splint-bone to a cartilaginous rod or plate I have already called osseous grafting " * . In my former paper the basisphenoidal " rostrum " and " basitemporals " were classed with the endoskeletal bones ; they will in the present paper be placed in the parosteal category , in accordance with their primordial condition . By the careful following out of these and numerous other details I have corrected and added to my previous knowledge of the early morphological conditions of the Bird 's cranium , and at the same time , I trust , have contributed to an enlarged and more accurate conception of the history and meaning of the Vertebrate skull in general .

112393

3701662

Determinations of the Dip at Some of the Principal Observatories in Europe by the Use of an Instrument Borrowed from Kew Observatory

280

286

Proceedings of the Royal Society of London

Lieut. Elagin

fla

6.0.4

http://dx.doi.org/10.1098/rspl.1868.0046

proceedings

http://corpora.clarin-d.uni-saarland.de/surprisal/6.0.3/?id=112393

10.1098/rspl.1868.0046

http://www.jstor.org/stable/112393

Meteorology

Astronomy

Meteorology

II . " Determinations of the Dip at some of the principal Observatories in Europe by the use of an instrument borrowed from Kew Observatory . " By Lieut. ELAGIN , Imperial Russian Navy . Communicated by BALFOUR STEWART , LL. D. Received February 2 , 1869 . Before I give a short account of the observations and the results deduced from them , I beg to express in the first place my best thanks to Dr. Balfour Stewart , Director of the Kew Observatory , who , having heard of my desire to take the dip at different places , was so kind as to lend me an instrument from the Kew Observatory , also to James Glaisher , Esq. , F.R.S. , &c. , who furnished me with a tripod-stand , which I found to be of great use to me on some stations . I may also remark that , having other duties to perform in obedience to instructions from the Russian Government , I could only devote a portion of my time to the observations of dip . The instrument I had from Kew Observatory was one of Barrow 's DipCircles , firnished with two 32-inch needles in the form generally used at the Observatory . The Dip-Circle used had been in use for some time at the Kew Observatory , until , it having been ascertained that one of its needles . was somewhat deteriorated , it was replaced with that now in use . Before I left Kew Observatory I was aware that one of the needles was not as good as might be desired ; but as Mr. Stewart had no other circle suitable for my purpose , I considered it desirable to take this circle . The observations were made according to the instructions of Lieut. General Sabine , given in the 'Admiralty Manual of Scientific Enquiry . ' The following Table I. shows the results of the observations with the circle from Kew ; in it the name of station and the date of observation are * See memoir " On the Shoulder-girdle and Sternum , " :Ray Soc. 1868 , p. 10 . 280 [ Feb. 11 , mentioned in the first column ; in the second column is noted the particular needle used , and whether in the first series of observations the marked end or " N. Pole " was dipping , in which case it has been indicated by the word " direct ; " in the case when the opposite or " S. Pole " was dipping first , it is indicated by the word " reversed . " Under the head of marked end , each of the two results is that formed from the mean of'four sets of observations ; in one of these two results the marked end is made a north pole , and in the other it is a south pole . The headings of the remaining columns explain themselves . TAiBL I. Marked end . Means of Means of Means of Station and Date . Needle . the two separate both N. Pole . S. Pole . results . Needles . Needles . 1868 . Kew Observatory ( Magnetic House ) . dh August 4 2 ... ... ... 5 05 ... ... . 5 23-0 ... ... ... , , 7 20 ... ... ... 5 25 ... ... ... 6 0-0 ... ... ... Royal Observatory , Greenwich ( Magnetic Offices ) . August 7 23-5 ... ... ... 8 3-5 ... ... ... , , 9 23-0 ... ... . . 10 25 ... ... ... , 10 3-5 ... ... ... , 10 22-5 ... ... ... 11 3-5 ... ... ... , 11 22-0 ... ... ... 12 22-0 ... ... . . 13 0-5 ... ... ... 13 25 ... ... ... 14 05 ... ... ... 14 225 ... ... ... 10 23-5 ... ... ... 11 235 ... ... ... 15 05 ... ... ... Norwich ( Mr. Firth 's garden , St. Giles Street ) . August 18 20 ... ... ... 21 3 ' 5 ... ... ... 24 20'5 ... ... ... 21 35 ... ... ... 24 205 ... ... ... ( Mr. Gibson 's garden , B3ethel Street ) . August 24 23-0 ... ... ... , , 24 230 ... ... ... A1 direct . 11 A2 direct . Al direct . A2 direct . , , , , A1 reversed . A1 direct . , , , , A , direct . A1 direct . , , Al direct . A2 delirect . A. direct . A2 direct . 67 59-50 68 1237 68 950 68 4-12 68 9-40 68 10-20 68 9-25 68 625 68 13-12 68 281 68 4-69 67 59 50 67 58-19 68 5-56 68 10-42 68 6-60 68 5-60 68 5-11 68 6-59 68 3-50 67 5875 68 2-12 68 30-8 68 170 68 24-4 68 2250 68 2050 68 7-80 67 50-12 67 57-00 68 0-00 68 3-20 67 58-20 67 51-30 67 44-38 67 49-88:67 47-77 67 47-77 67 52-06 67 52-22 67 49-12 67 55-25 67 55-10 67 44'70 68 0-45 67 49-00 67 55-38 68 0-12 67 57-19 68 13-4 68 5-6 68 10-5 68 13-9 68 18-9 68 68 68 68 68 68 68 3 ' , 12-1 6- : 465 25 25 06 20 20 68 027 67 55-32 68 1-50 67 55-09 67 56-23 67 55-78 67 55-33 67 57-34 68 2-83 68 0-85 67 55-05 68 2-93 67 57-84 67 59-44 67 69-43 67 59-65 68 22-10 68 1130 68 17-45 68 1820 68 1.970 68 23-19 68 9-37 68 16-28 68 23-12 68 1.5-50 68 19-31 o/ 68 2-55 } 68 5-20 67 58-25 67 59-51 }68 } 68 16-93 18-95 0/ }68 3-87 167 58-88 i 68 17.94 68 1628 68 17 86 68 19-31 68 178 II 281 TABLE I. ( continued ) . [ Feb. 11 , Marked end . Means of Means of Means of Station andc Date . Needle . the two separate both N. Pole . S. pole . results . Needles . Needles . 1868 . Brussels Observatory ( Magnetic House ) . dh August 31 23 ... ... ... September 2 0 ... ... ... 4 6 ... ... ... 3 ... ... ... , , 23 ... ... ... , , 2 4-5 ... ... ... , 4 50 ... ... ... Utrecht Meteorological Observatory ( Magnetic House ) . September 9 0 ... ... ... , , 10 0 ... ... ... , , 8 2 ... ... ... , 8 23 ... ... ... Vienna ( Theresianum Garden , Magnetic House ) . September 19 0 ... ... ... , 19 4 ... ... ... , 21 0 ... ... ... , 19 0 ... ... ... , 19 4 ... ... ... 21 0 ... ... ... Munich Observatory ( Magnetic House ) . September 29 22-5 ... ... ... , , 30 3-5 ... ... ... . , 29 35 ... ... ... , 29 22-5 ... ... ... 30 3-5 ... ... ... Paris Observatory ( in the garden close to the Magnetic House ) . October 14 22-5 ... ... , , 16 235 ... ... ... , , 20 1-0 ... ... . . , 14 225 ... ... ... 16 23-5 ... ... ... , 20 1'0 ... ... ... Royal Observatory , Greenwich ( Magnetic Offices ) . December 3 2 ... ... . . , 7 22 ... ... ... 3 2 ... ... ... , , 7 22 ... ... . . A , direct . A2 direct . Al direct . )I A0 , direct . A , direct . , A , direct . A1 direct . A2 direct . A1 direct . A2 direct . A , direct . A2 direct . O 1 : 67 15-2 67 10'55 67 6-7C 67 51C 67 18i1S 67 14-00 67 5-9C 67 50-2 52-4 67 49-8 49-8 63 42-7 47-1 44-0 63 44-3 43-3 42-3 64 64 11-7 19-9 13'0 14-9 12-2 65 55-7 54-6 2-2 65 55'1 53-4 56-95 C6 59-12 66 58-42 67 4-00 67 4-45 67 4-90 67 5'67 67 5-60 67 29-0 30-5 67 38-8 45-4 63 24-8 29-2 29-7 63 405 41-05 36-80 63 53-9 50-1 64 11-0 6-9 11-1 65 36-7 39.8 41-7 65 45.2 48-2 48-55 68 11-0 67 50-0 68 3-5 67 50-0 68 109 ' 68 11 67 514 o1 67 7-17 67 4-48 67 5-35 67 4-75 67 11-50 67 9-83 67 5-75 67 39-6 41-5 67 44-3 47-6 63 33-75 38-15 36-80 63 42-40 42-18 39-60 64 2-8 5'0 64 12-0 10'9 11-7 65 46-2 47-2 51-95 65 50-20 50-80 52-75 67 0-5 67 56-8 67 57-2 67 787 }67 40-6 J 67 46-0 }63 36-2 }63 41-40 } 64 3-9 }64 11-5 65 }65 48-4 51-3 67 58-7 67 57-2 }67 ) 6-77 67 43.3 63 388 }64 7-7 65 4985 J I67 58-0 At the Royal Observatory , Greenwich , I took more observations with one needle than the other ; and the reason for that was , I fonnd that this needle , A1 , gave two , distinctly different positions : for instance , at times I dips were found which differed from those obtained at other times about seven minutes , whilst the other needle , A2 , gave more uniform and satisfactory results ; and this is also the reason I preferred to take the separate means for each needle , and then means of both needles , and to give to them equal weights , notwithstanding the number of observations is greater in one case than the other . The cause of needle A1 giving different positions must be most probably in the axis of the needle , not in the agate plates ; otherwise both needles would indicate the same difference . Having given the results of my observations , I think it desirable to state the precautions I took to obtain the best results . First of all , whilst at the Royal Observatory , Greenwich , where I was for several months studying the several instruments in the magnetic department , through the kindness of the Astronomer Royal and Mr. Glaisher , I had made myself well acquainted with the necessary care in those observations ; besides , I several times visited the Kew Observatory , through the kindness of Dr. Balfour Stewart , and took some observations of dip . At all times my first efforts were directed to have a firm support ; next , to accurately levelling the instrument ; third , to see that the agate plates were clean , that the axis of the needle was also clean and tested by the use of cork , that the needles were free from dust and damp , their ends being passed in and out of cork , and their surfaces wiped with wash-leather ; and in damp weather increased attention was paid to everything ; but , as a rule , observations were not made at such times ; care was also had in determining the magnetic meridian corresponding , and in all cases several readings were taken in every position . The results of observations of dip with local instruments at different places were as follows : Kew Observatory , monthly observations of dip with an instrument No. 33 Circle , of the same pattern I had made by Barrow ; the length of the needle is about 3 ' inches . To compare No. 33 Circle with the Circle borrowed from Kew , I made simultaneous observations ; the mean from six observations with two needles gave for No. 33 Circle=68 ? ? 2 ' 19 , and for the Circle I had from Kew 68 ? ? 3'8 , this result being 1'6 larger . Royal Observatory , Greenwich.-Observations of dip are made frequently with Mr. Airy 's dip instrument , described in the yearly volumes of observations at the Royal Observatory . Six needles of three different lengths are observed on the same instrument ; the results derived from each separate needle seldom differ more than five minutes in the year . I took from the Royal Observatory observations the mean of the determined dip for the period from 1st July to 30th September , which was= 67 ? ? 56'15 , derived from twenty-seven observations , and nearly corresponds to the time of my observations . The dip obtained from my observations with Kew Circle was = 67 ? ? 58'"88 , being 2'"73 larger . Brussels Observatory.-The observations of dip were made with an instrument of old English construction , which was made in the year 1828 , VOI . XVII . y 1869 . ] 283 by the English makers Troughton and Simms ; two needles about 8 inches long are observed , and the observations are made in the usual manner , in the magnetic meridian . The dip is observed at the beginning of each year , in the month of March or April ; thus for the year 1868 there was bne observation made with two needles the 30th of March , and the dip obtained was 67 ? ? 11 ' 1 . The 5th of September Professor Quetelet 's son , according to my wish , was so kind as to observe the dip , and obtained almost the same result ( that is , 67 ? ? 11 '0 ) , whilst from observations with the Kew Circle I obtained the dip =67 ? ? 6'77 , being 4'2 smaller . Utrecht Meteorological Department.-The observations were made with an instrument not differing much from instruments of this class formerly used in England . It was constructed by Olland , a maker at Utrecht ; the dip is observed every fortnight , in the middle and at the end of each month , with two needles about 8 inches in length . The results of the separate needles are very close to one another , and the dip is generally observed about 9 o'clock in the morning . Simultaneous observations were made by Mr. It- . Welers Bethink and myself , each observing his own instrument . The dips obtained are as follows : With the Observatory instrument ... . 67 47'`7 With the Kew Circle ... ... ... ... . 67 ? ? 43'13 , being 4'"4 less . Vienna Meteorological Department.-The Dip Circle was made by Repsold , and a description of it is given in the 'Magnetische und meteorologische Beobachtungen zu Prag bei Karl Kreil , sechster Jahrgang , vorm Januar bis 31 . December 1845 . ' The instrumentis provided with eight needles , whose lengths are about 9 inches each ; the axis of the needle is perforated , and can be turned round the centre of the needle through a definite angle ; each dip is deduced from eight separate sets of observations , by turning each time the axis of the needle through an angle of about 45 ? . The separate results derived in this way differ sometimes about 1 ? from each other , and the means for separate needles differ in some cases about 20 ' ; so that the determinations of dip with this instrument are very uncertain , whilst the labour to obtain a pretty good result is very great ; at the same time a single determination with one of the Barrow 's Circles gives a result nearer to the truth . I must say here that the present Director of the Meteorological Institution in Vienna , Professor Yelynak , was so pleased with the instrument I had from Kew , that he asked my to order one for him of Mr. Barrow . The mean result derived from the observations from January 1 to September 18 , 1868 , is =630 32f'06 ; the result obtained with the Kew Circle is 63 ? ? 385'80 , being larger by 6 ' 7 . Macunich.-Regular observations of absolute dip are not made at the Observatory . The last determined dip was in 1866 , in September , and was 64 ? ? 16f'8 . The dip for the present time is deduced from the variation of horizontal force and the constant relation between it and the dip as found by Dr. Lament from a large series of observations ; according to this the 284 [ Feb. 11 , Ldip for September 1868 is 64 ? ? 10'9 . The observed dip with the Kew Circle is 64 ? ? 7 ' 7 , being smaller by 3 ' 2 . Paris.-The observations of dip at the Observatory are made with an instrument of Gambey regularly three times every day--that is , at 9 o'clock in the morning , at noon , and at 4 o'clock in the afternoon . This instrument gives only the variations of dip . To determine the absolute dip , a long series of simultaneous comparisons with a Dip-circle have been made . The following dip is deduced from observations with this instrument on the same days as my observations : it is = 65 ? ? 45'3 ; the result I obtained with the Kew Circle is 65 ? ? 49 ' 85 , being 4t'5 larger . These were all the stations at which I was able to make satisfactory observations ; but as at most of these stations comparative observations atadjoint stations had been made before and the differences found between them , there was less need to extend my observations beyond the principal observatories . Table II . contains the dips observed at the different stations before mentioned , and the differences between the local instruments and the Circle from Kew . TABLIE II . Septemn^ber 1868 . iBDips observed Dips observed Local instruStations . with local with Circle ments-Kew instruments . from Kew . Circle . Normal Observatory , Kew ... ... ... 68 2-19 68 3-80 -1-61 Royal Observatory , Greenwich ... 67 5615 67 58-88 -2'73 Norwich ... 6 ... ... ... ... ... ... ... ... 68 17-86 Brussels Observatory ... ... ... ... ... 67 1100 67 6-77 +4-23 Utrecht , Meteorol . Department ... 67 47-70 67 43-30 +4-40 Vienna , Meteorol . Institution ... . . 63 32-06 63 38-80 -6-74 Munich Observatory ... ... ..6 ... ... . 64 7-70 Paris Observatory ... ... ... ... ... . . 65 45-30 65 49-85 -4-55 I will now endeavour to deduce the most probable dips at each station . First I shall deduce the dip at Munich , as no observations are made there specially for dip , by taking the differences between the values I found at Munich and at every other station , and applying it to the result as found with the local instrument at each place . Thus the dip I obtained at Kew was 68 ? ? 3 ' 80 , and at Munich was 64 ? ? 7''70 ; the difference is 3 ? ? 56'1 ; and applying this to the result as found at Kew by the Kew instrument 68 ? ? 2 " 19 , I deduce 64 ? ? 6'09 as the dip for Munich ; and treating all the other stations in a similar way I find : Dip , from Kew ... ... ..= 64 6-09 , , Greenwich. . 4-97 Norwich ... .= 7'70 , Brussels ... .= . 11-93 , , Utrecht ... . . 12'10 Vienna ... ... 0-96 , Paris ... ... = 3 15 Mean , ... 64 6'70 1869 . ] 285 And in a similar way I calculated the dips for all the stations , taking Utrecht first , because the dip found for Munich from this station gave a result differing from the mean the most of any ; and then I treated Brussels in the same way , it being the next in order of discordance , and so on . I thus formed Table III . , giving the calculated dips , the observed dips with the local instruments and the Kew . Circle , and the corrections for the Kew Circle , TABLE III . Calculatel Dips observediDips observed Calcul.-Obs . Stations . acaeDip . with local with Circle with i. instruments . from Kew . Iew Circle . Kew ... ... ... 68 1-69 68 2-19 68 3-80 -2-11 Greenwich ... 67 56-84 67 56-15 67 58-88 -2-04 Norwich ... ... 68 1550 67 17-86 68 17-86 -2-36 Brussels ... . 67 4-12 67 11-00 67 6-77 --265 Utrecht ... . 67 41-37 67 47-70 67 43-30 -1-93 Vienna ... 63 36-73 63 32-06 63 38-80 -2-07 Munich ... . 64 6-70 ... ... ... ... ... . 64 7-70 -1-00 Paris ... ... ... 65 47-80 65 45-30 65 49-85 -2-05 Mean ... -2-03 This Table shows that the Circle from Kew gave at all stations the dip about 2 ' too large ; and only for Munich this difference is but 1 ' , which shows that the calculated dip for Munich is a little too large .

112394

3701662

On a New Class of Organo-Metallic Bodies Containing Sodium

286

287

Proceedings of the Royal Society of London

J. Alfred Wanklyn

fla

6.0.4

http://dx.doi.org/10.1098/rspl.1868.0047

proceedings

http://corpora.clarin-d.uni-saarland.de/surprisal/6.0.3/?id=112394

10.1098/rspl.1868.0047

http://www.jstor.org/stable/112394

Chemistry 2

Biography

Chemistry

III . " On a New Class of Organo-metallic Bodies containing Sodium . " By J. ALFRED WANKLYN , Professor of Chemistry in the London Institution . Communicated by Professor E. W. BRAYLEY . Received February 6 , 1869 . Up to the present time organo-metallic bodies containing ethylene in union with the metal have been often sought , but never recognized . I have to announce the existence of organo-metallic compounds of ethylene with the alkali-metals . In ethylate of sodium , or at any rate in the substance which is produced by heating up to 200 ? C. the well-known -crystals got by acting on alcohol with sodiumn , I see the hydrated oxide of ethylene-sodiumNa"'{ ( C{ H ' ) " which , as I have recently shown , yields alcohol and a new compound on being heated with the ethers of the fatty acids : thus Ilydrate of ethylenesodium . Acetate of ethyl . Acetate of ethylene-sodium . Na " ' ICO N ' OC ? } Q " ' C CI H0 286 Acetate of ethylene-sodium yields alcohol and common acetate of soda on treatment with water:2( Na " ' 21 o ) +2 HO =2C 0+2 NaO C , H O. The extreme lightness of the so-called ethylate of sodium ( it swims in ether ) is a reason for regarding it as a compound belonging to a less condensed order of sodium-compound than ordinary sodium-compounds . The property of yielding up its olefine in the shape of alcohol when it is treated with water is a reason for assigning to the new compound given by the action of acetic ether the above formula , and shows that the olefine is associated with the alkali-metal , not with the acid .

112395

3701662

On the Temperature of the Human Body in Health. [Abstract]

287

288

Proceedings of the Royal Society of London

Sydney Ringer|Andrew Patrick Stuart

abs

6.0.4

proceedings

http://corpora.clarin-d.uni-saarland.de/surprisal/6.0.3/?id=112395

http://www.jstor.org/stable/112395

Thermodynamics

Meteorology

Thermodynamics

IV . " On the Temperature of the Human Body in Health . " By SYDNEY RINGER , M.D. ( Lond. ) , Professor of Materia Medica in University College , London , and the late ANDREW PATRICK STUART . Communicated by Dr. BASTIAN . Received December 18 , 1868 . ( Abstract . ) These observations were conducted by the authors in order to learn with minuteness the fluctuations of the temperature in health . They were performed on persons of different ages , and were in many instances continued through the night and day . The temperature was noted every hour , and on many occasions much more frequently . The following subjects are discussed in this communication:1 . The daily variation of the temperature . 2 . The effects of food on the temperature . 3 . The effects of cold baths on the temperature . 4 . The effects of hot baths on the temperature . From their observations and experiments the authors have drawn the following conclusions : The average maximum temperature of the day in persons under 25 years of age is 99 ? ' 1 Fahr. ; of those over 40 , 98 ? ` 8 Fahr. There occurs a diurnal variation of the temperature , the highest point of which is maintained between the hours of 9 A.M. and 6 P.M. At about the last-named hour the temperature slowly and continuously falls , till , between 11 P.M. and 1 A.M. , the maximum depression is reached . At about 3 A.M. it again rises , and reaches very nearly its highest point by 9 A.M. The diurnal variation in persons under 25 amounts , on an average , to 2 ? '2 Fahr. ; but in persons between 40 and 50 it is very small , the average being not greater than 0 ? '87 Fahr. ; nay , on some days no variation whatever happens . In these elderly people the temperature still further differs 1869 . ] 2)87 from that of young persons ; for in the former the diurnal fall occurs at any hour , and not , as is the case with young persons , during the hours of night . Concerning the influence of food on the temperature of the body the authors have concluded that none of the diurnal variations is in any way caused by the food we eat . The experiments to prove this conclusion are very numerous . Some were made with the breakfast , others with the dinner and tea ; but all point to the conclusion just stated . This important question is very fully discussed in the section devoted to it . By cold baths both the surface of the body and the deep parts were lowered in temperature . The temperature of the surface was in some instances reduced to 8S ? Fahr. ; but the heat so soon returned to all parts as to show that the cold bath is of very little use as a refrigerator of the body . The cold bath produced no alteration in the time or amount of the diurnal variation . This began at the same hour , and Ieached the sane amount as on those days whel no bath was taken . By hot-water or vapour baths the heat of the body could be raised very considerably . Thus , on some occasions , when using the general hot bath , the temperature under the tongue was noted to be between 103 ? and 104 ? Fahr. , a fever temperature . The body being heated considerably above the point at which combustion could maintain it , it was then shown with what rapidity heat may be lost , simply by radiation and evaporation . The particulars of these results are given in the paper . The experiments tend to prove that hot baths in no way affect the diurnal variation of the temperature .

112396

3701662

Preliminary Note of Researches on Gaseous Spectra in Relation to the Physical Constitution of the Sun

288

291

Proceedings of the Royal Society of London

Edward Frankland|J. Norman Lockyer

fla

6.0.4

http://dx.doi.org/10.1098/rspl.1868.0049

proceedings

http://corpora.clarin-d.uni-saarland.de/surprisal/6.0.3/?id=112396

10.1098/rspl.1868.0049

http://www.jstor.org/stable/112396

Atomic Physics

Astronomy

Atomic Physics

V. ' Preliminary Note of lResearches on Gaseous Spectra in relation to the Physical Constitution of the Sun . " By EDWARD FRANKLAND , F.R.S. , and J. NOR , IANT LOCKYER , F..1A.S . Received February 11 , 1869 . 1 . For some time past we have been engaged in a careful examination of the spectra of several gases and vapours under varying conditions of pressure and temperature , with a view to throw light upon the discoveries recently made bearing upon the physical constitution of the sun . Altllough the investigations are by no means yet completed , we consider it desirable to lay at once before the Royal Society several broad conclusions at which we have already arrived . It will be recollected that one of us in a recent colmmunication to the Royal Society pointed out the following facts:i . That there is a continuous envelope round the sun , and that in the spectrum of this envelope ( which has been named for accuracy of description the " chromosphere " ) the hydrogen line in the green corresponding with Fraunhofer 's line F takes the form of an arrowhead , and widens from the upper to the lower surface of the chromosphere . ii . That ordinarily in a prominence the F line is nearly of the same thickness as the C line . iii . That sometimes in a prominence the F line is exceedingly brilliant , and widens out so as to present a bulbous appearance above the chromosphere . iv . That the F line in the chromosphere , and also the C line , extend on to the spectrum of the subjacent regions and re-reverse the Fraunhofer lines . v. That there is a line near D visible in the spectrum of the chromosphere to which there is no corresponding Fraunhofer line . vi . That there are many bright lines visible in the ordinary solar spectrum near the sun 's edge . vii . That a new line sometimes makes its appearance in the chromosphere . 2 . It became obviously , then , of primary importancei . To study the hydrogen spectrum very carefully under varying conditions , with the view of detecting whether or not there existed a line in the orange , and ii . To determine the cause to which the thickening of the F line is due . We have altogether failed to detect any line in the hydrogen spectrum in the place indicated , i. e. near the line D ; but we have not yet completed all the experiments we had proposed to ourselves . With regard to the thickening of the F1 line , we may remark that , in the paper by MM . Pliicker and Hittorf , to which reference was made in the communication before alluded to , the phenomena of the expansion of the spectral lines of hydrogen are fully stated , but the cause of the phenomena is left undetermined . We have convinced ourselves that this widening out is due to pressure , and not appreciably , if at all , to temperature per se . 3 . H-laving determined , then , that the phenomena presented by the F line were phenomena depending upon and indicating varying pressures , we were in a position to determine the atmospheric pressure operating in a promiinence , in which the red and green lines are nearly of equal width , and in the chromosphere , through which the green line gradually expands as the sun is approached* . With regard to the higher prominences , we have ample evidence that the gaseous medium of which they are composed exists in a condition of excessive tenuity , and that at the lower surface of the chromosphere itself the pressure is very far below the pressure of the earth 's atmosphere . The bulbous appearance of the F line before referred to may be taken to indicate violent convective currents or local generations of heat , the condition of the chromosphere being doubtless one of the most intense action . 4 . We will now return for one moment to the hydrogen spectrum . Ve have already stated that certain proposed experiments have not been carried out . We have postponed them in consequence of a further consideration of the fact that the bright line near D has apparently no representative among the Fraunhofer lines . This fact implies that , assuming the line to be a hydrogen line , the selective absorption of the chromosphere is insufficient to reverse the spectrum . It is to be remembered that the stratum of incandescent gas which is pierced by the line of sight along the sun 's limb , the radiation from which stratum gives us the spectrum of the chromosphere , is very great compared with the radial thickness of the chromosphere itself ; it would amount to something under 200,000 miles close to the limb . Although there is another possible explanation of the non-reversal of the D line , we reserve our remarks on the subject ( with which the visibility of the prominences on the sun 's disk is connected ) until further experiments and observations have been made . 5 . We believe that the determination of the above-mentioned facts leads us necessarily to several important modifications of the received theory of the physical constitution of our central luminary the theory we owe to Kirchhoff , who based it upon his examination of the solar spectrum . According to this hypothesis , the photosphere itself is either solid or liquid , and it is surrounded by an atmosphere composed of gases and the vapours of the substances incandescent in the photosphere . We find , however , instead of this compound atmosphere , one which gives us nearly , or at all events mainly the spectrum of hydrogen ; ( it is not , however , composed necessarily of hydrogen alone ; and this point is engaging our special attention ; ) and the tenuity of this incandescent atmosphere is such that it is extremely improbable that any considerable atmosphere , such as the corona has been imagined to indicate , lies outside it , -a view strengthened by the fact that the chromosphere bright lines present no appearance of absorption , and that its physical conditions are not statical . With regard to the photosphere itself , so far from being either a solid surface or a liquid ocean , that it is cloudy or gaseous or both follows both from our observations and experiments . The separate prior observations of both of us have shown:i . That a gaseous condition of the photosphere is quite consistent with its continuous spectrum . The possibility of this condition has also been suggested by Messrs. De La hue , Stewart , and Loewy . ii . That the spectrum of the photosphere contains bright lines when the 1869 . ] On the Structure of Rubies , Sapphires , Diamonds , 6c . 291 limb is observed , these bright lines indicating probably an outer shell of the photosphere of a gaseous nature . iii . That a sun-spot is a region of greater absorption . iv . That occasionally photospheric matter appears to be injected into the chromosphere . May not these facts indicate that the absorption to which the reversal of the spectrum and the Fraunhofer lines are due takes place in the photosphere itself or extremely near to it , instead of in an extensive outer absorbing atmosphere ? And is not this conclusion strengthened by the consideration that otherwise the newly discovered bright lines in the solar spectrum itself should be themselves reversed on Kirchhoff 's theory ? this , however , is not the case . We do not forget that the selective radiation of the chromosphere does not necessarily indicate the whole of its possible selective absorption ; but our experiments lead us to believe that , were any considerable quantity of metallic vapours present , their bright spectra would not be entirely invisible in all strata of the chromosphere .

112397

3701662

On the Structure of Rubies, Sapphires, Diamonds, and Some other Minerals

291

302

Proceedings of the Royal Society of London

H. C. Sorby|P. J. Butler

fla

6.0.4

http://dx.doi.org/10.1098/rspl.1868.0050

proceedings

http://corpora.clarin-d.uni-saarland.de/surprisal/6.0.3/?id=112397

10.1098/rspl.1868.0050

http://www.jstor.org/stable/112397

Optics

Thermodynamics

Optics

I. " On the Structure of Rubies , Sapphires , Diamonds , and some other Minerals . " By H1 . C. SoRBY , F.R.S. , and P. J. BUTLER . Received December 8 , 1868 . [ Plate VII . ] For many years Mr. Butler has had the opportunity of examining very many rubies , sapphires , and diamonds , and has taken advantage of it in forming a most interesting collection , cut and mounted as microscopical objects . He had very carefully studied the included fluid-cavities , and ascertained many curious facts . Mr. Sorby had for some time paid much attention to the microscopical structure of crystals , and published a paper* in which he showed that their microscopical characters often serve to throw much light on the origin of rocks . Mr. Butler therefore placed the whole of his collection in Mr. Sorby 's hands for careful examination , and it was decided that a paper should be written by the two conjointly ; and since Mr. Sorby had previously made many experiments in connexion with the expansion of liquids , as already described in a paper published in the Philosophical Magazinet , he took advantage of the opportunity to investiQuarterly Journal of Geol . Soc. , 1858 , vol. xiv . p. 453 . O"n the Expansion of Water and Saline Solutions at High Temperatures , " August 1859 , vol. xviii . p. 81 . gate the law of the expansion of the very interesting fluid met with in the cavities of sapphire . In describing the various facts , it will be well to consider them in relation to the following general principles:(1 ) The structure of the various minerals as mere microscopical objects . ( 2 ) The physical characters of the fluid-cavities , as throwing light on the origin of the minerals . ( 3 ) The influence of some included crystals on the structure of the surrounding mineral . Sapphires . By far the most interesting objects contained in sapphires are the fluidcavities . Their occasional presence has been already noticed by Brewster , who met with one no less than about : inch long , two-thirds full of a liquid which expanded so as to fill the whole cavity when heated to 82 ? F. ( 28 ? C. ) . He thought the liquid was less mobile than that described by him in topaz , and could not see a second liquid in the cavity . Though many thousand sapphires have been examined by the authors , no such large cavity has been found ; but several have been met with about - ? inch in diameter ; the greater number are far less , and some are very minute ; and they seem to contain only the liquid which expands so much when warmed . The size of the included bubble varies much , according to the temperature . At the ordinary heat of a room it is sometimes equal to one-half of the capacity of the cavity , whereas in other cases the cavity is quite fill . This is especially the case with the very small cavities , and is to some extent due to the forced dilatation of the liquid . But if we only take into consideration the larger cavities , the temperature required to expand the fluid so as to fill them certainly varies from 20 ? to 32 ? C. ( 68 ? to 90 ? F. ) , and this not only in different crystals , but also , to a less extent , in the same specimen . As illustrations of the form of such cavities , we refer to Plate VII . figs. 1 , 2 , 3 , and 4 , the extent to which they are magnified being shown in each case . At the ordinary temperature the bubble in the cavity shown by fig. 1 is about one-half its diameter , but disappears entirely at 30 ? C. By carefully measuring the size of the cavity in various positions , and comparing it with the diameter of the bubble at 0 ? C. , it appears that the liquid expands from 100 to 152 when heated from 0 ? to 30 ? C. Fig. 2 is a tubular cavity , and shows in a very excellent manner the boiling of the liquid when it cools after having been made to expand to fill the whole space . At the ordinary temperature the liquid occupies only about half the cavity ; but when heated in a water-bath to 32 ? C. , it fills it entirely . No bubble is formed until the temperature has fallen to 31 ? ; and then innumerable small bubbles are suddenly formed , which rise to the upper part and unite ; but instead of the liquid merely contracting by further cooling , it still continues to boil for some time , as represented in the drawing . Two other large cavities * S6chting 's Einschliisse von Mineralien in krystallisirten Mineralien , p. 121 , who refers to Edin . Journ. of Sc. , vol. vi . p. 115 . 29 contained in the same specimen also behave in the same manner , and become full and suddenly boil at almost absolutely the same temperature , as that figured . We need scarcely say that such cavities are extremely rare , and are very remarkable even when merely looked upon as microscopical objects , independently of their interest in connexion with physics . Fig. 3 is a tubular cavity of more irregular form , and is interesting on account of there being two plates of the sapphire projecting into the cavity so as to nearlydivide it into three portions . At the ordinary temperature these partitions prevent the passage of the bubble from one part to the other ; but by breathing on the object through a flexible tube , the slight increase of temperature expands the liquid so as to make the bubble small enough to pass into the next compartment ; and a repetition of the process causes it to pass into that at the other end . Such plates projecting into the cavities are very common ; and it is requisite to pay attention to this fact , since otherwise they might easily be mistaken for crystals of some other substance included in the cavity , which , if they ever occur , must be extremely rare , since no decided case has come under our notice . In examining sections of sapphire cut in a plane more or less parallel to the principal axis of the crystal , the double refraction is so strong that two images of every object lying at any depth below the surface are seen , in such a manner as to make them very confused . This may be avoided by using polarized light without an analyzer , and arranging the plane of polarization so as to coincide with one of the axes of the crystal . High powers may then be used with perfect definition ; and they show many small cavities , sometimes of most irregular forms , like fig. 4 ; and very often their sides are so inclined that they totally reflect transmitted light , and appear black and opake . In some specimens most of the cavities have lost their fluid . Besides fluid-cavities , there are many small crystals of other minerals included in sapphires , but not so many as in rubies . The most striking are small plate-like crystals , often of triangular form , with one angle very acute . They are very thin , and give the colours of thin plates so that when viewed by reflected light they look something like the scales from a butterfly . Seen edgewise , they appear as miere black lines , and are arranged parallel to the three principal plan-es of the sapphire , as shown by fig. 5 . These small crystals and the minute fluid-cavities cause many sapphires to appear milky by reflected , and somewhat brown by transmitted light ; and being arranged in zones related to the form of the crystal , they often show , as it were , lines of growth . Ruibies . Though the ruby and the sapphire are of course essentially the same mineral , yet their structure is in many respects as characteristically different as their colour . The numtber of the fluid-cavities in rubies is far less , and the larger cavities are very rare , and only contain what appears to be water or a saline aqueous solution , as is shown by the amount of expansion when the specimen is heated to the temperature of boiling water . Those containing a similar fluid to that included in sapphires do occasionally occur ; and when they are minute , they are extremely interesting , since they show the spontaneous movement of the bubbles to greater perfection than any mineral that has come under our notice . This is perhaps to some extent due to the nature of the liquid , which is more mobile than the saline aqueous solutions contained in the cavities of the quartz of granite and syenite . It is manifestly a molecular movement analogous to that seen in all matter when very minute particles are suspended in a liquid , so as to allow freedom of motion ; and the rapidity of the movement is certainly dependent on the size of the particles . It is not seen to advantage if the diameter of the bubbles is more than 1- , of an inch ; but when it is about -I they move to and fro in the most surprising manner , with such rapidity that the eye can scarcely follow them . The number of small crystals of other minerals included in rubies is often very great . There must be at least four different kinds ; but it would be difficult to determine what minerals they all are . Some are very well characterized octahedrons , variously modified ; and , as shown by fig. 5 , their planes are very generally arranged parallel to planes of the ruby , and to the small plate-like crystals already mentioned in describing sapphire . These octahedrons have no influence on polarized light , and in general form and character correspond so closely with spinel that it seems very probable that they are that mineral . For some time we thought they were angular fluid-cavities filled with liquid ; but when cut across in the sections they are clearly seen to be solid , though less hard than ruby . Many of the other included crystals are of such very rounded forms that , if it were not for their action on polarized light , they might easily be mistaken for cavities filled with some fluid . Most of these rounded crystals are colourless ; but some are of more or less dark orange-red colour , and are certainly not the same mineral as the colourless or the octahedral crystals ; and in all proba . bility the thin and flat are a fourth kind . Occasionally alternating plates of ruby with their axes in different positions gave rise to a beautiful series of coloured stripes when examined with polarized light . Spinel . The ruby spinels from Ceylon sometimes contain fluid-cavities which differ in a striking manner from those of any other mineral that has come under our notice . One of these is shown in fig. 7 . They are to a great extent filled with a yellow substance , indicated by the shading , which seems to be either a solid or a very viscous liquid . It encloses transparent , sometimes well-defined cubic crystals , which have no action on polarized light ; transparent , prismatic , or plate-like crystals , which strongly depolarize it ; and black opake crystals , either in larger pieces or mere grains . The rest of the cavity is in each case about one-third full of a colourless liquid , which seems to contract on the application of heat , because it passes entirely into 294 vapour , as occurred in some of the cavities in topaz described by Brewster . In this change it must expand about six hundred times less than when water passes into steam . Spinel also encloses crystals of several other minerals which we have not yet been able to identify . Aquamarina . The most striking peculiarity of this mineral is the occurrence of numbers of fluid-cavities containing two fluids and a vacuity , as shown by fig. 6 . Emerald . Some of the specimens which we have examined are so full of fluidcavities that they are only partially transparent . They differ entirely from those already described , and contain only one liquid , which does not sensibly expand when warmed . In all probability this is a strong saline aqueous solution , since the cavities also enclose cubic crystals , as shown by fig. 8 , which dissolve on the application of heat , and recrystallize on cooling . On the whole , therefore , these cavities are very similar to those found in the quartz of some granites , and in some of the minerals found in blocks ejected from Vesuvius , as described in Mr. Sorby 's paper on the microscopical structure of crystals , already referred to . Diamond . Few , if any , of the specimens of diamond that have come under our notice contain objects similar to those which , in the opinion of G6ppertx ' , are evidence of its having been derived from vegetable remains , but we have been able to study to great advantage some facts which do not appear to have presented themselves to either Goppert or Brewster . We have examined twenty-one objects similar to the two described by Brewster , in his paper in the Transactions of the Geological Societyt ; and this has enabled us to clear up some of the difficulties to which he alludes , and has led us to propose a different explanation . He thought that the black specks , which were surrounded by a black cross when examined with polarized light , were minute cavities ; but at the same time he admitted that they were so small that it was not possible to say whether they contained a fluid or were empty . Judging from what we have seen of such small examples , we consider it impossible to say whether they are cavities or enclosed crystals ; but fortunately we have met with several of such a size and character that it was quite easy to see that they were crystals . Fig. 9 is a most excellent example of this fact . The form is clearly that of a crystal , and it depolarizes light very powerfully . Its refractive power must be very much less than that of diamond ; for the inclined planes totally reflect the transmitted light , and thus look quite black , as shown in the figure . It is this circumstance which causes many smaller enclosed crystals to appear like mere black specks . * " Ueber Einschlisse im Diamant , " Natuurkundige Verhandelingen , Haarlem , 1864 . t 2nd series , vol. iii . p. 455 . Brewster has shown that the irregular depolarizing action of diamond is analogous to that of an irregularly hardened gum ; and this much interferes with the perfection of the black crosses seen round the enclosed crystals , and sometimes even neutralizes this action . Still , as a general rule , a black cross is seen ; and , as described by Brewster , when examined by means of a plate of selenite which gives the blue of the first order , the tints of the sectors in the line of its principal axis are depressed in the same manner as when such a black cross is produced by the compression of glass-thus proving that the enclosed crystals have exerted a pressure on the surrounding diamond . We , however , do not imagine that the crystals have increased in size , but that probably they have prevented the uniform contraction of the diamond , which , as already mentioned , must have been very irregular , even where no such impediment was present . A few of the crystals enclosed in rubies give rise to similar black crosses , as shown by fig. 11 ; and we are informed by Professor Zirkel that his brother-inlaw Professor Vogelsang has prepared a thin section of a specimen of partially devitrified glass , which also shows black crosses round the enclosed crystals . Brewster suggested that this phenomenon in diamond was due to the elastic force of an enclosed gas or liquid , and compared it with what is seen in the case of some cavities in amber . We , however , find that the optical character of the crosses seen round the undoubted cavities in amber is the very reverse of that in the case of diamond , and cannot be explained by the mere mechanical action of an included elastic substance , but is similar to the change to a crystalline state which has occurred over the whole external surface , and on both sides of cracks passing from it inwards . The optical properties , however , are not the only evidence of contraction round crystals enclosed in diamond ; for actual cracks are often seen to proceed from them . These present the striped appearance shown in fig. 10 , owing to more or less perfect total reflection from their waved surface . The same kind of phenomenon may be seen in sapphire , and still better in spinel , as shown by figs. 12 and 13 . Sometimes there is a system of radiating cracks nearly in one plane , terminating in a transverse crack which surrounds the whole , as in fig. 12 ; and in other cases there are various complicated wavy cracks in different planes , as in fig. 13 . There seems to be some conniexion between this structure and the nature of the included minerals ; for round some kinds it is very common , but round others very rare or quite absent ; and it appears probable that it may be referred to unequal contraction in cooling from a high temperature ; and , if so , the results would necessarily depend on a variety of circumstances . Now that attention has been directed to it , it will probably be found to be a very common peculiarity of certain classes of minerals , and serve to throw a good deal of light on their origin . Crystals surrounded by radiating cracks on a much larger scale have 296 been observed by Mr. David Forbes* , and may , we think , be explained in a similar manner . The crystals formed in blowpipe beads kept hot for some time over the lamp , also furnish good illustrations of these facts . Phosphate of zirconia is deposited in cubes from a borax bead to which much microcosmic salt has been added ; and when examined with the microscope whilst cooling , cracks like those described in diamond and spinel are seen to be formed round many of the crystals , which are evidently due to the crystals contracting less than the surrounding material . On the contrary , the long prisms of borate of baryta deposited from solution in borax are seen to separate from the borax on cooling , and to be filled with transverse cracks , like those in schorl enclosed in quartz , which is clearly owing to their contracting more than the borax . Fluid-cavities in general . Before discussing the nature of fluid-cavities in connexion with the origin of the various minerals , we think it best to describe the remarkable properties of the liquid included in the sapphire , and to point out what it seems to be . Brewster , in his paper on the fluid-cavities in topaz*^ , says that the more expansible liquid contained in them expands one-fourth its size , when heated from 50 ? to 80 ? F , or thirty-one and a quarter times as much as water ; and , as already stated , he found that the fluid in sapphire expands about one-half when heated to 82 ? F. Though this amount of expansion is very remarkable , yet , when the relative expansion at various temperatures is examined , it will be seen to be still more remarkable . Very fortunately the tubular cavity in sapphire , shown by fig. 2 , is most admirably fitted for experiment . Mere inspection shows that its general diameter is very uniform ; and that it is really so can be proved by causing the liquid to pass from one end to the other ; for at 17 ? C. the length of the column of liquid was -25of an inch , whether it was at the end A or B. The total effective length of the cavity is -4atr . The specimen inelosing this cavity was fastened to a piece of glass , and this was fixed in beakler containing water , supported so that the cavity was in the focus of the microscope under a low power . The temperature was raised very slowly , and was maintained for some minutes at each particular degree at which it was thought desirable to measure the volume of the liquid ; and this was usually repeated over and over again when the heat was both rising and falling , so as to obtain as accurate a result as possible . In making the measurements with the micrometer , care was taken to ' allow for the tapering ends of the cavity and the curved surface of the liquid . The results are given in degrees Centigrade . Though the expansion below 30 ? was very great , compared with that of any other known substances except liquid carbonic acid and nitrous oxide , when the temperature rose above 30 ? it was so very extraordinary that it was not until after having performed the experiment over and over again that Mr. Sorby felt confidence in the results . This will not be thought surprising when we state that from 31 ? to 32 ? the apparent expansion of the liquid is no less than one-fourth of the bulk it occupies at 31 ? ; the length of the column increasing for that single degree from io4to -50 inch . This is about 780 times as great as the expansion of water would be , and even 69 times as much as that of air and permanent gases . It was not possible to ascertain the amount of expansion above 32 ? C. , because the cavity was quite filled at that temperature . If the expansion increase at the same increased rate , the liquid would soon occupy several times as much space ; but it seems very probable that before then it would pass into the state of gas . At all events it appears as if this enormous rate of expansion indicated a close approach to a fresh physical condition . The following Table gives the results of the experiments ; and it has been found , by drawing them as a curve , that their general relations indicate that there cannot be any serious error ; but at the same time , considering all the circumstances , they must only be looked upoin as tolerably good approximations to the truth . Temperature . Volume . t C ... ... ... ... ... . . 100 17 ... ... . . 1(9 20 ... ... ... ... . . 11.3 25 ... ... ... ... ... . 122 28 ... ... ... ... ... . 130 29 ... ... ... ... ... . 139 30 ... ... ... ... ... . 150 31 ... ... ... ... ... . 174 32 ... ... ... ... ... . 217 The apparent expansion of the liquid is doubtless to some extent increased by the condensation of the gas , as the space occupied by it is diminished . When in the highly expanded condition this liquid appears to be remarkably elastic . Berthelot has shown , in his paper on forced dilatation* , that the force with which liquids adhere to the interior of a glass tube is sufficient to prevent their contraction to the normal volume , if they have been heated so as to expand and quite fill the tube , and then cooled to a temperature below that requisite ti fill it . This fact must always be borne in mind in studying fluid-cavities , and explains why the bubbles , as it were , hesitate to return , and then make their appearance with a sudden start . Such a forced dilatation is very remarkable in the case described ; for though it was requisite to raise the temperature to 32 ? C. to fill the cavity , no vacuity was formed until it fell to 31 ? ; and therefore it seems as if the force of cohesion were sufficient to stretch it to considerably ? Annals de Chimie s6r . 3 . t. xxx . p. 232 . 298 more than its normal bulk , even perhaps to the extent of one-fifth or onefourth . Moreover , in the case shown in fig. 1 . , the liquid expanded so as to fill the cavity at about 30 ? C. ; and yet it can be heated up to 42 ? without bursting it , though , even if the expansion did not continue to increase , and were the same for each degree as from 31 ? to 32 ? , the normal volume would be about four times that of the cavity , -which in any case seems only to be explained by supposing that its elasticity is most remarkably great , more like that of a gas than of a liquid . There was no decided evidence of its passing into a gaseous state , as does occur when cavities contain a less amount of liquid . Simmler * has shown that the physical properties of the liquid in topaz , as observed by Brewster , agree more nearly with those of liquid carbonic acid than with those of any other known substance . Dana , in his 'Mineralogy ' ( 5th edition , 1868 , p. 761 ) , calls it Brewsterlinite , and , says that its composition is unknown . The facts at Simmler 's command were not in all respects satisfactory-since the amount of expansion given by Brewster was from 10 ? to 26 ? '7 C. , whereas that of liquid carbonic acid observed by Thilorier was from 0 ? to 30 ? , and , as shown above , the expansion increases so much as the temperature rises that the average rate for 1 ? is very indefinite . The only reliable method is therefore to compare the expansion between equal degrees of temperature . According to Thiloriert liquid carbonic acid , when heated from 0 ? to 30 ? , expands from 100 to 145 . One of the experiments described above showed that the liquid in sapphire expands from 100 to 152 ; and the other from 100 to 150 , which is the most reliable . This agrees so closely with the expansion of liquid carbonic acid , that the difference might easily be due to a slight error in the thermometers . The expansion of ordinary liquids is notto be compared with it , nor is that of liquid sulphurous acid . Dr. Franklanil has kindly ascertained this fact , with special reference to the case in question , and found that from 0 ? to 32 ? C. the expansion was only from 100 to 104'36 instead of to 217 . According to AndreeffJ the expansion of liquid nitrous oxide is not much inferior to that of liquid carbonic acid , being , from 15 ? to 20 ? , '00872 for each degree , which differs decidedly from that of the liquid in sapphires . The occurrence of nitrous oxide in minerals is also so very much more improbable , that , on " the whole , it seems as if we should be justified in concluding provisionally that it is liquid carbonic acid , which , like water , should therefore be classed amongst natural liquid mineral substances . Brewster has shown ? that when cavities in topaz contain less than onethird of their volume of the expansible liquid , it does not expand when heated , but passes entirely into the state of a compressed vapour . Un " Pogg . Ann. vol. cv . p. 460 . t Gmelin 's Handbook of Chemistry , Cavendish Society 's Translation , vol. i. p. 225 . + Liebig 's Ann. vol. cx . p. 1 . ? Trans Roy . Soc. Edin . vol. x. p. 25 . fortunately he does not state the temperature at which this occurs , nor does he seem to have tried to ascertain the exact limit of the volume , which must , however , lie between one-half and one-third . Cagniard-Latour * found that when ether and other liquids sealed up in small strong tubes , with a certain space left empty , were heated , they expanded very much , and suddenly passed into the state of vapour . The temperature , pressure , and volume at which this change took place varied very considerably . Ether expanded to nearly double its volume , and passed into vapour at about 200 ? C. , with an elastic force of 37 or 38 atmospheres . Alcohol expanded to about three times its volume , and passed into vapour at about 260 ? C. , with an elastic force of 119 atmospheres ; whereas water appeared to expand to nearly four times its volume , and required a temperature near that at which zinc melts ( 328 ? C. , Daniel ) . When in this highly expanded state , the liquids were very mobile , and seemed much more compressible than under other circumstances ; for they did not burst the tube , if too much had been sealed up in it , until after their normal volume would have been decidedly greater than its capacity . No one could fail to see that these phenomena have much in common with what occurs at a lower temperature in the case of the liquid enclosed in sapphire , and that they are of great importance in connexion with the origin of fluid-cavities . Since they become full of liquid at a comparatively low temperature , it was not unreasonable to suppose that the minerals in which they occur must have been formed where the heat was scarcely above that of the atmosphere ; but these facts seem to show that the occurrence of such fluid-cavities is quite reconcilable with a very high temperature ; for it is obvious that if , at a great depth below the surface , heated , highly compressed yaseous carbonic acid were enclosed in growing crystals , it might condense on . cooling so as to more or less completely fill the cavities with the liquid acid . If the same principles could be applied in the case of water , we should be led to infer that it could not exist in a liquid state at a higher temperature than that of dull redness , corresponding closely with what Mr. Sorby deduced from the fluid-cavities in some volcanic rocks . In that case , according to Cagniard-Latour , the liquid when condensed would occupy only one-fourth part of the cavity , and it would scarcely be likely to contain any fixed salt in solution ; whereas the fluid-cavities in the minerals of ejected blocks are often two-thirds full of what seems to have been a supersaturated solution of alkaline chlorides . The phenomena now under consideration should certainly be borne in mind in studying volcanic action ; and it is possible that some cavities now containing water may have been formed by the enclosure of very highly compressed steam . In some cases the requisite pressure would be enormous , and other facts seem to show that it was more generally caught up in a liquid state . The cavities in emerald are very interesting in connexion with this subject , and also furnish strong evidence against the opinion that the liquid was not present when the crystals were formed , but penetrated into the fluid-cavities at a subsequent period , and either filled vacant spaces , or removed and replaced the material of glass cavities , as suggested by Vogelsang I. In the specimens which we have examined , each of the cavities contains what is no doubt an aqueous saline solution , and , as shown by fig. 8 , one or more cubic crystals , probably chloride of potassium , which dissolve on the application of heat , and are deposited again on cooling . These cavities are thus analogous to those met with in the quartz of some granite , and in the minerals of blocks ejected from Vesuvius ; and it seems difficult , if not impossible , to explain them except by supposing that a strong saline solution was caught up by the mineral at the time of its formation . In some cases the amount of such saline matter is so great in comparison to the liquid , that a high temperature would be requisite to make it all dissolve . It also seems probable that , if water could penetrate into such crystals , it would soon be lost when they were kept dry . This certainly occurs in some soluble salts , especially those containing combined water , and in some minerals of loose texture ; but we have never seen evidence of it when fluid-cavities are completely enclosed in hard and dense substances like quartz or emerald . Though in some instances the size of the bubbles does not bear a uniform relation to that of the cavities , yet in many cases the general proportion is very similar in each specimen ; and the exceptions can easily be explained by supposing that occasionally small bubbles of gas were caught up along with the water , or that there was some variation in either temperature or pressure during the growth of the crystal ; all of which conditions were discussed in Mr. Sorby 's paper already referred to . We have not had the opportunity of studying many examples of cavities which contain two fluids , probably water and liquid carbonic acid , and therefore forbear to say much about them . According to Brewstert the temperature at which those in topaz become full corresponds very closely with what we have observed in the case of sapphire , so that the carbonic acid might have been enclosed either as a highly dilated liquid , or as a highly compressed gas ; but since the other liquid has deposited crystals which dissolve on the application of heat+ , it seems most probable that the water was caught up in a liquid state , sometimes perhaps holding a considerable amount of carbonic acid in solution as a gas . On the whole , therefore , the various facts described in this paper seem to show that ruby , sapphire , spinel , and emerald were formed at a moderately high temperature , under so great a pressure that water might be present in a liquid state . The whole structure of diamond is so peculiar that it can scarcely be looked upon as positive evidence of a high temperature , though not at all opposed to that supposition . The absence of fluid-cavities containing water or a saline solution does not by any means prove that water * Philosophie der Geologic und mikroskopisehe Gesteinsstudien , ( Bonn , 1867)pp . 155 , 196 . 1Trans . Roy . Soc. Edin . vol. x. p. 1 et seq. . See Brewstcr 's paper , Phil. Mag. 1847 , vol. xxxi . p. 497 , z 0Mr . Huuggins on Solar Pronzinences . C)~~~~~~~~~~ was entirely absent , because the fact of its becoming enclosed in crystals depends so much on their nature . At the same time the occurrence of fluid-cavities containing what seems to be merely liquid carbonic acid is scarcely reconcilable with the presence of more than a very little water in either a liquid or gaseous form . We may here say that we do not agree with those authors who maintain that the curved or irregular form of the fluid-cavities is proof of the minerals having been in a soft state , since analogous facts are seen in the case of crystals deposited from solution . EXPLANATION OF PLATE VII . Figs 1 . & 2 . Fluid-cavities in sapphire ; magnified 20 linear . Fig. 3 . Fluid-cavity in sapphire , partially divided by plates of sapphire ; mag . 50 . Fig. 4 . Branched fluid-cavity in sapphire ; mag . 50 . Fig. 5 . Crystal of spinel ? enclosed in ruby ; mag . 50 . Fig. 6 . Cavity in aquamarina , with two fluids ; mag . 150 . Fig. 7 . Cavity in ruby spinel ; mag . 100 . Fig. 8 . Fluid-cavity in emerald , with soluble crystals ; mag . 200 . Fig , 9 . Crystal enclosed in diamond , surrounded by a black cross , as seen with polarized light ; mag . 100 . Fig. 10 . Crystal enclosed in diamond , with a crack proceeding from it ; mag . 100 . Fig. 11 . Crystal enclosed in ruby , surrounded by a black cross , seen by polarized light ; mag . 75 . Figs. 12 & 13 . Crystals in ruby spinel , surrounded by various cracks ; mag . 50 . Sorby & Ja Baer -roc . J oI.o 3c oU,.XiZi Plae a 1Y . L~~ 11 C1I , 3 . , 6 . K\_"~ '/ - & H , C Sofby yael . V.H.Wesiey Ith . 0 M.,4 , O gU , 0 1 , 00.,3 O0I0 " O ? O ' a ; o 61 -PI 1.O . 11. . 12 W.Pe.t , izTurp . -11~5- , wftil Ai ii sXI I : I : I ift Ik.1 . 'k A1 8 . ~~ ~ , t WAt Ir > I.I ( Whij~:ir L ; " :~~~~~~~~~~~~~~~~ , "

112398

3701662

Note on a Method of Viewing the Solar Prominences without an Eclipse

302

303

Proceedings of the Royal Society of London

William Huggins

fla

6.0.4

http://dx.doi.org/10.1098/rspl.1868.0051

proceedings

http://corpora.clarin-d.uni-saarland.de/surprisal/6.0.3/?id=112398

10.1098/rspl.1868.0051

http://www.jstor.org/stable/112398

Optics

Astronomy

Optics

II . " Note on a Method of viewing the Solar Prominences without an Eclipse . " By WILLIAM HUGGINS , F.R.S. ReceivedFebruary 16 , 1869 . Last Saturday , February 13 , I succeeded in seeing a solar prominence so as to distinguish its form . A spectroscope was used ; a narrow slit was inserted after the train of prisms before the object-glass of the little telescope . This slit limited the light entering the telescope to that of the refrangibility of the part of the spectrum immediately about the bright line coincident with C. The slit of the spectroscope was then widened sufficiently to admit the form of the prominence to be seen . The spectrum then became so impure that the prominence could not be distinguished . A great part of the light of the refrangibilities removed far from that of C was then absorbed by a piece of deep ruby glass . The prominence was then distinctly perceived , something of this form . [ Feb. 18 , o03 A more detailed account is not now given , as I think I shall be able to modify the method so as to make the outline of these objects more easily visible .

112399

3701662

Additional Observations of Southern Nebulae

303

307

Proceedings of the Royal Society of London

J. Herschel

fla

6.0.4

http://dx.doi.org/10.1098/rspl.1868.0052

proceedings

http://corpora.clarin-d.uni-saarland.de/surprisal/6.0.3/?id=112399

10.1098/rspl.1868.0052

http://www.jstor.org/stable/112399

Astronomy

Atomic Physics

Astronomy

I. " Additional Observations of Southern Nebulae . " In a Letter to Professor STOKES , Sec. R.S. , by Lieut. J. HERSCHEL , R.]E . Communicated by Prof. STOKES . Received January 4 , 1869 . 3angalore , Dec. 1 , 1868 . DEAR SIR , -I have the pleasure to subjoin a few additions to my former list of Southern Nebulae spectroscopically examined . The observations extend from the 24th October to the 20th November . I will first enumerate those of which no trace of a spectrum of any kind has been detected , and which , I can with confidence state , have no other than a continuous spectrum . I am enabled to do this for the following reason-that even when the jaws of the slit were entirely removed , so as to command a perfectly free field of view ( in which stellar spectra were frequently recognized ) , no light from these objects was visible . That no doubt might remain as to the justice of this conclusion , three faint planetary nebulae were looked at in the same way , and were more or less easily recognized as spots of light in the spectroscopic field . It is much to be regretted that I did not long ago make the experiment ; had I done so I should unquestionably have saved myself many tedious hours lost in vain searching . The following may safely be erased from a list of nebulk to be examined for evidence of a " linear " character : Nos. 4757 . " Very bright ; pretty small . " 27 . " Very bright ; very large . " 67 . " Very bright ; large . " 1 62 . " Globular cluster ; bright ; large . " 163 . " Very bright ; large . " 339 . " Bright ; large . " *342 . " Very bright ; pretty large . " 361 . " Very bright ; very large . " 369 . " Bright ; pretty large . " t544 . " Very bright ; very large . " 604 . " Very bright ; pretty large . " t610 . " Very bright ; large . " " Very bright ; small . " 721 . " Bright ; large . " 731 . " Very remarkable ; very bright ; very large ; barely resolvable . " 741 . " Globular cluster ; bright ; pretty large . " 744 . J " Globular cluster ; very bright ; pretty large . " 746 . " Bright ; pretty small . " 748 . " Globular cluster ; very bright ; pretty large ; partially resolved . " 750 . J " Very bright ; pretty large . " 747 . } " Considerably bright ; pretty small . " 752 . J " Very bright ; large . " 755 . " Bright ; pretty small . " 767 . " Very bright ; large . " 808 . " Globular dluster ; bright ; considerably large ; partially resolved . " 823 . } " Bright ; very large . " 822 . J " Pretty bright ; pretty large . " 828 . " Very bright ; pretty small " 1009 . " Very bright ; very large ; partially resolved . " 1288 . " Globular clusteOr ; bright ; pretty large . " The following were not spectroscopically examined , only because they appeared too faint in the telescope : Nos. 279 . " Bright ; small . " 81 1 " Bright ; large . " 813 . " Bright ; large . " 815 . J " Pretty bright ; round . " 824 . " Very bright ; very large . " 916 . " Very bright ; large . " The follow ng wer'e C : not identifed : Nos. 73 . " Very bright ; small . " [ Not seen on three different nights , wi t clear sky . ] 243 . " Bright ; small . " Several small indistinct objects in the field . 273 . " Very bright ; small . " Not fund : two indepeendent settings gave the same field . 411 . " Bright ; small . " [ No remark . ] 670 . " Very bright ; round . " No such object . No. 685 precedes by 2min . , and has the same N.P.D. ; it appears as described , very iright in the mriddle , and has a small star involved . 769 " Globular cluster ; very bright- " Not f , :nd on two nights . Checked AI byNo . 767 ; " very bright ; large . " In searching for it , found a nebula which agreed well with No. 766 , " pretty faint ; small . " 1401 . " Very bright ; small . " Not recognized ; twice . I come now to those of which the spectrum has been recognized . The following have continuous spectra : Nos. 138 . " Very remarkable ; extremely bright ; extremely large . " A fine object , and certainly very bright ; but the spectrum was recognized with great difficulty ( through the slit ) . 600 . " Verybright ; pretty large ; partially resolved . " Spectrum continuous . 685 . " Globular cluster ; very bright ; pretty large ; round ; easily resolvable . " Spectrum continuous-readily . 697 . l " Very bright ; considerably large . " Spectrum continuous --without difficulty . 698 . J " Pretty bright ; pretty small . " ? ? 715 . " Very bright ; pretty small . " Spectrum continuous-barely visible . 748 . " Globular cluster ; very bright ; pretty large ; round ; partially resolved . " Spectrum continuous . 1061 . " Globular cluster ; remarkable ; very bright ; very large ; round ; well resolved . " Spectrum continuous-bright . 1076 . " Very bright ; large ; rouind ; barely resolvable . " Spectrum continuous . 4687 . " Remarkable ; globular cluster ; bright ; large ; stars . " Spectrum continuous-bright , almost stellar in middle . Lastly , I am able to report that one globular cluster proves to be of the same character as the " planetary " nebula , viz.:No . 826 . " Globular cluster ; very bright ; small ; round ; barely resolvable ( IV . 26 ) . " Spectrum " ; linear . " This object shows one principal , one secondary , and one very faint line in the usual places . It also shows an undoubted continuous spectrum , principally ( but not only ) on the more refrangible side . This is visible even when the slit is very narrow . T'he following measurements were taken-that of D by a spirit flame before the object-glass : Prin . line =5'17 ( D=3 ' 02 ) or D ? 2 16 . p , , =5 19 ( D=3',02)J No. 1225 . " A planetary nebula ; pretty bright ; very small ; very little extended ; barely resolvable " ? No spectrum of this planetary nebula had been obtained in April . It was now recognized instantly , and without the smallest doubt , as " linear , " or at least apparently monochromatic , in the open field of the 305 spectroscope . The position of the line has not been measured . No. 1565 . " A planetary nebula ; pretty bright ; pretty small ; extremely little extended ; barely resolvable . " The " linear " character of the spectrum of this object has been already recognized ; but it was again examined , as a test of the advantage of removing the slit . It is a considerably larger and less bright object than No. 1225 , and situated in a magnificent cluster of stellar points . In the open field of the spectroscope it appeared as a similar faint patch of light , in the midst of an infinity of streaks . Nothing could have bleen more conclusive as a test . No. 1185 . " IRemalkable ; very bright ; very large ; round ; with tail ; much brighter in middle , a star of 8'9 magnitude . " A neighbour of the great nebula of Orion . Examined with/ the slit repeatedly . On the first occasion the spectrum was described as " linear , but faintly seen ; not certainly seen in presence of the central star . When the latter is put out , the spectrum becomes broadly continuous , with monochromatic light across it . " On the next it was , " To-night I could trace no lines . There is ample light , but it is not 'linear , ' though certainly confined principally to the neighbourhood of the position of the ordinary lines . The spectrum in any case occupies nearly the width of the field , and is not much less in length . " On a third occasion I noted that I could " barely trace any lines , while there is a broad patch of spectral light on either side , which is certainly not due to the stellar centre . " The trace of lines is confirmed on a fourth occasion . I think I am justified in saying that we have here a -nebula of a class or description intermediate between those which show a clear continuous spectrum only , and those which show bright lines only . Not that the apparent character of these two extremes is necessarily absolute ; it is far more probable that the non-appearance in either , of the distinguishing characteristic of the other , is relative only . Indeed there are net wanting instances of nebulae whose place in a series would be short of the latter extreme . For instance , No. 826 , suplra , and No. 4964 . " Extremely remarkable ; a planetary nebula ; very bright ; pretty small ; round ; blue . " Presented " a continuous spectrum and a fourth line ( besides the three usual ones ) ; the first strongly suspected , the last less so . " The fourth line I find has been noted by Mr. Huggins . And the great nebula of Orion appears to be of the same order . I have examined this nebula repeatedly of late , because on the first occasion of looking at No. 1185 I had appended a remark that " the principal nebula shows a great deal of continuous light on this side , " an observation which seemed to require confirmation . The following extracts from my notebook must speak for themselves : No. 1179 . The great Nebula of Orion . Oct. 25 . " A fourth line , almost beyond question : measured twice with reference to principal line , 7'3-5'05 =2'25 , 7-6-5'06=2'54 , mean 2-4 ; con . tinuous spectrum suspected , but , owing to moonlight and low altitude , there was no conviction . " Nov. 7 . " Previous observation confirmed . The fourth line is a fact . The diffused light , which also is certainly visible , to the extent of rendering the edges of the field visible beyond the immediate neighbourhood of the lines , can only be a continuous spectrum . " Nov. 9 . " Fourth line , 7'9-5'1=-2'8 , very rough . I am satisfied that there is a continuous spectrum , though I am not certain it may not be dispersed stellar light . " Ditto , later : " I have no longer any hesitation as to the continuous spectrum . " Nov. 10 . " Fourth line , 7'92 , 7'88 , 7-91 , --5'09 2'81 * . Continuous spectrum distinctly ending coincidently with the bright lines at the edge of the bright part of the nebula . " 'here is nothing very remarkable in the presence either of an additional line or of a continuous spectrum ; but as this nebula has been examined very carefully in England without the detection of eithert , it appeared necessary to put both beyond question ; taken , too , in connexion with the very different character of its near neighbour , 1185 , and with others in which the relative intensity of the two kinds of spectra varies in degree , it appears to break down , to a considerable extent , the barrier between " gaseous " and " solid " nebulous matter , and to lead towards the inference that condensation is in a more or less advanced stage in all nebulae , and in the vast majority of cases , including all " clusters , " has become complete . I am sorry to say that I shall be unable to prosecute these observations for some months , as my survey duties require my presence elsewhere . In the meanwhile I should be glad to learn whether the course I have been pursuing appears a desirable one to continue , now that so large a number of the southern nebule have been tested , or whether a reexamination would be preferred . I remain , dear Sir , yours truly , J. IHERSCHEL .

112400

3701662

Note on the Separation of the Isomeric Amylic Alcohols Formed by Fermentation

308

309

Proceedings of the Royal Society of London

Ernest T. Chapman|Miles H. Smith

fla

6.0.4

http://dx.doi.org/10.1098/rspl.1868.0053

proceedings

http://corpora.clarin-d.uni-saarland.de/surprisal/6.0.3/?id=112400

10.1098/rspl.1868.0053

http://www.jstor.org/stable/112400

Chemistry 2

Optics

Chemistry

II . " Note on the Separation of the Isomeric Amylic Alcohols formed by Fermentation . ' By ERNEST T. CHAPMAN and MILES H. SMITI- . Communicated by Prof. E. W. BRAYLEY . Received January 14 , 1869 . At present we are acquainted with two amylic alcohols formed by fermentation . They were discovered by Pasteur , who observed that different specimens of amylic alcohol caused a ray of polarized light to rotate to different degrees . He succeeded in devising a separation of these alcohols , which consisted in converting them into sulphamylates of barium and recrystallizing these salts . The one alcohol is without action on polarized light , and the other rotates it . This method of separation is beset with great practical difficulties , and has , we believe , only once been repeated , viz. by Mr. Peddler . He gives no detailed account of the separation , but gives some of the leading properties of the alcohols . He found that the rotating alcohol caused a ray of polarized light to rotate 17 ? with a column of 500 millims. of liquid . The following are some examples of the rotations effected by eleven different samples of amylic alcohol in a column of 385 millims. For comparison with Pedler 's number , the observed numbers have been reduced in the second column to observations on 500 millims.:Designation of Rotation observed on Reduced to observations specimen . column of 585 millims. on 500 millims. 00 1 . 3-5 4-55 2 . 3-7 4-81 3 . 4 5-2 4 . 3.7 4-81 5 . 4.7 6.11 6 . 4 5-2 7 . 3.5 4-55 8 . 2-7 3.51 9 . 5 6-5 10 . 4 5-2 11 . 3-8 4-94 Pedler 's rotating alcohol ... ... ... ... ... ... ... ... . 17'0 If Pedler 's number be absolutely correct , it follows that these specimens of amylic alcohol cotntained from 15*9 per cent. as a minimum , to 38 2 as a maximum of the rotating alcohol . The boiling-points of the whole of the samples lay between 131 ? -5 and 133 ? . We have effected the separation of these alcohols more simply . If soda , potash , chloride of calcium , or , apparently , any salt easily soluble in amylic alcohol be dissolved in that alcohol at the boiling-point , and the saturated solution be distilled , the non-rotating alcohol will be to a great extent retained and the rotating alcohol distils off . The substance which appears to lend itself most conveniently to this operation is caustic soda . Amylie alcohol is boiled with excess of caustic soda ; when saturated , 308 Mr. tHuggins on the Heat of the Stars . the hot solution is decanted into a flaskl and distilled from an oil-bath , the temperature of which may be allowed to rise to 200 ? . The alcohol distils off at first readily , after a while with greater difficulty ; finally the contents of the distilling flask solidify , and it becornes extremely difficult to drive over any more amylic alcohol . On now adding water to the contents of the flask and again distilling , amylic alcohol comes over of about half the rotating power of the alcohol employed . If the power of rotation be very small , the reduction is considerably greater ; thus , operating on an alcohol rotating 1 ? '3 on the 385 millims. , by one operation we have reduced it to 0'3 . By a sufficient number of repetitions of the process , it is possible.to effect a separation of the alcohols , and very easy to obtain considerable quantities of the non-rotating alcohol quite pure . No valerianic acid is formed ; and the soda-solution remaining in the flask after the operation is completed is barely coloured . The separation of the alcohols may also be effected by dissolving metallic sodium in amylic alcohol , and distilling , &c. , as above described , the resulting solution of amylate of soda in amylic alcohol . The process appears to present no point of advantage over that with caustic soda . We shall shortly publish a detailed account of differences in structure of these alcohols , together with a description of some of their principal derivatives .

112401

3701662

Note on the Heat of the Stars

309

312

Proceedings of the Royal Society of London

William Huggins

fla

6.0.4

http://dx.doi.org/10.1098/rspl.1868.0054

proceedings

http://corpora.clarin-d.uni-saarland.de/surprisal/6.0.3/?id=112401

10.1098/rspl.1868.0054

http://www.jstor.org/stable/112401

Astronomy

Electricity

Astronomy

III . " Note on the Heat of the Stars . " By WILLIAM HUGGINS , F.R.S. lReceived February 18 , 1869 . In the summnner of 1866 it occurred to me that the heat received on the earth from the stars might possibly be more easily detected than the solar heat reflected from the moon . Mr. Becker ( of Messrs. Elliott Brothers ) prepared for me several thermopiles , and a very sensitive galvanometer . Towards the close of that year , and during the early part of 1867 , I made numerous observations on the moon , and on three or four fixed stars . I succeeded in obtaining trustworthy indications of stellar heat in the case of the stars Sirius , Pollux , and Regulus , though I was not able to make any quantitative estimate of their calorific power . I had the intention of making these observations more complete , and of . extending them to other stars . I have refrained hitherto from making them known ; I find , however , that I cannot hope to take up these researches again for some months , and therefore venture to submit the observations in their present incomplete form . An astatic galvanometer was used , over the upper needle of which a small concave mirror was fixed , by which the image of the flame of a lamp could be thrown upon a scale placed at some distance . Usually , however , I preferred to observe the needle directly by means of a lens so placed that the divisions on the card were magnified , and could be read by the observer when at a little distance from the instrument . The sensitiveness of the instrument was made as great as possible by a very careful adjustment from time to time of the magnetic power of the needles . The extreme delicacy of the instrument was found to be more permanently preserved when the needles were placed at right angles to the magnetic meridian during the time that the instrument was not in use . The great sensitiveness of this instrument was shown by the needles turning through 90 ? when two pieces of wire of different kinds of copper were held between the finger and thumb . For the stars , the images of which in the telescope are points of light , the thermopiles consisted of one or of two pairs of elements ; a large pile , containing twenty-four pairs of elements , was also used for the moon . A few of the later observations were made with a pile of which the elements consist of alloys of bismuth and antimony . The thermopile was attached to a refractor of eight inches aperture . I considered that though some of the heat-rays would not be transmitted by the glass , yet the more uniform temperature of the air within the telescope , and some other circumstances , would make the difficulty of preserving the pile from extraneous influences less formidable than if a reflector were used . ci/ /f/ // e Ueill / W___ E j < \ s39I y ---------I h The pile a was placed within a tube of cardboard , b ; this was enclosed in a much larger tube formed of sheets of brown paper pasted over each other , c. The space between the two tubes was filled with cotton-wool . At about 5 inches in front of the suiface of the pile , a glass plate ( e ) was placed for the purpose of intercepting any heat that might be radiated from the inside of the telescope . This glass plate was protected by a double tube of cardboard , the inner one of which ( d ) was about half an inch in diameter . The back of the pile was protected in a similar way by a glass plate ( g ) . The small inner tube ( h ) beyond the plate was kept plugged with cottonwool ; this plug was removed when it was required to warm the back of the pile , which was done by allowing the heat radiated from a candle-flame to pass through the tube to the pile . The apparatus was kept at a distance of about 2 inches from the brass tube by which it was attached to the telescope by three pieces of wood ( i ) , for the purpose of cutting off as much as possible any connexion by conduction with the tube of the telescope . The wires connecting the pile with the galvanometer , which had to be placed at some distance to preserve it from the influence of the ironwork of the telescope , were covered with gutta percha , over which cotton-wool was placed , and the whole wrapped round with strips of brown paper . The binding-screws of the galvanometer were enclosed in a small cylinder of sheet gutta percha , and filled with cotton-wool . These precautions were necessary , as the approach of the hand to one of the binding-screws , or even the impact upon it of the cooler air entering the observatory , was sufficient to produce a deviation of the needle greater than was to be expected from the stars . The apparatus was fixed to the telescope so that the surface of the thermopile would be at the focal point of the object-glass . The apparatus was allowed to remain attached to the telescope for hours , or sometimes for days , the wires being in connexion with the galvanometer , until the heat had become uniformly distributed within the apparatus containing the pile , and the needle remained at zero , or was steadily deflected to the extent of a degree or two from zero . When observations were to be made , the shutter of the dome was opened , and the telescope , by means of the finder , was directed to a part of the sky near the star to be examined where there were no bright stars . In this state of things the needle was watched , and if in four or five minutes no deviation of the needle had taken place , then by means of the finder the telescope was moved the small distance necessary to bring the image of the star exactly upon the face of the pile , which could be ascertained by the position of the star as seen in the finder . The image of the star was kept upon the small pile by means of the clock-motion attached to the telescope . The needlewas then watched during five minutes or longer ; almost always the needle began to move as soon as the image of the star fell upon it . The telescope was then moved , so as to direct it again to the sky near the star . Generally in one or two minutes the needle began to return towards its original position . In a similar manner twelve to twenty observations of the same star were made . These observations were repeated on other nights . The mean of a number of observations of Sirius , which did not differ greatly from each other , gives a deflection of the needle of 2 ? . The observations of Pollux 1 ? . No effect was produced on the needle by Castor . Regulus gave a deflection of 3 ? . In one observation Arcturus deflected the needle 3 ? in 15 minutes . The observations of the full moon were not accordant . On one night a sensible effect was shown by the needle ; but at another time the indications of heat were excessively small , and not sufficiently uniform to be trustworthy . It should be stated that several times anomalous indications were observed , which were not traced to the disturbing cause . The results are not strictly comparable , as it is not certain that the sensitiveness of the galvanometer was exactly the same in all the observations , still it was probably not greatly different . Observations of the heat of the stars , if strictly comparable , might be of value , in connexion with the spectra of their light , to help us to determine the condition of the matter from which the light was emitted in different stars . I hope at a future time to resume this inquiry with a larger telescope , and to obtain some approximate value of the quantity of heat received at the earth from the brighter stars .

112402

3701662

On the Fracture of Brittle and Viscous Solids by Shearing

312

313

Proceedings of the Royal Society of London

W. Thomson

fla

6.0.4

http://dx.doi.org/10.1098/rspl.1868.0055

proceedings

http://corpora.clarin-d.uni-saarland.de/surprisal/6.0.3/?id=112402

10.1098/rspl.1868.0055

http://www.jstor.org/stable/112402

Measurement

Fluid Dynamics

Measurement

IV . " On the Fracture of Brittle and Viscous Solids by Shearing . ' " By Sir W. THOMsON , , F.R.S. Received January 2 , 1869 . On recently visiting Mr. Kirkaldy 's testing works , the Grove , Southwark , I was much struck with the appearances presented by some specimens of iron and steel round bars which had been broken by torsion . Some of them were broken right across , as nearly as may be in a plane perpendicular to the axis of the bar . On examining these I perceived that they had all yielded through a great degree to distortion before having broken . I therefore looked for bars of hardened steel which had been tested similarly , and found many beautiful specimens in M ? r. Kirkaldy 's museum . These , without exception , showed complicated surfaces of fracture , which were such as to demonstrate , as part of the whole effect in each case , a spiral fissure round the circumference of the cylinder at an angle of about 45 ? to the length . This is just what is to be expected when we consider that if ABDC ( fig. 1 ) represent an infinitesimal square on the surface of a round bar with its sides AC and BD parallel to the axis of the cylinder , before torsion , and AB D ' CO the figure into which this square becomes distorted just before rupture , the diagonal AD has become elongated to the length A D ' , and the diagonal BC has become contracted to the length B C ' , and that therefore there must be maximum tension everyFig , 1 . Fig. 2 . C ( C _ __ C J ; D / 7_ Dt A B.A.'p--where , across the spiral of which B C ' is an infinitely short portion . But the specimens are remarkable as showing in softer or more viscous solids a tendency to break parallel to the surfaces of " shearing " A B , C D , rather than in surfaces inclined to these at an angle of 45 ? . Through the kindness of Mr. Kirkaldy , his specimens of both kinds are now exhibited to the Royal Society . 01 a smaller scale I have made experiments on round bars of brittle sealing-wax , hardened steel , similar steel tempered to various degrees of softness , brass , copper , lead . Sealing-wax and hard steel bars exhibited the spiral fracture . All the other bars , without exception , broke as l3Mr . Kirkaldy 's soft steel bars , right across , in a plane perpendicular to the axis of the bar . These experiments were conducted by Mr. Walter Deed and Mr. Adam Logan in the Physical Laboratory of the University of Glasgow ; and specimens of the bars exhibiting the two kinds of fracture are sent to the Royal Society along with this statement . I also send photographs exhibiting the spiral fracture of a hard steel cylinder , and the " shearing " fracture of a lead cylinder by torsion . These experiments demonstrate that continued " shearing " parallel to one set of planes , of a viscous solid , developes in it a tendency to break more easily parallel to these planes than in other directions , or that a viscous solid , at first isotropic , acquires " cleavage-planes " parallel to the planes of shearing . Thus , if CD and AB ( fig. 2 ) represent in section two sides of a cube of a viscous solid , and if , by " shearing " parallel to these planes , CD be brought to the position C ' D ' , relatively to AB supposed to remain at rest , and if this process be continued until the material breaks , it breaks parallel to AB and C ' D ' . The appearances presented by the specimens in Mr. Kirkaldy 's museum attracted my attention by their bearing on an old controversy regarding Forbes 's theory of glaciers . Forbes had maintained that the continued shearing motion which his observations had proved in glaciers , must tend to tear them by fissures parallel to the surfaces of " shearing . " The correctness of this view for a viscous solid mass , such as snow becoming kneaded into a glacier , or the substance of a formed glacier as it works its way down a valley , or a mass of debris of glacier-ice , reforming as a glacier after disintegration by an obstacle , seems strongly confirmed by the experiments on the softer metals described above . I-opkins had argued against this view , that , according to the theory of elastic solids , as stated above , and represented by the first diagram , the fracture ought to be at an angle of 45 ? to the surfaces of " shearing . " There can be no doubt of the truth of Hopkins 's principle for an isotropic elastic solid , so brittle as to break by shearing before it has become distorted through more than a very small angle ; and it is illustrated in the experiments on brittle sealing-wax and hardened steel which I have described . The various specimens of fractured elastic solids now exhibited to the Society may be looked upon with some interest , if only as illustrating the correctness of each of the two seemingly discrepant propositions of those two distin . guished men .

112403

3701662

Note by Professor Cayley on His Memoir on the Conditions for the Existence of Three Equal Roots, or of Two Pairs of Equal Roots, of a Binary Quartic or Quintic

314

314

Proceedings of the Royal Society of London

Professor Cayley

fla

6.0.4

http://dx.doi.org/10.1098/rspl.1868.0057

proceedings

http://corpora.clarin-d.uni-saarland.de/surprisal/6.0.3/?id=112403

10.1098/rspl.1868.0057

http://www.jstor.org/stable/112403

Formulae

Biography

Mathematics

V. Note by Professor CAYLEY on his Memoir ' " On the Conditions for the Existence of Three Equal Roots , or of Two Pairs of Equal Roots , of a Binary Quartic or Quintic . " Received February 20 , 1869 . The title is a misnomer ; I have in fact , in regard to the quintic , considered not ( as according to the title and introductory paragraph I should have done ) the twofold relations belonging to the root-systems 311 and 221 respectively , but the threefold relations belonging to the root-systems 41 and 32 respectively . The word " quadric , " p. 582 , line 1 , should be read '"cubic . " The proper title is , " On the Conditions for the Existence of certain Systems of Equal Roots of a Binary Quartic or Quintic . "

112404

3701662

Appendix to the Description of the Great Melbourne Telescope. [Abstract]

314

317

Proceedings of the Royal Society of London

T.R. Robinson

abs

6.0.4

proceedings

http://corpora.clarin-d.uni-saarland.de/surprisal/6.0.3/?id=112404

http://www.jstor.org/stable/112404

Optics

Astronomy

Optics

I. " Appendix to the Description of the Great Melbourne Telescope . " ByT . R.RoBINSON , D.D. , F.R.S. , &c. Received February10,1869 . ( Abstract . ) Since this paper was read the author has made several observations of the quantity of light transmitted by object-glasses , and determined the index of absorption in various specimens of glass . The results of some of these are in accordance with the opinion expressed in the paper ; but others present a difference which is very satisfactory as indicating a surprising progress in the manufacture of optical glass . The observations were made by means of Zollner 's photometer . The following results were obtained for the intensity of the light transmitted by a variety of object-glasses : Description . Aperture . Focus . Intensity . in . in . a. Triple object-glass ... ... ... ... ... ... ... . . 2-75 48 0-5497 b. Double ... ... ... ... ... ... ... ... ... ... ... 3'80 63 0-5962 c. Double ... ... ... ... ... ... ... ... ... ... ... ... . 3-25 48 0-6567 cl. Double ... ... ... ... ... ... ... ... ... ... ... ... . . 6-50 96 0-6772 e. Double ... ... ... ... ... ... ... ... ... ... ... ... . . 550 0-7928 e. Double ... ' ... , 07928 f. Double , inner surface cemented ... ... ... 500 ... 08739 g. Double , cemented ... ... ... ... ... ... . . 12-00 224 0-8408 h. Double ... ... ... ... ..3 ... ... ... ... ... . . 320 ... 07393 Of the above , a belongs to the Armagh Observatory ; it is by one of the Dollonds , older than 1790 , and is probably one of their first attempts at a triple combination . b is the original object-glass of the Armagh circle ; it was made by Tulley about 1828 ; the crown is greenish , and is supposed to be English ; the flint is believed to have been from Daguet . c was made for the author by Tulley in 1838 ; its glass is French , the crown is greenish . d is by Cauchoix ; the crown is greenish , and has probably a high n , but its mean thickness is only 0'39 . e is by Messrs. Cooke ; the glass is Chance 's . f is by Grubb , the glass Chance 's : the very high transmission of this lens is in part due to the cementing of the adjacent surfaces , which , while it makes more difficult the correction of spherical aberration , removes almost entirely the reflection at a surface of crown and one of flint : the factor for this =0-9036 ; and if the I be multiplied by this , we obtain 0'7806 , nearly that of e , the difference being due to the reflectiln at the film of cement . g is also by Grubb , and cemented ; the glass is by Chance . A is by Fraunhofer . On examining this Table the progressive increase in the light of the object-glasses is evident . The first two , which may be considered good specimens of the early achromatics , have less illuminating-power than the Herselielian reflector . A great advance was made by Guinand and those who followed in his steps ; and a still greater one by Chance , whose glass is nearly perfect as to colour and transparency . The same inference follows from the author 's measure of the index of 2A2 " absorption , . The specimens examined wre , with two exceptions , prisms ; and this form is very convenient . If a ray is incident on an isosceles prism parallel to its base , it emerges parallel to itself after undergoing total internal reflection at the base ; and the length of the path of the light within the glass , and the loss by the two reflections , are easily calculated from the known angle and refractive index . The mean index used in the calculation was that of the line E. The results are given in the following Table , in which are introduced those given in the paper that they may be referred to at once ; and there is added to them one found in Bouguer 's 'Traite d'Optique , ' which seems trustworthy . Description . 9 1 . Prism , originally Captain Kater 's ... ... 0'1829 2 . French plate , 3Mr . Gribb ... ... ... . . 0-1728 3 . London plate , Mr. Grubb ... ... ... ... 02140 4 . Two of same , Mr. Grubb ... ... ... ... 01446 5 . Prism , Mr. Grubb ... ... ... ... ... ... 0-0617 6 . Bouguer 's glass ... ... ... ... ... ... 0 1895 7 . Gassiot 's prisms ... ... ... ... ... ... . . 06209 8 . Prism by Dubosq , flint ... ... ... ... . . 0-1504 9 . Prism by Merz , flint ... ... ... ... ... . 01089 10 . Prism by Merz , crown ... ... ... ... ... . 0-0858 11 . Prism by Merz , flint ... ... ... ... ... . 01065 12 . Prism by Grubb ... ... ... ... ... ... . . 0-0218 13 . Cylinder of crown ... ... ... ... ... ... 0-0272 14 . Cylinder of flint ... ... ... ... ... ... . . 0'0090 No. 1 was shown to the author in 1830 by Captain Kater , as the chefd'cuvre of the Glass-Committee ; he used it as the small speculum of his Newtonian . Afterwards it came into the possession of the late Lord Rosse , who made the above measures with Bunsen 's photometer in 1848 . It is English plate , greenish . Nos. 2 , 3 , 4 , 5 were measured by Mr. Grubb in 1857 . No. 5 was a prism of 90 ? . He does not remember its history ; but evidently it was of Chance 's glass . No. 6 is described by Bouguer as " glace , " 3 Paris inches thick . It was probably that of St. Gobain , which has probably not varied in composition , and its ! a has been used in the computation . No. 7 consists of two prisms of 60 ? , which Mr. Gassiot , with his*'wonted kindness , entrusted to the author for some inquiries about the improvement of the spectroscope . They are by Merz , of glass which seems nearly identical with Faraday 's dense glass , having a specific gravity of 5-1 , and a mean p =17664 . It is very pellucid , but , like its prototype , has a yellowish tinge , probably given by the large proportion of lead . As Merz does not polish the base or ends of his prisms , the usual method could not be employed ; but the prisms were put together with the angles opposed , and a drop of olive-oil between , and the reflections allowed for . The great absorption is remarkable , and apparently cannot be explained by the colour of the glass . No. 8 is of 60 ? ; its p for E= 1620 . It is free from colour , and an evident improvement on the earlier ones . No. 9 , a prism of 90 ? , was given to the author by Dr. Lloyd for a small mirror in the Newtonian form of the Armagh 15-inch reflector ; its / for E= 16188 . No. 10 , of 90 ? , was obtained by the late Lord Rosse to be similarly used in his 3-feet Newtonian ; its p for E= 1-5321 . No. 11 , of 60 ? , obtained at Munich in 1837 . For these measures the ends were polished flat ; its Mt for E= 1'6405 . These three show considerable progress , and an object-glass made of such materials would have a great power of transmission , though much behind the following . No. 12 is of 90 ? . Its glass is from Chance ; its / for E=-16216 . No. 13 is a cylinder 2'2 inches in diameter , and 4'3 long , which Mr. Grubb obtained from Messrs. Chance for these measures ; its , for E= 15200 . No. 14 is a cylinder got at the same time , 2'1 inches in diameter and 4'4 long ; its u for E=1 6126 ; the ends of both are polished flat , and they are of wonderful transparency . If , as there is good ground for hoping , Messrs. Chance shall succeed in manufacturing large disks of the same perfection as these two cylinders , the author 's comparison of the achromatic and the reflector must be considerably modified . Assuming n='02 , he calculates that the aperture of an achromatic , of focal length equal to 18 times the aperture , equivalent to a 4-feet Newtonian , is 35*435 inches . This aperture would be diminished if the process of cementing were found applicable to lenses of such magnitude . The author concludes with suggesting that , as very slight variations in the manufacture of glass seem to make great changes in its absorptive power , it would be prudent to examine the value of n in the disks intended for lenses of any importance . This could be done by polishing a couple of facets on their edges , and need not involve the sacrifice of many minutes .

112405

3701662

Note on the Formation and Phenomena of Clouds

317

319

Proceedings of the Royal Society of London

John Tyndall

fla

6.0.4

http://dx.doi.org/10.1098/rspl.1868.0058

proceedings

http://corpora.clarin-d.uni-saarland.de/surprisal/6.0.3/?id=112405

10.1098/rspl.1868.0058

http://www.jstor.org/stable/112405

Thermodynamics

Chemistry 1

Thermodynamics

II . " Note on the Formation and Phenomena of Clouds . " By JOHN TYNDALL , LL. D. , F.R.S. Received January 25 , 1869 . It is well known that when a receiver filled with ordinary undried air is exhausted , a cloudiness , due to the precipitation of the aqueous vapour diffused in the air , is produced by the first few strokes of the pump . It is , as might be expected , possible to produce clouds in this way with the vapours of other liquids than water . In the course of the experiments on the chemical action of light which have been aready communicated in abstract to the Ioyal Society , I had frequent occasion to observe the precipitation of such clouds in the experimental tubes employed ; indeed several days at a time have been devoted solely to the generation and examination of clouds formed by the sudden dilatation of the air in the experimental tubes . The clouds were generated in two ways : one mode consisted in opening the passage between the filled experimental tube and the air-pump , and then simply dilating the air by working the pump . In the other , the experimental tube was connected with a vessel of suitable size , the passage between which and the experimental tube could be closed by a stopcock . This vessel was first exhausted ; on turning the cock the air rushed from the experimental tube into the vessel , the precipitation of a cloud within the tube being a consequence of the transfer . Instead of a special vessel , the cylinders of the air-pump itself were usually employed for this purpose . It was found possible , by shutting off the residue of air and vapour after each act of precipitation , and again exhausting the cylinders of the pump , to obtain with some substances , and without refilling the experimental tube , fifteen or twenty clouds in succession . The clouds thus precipitated differed from each other in luminous energy , some shedding forth a mild white light , others flashing out with sudden and surprising brilliancy . This difference of action is , of course , to be referred to the different reflective energies of the particles of the clouds , which were produced by substances of very different refractive indices . Different clouds , moreover , possess very different degrees of stability ; some melt away rapidly , while others linger for minutes in the experimental tube , resting upon its bottom as they dissolve like a heap of snow . The particles of other clouds are trailed through the experimental tube as if they were moving through a viscous medium . Nothing can exceed the splendour of the diffraction-phenomena exhibited by some of these clouds ; the colours are best seen by looking along the experimental tube from a point above it , the face being turned towards the source of illumination . The differential motions introduced by friction against the interior surface of the tube often cause the colours to arrange themselves in distinct layers . The difference in texture exhibited by different clouds caused me to look a little more closely than I had previously done into the mechanism of cloud-formation . A certain expansion is necessary to bring down the cloud ; the moment before precipitation the mass of cooling air and vapour may be regarded as divided into a number of polyhedra , the particles along the bounding surfaces of which move in opposite directions when precipitation actually sets in . Every cloud-particle has consumed a polyhedron of vapour in its formation ; and it is manifest that the size of the particle must depend , not only on the size of the vapour polyhedron , but also on the relation of the density of the vapour to that of its liquid . If the vapour were light , and the liquid heavy , other things being equal , the cloud-particle would be smaller than if the vapour were heavy and the liquid light . There would evidently be more shrinkage in tKe one case than in the other : these considerations were found valid througohut the experiments ; the case of toluol may be taken as representative of a great number of others . The specific gravity of this liquid is 0'85 , that of water being unity ; the specific gravity of its vapour is 3'26 , that of aqueous vapour being 0'6 . Now , as the size of the cloud-particle is directly proportional to the specific gravity of the vapour , and inversely proportional to the specific gravity of the liquid , an easy calculation proves that , assuming the size of the vapour polyhedra in both cases to be the same , the size of the particle of toluol cloud must be more than six times that of the particle of aqueous cloud . It is probably impossible to test this question with numerical accuracy ; but the comparative coarseness of the toluol cloud is strikingly manifest to the naked eye . ' The case is , as I have said , representative . In fact , aqueous vapour is without a parallel in these particulars ; it is not only the lightest of all vapours , in the common acceptance of that term , but the lightest of all gases except hydrogen and ammonia . To this circumstance the soft and tender beauty of the clouds of our atmosphere is mainly to be ascribed . The sphericity of the cloud-particles may be immediately inferred from their deportment under the luminous beams . The light which they shed when spherical is continuous : but clouds may also be precipitated in solid flakes ; and then the incessant sparkling of the cloud shows that its particles are plates , and not spheres . Some portions of the same cloud may be composed of spherical particles , others of flakes , the difference being at once manifested through the calmness of the one portion of the cloud , and the uneasiness of the other . The sparkling of such flakes reminded me of the plates of mica in the liver Rhone at its entrance into the lake of Geneva , when shone upon by a strong sun .

112406

3701662

On the Behaviour of Thermometers in a Vacuum

319

328

Proceedings of the Royal Society of London

Benjamin Loewy

fla

6.0.4

http://dx.doi.org/10.1098/rspl.1868.0059

proceedings

http://corpora.clarin-d.uni-saarland.de/surprisal/6.0.3/?id=112406

10.1098/rspl.1868.0059

http://www.jstor.org/stable/112406

Thermodynamics

Measurement

Thermodynamics

III . " On the Behaviour of Thermometers in a Vacuum . " By BENJAMIN LOEWY , F.R.A.S. Communicated by Prof. STOKEs , Sec. R.S. Received January 8 , 1869 . 1 . In the year 1828 General Sabine made a series of pendulum-experiments* in a receiver from which the air was exhausted , and observed incidentally that on the pump being worked the thermometer in the receiver fell about 7-tenths of a degree of Fahrenheit 's scale when the pressure was reduced to 7 inches , while the converse took place when the air was readmitted . He ascribed this effect to the removal of the pressure of the atmosphere on the exterior of the bulb and tube of the thermometer ; and to ascertain whether this explanation was correct the following experiment was made:-A thermometer being immersed in pounded ice and placed on the brass plate of an air-pump , the mercury coincided exactly with the division of 32 ? ; it was then covered with a receiver , and the air withdrawn ; the thermometer fell as the pump was worked , and when the gauge indicated a pressure of half an inch the mercury stood at 31 ? '25 ; on readmitting the air it rose again to 32 ? . The experiment was repeated , with precisely similar results ; and a correction was ultimately adopted , corresponding to the varying pressures in the receiver , in order to reduce the pendulum-experiments to the true temperature at which they were made . 2 . It was generally admitted that this apparent fall of the mercury arose from a change in the capacity of the interior of the thermometer ; and the physicists , especially the pendulum-experimenters who followed in General Sabine 's steps , never neglected this correction when their object was to discuss the results of experiments made in a vacuum , and in the reduction of which the temperature entered as an element . In the pendulum-experiments which were made at the Kew Observatory in connexion with the Great Trigonometrical Survey of India ( vide Proceedings of the Royal Society , No. 78 , 1865 ) , the thermometers used were , before the discussion of the observations , subjected to independent experiments , to determine tlieir " vacuum-correction , " which was found nearly the same for each of the two thermometers employed , viz. 0 ? 043 . In these experiments the two thermometers were suspended , together with another ( the latter enclosed in a sealed glass tube , and hence surrounded by air ) , in the receiver , and their readings taken some time after the exhaustion , sufficient to equalise its effect upon all three thermometers , bearing in mind the fact that the thermometer in the glass case would take a somewhat longer time for showing changes of temperature than those without such an enclosure . The arrangement of the experiments was precisely the same as that originally adopted by General Sabine ; and the precaution taken as regards the time of reading the different thermometers left no doubt on my mind that the observed difference of 0 ? '43 , by which amount the thermometers exposed to the effect of exhaustion were in every experiment found to read less than that enclosed in a glass tube , gave the required vacuum-correction in this particular case . It is also clear that in this method of carrying on the experiment the refrigeration due to the work done by the expanding air during the process of exhaustion will affect all thermometers alike , and that consequently the residual difference must be due to other causes . 3 . One point , however , was overlooked in these experiments , viz. to wait a number of hours and then to take another series of readings , in order to determine whether the effect of the removal of the atmosphere upon the capacity of a thermometer was only transient or permanent . Professor Oscar Meyer , in Breslau , was the first to call attention* to this question . While making some experiments on the internal friction of gases , he found that the primary effect of the exhaustion upon a thermometer was quite in accordance with the observations of General Sabine , but that after some time ( for the thermometer employed by him , after about half an hour ) this effect entirely disappeared . Captain Basevi , who has charge of the pendulum-experiments in India , communicated to me that the results of some experiments made by him strengthened Professor Meyer 's conclusion , and caused him grave doubts as to the necessity of applying the vacuum-correction in pendulum-experiments , one swing often lasting in such experiments from five to eight hours . 4 . It appeared to me that there were various sources of error in the experiments previously made . The only experiments which seem conclusive are those made by General Sabine with thermometers placed in ice ; but we are not informed in the account of these experiments how long each of them lasted , probably because there was no reason to regard the element of time as of importance . In the experiments made by comparing the thermometers with one enclosed in a glass tube and surrounded by air , it is obvious that the thermometers under comparison are throughout under different circumstances as regards their sensitiveness , and that this difficulty cannot be entirely overcome by allowing some time for the equalization of the original effect of the exhaustion . Again , it is questionable whether the glass tube which surrounds the thermometer which must be considered the standard of comparison has not , during the process of being closed up before the blowpipe , been so heated that the remaining air , instead of representing the pressure of a whole atmosphere , is really of a much less density . Further , there is the question of time , raised by Professor Meyer and Captain Basevi . In Professor Meyer 's experiments one thermometer was placed within the receiver , and another suspended outside , on the exterior of the receiver itself . JIe found that exhaustion lowered the reading of the former by from one-half to one degree of the centesimal scale , but that after about half an hour both thermometers agreed again : the readmission of air caused the thermometer in the receiver to rise by the same quantity by which it had previously fallen ; but after the lapse of some time the two thermometers read again alike . This lowering of the mercury on evacuation , and rising on readmission of the air , ceased almost entirely when the thermometer was introduced into the receiver immersed in dehydrated glycerine . From these observations Professor Meyer concludes that it is solely the mechanical labour of the air during expansion or compression which produces these fluctuations , and that they do not depend on the varying pressure upon the bulb of the thermometer . This conclusion may be correct as far as the particular thermometer is concerned which Professor Meyer employed , for it will be seen in the sequel that certain thermometers really behave exceptionally ; but it will also appear on examining the experiments given in Table II . that two thermometers , under precisely the same external circumstances , and in close juxtaposition , often differ in their readings by half a degree of Fahrenheit 's scale , and even more , without any assignable cause . We may obviously infer from this that two thermometers , arranged as in Professor Meyer 's experiments , are not strictly comparable when small differences of temperature have to be ascertained . 5 . In order to decide the question of the " vacuum-correction " by avoiding the above indicated sources of error , I had three _A pairs of thermometers made , each pair of equal shape 1 ? ] and size as regards bulb atid tube , but these pairs differing in this respect among themselves . These six thermometers were , in the manner which is shown in the annexed figure for one pair of them , enclosed in glass cases , which terminated in narrow tubes of about 5 inches in length . One case with its thermometer was left open at the top ( A ) , while the other ( A ' ) with the corresponding thermometer was closed by a rapid puff of the blowpipe , without the possibility of heating the enclosed air and thus diminiishing the pressure upon the enclosed thermometer . It ii Tliere were thus subjected to experiment six thersmoI |I meters , of three different forms , as may be seen from the , 'i following description of them:i ( 1 ) A* ( No. 6700 ) , Spherical 6bzlb , diameter of 'iulb 1 8| inch , length of stem 13 inches , enclosed in open i case . | ( 2 ) A ' ( No. 6701 ) , Spherical bulb , dianeter of bulb 2o inch , length of stem 13 inh ies , enclosed in shut case . | ( 3 ) B ( No. 6703 ) , Cylindrical bulb , 11 ? inchl long , i '3 inch wide , length of stem 15 inches , enclosed in 1i open case . || ; I %i ( 4 ) B ' ( No. 6702 ) , Cylindrical bulb , 1-u inch long , \ ) : I ~$ inch wide , length of stem 15 inches , encelosed in aI shut case . i J , =J ( 5 ) C ( No. 6704 ) , Spherical bulb , diameter of bulb inch , length of stem 27 inches , enclosed in open case . ( 6 ) C ' ( No. 6982 ) , Spherical bulb , diameter of bulb i inch , length of stem 27 inches , enclosed in shut case . The thermometers A , A ' , B , B ' represent the usual form and size of these instruments , while those marked C , C ' are unusually large , and would hardly be employed except for special purposes . The former had each degree divided into five parts , hence reading by estimation to of a degree , while the latter had each degree divided into ten parts , each of which occupied about the space of one degree in the common form ; T-1 of a degree of Fahrenheit 's scale could thus be read with thie uttmost accuracy . 6 . The thermometers and the receiver employed in these observations were made by Mr. L. Casella , who took the greatest interest in the purpose of the experiments , and consequently took especial care to make the instruments as perfect as possible . The thermometers were tested before putting them into the glass cases by comparing them from three to three degrees with the Kew standard , taking a great number of readings by two independent observers for this purpose . From this comparison and by interpolation , the following Table of corrections for every degree over the range of temperature during the experiments was constructed . It will not only prove that the utmost precaution was taken to ensure the experiments against errors inherent in the instruments employed , but will also show the excellency of the thermometers and the degree of accuracy now obtained by eminent makers in the construction of these instruments . TABLE I. Corrections to be applied to the Readings of the Thermometers . N.B. The corrections are in all cases subtractive . meters . 40 4I 424 ? ? 4 40 4 9514484990 500 ? ? 510 5o0 530 540 55 ? ? 5859 ? ? 6o ? No. 6700.Iz 2 12 '12 'I i 'S '7 '12II 'i3 6 'i9 I '17 'I7 9 '20 'I7 'I5 No. 6701 . '13 'I3 'I3 ' Iz2 '15 'I 19 '22 1'19 'I8 'I7 'IS 14 'IS 'I5 'I7 'I9 '20 " '9 '18 No. 6702 . 13 '*3 II '09 'o8 '09 'Io 'II 'II.1 'I I 'II 'I I ' 12 '13 '1 4 'I5 '13 'II No. 6703.'09 -09 '0I 'I2 'I3 'I6 'i8 '20 'I9 'I8 'i8 'I6 '13 'Io 'o8 '07 'o8 '09 'Io Io 'og No. 6704.'o9 0o9 'Io 'io " II 'I3 *I6 Ig9 '17 '15 'I3 'I3 'I 2 '12 *I ' '2 'I2 No. 6982 . '24 '24 '23 '22 '21 '22 '24 '25 '25 '25 '25 25 '26 '27 '28 '28 '30 '32 7 . The thermometers were placed in the receiver , arranged close to each other on a board fixed to a support , the four smaller thermometers on one side , the two larger ones on the other ; and the manner of proceeding with each experiment was the following . Before pumping , all the thermometers were twice read in rapid succession ; after exhausting the receiver to between one and two inches of pressure ( a manipulation which generally lasted about ten minutes ) , two or more readings were again taken to determine the " immediate effect of exhaustio n " on each thermometer . After an interval of several hours the thermometers were supposed to have assumed the surrounding temperature , and two readings were now taken for the '"residual effect of exhaustion . " The whole apparatus was then left undisturbed for nearly a whole day , when another set of readings were taken , and the apparatus was refilled . After readmission of the air the temperature shown by the instruments was immediately registered to find the heating-effect upon them of the inrush of air . The readings , both for the comparison of the instruments and during the experiments themselves , were taken alternately by Mr. Thomas Baker , Assistant at the Kew Observatory , and myself . By the kind permission of Mr. Balfour Stewart , Superintendent of the Kew Observatory , I was enabled to avail myself of the obliging assistance of Mr. Baker and his great experience in thermometric experiments . I take this opportunity of expressing to both these gentlemen my gratitude for the aid given to me in the pursuit of this inquiry . 8 . In the following Table I give the results of six experiments which were made for my purpose , leaving their discussion for the next paragraphs . A number of experiments made previously to these here given , in the large Kew receiver , had to be rejected ; for the apparatus has leaked latterly to a considerable amount during a day , causing a feeble but conTABLE II . Experiments for determining the Vacuum-correction of Thermometers . I 4-1 0 4 ? Z I. A A ' BC C ' 52'40 52'47 52'56 52'60 51-'82 51-48 50'56 5I'55 50'79 5r'55 50'21 50'-14 in . hm 3'07 3 I5 o. , ,r , o ? ?r e , , 50364 51-02 5o'45 50'92 50o63 50'57 3'I6 18 37 5I'47 52'79 5I'39 51'7 52'32 51-32 5x'3z 3'5c . , 53'44 53'03 53'08 52'99 52'79 52'33 II . A 5363 51'77 2'4 3 40 53'45 'zo2 20 15 48'972'47 50'55 A ' 5334 5'64 ... 53'85 ... . 49'45 ... ... 50'07 B 531'7 5I'62. . 53'26 ... 49'o9 ... ... 5083 B ' 53'24 52'45. . 53'74 ... . 49'45 ... ... 50'31 C 52z94 51'42. . 53'33 ... . 492. . 50'43 C ' 5'5o0 5I'3a. . 53'28 . 349'27 ... 49'95 II . A 509449 ' I'5163 2 20 537 I1 74 20 5 47-10 i ... . 4874 A'50-93 49'96 ... . 5 68 ... . 47'40 ... ... . 48'02 B 50'78 49'I3 ... . 5'1 ... . 46'97 ... ... 48'78 50'79 49'84 . 5 '58 | 47'32 - . I. . 48'20 ' 50267 494 ... . 5'o 96..8. . 6'. . 47-264 ' 50'z5 48'94 502..5. . 4 4 ... . 4696 4764 IV . nA 49'53 47'78 i'7l 3o 49-9z -8 9 55 '5 ... . 5272 A'49zo 20 48-29 50'.3 1. . 5o.54z3* 5Z'7 13 48994742 ... . 49'71 ? . . 5109 ... ... 52z86 ' 49o8 48 ' i I ... . 5015 ... .5 ' 47 ... ... 52-23 C 4880 47'28 ... . 49'65 ... . 50693 52.25 48 4 4703 ... . 4959 50'93 . i'6i V. A 55'03 52'64 i'6 o 35 52'68 I'I6 ! iS 5 47'55 43 ... ... 4896 A ' 54'86 53'69 ... . 53'20 . 48-05 ... ... 48-56 B 54-63 52-68 ... . 5370 ... . 47-86 ... ... . . 49'5 5 13 ' 54'77 53'55 ... . 53'6 I. 48I6 ... ... . . 4884 C 54'58 52'72 ... . 5290. . 47'73 48-88 C ' 54 ' ? 09 5z'6I. . 52'82. . ' 47'93| ... . 48'48 VI . A 5034 48-4 0-91o 025 ' 4933 o9I 20 0o43 0'024 50 4688I'44 48'52 A ' 50'16 49 ' 20 4972 429 ... . 473. . 4780 B 50-04 48-37 ... 49-2 ... . 4248. . 4.6-70 . 48-78 '50'o2 49 ... . 49'45 ... . 42'94 ... 4706. . 48'00 C 49'87 4819 ... . 49o6 ... . 42'60 ... . 4665. . 47'84 C ' 49'40 48-1 ... . 4889 ... . 4259 ... . 46'48. . 4723 I 0 ? e stant inrush of air , which vitiated the ultimate results . Only those experiments are here given and discussed which were made in a smaller receiver expressly constructed for my purposes by Mr. Casella . In this Table the corrected means of the individual observations are given , while a larger Table , embodying also the latter , has been deposited with the Royal Society for future reference . It is seen from this larger Table that the average amount of error in these observations is not more than about two-hundredths of a degree of Fahrenheit . In a very few cases only , where the thermal effect was not quite completed when the readings were taken , errors of about one-tenth of a degree occur ; care , however , was taken in these solitary cases to ascertain the completion of the effect by the more close agreement of a new series of observations . 9 . A glance at the preceding Table will at once show that the immediate effect of exhaustion is a fall , that of readmission of air a rise of all thermometers , and that there is at once a difference in the behaviour between the thermometers A ' , B ' , Ct , which are still surrounded by air , and A , B , C , which are in a vacuum . But this difference is also observable to a certain extent when the receiver is refilled , and when , as regards external pressure , all thermometers are in the same condition ; hence this immediate difference must have another cause than the supposed change in the capacity of the instruments ; at any rate if a permanent difference is found afterwards in consequence of such a change , it must be included in that difference which shows itself immediately . The cause of the latter is obvious . The thermometers in closed cases lag a little behind when they are affected by such sudden fluctuations as those produced in these experiments , and they assume , as the experiments have shown , the normal temperature a little later . The following Table gives the immediate fall and rise of all thermometers , observed respectively on evacuating and refilling the receiver , and the immediate mean difference between the differently placed thermometers . It exhibits a very close agreement between the effect of exhaustion and that of readmission of air ; but its more important practical purpose is to show that an error of nearly two degrees of Fahrenheit is made in thermometerreadings in a receiver immediately after exhazstion or readmission of air . Immediate effect of exhausting the Receiver . Thermometers falling . A. A ' . 3 ... C. C ' . Experiment 1 ... ... ... . 184 o9I x'77 1'o5 I'6i '34 , , II ... ... ... 86 0'70 I'55 0'79 I'52 x'8 , III ... ... . . 1-79 097 I'65 0'95 1'59 1I31 IV ... ... . . 1'75 o'9I I'57 0'97 1'52 'z23 V ... ... ... 2'39 II7 1'95 I'2 I '86 x'48 , , VI ... ... ... 2'Io 96 i'67 1'o0z '68 I'29 Means ... ... ... ... . '95 0-94 I'69 I'oo ir63 1'3o Differenoes immediately 69 observable . , ... . . o 'I ? '69 ? 33 Immediate effect of refilling the Receiver . Thermometers rising . A. A ' . B. B ' . C. C ' . oo Experiment I ... 97 1'24 , , II ... ... ... 158 o062 , , III ... ... ... 64 o'62 , , IV ... ... ... '47 0o56 , , ... . . I'1-41 o'5 VI ... ... . 64 067 Means ... ... ... ... ... ... o6z 070 Differences immediately observable ... ... . . ) 0'9z oo I169 I-28 1'74 o086 I'8I o088 '77 0o76 I-69 o'68 2'08 0'94 Ir63 o9go 0'73 oo I'47 I'oI I'22 o068 '30o o'68 1I20 o-68 I'15 0'55 1'38 0-75 I-29 0'73 0'56 10 . Now if this immediate difference would entirely disappear after some time(say , after a number of hours , or a whole day ) , or would become so small as to be within the limits of experimental errors , the question whether a vacuum-correction is necessary would have to be negatived . We may presume that after some time the refrigeration caused by the exhaustion disappears , and that the thermomieters are then solely or chiefly influenced by the temperature of the surrounding air ; if then a difference still appears in the behaviour of the thermometers , this permanent difference must obviously be caused by something independent of the temperature , and its source must be looked for in a change of the instruments themselves . The thermometers C , C ' ( that is , those with unusually large spherical bulbs and long stems ) differed in their behaviour entirely from the others of common form and size ; they will be spoken of afterwards . The thermometers A , A ' , B , B ' exhibited , on the contrary , as the following Table shows , constant differences when read from three hours to as long as two days after exhaustion . A , A ' , B , B ' signify in this Table the readings of the corresponding thermometers taken so lonR a time after exhaustion as to exclude all possibility of introducing the effect of it . The Table gives only the differences , the readings themselves are given in Table II . , with the times at which they were taken . A'-A . B'-B3 . o Experiment ... ... ... ... ... 38 0o32 , , II ... ... ... ... ... . . o'4.o II . 0o48 o'3o , , IY . , ... ... ... ... ... . 0'3 o50 , , VI ... ... ... ... ... . . o0-2I 0-50 Meal difference ... . . 037 o 047 ... ... ... ... ... . o0'47 ... ... ... ... ... ... ... ... o0-48 ... ... ... ... ... . 036.8 ... ... ... ... . 0-48 ... ... ... ... ... . 0'35 o'044 ... ... ... ... ... . 0'38 ... ... ... ... ... . 0'46 ... ... ..- ... . o0'30 ... ... ... ... ... . -'3 3.033 ... ... ... . . 0'46 ... ... ... ... ... . 0o-36 o ... s ... ... ... . 0'40 11 . These readings tell all the same thing , and taken separately agree closely with the mean result . If the result , found by another method , for the thermometers tested for the vacuum-correction during the pendulumexperiments for the Indian Survey , which gave 0 ? 43 , is added , it may be stated , as first result of these experiments , that a thermometer of common form and size will , if used in the vacuum of a receiver , require an additive correction of four-tenths of a degree of Fahrenheit 's scale , provided that no readings are taken until the immediate effect of exhaustion , which amounts to nearly two degrees , is equalised . 12 . The two large thermometers gave the following differences:-As some of them are in an opposite direction , I denote the expected differences by the sign + , and those on the wrong side by - . C'-C . C '-C . Experiment I ... ... . . -oo6 ExperimentIV ... ... ... . . -o-o6 0'00 0'00 II . - ... ... 05 , ,.-o08 +-oo6 +o020 , , III ... ... . . -oo6 , , VI . -0-7 +0-03 -0o'0 These results only strengthen the validity of the others ; for obviously we have , in regard to these large thermometers , in fact no other difference but that arising from experimental errors , local currents , &c. The first explanation of this behaviour that suggested itself was , that the thermometer which was supposed to be surrounded by air , had some flaw in the glass envelope , which allowed the air to escape during the pumping , so that there was really no difference of condition between it and its companion thermometer . A most careful examination of the case did not lead to the discovery of such a cause of leakage ; and as the thermometer in the closed case lagged behind the other in the same manner as the other thermometers in a similar condition did , I can only come to the conclusion that thermometers with large bulbs and stems really behave differently , or that the permanent effect of exhaulstion is imperceptible . [ With a view of determining whether the exceptional behaviour of the large thermometers could be accounted for by greater strength of their glass bulbs , Professor Stokes kindly suggested to me a comparison of the relative thickness of the glass of the bulbs by placing on it a very minute opaque dot , and measuring the apparent distance of the dot from its reflected image by a lens . I found the following results : 1st . The thickness of the glass varies not inconsiderably in different parts of the bulb of one and the same thermometer . 2nd . The thickness of the glass in the bulbs of the large thermometers was , on the average , twice that of the small spherical bulbs . 3rd . The thermometers with cylindrical bulbs had nearly three times the thickness of those with small spherical bulbs ; this thickness , however , was considerably less at the base of the cylinder . The behaviour of the large thermometers may thus be referred to their greater strength ; but it also appears that in thermometers with cylindrical bulbs great strength will not obviate the necessity of a vacuum-correction . -Added February 27th . ] 13 . In order to test the accuracy of the preceding results , the closed cases of the thermometers were opened ; hence all instruments were in the same condition when the receiver was exhausted . The result was the following : Thermometers . A. A ' . B. ' C. C. . Corrected lmean of readings 35 before exhaustion ... ... . . 56 56'03 56.23 56-o 55.'7 553 Corrected mean of readings 54 5424 544 5300 5303 after exhaustion ... ... . . 5365 4 544 544 53o 533 Corrected mean of readings 6 587 5185 after aninterval of 26h I5 556 57 547 5249 Differences ... ..'29 - . 0o'02 that is , the difference shown is either inappreciable , or due to accidental causes . 14 . These experiments have sufficiently established the fact that in vacuum-experiments due attention must be given to the causes which influence the thermometers employed in the receiver , and that in delicate experiments an independent determination of the vacuum-correction is indispensable . No new explanation of the cause of the permanent fall in a vacuum has suggested itself during the experiments . General Sabine 's original explanation , that the removal of the atmospheric pressure alters the capacity of the thermometer , is probably the most correct , especially when it is considered that the only objection ever raised against it , that of time reproducing the original state of the instrument , has been proved groundless by these experiments . In conclusion I have to thank the President and Council of the Royal Society for defraying the expenses incurred in these experiments .

112407

3701662

Account of the Building in Progress of Erection at Melbourne for the Great Telescope

328

329

Proceedings of the Royal Society of London

R. J. Ellery

fla

6.0.4

http://dx.doi.org/10.1098/rspl.1868.0060

proceedings

http://corpora.clarin-d.uni-saarland.de/surprisal/6.0.3/?id=112407

10.1098/rspl.1868.0060

http://www.jstor.org/stable/112407

Biography

Measurement

Biography

IV . C"Account of the Building in progress of erection at Melbourne for the Great Telescope . " In a Letter addressed to the President of the Royal Society by Mr. It . J. ELLERY , of the Observatory , Melbourne . Communicated by the President . Received February 27 , 1869 . Observatory , Melbourne , Jan. 4 , 1869 . MY DriAR Sint , -The telescope has at length arrived , and we are now very busy getting it erected ; for nothing could be done towards it till the great machine itself came to hand . It will be nearly two months before it can be fairly tried , when a spacious rectangular building and its travelling roof will be completed . Mr. Le Sueur arrived nearly two months before the telescope , having come by the overland mail , and the ship carrying the telescope making an unusually long passage . The principal or more delicate portions of the instrument came out in good order : the specula are still in thin coats of varnish , and their surfaces appear in perfect good order . Some of the large castings and portions of the gearing had got rusted , but not to an injurious extent . The piers were completed on New Year 's morning , and form a magnificent piece of masonry , the stone employed being the grey basalt , so common here ( called " blue stone " ) , in blocks from one to three tons in weight each . The building we have finally decided upon is of stuccoed brickwork 80 feet long by 40 wide . Forty in length is taken up by the telescope-room , which is covered by a ridged roof of iron travelling on rails on the walls , and moves back on the other 40 feet of the building , leaving the telescope in the open air . The back 40 feet is covered by a fixed roof lower than the moveable one , and will contain a polishingand engine-room , a capacious laboratory , and an office for observer . The cost of piers , building , and roof will be about ? 1700 . The Government , with hard economy in all other directions , have still acted very liberally about this work ; and I only trust the telescope itself will turn out all that is expected of it . The micrometer and spectrum-apparatus have not arrived yet . Our magnetographs do their work smoothly and satisfactorily . The photography has become a part of the routine of the Observatory now . I have been anxiously awaiting the arrival of the baroand thermographs , and we look for them every day , although I have had no advices of their having been shipped . I suppose you will have seen Mr. Verdon long before this reaches you . I remain , my dear Sir , Major-General Sabine , Yours faithfully , Royal Society , London . ROBERT J. ELLERY .

112408

3701662

Contributions to the Fossil Flora of North Greenland, Being a Description of the Plants Collected by Mr. Edward Whymper during the Summer of 1867. [Abstract]

329

332

Proceedings of the Royal Society of London

Oswald Heer

abs

6.0.4

proceedings

http://corpora.clarin-d.uni-saarland.de/surprisal/6.0.3/?id=112408

http://www.jstor.org/stable/112408

Geography

Biography

Geography

I. " Contributions to the Fossil Flora of North Greenland , being a Description of the Plants collected by Mr. Edward Whymper during the Summer of 1867 . " By Prof. OSWALD HEER , of Zurich . Communicated by Prof. G. G. STOKES , Sec. R.S. ( Abstract . ) The author stated that the examination of the fossil plant-remains which had been at various times brought to Europe from North Greenland by M'Clintock , Inglefield , Colomb , and others , as well as by 3Mr . Olrik , formerly Inspector of North Greenland , the results of which were pub lished in his work , 'Flora Fossilis Arctica , ' had led him to certain conclusions , the verification of which , by means of additional material , became very important . Accordingly Mr. R. H. Scott had applied to the British Association at the Nottingham Meeting in 1866 for a grant of money towards the expenses of an expedition to Greenland . A sum of money was voted to a Committee , consisting of Dr. H-ooker , Sir W. Trevelyan , Dr. E. Perceval Wright , and Mr. E. Whymper , with Mr. Scott as Secretary . This grant was subsequently most liberally augmented by the Government-Grant Committee of the Royal Society . The condition laid down by both of these bodies was that a complete series of specimens should be deposited in the British Museum . Mr. Scott being unable to go to Greenland himself , Mr. Whymper , who had , previously to the nomination of the Committee , formed the plan of travelling in Greenland , undertook to visit the shores of the Waigat , and to carry out the wishes of the Committee , if his time would permit him ; and grants of money were accordingly entrusted to him conditionally . Mr. Whymper took with him Mr. Robert Brown , to assist in the collection of the specimens ; and the party ultimately arrived in Greenland on the 16th of June , 1867 . Prof. Heer then gives extracts from Mr. Whymper 's Report , submitted by the Committee to the British Association in August last , and also from notes furnished to him by Mr. Brown . From these statements a considerable amount of information as to the geology of the district is derived . All the specimens which had been previously brought to Europe , with the exception of a few brought by Dr. Lyall , had been found at a place called Atanekerdluk , on the mainland of Greenland , in lat. 70 ? or thereabouts . Dr. Lyall 's specimens were found on Disco Island , at the opposite side of the Waigat Strait from Atanekerdluk . Mr. Whymper accordingly , having engaged a number of natives as labourers , went to Atanekerdluk in the first instance , reaching it on the 22nd of August . The party remained at the spot for some days , and made a large collection of specimens . The plant-beds are reported to be on a hill , at a height of nearly 1200 feet above the sea , and the deposit is limited in extent . Details of the different beds observed are contained in the paper . Professor ieer observes that the statements of Messrs. Whymper and Brown confirm the accounts of Olrik and Inglefield respecting the stratification of the coal-deposits and plant-beds of Atanekerdluk . They show that there is a considerable succession of sedimentary strata , pierced by volcanic rocks which form the summits of the mountains . Fossil plants occur in all the beds ; but the Siderite and Limonite contain them in the greatest abundance and in the best state of preservation . In fact the slabs from these beds are quite covered with specimens , lying in every direction . With the vegetable remains two land-insects were discovered . Of the plants many species were inhabitants of marshy or moory ground , viz. Phragmites , Sparganium , Taxodium , and Menyanthes , which are all indlcative of a freshwater deposit , as is also a Cyclas , of which mollusk one valve was found . These facts , taken together with the absence of marine forms , show the deposit at Atanekerdluk to have been a strictly freshwater formation . After completing the examination of the mainland at this point , the party crossed the Waigat , and landed on Disco Island , where they found plant-remains at two localities , Ujararsusuk and Kudliset . Coal-seams are exposed at several points on the east and south coasts of Disco ; but no specimens showing impressions of leaves , like those of Atanekerdluk , had ever been brought to Europe , except those obtained by Dr. Lyall . However , Sir C. Giesecke , in his MS . journal , of which a copy is in the possession of the Royal Dublin Society , mentions that he had noticed such impressions . The coal has been worked at several points , if the rough operations which have been carried on deserve the name of workings . It is at present only obtained at the one spot , Ujararsusuk . The coal occurs interstratified with sandstones and shales , which rest on trap . The fossils were discovered among the debris brought down by the streams , and were traced up to a bed of brown sandstone about 100 feet above the sea . At Kudliset , the deposits are very similar to those just described ; and there also the fossils were found , in the first instance , in a torrent-bed . The shores of the Waigat were examined for some distance to the northwards , on each side of the strait , without any fresh discoveries being made , and the party returned to Atanekerdluk . Mr. Whymper , in concluding his report , says that the success of the expedition has been " primarily due to the invaluable information given by Herr C. S. M. Olrik , the Director of the Greenland Trade . Scarcely less are our thanks due to Herr K. Smith , the present Inspector of North Greenland , and to Herr Anderson , of Ritenbenk . Both of these gentlemen gave much assistance at considerable personal trouble ; and without their assistance it would have been almost impossible to obtain the collections . " The general conclusion to be drawn from the accounts of the succession of strata &c. is that , on both sides of the Waigat , the sedimentary rocks are covered by Miocene deposits pierced by volcanic rocks , which appear in places as thick beds of basalt and trap . In his summary of the botanical results of the expedition , the author announces the identification of fourteen species from Disco Island , among which Platanus Guillelmce ( Gopp . ) and Sequoia Couttsie ( Hr . ) are the most common . Of Magnolia Inglefieldi , a species originally identified by means of leaves found at Atanekerdluk , two cones were found in the Disco beds , thus corroborating the previous determination , and proving to us that this splendid evergreen ripened its fruit so fiar north as the parallel of 70 ? . Seven out of the Disco species occur also at Atanekerdluk ; and eight agree with those of the Lower Miocene of Europe . The age of the deposit is accordingly well ascertained . The collection from Atanekerdluk contains 73 species , of which 25 are new to Greenland . Some of these are known European forms , especially Smilax grandifolia , which , at the Miocene epoch , occurred over the whole of Europe . Of Sequoia Langsdoyffii , as was to be expected , abundant evidence has been accumulated , showing how favourable the conditions of climate and soil were to its growth . Among the most interesting specimens are the flowers and fruit of a chestnut , the latter in a very perfect condition . The discovery of these proves to us that the deposits in which they are found were formed at different seasons , in spring as well as in autumn . The Miocene plants discovered in Greenland have now reached the number of 137 species , and those of the Arctic Miocene Flora 194 . Of the Greenland species 46 , or exactly one-third , agree with those of the Miocene deposits of Europe . The determination of the age of the beds as Lower Miocene has accordingly been confirmed . Four of the species agree with those of Bovey Tracey , among them Sequoia Couttsice , the commonest tree in the latter locality . In concluding the first part of his paper , the author offers a r6sumne of the grounds on which the determinations of the species have been based . Seventeen species are represented by the leaves and organs of fructification among the Greenland specimens . Ten species are only represented by leaves in Greenland ; but their organs of fructification occur elsewhere . Seventeen species of those of which only leaves are found exhibit , however , such marked characteristics , that there can be no doubt about their identification . Five Cryptogams have been satisfactorily recognized . Accordingly , though it must be allowed that the systematic position of many of the plants from North Greenland is still uncertain , yet the considerable number of absolutely identified species which can be produced enables us to form a clear idea of the Miocene Flora of North Greenland . The second part of the paper contains the specific descriptions of the various forms . The collection , consisting of some 300 specimens , has been deposited in the British Museum .

112409

3701662

On the Specific Heat and other Physical Properties of Aqueous Mixtures and Solutions. [Abstract]

333

337

Proceedings of the Royal Society of London

A. Dupr\#xE9;|F. J. M. Page

abs

6.0.4

proceedings

http://corpora.clarin-d.uni-saarland.de/surprisal/6.0.3/?id=112409

http://www.jstor.org/stable/112409

Thermodynamics

Tables

Thermodynamics

II . " On the Specific Heat and other physical properties of Aqueous Mixtures and Solutions . " By A. DUPRi , Ph. D. , Lecturer on Chemistry at the Westminster Hospital , and F. J. M. PAGE . Communicated by C. BROOKE , F.R.S. Received February 4,1869 . ( Abstract . ) PART I. Mixtures of Ethylic Alcohol and Water . Section 1 . Specifc Heat . For the methods employed in estimating the specific heat of these mixtures , see a former abstract , 'Proceedings of the Royal Society , ' vol. xvi . p. 336 . In the present paper the authors give the specific heat of an additional number of mixtures , so as to complete the series for every 10 per cent. from water to absolute alcohol . The following Table gives the mean of the results obtained in all experiments , details of seventy-four of which are given : Percentage of Specific heat Specific heat Differene . alcohol , by weight . found . calculated . 5 502 ... ... . . 10 103-576 96'043 + 7'533 20 104'362 92-086 12*276 30 102'6o2 88-129 x4'473 40 96'805 84'I72 12'633 45 94'I92 82-193 II'999 50 90'633 80'215 10'418 60 84'332 76'258 8'074 70 78'445 72'30I 61'44 80 71'69o 68'344 3'346 90 65'764 64'387 3'377 100 60'430 ... ... ... ... ... . Section 2 . Heat produced by the mixing of Alcohol and Water . This was estimated as follows:-The liquid which formed the smallest portion of the mixture was sealed up in a thin glass bulb ; this was then introduced into the calorimeter , the glass bulb was broken , the mixture formed , and the rise in the temperature of the calorimeter observed . The units of heat evolved in the formation of 5 grms. of each mixture were thus calculated , and found to be10 per cent. spirit ... . 26-6850 50 per cent. spirit ... .35'5850 20 , , , , ... . 439545 60 , , , ... 27-2620 30 , , , , ... . 479800 70 , , , , ... .18-8200 40 , , , ... . 44-8630 80 , , , , ... .124775 45 , , ... .38 8095 90 , , , , ... 77025 Section 3 . Boiling-points . A small flask was taken ; into this 100 cub. centims. of the mixture was introduced , and the mouth of the flask closed by a doubly perforated cork . Into one of these perforations a thermometer was introduced , into the other a bent tube , dipping beneath the surface of the liquid in the flask , and connected at its other extremity with a Liebig condenser . This tube had a lateral opening ( inside the flask ) just beneath the cork ; by means of this the vapour escaped to the condenser , and trickled back into the flask after being condensed . Thus the composition of the mixture was retained as uniform as possible . Thus estimated , the barometer standing . at 744'4 millims. , the boiling-points are given in the following Table . Percentage of Boiling-point Boiling-point Diference . alcohol , by weight . observed . calculated* . o 99'4 ... ... . . 1o 0 90-98 97'25 -6'27 20 86-50 95'10 -8-60 30 84-oI 92'95 --894 40 82'52 90'90 --838 45 81 99 89'72 -7'73 50 8 8'8860o --727 60 80'47 86'50 60o3 70 79'6i 84'35 ' --4-7 8o 78'84 82'20 --3'36 90 78o01 800o5 --204 0oo 77'89 ... Section 4 . Capillary Attraction . This was estimated by carefully observing the heights to which the several mixtures rose in a capillary tube 0'584 millim. in diameter . These heights were measured by means of a telescope and a millimetrescale etched on a glass rod . This glass rod was fixed to the capillary tube , and terminated at its lower extremity in a point , which was made just to touch the surface of the liquid . Several precautions were necessary to render the measurements accurate . The results are contained in the following Table:-Percentage lIeight , asstlumig IRelaive molecular of alcohol , by water Cl eight calculated . Difference . attraction . weight . =ioo mnillims . 0 I100'00 1 0000 10000 ... . . 10 691'7 68'o7 93'II -25'04 20 56'43 54'83 86-22 -3I'39 30 48'I9 46Ix5 79'34 --3319 40 45'30 42'56 72'45 -z9'89 45 43*74 40'64 69oo00 -2836 50 42'93 39'43 65'56 -2z6'I3 60 42'30 37'89 58'68 --20'79 7 ? ? 4i'76 36'42 5 V79 -5'37 8o 4I'29 35'03 4490 9 ' 87 90 40'54 1 33'35 38'oz 467 o00 39'I2 2'.3 3'13 ... The third column gives the length of a column of water equal in weight ' Calculated on tho assumptiou that the a.lcohol and water in a mixture have an influence on tho boiling-point of the mixture proportional to their rospective weights . to the thread of alcoholic mixture contained in the second column , and gives , therefore , a measure of the relative strength of the molecular attraction in the various mixtures . The experiments were made at a temperature of 16 ? C. Section 5 . Rate of Expansion . This was determined by estimating the specific gravity of the different mixtures at the temperatures 10 ? C. , 15 ? 05 C. , 20 ? C. The specific-gravity bottle has two necks ; into one was fitted a thermometer with a long bulb , whilst the other ended in a capillary tube . This bottle was placed in a water-bath , whose temperature was under perfect control , and thus the specific gravity could be accurately estimated at the above-named temperatures . Section 6 . Compressibility . This property was estimated by an apparatus similar to the one employed by Regnault and Grassi , but of simpler construction . The piezometer was of glass ; pressure was applied to the inside and outside by forcing air into the apparatus by means of a small pump ; 0 000002 was always added as a correction for the compressibility of the piezometer . The two following Tables give the results obtained in Sections 5 and 6 . Percentag Volume at Volumne at2 so ? . , Volume at 2 ? en . of aloohol , by I)iC found , calculated . weight . o I0o Ioo'154 I0o'o54 ... ... . . I0 00 1 00'212 iz00272 --060 2 100 oo100 405 Ioo'386 +--o9 30 100 Ioo 632 100-498 +--'34 40 Ioo I9o'783 oo'6oi +-'82 45 o00 oo00827 I00'652 +-'75 50 ioo ioo'868 Ioo'70o + --68 59'77 00 oo 00-914 100o789 +'-25 69'73 100 oo00980 0oo'874 -+-*o6 79'81 1oo 101o020 100-954 -'o66 89-89 10oo 101052 Ii'o034 --'oi8 o'0000 100 IroI088 Ioi0o88 ... ... . Percentage Compressibility Coimpressibility for of alcol ol , by for one one atmosphere , Difference . weight . atmosphere , found . calculated . o 000ooo04774 0'00004774 ... ... . . O1 0o00004351 0'00005387 oo0000oo036 20 0-00003911 000005998 0o00002087 30 o. ooooo3902 ooooo6584 0oo00002682 4 ? 0o00004347 0o00007118 0o00002771 45 ooo000468 0000oooo7366 ooo00oo758 50 o0oooo4878 0'00007600 o0o00002722 59'77 00oo00560 ooooo8029 oooo00002409 69'73 oo00006159 0'00008426 000ooo2267 78'81 ooooo6942 0o00008775 ooo00001833 9'S89 0o00007950 000oooo0094o oo00001190 r10000 oo'ooo9349 oo00009349 ... ... . . 1869 . ] 335 Weight of water contained in the piezometer 114'9727 grms. In conclusion the authors confine themselves to pointing out certain relations which connect the various physical properties examined . These properties may be divided into two classes , according as they reach a maximum deviation from the theoretical mean at 30 per cent , or 40 per cent. ; each of these is divided into two subclasses , one containing those properties in which the numbers found are above those calculated , and the other containing those in which they are below . Class I. Subclass a. Specific heat . HEeat produced by mixing . , , b. Boiling-point . Capillary attraction . Class II . Subclass c. Rate of expansion . , , d. Compressibility . Other characters , examined by previous investigators , are:1 . Vapour-tension : this falls under Class I. Subclass b. 2 . Specific Gravity . 3 . Index of Refraction . The two latter form a new class , coming to a maximum deviation from their theoretical value at 45 per cent. In subclass a , specific heat--by reference to the Tables given , it will be seen that the first addition of alcohol to water ( though alcohol has a specific heat much lower than that of water ) produces mixtures which have a higher specific heat than water , and that a mixture containing between 30 and 40 per cent. alcohol has the same specific heat as water . Similarly alcohol , though much more compressible than water , yet , when added to it , forms mixtures less compressible than water ; so that a mixture containing between 45 and 50 per cent. alcohol has the same compressibility as water . The rate of expansion is remarkable , as , starting from water , it at first is below the theoretical value , then rises ; at 17 to 18 per cent. the rate of expansion is identical with the calculated expansion ; for all mixtures stronger than this , the rate of expansion is constantly above that calculated . The whole of the physical characters of mixtures of alcohol and water come to a maximum deviation from their theoretical values somewhere between 30 per cent. and 45 per cent. alcohol by weight . The 30 per cent. nearly corresponds to the formula C2 I 60 +6 0 H2 ( =29'87 per cent. ) ; the 45 per cent. has approximately the formulaC2 H0+30 1H ( =-46 per cent. ) . Some of the physical properties examined seem to be especially connected with each other ; these are:1 . Specific heat and heat produced by mixing ; for by dividing the number of units of heat evolved by 5 grammes of any mixture by 3'411 , the elevation of the specific heat of such mixture above the theoretical specific heat is obtained . 2 . Boiling-point and capillary attraction ; by dividing the depression of the capillary attraction by 3'6 , the depression of the boiling-point is obtained . Deville & Hoek have shown the specific gravity and index of refraction to be connected with each other ( Ann. de Chim . et de Physique , 3rd ser. vol. v. Pogg . Ann. vol. cxii . ) . Whether the relations thus established between the various physical properties of alcoholic mixtures hold good with other similar substances , or whether these mixtures form a singular exception , must be decided by further research .

112410

3701662

Researches into the Chemical Constitution of Narcotine, and of Its Products of Decomposition.--Part III. [Abstract]

337

339

Proceedings of the Royal Society of London

A. Matthiessen

abs

6.0.4

proceedings

http://corpora.clarin-d.uni-saarland.de/surprisal/6.0.3/?id=112410

http://www.jstor.org/stable/112410

Chemistry 2

Chemistry 1

Chemistry

I. " Researches into the Chemical Constitution of Narcotine , and of its Products of Decomposition."-Part III . By A. MATTIIESSEN , F.R.S. , Lecturer on Chemistry in St. Bartholomew 's Hospital . Received February 18 , 1869 . ( Abstract . ) In this part the preparation is described of two new bases derived from narcotine . 1 . On the Action of Hydriodie Acid on Narcotine.-When narcotine is heated with fuming hydriodic acid , iodide of methyl is evolved , and on investigating the residue it is found to consist of the iodide of a new base . In two experiments made with 50 grms. of narcotine , 45*7 and 46'2 grms. of iodide of methyl , and in a third experiment with 100 grms. of narcotine , 91'8 grms. of iodide of methyl , were obtained , 51'5 grms. and 103'1 grms. being the theoretical quantity required for the following reaction : CP H23 N 07+3 HI=C , , H17 N 07+3 CH3 I. If the reaction C2 , 23 , N 07+2 2 HI= IC H19 , N 07+ 2C3I took place , the theoretical quantity of iodide would only be 34'3 grms. and 68'7 respectively . The endeavours to obtain the base in a state fit for analysis have been fruitless , owing to its oxidizing rapidly when exposed to the air ; to establish its composition , the chloride was analyzed , and led to the following result : C9 I , N 07 II C1 . The base itself is , when newly precipitated , nearly white , but as soon as it is exposed to the air it becomes almost black ; it is soluble in carbonate of sodium , caustic soda , potash or ammonia , slightly soluble in hot alcohol , quite insoluble in ether , and nearly so in water . All endeavours to obtain it or its salts in a crystalline state have hitherto failed . The base may be called normal narcotine , or , shorter , nornarcotine , as it contains , in all probability , normal meconin combined with cotarnimide . 2 . On the Action of IHydrochloric Acid on NTarcotine.--When narcotine is heated with hydrochloric acid for about two hours , chloride of methyl is evolved , and on examining the residue it will be found to contain the chloride of a new base . The reaction which takes place is simply that one atom of methyl in the narcotine is replaced by one of hydrogen ; thus : C,2 H2,3 N 07 +t C1-C , H1 N OqC Cl. The pure base forms a white amorphous powder , almost insoluble in water and ether , very , soluble in alcohol . Its salts , like those of the other bases derived from narcotine , are , as far as they have been prepared , amorphous . The base may be called dimethyl-normal-narcotine , or , shorter , dimethyl-nor-narcotine . In the annexed Table the properties and reactions of the narcotine bases are given side by side . Neither of the above bases has any marked physiological effects ; for in working with them , as well as in taking grain doses , no ill effects have been observed . It is worthy of notice that the taste of the chlorides varies so markedly by the replacement of one atom of methyl by one of hydrogen . Form . Trimethyl-nor mal-narco'ine ( ordinary narcotine ) , Dimethyl normal-narcotine , C21 IH1 N 0 , . Methyl-normalnarcotine , C20 Hl ) 07 . White crystals . White , amorphous . White when freshly precipitated , sometimes brown ; amorphous . iNorm-al narcoWhite when time , freshly preciC19 [ 7 N 07 . pitated , turns ^ brown imme . r diatelj on ex ' o posure to air ; ' amorphous . 1-~~~~~~~~~~~~~~~~~ Cotarnine , C12 H3 N 03 . White , generally buff-colour , crystalline . Solubility in o -4 § 22 C ) 2211 A. 02 o 2C 02 r^ d 224 2 " 25 q0 < .1 0.I rQ i 25 IP4 < 2C 02 Reactions of the Chlorides in solution with Concentrated Solution of Chloride . Not precipitated by H C1 . Solution in H Cl not precipitated by water . Precipitated partially by H C1 . Solution in strong H Cl precipitated by water ; the precipitated chloride is tarry . Mostly precipitated by H Cl. Solution in strong H Cl precipitated by water ; the precipitated chloride granular . Almost wholly precipitated by H C1 . Solution in strong H Cl precipitated by water ; the precipitated chloride granular . Not precipitated by H C1 . Solution in H C1 not precipitated by water . Taste of Chloride . Bitter . Bitter . Astringert . Tasteless . Bitter . Pt C14 , . KHO . N E4H:O . Na C O0 . Yellow preciPrecipitate inPrecipitate inPrec:pitate inpitate . soluble in exsolvble in exsoluble in excess . cess . cess . Yellow preciPrecipitate sopitate . lvble in excess . Yellow precipitate , slowly turning brown . Yellow precipitate , imirediately turning brown . Yellow precipitate . Precipitate slightly soluble in excess . Precipitate insoluble in excess . Precipitate soPrecipitate soPrecipitate soluble in excess . luble in excess . luble in excess . Precipitate soPrecipitate soPrecipitate soluble in excess . luble in excess . luble in excess . II I~~~~~~~~ Precipitate Precipitate soslightly soluluble in excess . ble in excess . Precipitate soluble in excess . Co co C ? . I 03 cD * All these precipitates decompose on boiling with excess of platinum chloride .

112411

3701662

Researches into the Chemical Constitution of Narcotine, and of Its Products of Decomposition.--Part IV. [Abstract]

340

343

Proceedings of the Royal Society of London

Augustus Matthiessen|C. R. A. Wright

abs

6.0.4

proceedings

http://corpora.clarin-d.uni-saarland.de/surprisal/6.0.3/?id=112411

http://www.jstor.org/stable/112411

Chemistry 2

Headmatter

Chemistry

II . " Researches into the Chemical Constitution of Narcotine , and of its Products of Decomposition."-Part IV . By AUGUSTUS MATTHIESSEN , F.R.S. , Lecturer on Chemistry in St. Bartholomew 's Hospital , and C. R. A. WRIGHT , B.Sc. London . Received February 18 , 1869 . ( Abstract . ) In Section I. of this memoir some new reactions of narcotine are described . A. When narcotine is submitted to the action of water , either boiling in open vessels or at temperatures above 100 ? C. in sealed tubes , it splits up into meconin and cotarnine . C , , H23 N07 =C , 0o H4+ C12 H13 NO , . The splitting up of narcotine under the influence of heated water may explain the occurrence of meconin in opium-residues , as probably the small amount of meconin always found there is simply due to the partial decomposition of the narcotine during the processes of extraction of morphia . B. Narcotine heated per se to a little above 200 ? splits up as above into meconin and cotarnine , the latter being immediately decomposed at that temperature . C. When hydrochlorate of narcotine is heated along with ferric chloride solution , the latter is reduced and the narcotine converted into opianic acid and cotarnine . C , , HI , NO7 , O+ -C , o 10 0+ HC12 13 NTO . Section II . treats of the decompositions of the narcotine-bases . A. Dimethyl-nornarcotine , when heated to above 100 ? C. with water il sealed tubes , undergoes decomposition : from the corresponding narcotine reaction it would seem that this decomposition might take place in either of two ways : Narcotine . Meconin . Cotarnine . C1 , , 14 ( CH , ) , NO , = C , 14 ( C1i3)2 04 + C1 , I1 , ( CH , ) 3O , . Dimethvl-nornarcotine . Methyl-normeconin . Cotarnine . C , , H , , ( CHI ) , NO , = C , H , ( CI , ) 04 + C , , 11 ( CIH , ) NO , , or Meconin . Cotarnimide . C , , 1H ( H3 ) , NO , = C , H ( CH , )2 0+ C , 1 NO , . Of these the former reaction is apparently the one which thus takes place . This conclusion is borne out by the fact that , when treated with ferric or platinic chloride , the hydrochlorate of dimethyl-nornarcotine forms methylnoropianic acid and cotarnine , and not opianic acid and cotarnimide . Dimethyl-nornarcotine . Methyl-noropianic acid . Cotarnine . C , , I-1 , ( CH , ) , NO + O=C , H1 ( CH3 ) 0 , + C1 H11o ( CH3 ) NO , , and not Opianic acid . Cotarnimide . C , , I , , ( C-I , ) , NO , += C H , ( CH3 , ) , 0 , + C 11 I-I , O , . B. From reasons given in the memoir , the reactions of methyl-nornarcotine and nornarcotine with heated water and oxidizing agents are as follows : Methyl-nornarcotine . Normeconin . Cotarnine . C1 HC ( CH3 ) NO , = C8 H 04 +C Io ( CH13 ) NO , , and not Methyl-normeconin . Cotarnimide . C1 110 ( CI-3 ) NO , = C , H ( CI3 , ) 0o + C , , I , , NO , , Methyl-nornarcotine . Noropianic acid . Cotarnine . C1 , H11 ( CIH ) NO , +0= CH , [ 0 , + C11 Hl ( CH13 ) NO , , and not Methyl-noropianic acid . Cotarnlimide . C01 II ( C313 ) NO07 O= C8 , 1I ( CH , ) 05 + 0C11 1 NO , , Nornarcotine . Normeconin . Cotarnimide . 19 H17 , NO7 = C8 , H 0 , + C0 , , H , NO , , Noropianic acid . Cotarnimide . C19 17NO += 0118 0 , + Cl111 NO3 . Section III . contains some miscellaneous observations on opianic acid , meconin , and hemipinic acid . A. Opianic acid treated with sulphuric acid and dilute solution of bichromate of potassium becomes oxidized to hemipinic acid . CI I10 ? o + O-+ CIO Hl O , . When heated a few degrees above its melting-point , opianic acid loses water and yields a substance crystallizable from hot alcohol , differing in properties from opianic acid , and apparently containing C1o H1E3 09 , being formed thus : 4 C01 H0o 05=H2 0+ C40 H38 01 . B. All attempts to oxidize meconin to opianic or hemipinic acid were failures . Nitrous acid gas passed into melted meconin caused the formation of nitromeconin , identical with that got by the action of nitric acid , each sample , however , giving rather different qualitative reactions from those usually ascribed to this substance . C. IHemipinic acid , when heated to 170 ? , loses water and becomes an anhydride , Co1 H1 O , , which may be crystallized unaltered from absolute alcohol , but when treated with ordinary spirit of 90 per cent. alcohol forms ethyl-hemipinic acid , C10 HS ( C2 I4 ) 0o . Resume of results obtained in thefour portions* of this research . ( 1 ) It has been shown from the analyses of various samples of narcotine derived from various sources , that narcotine has always the same composition , viz. C22 H23 NO , ( vol.xii . p. 501 ) . ( 2 ) As stated by former observers , narcotine under the influence of oxidizing agents splits up into opianic acid and cotarnine . 22 23 NO7 + C0 =o H10o 0+ C12 H13 NO3 . ( 3 ) When heated to a little above 200 ? per se , or for a considerable time in contact with water , narcotine splits up into meconin and cotarnine ( vol. xvii . p. 340 ) . C2 23 NO7 = C10o O0 4+ C12 1N O3 . ( 4 ) When narcotine is heated with excess of hydrochloric acid for a short time ( about two hours ) , chloride of methyl is formed , and one atom of H substituted for Ci3 in the narcotine ; if heated for a long time ( some days ) , two atoms of 11 are substituted for two of CH3 ; when heated with fuming hydriodic acid , iodide of methyl is formed in such quantities as to prove that three atoms of H are substituted for three of CH3 . A series of homo-^ logous bases is thus formed , whose decompositions are analogous to those of narcotine . ( 5 ) Cotarnine has been shown to have the formula C32 H13 NO3 , and not C3 13 NO3 , and is capable of crystallizing with half a molecule , and with a whole molecule , of water of crystallization . ( 6 ) When cotarnine is heated with dilute nitric acid , under certaini not clearly understood circumstances , cotarnic acid and methylamine is produced , Ca1 NO3 3 ? +2 20 OC 1112 O5 + CHI N ; with strong nitric acid , as stated by previous observers , apophyllic acid is produced ; other oxidizing agents give no definite results ( vol. xi . p. 59 ) . ( 7 ) When cotarnine is heated with strong hydrochloric acid , chloride of methyl is formed , and hydrochlorate of cotarnamic acid . C12 H13 NO3+ H2 +2 H1C1= CI3G Cl + C3 H113 NO4 , IIC1 . Hydriodic acid produces a similar reaction , only one equivalent of ClI-3 being removed for one of cotarnine ( vol. xii . p. 503 ) . ( 8 ) Opianic acid under the influence of nascent hydrogen ( as when treated with sodium-amalgam or zinc and sulphuric acid ) is reduced to meconin ( vol. xii . p. 503 ) . C1o lo 0+ H2 =1 H CO+C 1 3o 04 . ( 9 ) Opianic acid heated with bichromate of potassium and dilute sulphuric acid becomes oxidized to hemipinic acid ( vol. xvii . p. 341 ) . Clo 1i 05 + 0=Clo Hio 0.0 ( 10 ) Opianic acid heated with caustic potash splits up into meconin and hemipinic acid ( vol. xi . p. 57 ) . 2 C1o 11C0 05= CIo H1o 04 + Clo Hoo 06(11 ) Opianic acid heated with excess of hydrochloric acid forms chloride of methyl , hydrogen being substituted for CHa in the opianic acid : it appears probable that two distinct substances are thus produced , noropianic acid and methyl-noropianic acid the former by substitution of 113 for ( OH3)2 , and the latter by substitution of 1-1 for CH , ; only the latter has been isolated in a pure state , the former decomposing spontaneously . C0o Ho 10 5+2 HC1=2CH,3 C1+ C , H , O0 , C1 H0 0+ -IC = C0I3 C1 + C9 -t 10 . iHydriodic acid apparently produces similar decompositions . Like opianic acid , methyl-noropianic acid is monobasic ( vol. xvi . p. 39 ) . ( 12 ) All experiments to oxidize meconin to opianic acid or hemipinic acid or any other product have proved failures . ( 13 ) Meconin treated with excess of hydrochloric or hydriodic acid forms chloride or iodide of methyl , and a body derived from meconin by substitution of H for CH03 , methyl-normeconin . C1o H1l 0+ 1CC1 CH3 C1+ C3 80 , . Attempts to procure ( hypothetical ) normeconin by substituting II2 for ( CHI- , ) did not yield anything capable of isolation in a pure state ( vol. xvi . p. 39 ) . ( 14 ) I-Iemipinic acid treated with various reducing agents has in no case been reduced to opianic acid or meconin ; nor have experiments to form opianic acid by the union of hemipinic acid and meconin been successful ; nor has hemipinic acid been oxidized to any other compound . ( 15 ) When hemipinic acid is heated with excess of hydrochloric acid , chloride of methyl and carbonic acid are formed , together with a new acid , methyl-hypogallic acid , in accordance with the following equation : C , O H , lo O+ HCl= C1H3 Cd Ch O , C , H , 0 When heated with hydriodic acid , hypogallic acid is found , together with iodide of methyl and carbonic acid : thus , 0o H00-+2HI-=2CH3 +CO +07 11 0 ( vol. xvi . p. 40 ) . C10 H10 OC 1 2I-3 1E + C ? 2 +C 72 + Cl 1 , 04 ( VO1 . XVi ' P 40 ) ( 16 ) The observations of Anderson , that hemipinic acid is bibasic , have been confirmed , and an anhydride obtained by simple desiccation ( vol. xvii . p. 341 ) . C0 o I , -0 0=H , 0+0 018 0 , . Methyl-hypogallic acid , however , is monobasic ( vol. xvi . p. 40 ) . ( 17 ) Hemipinic acid is capable of crystallizing with different amounts of water of crystallization , crystals with half a molecule , with a whole molecule , and with two molecules of water having been obtained ( vol. xvi . p. 40 ) . ( 18 ) All the reactions of narcotine and of its products of decomposition may be satisfactorily accounted for by the following rational formula:0H3 ( 03l 119 02 ) " }N . ( C , 114 0 ) " } 03 , ( CH3 ) 1 }03 .

112412

3701662

On the Corrections of Bouvard's Elements of Jupiter and Saturn (Paris, 1821)

344

346

Proceedings of the Royal Society of London

Hugh Breen

fla

6.0.4

http://dx.doi.org/10.1098/rspl.1868.0065

proceedings

http://corpora.clarin-d.uni-saarland.de/surprisal/6.0.3/?id=112412

10.1098/rspl.1868.0065

http://www.jstor.org/stable/112412

Astronomy

Tables

Astronomy

III . " ' On the Corrections of Bouvard 's Elements of Jupiter and Saturn ( Paris , 1821 ) . " By HUGH BREEN , formerly of the Royal Observatory , Greenwich . Communicated by Professor G. G. STOKES , Sec. RI . S. Received December 17 , 1868 . The Tables of Jupiter and Saturn which have been used for some years past in the computations of the ' Berliner Jahrbuch ' and ' Nautical Almanac , ' differ more from observation than is consistent with the present requirements of astronomy ; and , moreover , abundant means for the correction of Bouvard 's ' Elements ' exist in the publication of the Greenwich Planetary Observations , 1750-1835 , and the annual volumes issued from the Royal Observatory since 1836 . The present work , which has been undertaken for this purpose , is based exclusively on the Greenwich Observations , 1750-1865 . Each mean group of observations in the Greenwich Planetary Reductions &c. gives the mean error of the planet 's tabular geocentric place , with its equivalent in terms of the heliocentric errors of the earth and planet ; but in the present investigation the places of Carlini 's Solar Tables , which have been used throughout the whole period ( with the exception of 1864 and 1865 ) , have been accepted without alteration ; for Jupiter and Saturn the factors of the earth 's heliocentric errors are so small , that the difference of Carlini 's Solar Tables from the recent investigations of Leverrier may be neglected . The coefficients of the errors of the elements in heliocentric longitude and radius vector , for different values of the mean anomaly , are calculated in the usual way ; and the formation of the equations of condition is effected by their multiplication by the printed factors of the heliocentric errors of the planet in the Greenwich Observations . A weight is assigned to each equation of condition , dependent on the number of observations in the group , and the relation of the geocentric and heliocentric errors . The equations thus , multiplied by the weights , are then solved by the method of least squares . The results are given in the following Table : Jupiter . 1750 , October 29 , to 1771 , July 14 . 6a =_0-000331873 . 'e =+ 000000123252 . t =-4"'284354 . 8r =2 2 " ' 36544 . 3I =-0"311 . aN= + 99"-1319 ( neglecting al as insensible ) . 6a is the error of the planet 's semiaxis major , ae is the error of the eccentricity , 3t is the error of the epoch of the mean longitude , and 'r is the error of the longitude of the perihelion , 81 is the error of the inclination , and AN is the error of the longitude of the node . 1772 , August 31 , to 1810 , Jannary 9 . aa 0-000181527 . 8e = 0-000000211230 . t =1"'50080 . at =--41 " 7566 . 1 =-=0 " ? 561 . KN= ? +24"'911 . 1811 , February 12 , to 1839 , M/ Eay 30 . a -0'0000355943 . 8e ==+ 0-00000126876 . 4t -2"'9489 . =--58 ' 9578 . aI iL 1"'433 . sN=--72"0634 . 1840 , January 18 , to 1865 , August 8 . 6c -= 0-000166480 . Be =0-00000677360 . t--4"'88982 . T =-77"'3245 . 11 =-1"'668 . N= --118"266 . Saturn , The tabular results of the ' Nautical Almanac ' and Berlin Ephemeris ' have been reduced to the value of the mass of Jupiter adopted in the Greenwich Planetary Reductions , 1750--1830 ; and the equations are formed as before mentioned . 1751 , February 19 , to 1783 , September 28 . Ia = 0-00048429 . o 0 0000335957 . at =7'`86558 . are =-214 " 9774 . 1I = O-10"7538 . N==157"'t156 . 1784 , July 12 , to 1814 , July 19 . cac = +0-0000371094 . Ie =0'00000436038 . t ==4"38974 . I =+4121"-9323 . I1 =9"'046 . aN= + 107"67 . 345 2c 1815 , July 29 , to 1839 , July 13 . 6a =+ 0-00081572 . e =+ 0-000000334917 . 6t =6"'71499 . & r =+ 40 " 71125 . 1 =-lQ0"418 . N= ? + 95"'207 . 1840 , March 9 , to 1865 , June 9 . a = ? + 0-00076325 . de =q+ 0-0000286012 . 1t =2"'89008 . 8t =-3"47275 . I =-1]1"'233 . N= +38 " 16 .

112413

3701662

On the Structure of the Red Blood-Corpuscle of Oviparous Vertebrata

346

350

Proceedings of the Royal Society of London

William S. Savory

fla

6.0.4

http://dx.doi.org/10.1098/rspl.1868.0066

proceedings

http://corpora.clarin-d.uni-saarland.de/surprisal/6.0.3/?id=112413

10.1098/rspl.1868.0066

http://www.jstor.org/stable/112413

Biology 3

Biology 2

Biology

IV . " On the Structure of the Red Blood-corpuscle of Oviparous Vertebrata . " By WILLIAAM S. SAVORY , F.R.S. Receive d February 20 , 1869 . The red blood-cell has been perhaps more frequently and fully examined than any other animal structure ; certainly none has evoked such various and even contradictory opinions of its nature . But without attempting here any history of these , it may be shortly said that amongst the conclusions now , and for a long time past , generally accepted , a chief one is that a fundamental distinction exists between the red corpuscle of Mammalia and that of the other vertebrate classes-that the red cellof the oviparous vertebrata possesses a nucleus which is not to be found in the corpuscle of the other class . This great distinction between the classes has of late years been over and over again laid down in the strongest and most unqualified terms . But I venture to ask for a still further examination of this important subject . As the oviparous red cell is commonly seen , there can be no doubt whatever about the existence of a " nucleus " in its interior . It is too striking an object to escape any eye ; but I submit that its existence is due to the circumstances under which the corpuscle is seen , and the mode in which it is prepared for examination . I think it can be shown that the so-called nucleus is the result of the changes which the substance of the corpuscle undergoes after death ( and which are usually hastened and exaggerated by exposure ) , and the disturbance to which it is subjected in being mounted for the microscope . When a drop of blood is prepared for examination , little or no attention is given to the few seconds , more or less , which are consumed in the manipulation . It is usually either pressed or spread out on the glass slip , and often mixed with water or some other fluid , But it is possible to place blood-cells under the microscope for examination so quickly , and with such slight disturbance , that they may be satisfactorily examined before the nuclei have begun to form . They may then be shown to be absolutely structureless throughout ; and , moreover , as the examination is continued the gradual formation of the nuclei can be traced . The chief points to be attended to are--to mount a drop of blood as quickly as possible , to avoid as much as possible any exposure to air , to avoid as much as practicable contact of any foreign substance with the drop , or any disturbance of it . After many trials of various plans , I find that the following will often succeed sufficiently well . Iaving the microscope , and everything else which is required , conveniently arranged for immediate use , an assistant secures the animal which is to furnish the blood ( say , a frog or a newt ) , in such a way that the operator may cleanly divide some superficial vessel , as the femoral or humeral artery . He then instantly touches the drop of blood which exudes with the under surface of the glass which is to be used as the cover , immediately places this very lightly upon the slide , and has the whole under the microscope with the least possible delay . Thus for several seconds the blood-cells may be seen without any trace of nuclei ; then , as the observation is continued , these gradually , but at first very faintly , appear ; and the study of their formation affords strong proof of their absence from the living cells . The " nucleus " first appears as an indistinct shadowy substance , usually , but not always , about the centre of the cell . The outline of it can hardly , for some seconds , be defined ; but it gradually grows more distinct . Often some small portion of the edge appears clear before the rest . At the same time the nucleus is seen to be paler than the surrounding substance . Synchronously with this change-and this is noteworthy the outline of the corpuscle ( the " cell-wall " ) becomes broader and darker . What was at first a mere edge of homogeneous substance , becomes at length a dark border sharply defined from the coloured matter within . Thus a corpuscle , at first absolutely structureless , homogeneous throughout , is seen gradually to be resolved into central substance or nucleus , external layer or cellwall , and an intermediate , coloured though very transparent , substance . But-and this is significant-these changes are not always thus fully carried out . It not seldom happens that the nucleus does not appear as a central well-defined regularly oval mass . Sometimes it never forms so as to be clearly traced in outline , but remains as an irregular shapeless mass , in its greater portion very obscure . Sometimes only a small part , if any , of an edge can be recognized , most of it appearing to blend indefinitely with the rest of the cell-substance . Sometimes it happens that in many corpuscles the formation of a nucleus does not proceed even so far as this . No distinct separation of substance can anywhere be seen , but shadows , more or less deep , here and there indicate that there is greater aggregation of matter at some parts than at others . Occasionally some of the cells 2c2 present throughout a granular aspect . I have almost invariably observed , too , a relation between the distinctness of the nucleus and of the cell-wall . When the nucleus is well defined , the cell-wall is strongly marked ; -when one is confused , the other is usually fainter . This , however , does not apply to colour ; on the contrary , when the nucleus is least coloured it contrasts most strongly with the surrounding cell . As a rule , the wall of the cell is more strongly marked than the nucleus . It will of course be said that the nuclei are present all the while , but are at first concealed by the surrounding substance the contents of the cell . Thus the fact has been accounted for , that the nuclei are not so obvious at first as they subsequently become . But I think a careful comparison of cells will show that those in which a nucleus may be traced are not more transparent than others which are structureless ; and , moreover , when one cell overlaps another , the lower one is seen through the upper clearly enough to show that the substance of these cells is sufficiently transparent to allow of a nucleus being discerned if it exists . When a nucleus , is fully formed , it hides that portion of the outline of a cell which lies beneath it . How is it , then , if the nucleus is present from the first , that the portion of the cell over which it subsequently appears is , for a while , plainly seen ? The success of the observation is of course influenced by numerous circumstances . The rate at which the nuclei form in the corpuscles varies in different animals . I have usually found that in the common frog they are more prone to form than in many other animals-quicker than in most fishes , or . even than in some birds . But this does not seem always to depend upon their larger size ; for in the common newt the cells , which are larger than those of the frog , remain , as I have noticed , for a longer period without any appearance of nuclei . But even in the frog it can be satisfactorily demonstrated that the corpuscle is structureless . I have found , too , , that the observation succeeds best with the blood of animals which are healthy and vigorous . Thus the first observations upon fresh animals are usually the most satisfactory . After they have been repeatedly wounded or have lost much blood , the cells are more prone to undergo the changes which result in the production of nuclei . Again , the formation of nuclei may be hastened , and their appearance rendered more distinct at last , by various reagents . Acids and many other reagents are well known to have this effect . The addition of a small quantity . of water acts in the same way , but less energetically . It hastens the appearance of an indistinct . nucleus , but interferes with the formation of a well-defined mass , so that , after the addition of water , neither the outline of the cell nor of the nucleus becomes so strongly marked as it often does without it . Exposure to air also promotes their formation ; indeed , as a rule , the nuclei form best under simple exposure . Any disturbance of the drop , as by-moving the point of a needle in it , certainly hastens the change ; and perhaps it is influenced by temperature . Sometimes , ' when the drop of blood has been skilfully mounted , the majority of cells will remain for a long while without any trace of nucleus ; but , again , in almost every specimen , the nucleus in some few of the cells , particularly in those nearest the edges , begins to appear so rapidly that it is hardly possible to run over the whole field without finding some cells with an equivocal appearance . It would follow , of course , from these observations that , if the living blood were examined in the vessels , the corpuscle would show no trace of any distinction of parts ; and this is so . Indeed , in my earlier observations * , before I had learnt to mount a drop of blood for observation in a satisfactory manner , I examined , at.some length , blood in the vessels of the most transparent parts I could select ; and several observations on the web and lung of the frog and elsewhere were satisfactory . But still , when the cells were thus somewhat obscured by intervening membrane , one could not generally feel sure that the observation was so clear and complete , but that a faintly marked nucleus might escape detection . While , therefore , the result of observations on blood-cells in the vessels fully accords with the description I have given , I do not think that the demonstration of the fact , that while living they have no nucleus , can be made so plain and unequivocal as when they are removed from the vessels . The question naturally arises , Why , then , does not a nucleus form in the mammalian corpuscle ? But while it is accepted that the great majority of these corpuscles exhibit no nuclei after death , excellent observers still affirm their occasional existence ; and I am convinced that an indistinct , imperfectly formed " nucleus " is often seen ; and the shadowy substance seen in many of the smaller oviparous cells after they have been mounted for some time is very like that seen under similar circumstances in some of the corpuscles of Mammalia . Many , too , affirm that these corpuscles do not exhibit that distinction of wall and contents which is generally described . It appears to me that this difference of opinion depends on the changes they are prone to undergo . How far the absence of a distinctly defined " nucleus " after death depends on their smaller size I am not prepared to say . AMany questions of course follow . For example , how far is this separation of the substance of a homogeneoust corpuscle into nucleus , cellmembrane , and contents to be compared to the coagulation of the blood ? and how do the agents which are known to influence the one process affect the other ? A still fLrther and more important question is , -Iow are these changes in the corpuscles , and in the blood around them , related ? But in this paper I propose to go no firther than the statement that the red corpuscle of all vertebrata is , in its natural state , structureless . When living , no distinction of parts can be recognized ; and the existence of a nucleus in the red corpuscles of ovipara is due to changes after death , or removal from the vessels . I cannot conclude this paper without acknowledging the great help I have received in this investigation from Mr. Howard Marsh , Demonstrator of Microscopical Anatomy at St. Bartholomew 's Hospital .

112414

3701662

Spectroscopic Observations of the Sun.--No. III

350

356

Proceedings of the Royal Society of London

J. Norman Lockyer

fla

6.0.4

http://dx.doi.org/10.1098/rspl.1868.0067

proceedings

http://corpora.clarin-d.uni-saarland.de/surprisal/6.0.3/?id=112414

10.1098/rspl.1868.0067

http://www.jstor.org/stable/112414

Atomic Physics

Astronomy

Atomic Physics

V. ( Spectroscopic Observations of the Sun.-No . III . " By J. NORMAN LocKYEn , F.R.A.S. Communicated by Dr. FRANKLAND , F.R.S. Received March 4 , 1869 . Since my second paper under the above title was communicated to the Royal Society , the weather has been unfavourable to observatory work to an almost unprecedented degree ; and , as a consequence , the number of observations I have been enabled to make during the last four months is very much smaller than I had hoped it would be . Fortunately , however , the time has not been wholly lost in consequence of the weather ; for , by the kindness of Dr. Frankland , I have been able in the interim to familiarise myself at the Royal College of Chemistry with the spectra of gases and vapours under previously untried conditions , and , in addition to the results already communicated to the Royal Society by Dr. Frankland and myself , the experience I have gained at the College of Chemistry has guided me greatly in my observations at the telescope . In my former paper it was stated that a diligent search after the known third line of hydrogen in the spectrum of the chromosphere had not met with success . When , however , Dr. Frankland and myself had determined that the pressure in the chromosphere even was small , and that the widening out of the hydrogen lines was due in the main , if not entirely , to pressure , I determined to seek for it again under better atmospheric conditions ; and I succeeded after some failures . The position of this third line is at 2796 of Kirchhoff 's scale . It is generally excessively faint , and much more care is required to see it than is necessary in the case of the other lines ; the least haze in the sky puts it out altogether . Hence , then , with the exception of the bright yellow line , the observed spectra of the prominences and of the chromosphere correspond exactly with the spectrum of hydrogen under different conditions of pressure-a fact not only important in itself , but as pointing to what may be hoped for in the future . With regard to the yellow line which Dr. Frankland and myself have stated may possibly be due to the radiation of a great thickness of hydrogen , it became a matter of importance to determine whether , like the red and green lines ( C & F ) , it could be seen extending on to the limb . I have not observed this : it has always in my instrument appeared as a very fine sharp line resting absolutely on the solar spectrum , and never encroaching on it . 350 [ Mar. 18 , Dr. Frankland and myself have pointed out that , although the chromosphere and the prominences give out the spectrum of hydrogen , it does not follow that they are composed merely of that substance : supposing others to be mixed up with hydrogen , we might presume that they would be indicated by their selective absorption near the sun 's limb . In this case the spectrum of the limb would contain additional Fraunhofer lines . I have pursued this investigation to some extent , with , at present , negative results ; but I find that special instrumental appliances are necessary to settle the question , and these are now being constructed . If we assume , as already suggested by Dr. Frankland and myself , that no other extensive atmosphere besides the chromosphere overlies the photosphere , the darkening of the limb being due to the general absorption of the chromosphere , it will follow : I. That an additional selective absorption near the limb is extremely probable . II . That the hydrogen Fraunhofer lines indicating the absorption of the outer shell of the chromosphere will vary somewhat in thickness : this I find to be the case to a certain extent . III . That it is not probable that the prominences will be visible on the sun 's disk . In connexion with the probable chromospheric darkening of the limb , an observation of a spot on February 20th is of importance . The spot observed was near the limb , and the absorption was much greater than anything I had seen before ; so great , in fact , was the general absorption , that the several lines could only be distinguished with difficulty , except in the very brightest region . I ascribe this to the greater length of the absorbing medium in the spot itself in the line of sight , when the spot is observed near the limb , than when it is observed in the centre of the diskanother indication of the great general absorbing power of a comparatively thin layer , on rays passing through it obliquely . I now come to the selective absorption in a spot . I have commenced a map of the spot-spectrum , which , however , will require some time to complete . In the interim , I may state that the result of my work up to the present time in this direction has been to add magnesium and barium to the material ( sodium ) to which I referred in my paper in 1866 , No. I. of the present series ; and I no longer regard a spot simply as a cavity , but as a place in which principally the vapours of sodium , barium , and magnesium ( owing to a downrush ) occupy a lower position than they do ordinarily in the photosphere . I do not make this assertion merely on the strength of the lines observed to be thickest in the spot-spectrum , but also upon the following observations on the chromosphere made on the 21st and 28th ultimo . On both these days the brilliancy of the F line taught me that something unusual was going on ; so I swept along the spectrum to see if any materials were being injected into the chromosphere . 1869 . ] 351 MOn the 21st I caught a trace of magnesium ; but it was late in the day , and I was compelled to cease observing by houses hiding the sun . On the 28th I was more fortunate . If anything , the evidences of intense action were stronger than on the 21st , and after one glance at the F line I turned at once to the magnesium lines . I saw them appearing short and faint at the base of the chronmosphere . My work on the spots led me to imamgine that I should ind sodium-vapour associated with the magnesium ; and on turning from b to DI found this to b th e case . I afterwards reversed barium in thel same wav . The spectruma of the chromosphere seemed to be fulil of lines , and I do not think the three substanees I have named accounted for all of them . The observation was one of excessive delicacy , as the lines were short and ver ? y thin / . The prominence was a small one , about twice the usual heigh-t of the chromosphere ; but the hydrogen lines towered higoh abov se du o those e due to the newly injected aterials . The lin fes i of magunesiuin edeuldd perhaps one-sixth Of the height of the F line , barium a little less , and sodium least of all We have , then , the following facts : I. The lines of sodium , mtngues'iural , and barium , when observed in a spot , are thicker than their usual Fraunhofer lines . II . The lines of sodium , -magicesium , and barium , when observed in the chromosphere , are thinner tShan their usual Fraunhofer lines . *A series of experiments bearing upon these observations is now in progress at the College of Chemistry , and will form the subject of a communication from Dr. Frankland and my ? slf . I maty at once , however , relmarkl that we have here additional evidence of a fact I asserted in 1865 on telescopic evidence the fact , 1namnely , that silot is the seat of a downrush , a downrush to a region , as we now kinow , whiere the selective absorption of the upper strata is different f romz what it rwould ibe(and , indeed , is elsewhere ) at a higher level . MIessrs . De La Pue , Ste art , and Loewy , ho brough t forward the theory of a downrush about the same ime as my observatsions were 1made in 1865 , at once suggested as one advant'agse of this explanation that all the gradations of darkness , from the facue to tuhe ce ntr ; al umbra , are thus supposed to be due to the same cause , namely , the presence to a greeater or less extent of a relatively cooler absorbing atmosphere . oThis I think is now spectroscopically established we h.ave , in fct , two causes for the darkening of a spot : I. The general absorption of the chromosplere , thicker here than elsewhere , as the spot is a cavity . II . The greater selective absorption of the lower sodium , barium , magnesium stratum , the surface of its last layer being below the ordinary level..iesssrs . Ie La li no , Ste.wart , and Loewy also suggested , in their ' Researches on Solar Thysics , ' that if the photosphere of the sun be the 'plaie of condensatioon of gaseous matter , the plane may be fouand to be subject to 352 [ Afar . 18 , periodical elevations and depressions , and that at the epoch of minimum sun-spot-frequency the plane might be uplifted very high in the solar atmosphere , so that there was comiparatively little cold absorbing atmosphere above it , and therefore great difficulty in forming a spot . This suggestion is one of great value ; and , as I pointed out in my previous paper , its accuracy can fortunately now be tested . It may happen , however , that in similar periodical fluctuations the chromosphere may be carried up and down with the photosphere ; and I have already efidence that possibly such a state of things may have occurred since 1860 , for I do not find the C and F Fraunhofer lines of the same relative thickness as they were in that year* . I am waiting to make observations with the large Steinheil spectroscope before I consider this question settled . But the well-known great thickness of the F line in Sirius and other stars will point out the excessive importance of such observations s as a nethod of ascertaining not only the physical constitution , but the actual pressures of the outer limits of stellar atmospheres , and of the same atmosphere at different epochs . And when other spectra have been studied as we have now studied hydrogen , additional means of continuing similar researches will be at our command ; indeed a somewhat careful examination of the spectra of the different classes of stars , as defined by Father Seechi , leads me to believe that several broad conclusions are not far to seek ; and I hope soon to lay them before the Royal Society . For some time past I have been engaged in endeavouring to obtain a sight of the prominences , by using a very rapidly oscillating slit ; but although I believe this miethod will eventually succeed , the spectroscope I employ does not allow me to apply it under sufficiently good conditions , and I am not at present satisfied with the results I have obtained . Hearing , however , from Mr. De La Rue , on February 27th , that Mr. }Iuggins had succeeded in anticipating me by using absorbing media and a wide slit ( the description forwarded to me is short and vague ) , it immediately struck me , as possibly it has struck Mr. Huggins , that the wide slit is quite sufficient without any absorptive media ; and during the last few days I have been perfectly enchanted with the sight which my spectroscope has revealed to me . The solar and atmospheric spectra being hidden , and the image of the wide slit alone being visible , the telescope or slit is moved slowly , and the strange shadow-forms flit past . IHere one is reminded , by the fleecy , infinitely delicate cloud-films , of an English hedgerow with luxuriant elms ; here of a densely intertwined tropical forest , the intimatelv interwoven branches threading in all directions , the prominences generally expanding as they mount upwards , and chnanging slowly , indeed almost imperceptibly . By this:mnethod the smallest details of the pro* I have learnt , after handing this paper in to the Royal Society , that in Angstr6m 's Map the C and F lines are nearly of the same breadth : this I had gathered from observations made with my own spectroscope . Mr. J. N. Lockyer on Spectroscopic minences and of the chromosphere itself are rendered perfectly visible and easy of observation . ADDENDUM . -Received March 17 , 1869 . Since the foregoing paper was written , I have had , thanks to the somewhat better weather , some favourable opportunities for continuing two of the lines of research more especially alluded to in it ; I refer to the method I had adopted for viewing the prominences , and to the injection of sodium , magnesium , &c. into the chromosphere . With regard to seeing the prominences , I find that , when the sky is fice from haze , the views I obtain of them are so perfect that I have not thought it worth while to remount the oscillating slit . I am , however , collecting red and green and violet glass , of the required absorptions , to construct a rapidly revolving wheel , in which the percentages of light of each colour may be regulated . In this way I think it possible that we may in time be able to see the prominences as they really are seen in an eclipse , with the additional advantage that we shall be able to see the sun at the same time , and test the connexion or otherwise between the prominences and the surface-phenomena . Although I find it generally best for sketching-purposes to have the open slit in a radial direction , I have lately placed it at a tangent to the limb , in order to study the general outline of the chromosphere , which in a previous communication I stated to be pretty uniform , while M. Janssen has characterized it as " a niveaufort inegal et tourmente . " lie opinion is now that perhaps the mean of these two descriptions is , as usual , nearer the truth , unless the surface changes its character to a large extent from time to time . I find , too , that in different parts the outline varies : here it is undulating and billowy ; there it is ragged to a degree , flames , as it were , darting out of the general surface , and forming a ragged , fleecy , interwoven outline , which in places is nearly even for some distance , and , like the billowy surface , becomes excessively uneven in the neighbourhood of a prominence . According to my present limited experience of these exquisitely beautiful solar appendages , it is generally possible to see the whole of their structure ; but sometimes they are of such dimensions along the line of sight that they appear to be much denser than usual ; and as there is no longer under these circumstances any background to the central portion , only the details of the margins can be observed , in addition to the varying brightnesses . Mioreover it does not at all follow that the largest prominences are those in which the intensest action , or the most rapid change , is going on , the action as visible to us being generally confined to the regions just in , or above , the chromosphere , the changes arising from violent uprush or rapid dissipation , the uprush and dissipation representing the birth and death of a prominence . As a rule , the attachment to the chroinosphere 354 [ Miar . 18 , is narrow and is not often single ; higher up , the stems , so to speak , intertwine , and the prominence expands and soars upward until it is lost in delicate filaments , which are carried away in floating masses . Since last October , up to the time of trying the method of using the open slit , I had obtained evidence of considerable changes in the prominences from day to day . With the open slit it is at once evident that changes on the small scale are continually going on ; it was only on the 14th inst . that I observed any change at all comparable in magnitude and rapidity to those already observed by M. Janssen . About 9 " 45 " on that day , with a tangential slit I observed a fine dense prominence near the sun 's equator , on the eastern limb . I tried to sketch it with the slit in this direction ; but its border was so full of detail , and the atmospheric conditions were so unfavourable , that I gave up the attempt in despair . I turned the instrument round 90 ? and narrowed the slit , and my attention was at once taken by the F line ; a single look at it taught me that an injection into the chromosphere and intense action were taking place . These phenomena I will refer to subsequently . At 10h 5011 , when the action was slackening , I opened the slit ; I saw at once that the dense appearance had all disappeared , and cloud-like filaments had taken its place . The first sketch , embracing an irregular prominence with a long perfectly straight one , which I called A , was finished at 11 " 51 , the height of the prominence being 1 ' 5 " , or about 27,000 miles . I left the Observatory for a few minutes ; and on returning , at h11 15"1 , I was astonished to find that part of the prominence A had entirely disappeared ; not even the slightest rack appeared in its place : whether it was entirely dissipated , or whether parts of it had been wafted towards the other part , I do not know , although I think the latter explanation the more probable one , as the other part had increased . We now come to the other attendant phenomena . First , as to the F line . In my second paper , under the above title , I stated that the F line widens as the sun is approached , and that sometimes the bright line seems to extend on to the sun itself , sometimes on one side of the F line , sometimes on the other . Dr. Frankland and myself have pointed out , as a result of a long series of experiments , that the widening out is due to pressure , and apparently not to temperature per se ; the F line near the vacuum-point is thin , and it widens out on both sides ( I do not say to the same extent ) as the pressure is increased . Now , in the absence of any disturbing cause , it would appear that when the wider line shows itself on the sun on one side of the F line , it should at the same time show itself on the other ; this , however , it does not always do . I have now additional evidence to adduce on this point , and this time in the prominence line itself , off the sun . In the prominence to which I have referred , the F bright line underwent the most strange contortions , as if there were some disturbing cause which varied the refrangibility of the hydrogen-line under certain conditions and pressures . 1869 . ] Observations of the Suln . 355 The D line of hydrogen ( ? ) also once bore a similar appearance . Secondly , as to the other phenomena which accompanied this strange behaviour of the F line , and were apparently the cause of it . In the same field of view with F , I recognized the barium-line at 1989'5 of Kirchhoff 's scale . Passing on , the magnesium-lines and the enclosed nickel-iron-line were visible in the chromosphere . The magnesilm was projected highl)er into the chromnosphere than the barium , and the.nickel or iron was projected higher than the magnesinm . I carefully examined whether the other iron-lines were visible in the spectrum of the chronosphere ; they were not . I also searched for the stronger barium-lines in the brighter portion of the spectrum ; but I did not find them , probably owing to the feeble elevation of the barium-vapour above the general level of the photosphere , which made the observation in this region a very delicate one . I detected another chromosphere-line very near the iron-line at 1569'5 ( on the east side of it ) . The sodium-lines were also visible . Unfortunately clouds prevented my continuing these interesting observations ; but the action was evidently toningl down . Here , then , we have ans uprush of Barium , Magnesium , ? Nickel , and an unknown substtace from the photosphere into the chromosphere , and with the uprush a dense prominence ; accompanying the uprush we have changes of an enormous magnitude in the prominence ; and as the uprush ceases the prominence melts away . As stated in the former part of this paper , the bariumand mgagnesiumlines were thinane t the corresponding Fraunhofer lines . In connexion with this subject , I beg to be allowed to state that I have commenced a careful comparison of Kirchhoff 's map with the recently published one of Angstrim . From wThat I have already seen , I believe other important conclusions , in addition to that before alluded to , may be derived from this comparison ; but I hesitate to say more at present , as I have not yet been able to compare Angstrim 's maps wiith the sun itself , or to examine the angular diameters of the sun registered at Greenwrich during the present century . On the 14th inst . I also succeeded in detecting the hydrogen-line in the extreme violet in the spectrum of the chromosphere .

112415

3701662

Note on the Blood-Vessel-System of the Retina of the Hedgehog (Being a Fourth Contribution to the Anatomy of the Retina)

357

358

Proceedings of the Royal Society of London

J. W. Hulke

fla

6.0.4

http://dx.doi.org/10.1098/rspl.1868.0068

proceedings

http://corpora.clarin-d.uni-saarland.de/surprisal/6.0.3/?id=112415

10.1098/rspl.1868.0068

http://www.jstor.org/stable/112415

Neurology

Biology 3

Neurology

" Note on the Blood-vessel-system of the Retina of the Hedgehog ( being a fourth Contribution to the Anatomy of the Retina ) . " By J. W. HULKE , F.R.S. , Assistant-Surgeon to the Middlesex Hospital and the Royal London Ophthalmic Hospital . Received May 26 , 1868* . The distribution of the retinal blood-vessels in this common British Insectivore is so remarkable that I deem it worthy of a separate notice-only capillaries enter the retina . The vasa centralia pierce the optic nerve in the sclerotic canal , and , passing forwards through the lamina cribrosa , divide , at the bottom of a relatively large and deep pit in the centre of the intraocular disk of the nerve , into a variable number of primary branches , from three to six . These primary divisions quickly subdivide , furnishing many large arteries and veins , which , radiating on all sides from the nerve-entrance towards the ora retinre , appear to the observer 's unaided eye as strongly projecting ridges upon the inner surface of the retina . When vertical sections parallel to and across the direction of these ridges are examined with a quarter-inch objective , we immediately perceive that the arteries and veins lie , throughout their entire course , upon the inner surface of the membrana limitans interna retinee , between this and the membrana hyaloidea of the vitreous humour , and that only capillaries penetrate the retina itself . In sections of the retina across the larger vessels the membrana limitans may be seen as a clean distinctly unbroken line passing over the divided vessels , with which it does not appear to have any direct structural connexion . The relation of the hyaloidea to the large vessels seems to be more intimate , but its exact nature can be less certainly demonstrated , owing to the extreme tenuity of this membrane . In my best sections I saw the hyaloidea also crossing the large vessels , as does the limitans , but excessively delicate extensions of the hyaloidea appeared to me to lose themselves upon the vessels . The capillaries , shortly after their origin , bend outwards away from the large vessels , and , piercing the retina vertically to its stratification in a direction more or less radial from the centre of the globe , and branching dichotomously in the granular and inner granule-layers , they form loops , the outermost of which reach the intergranule-layer . As they enter the retina the membrana limitans interna is prolonged upon the capillaries in the form of a sheath , which is wide and funnel-like at first , but soon embraces the vessels so closely as to become indistinguishable from their proper wall ; so that , notwithstanding the existence of a sheath , there is no perivascular space about the retinal capillaries , such as His has described in the brain or spinal cord , and has stated to occur in the retina and elsewhere . In all other mammals , except the hedgehog , as far as my present knowledge extends , the arteries , veins , and capillaries lie in the retina . In fish , amphibia , reptiles , and birds , however , as H. Miiller and others ( myself as regards amphibia and reptiles ) have shown , the retina is absolutely nonvascular , the absence of proper retinal blood-vessels being compensated for in fish , amphibia , and some reptiles by the vascular net which in these animals channels the hyaloidea , and by the highly vascular pecten present in other reptiles and in birds . Thus it is possible to divide vertebrates into two classes , according as their retina is vascular or non-vascular ; and these classes would be connected by the hedgehog , the larger branches of whose vasa centralia lying upon the membrana limitans in intimate relation with the hyaloidea , represent the equivalent vessels of the hyaloid system , which forms so exquisite a microscopic object in the frog ; whilst the capillary vessels channelling the retinal tissues occupy the same position which they do in most mammalia . [ The drawings in illustration of this paper are preserved for reference in the Archives of the Royal Society . ]

112416

3701662

On the Measurement of the Luminous Intensity of Light

358

369

Proceedings of the Royal Society of London

William Crookes

fla

6.0.4

http://dx.doi.org/10.1098/rspl.1868.0069

proceedings

http://corpora.clarin-d.uni-saarland.de/surprisal/6.0.3/?id=112416

10.1098/rspl.1868.0069

http://www.jstor.org/stable/112416

Optics

Measurement

Optics

" On the Measurement of the Luminous Intensity of Light . " By WILLIAM CROOKES , F.R.S. &c. Received June 27 , 1868* . The measurement of the intensity of a ray of light is a problem the solution of which has been repeatedly attempted , but with less satisfactory results than the endeavours to measure the other radiant forces . The problem is susceptible of two divisions the absolute and the relative measurement of light . I. Given a luminous beam , we may require to express its intensity by some absolute term having reference to a standard obtained at some previous time , and capable of being reproduced with accuracy at any time and at any part of the globe . Possibly two such standards would be necessary , differing greatly in value , so that the space between them might be subdivided into a definite number of equal parts ; or the same result might perhaps be obtained by the well-known device of varying the apparent intensity of the standard light by increasing and diminishing its distance from the instrument . II . The standard of comparison , instead of being obtained once for all , like the zeroand boiling-points of a thermometer , may be compared separately at each observation ; and the problem then becomes somewhat simplified into the determination of the relative intensities of two sources of light . The absolute method is of course the most desirable ; but as the pre** Read December 17 , 1868 : see Abstract , antea , p. 166 . 358 liminary researches and discoveries are yet to be made , before a photometer analogous to a thermometer in fixity of standard and facility of observation could be devised , the realization of an absolute light-measuring method appears somewhat distant . The path to be pursued towards the attainment of this desirable object appears to be indicated in the observations which from time to time have been made by M. Becquerel , Sir John I-erschel , R. Hunt , and others , on the chemical action of the solar rays , and the production thereby of a galvanic current , capable of measurement on a delicate galvanometer , by appropriate arrangements of chemical baths and metallic plates connected with the ends of the galvanometer wires . Many so-called photometers have been devised , by which the chemical action of the rays at the most refrangible end of the spectrum have been measured , and the chemical intensity of light tabulated by appropriate methods ; and within the last few years Professors Bunsen and Roscoe have contrived a perfect chemical photometer , based upon the action of the chemical rays of light on a gaseous mixture of chlorine and hydrogen , causing them to combine with formation of hydrochloric acid . But the measurement of the chemical action of a beam of light is as distinct from photometry proper as is the thermometric registration of the heat-rays constituting the other end of the spectrum . What we want is a method of measuring the intensity of those rays which are situated at the intermediate parts of the spectrum , and produce in the eye the sensation of light and colour ; and , as previously suggested , there is a reasonable presumption that further researches may place us in possession of a photometric method based upon the chemical action of the luminous rays of light . The rays which affect an ordinary photographic sensitive surface are so constantly spoken of and thought about as the ultra-violet invisible rays , that it is apt to be forgotten that some of the highly luminous rays of light are capable of exerting chemical action . Fifteen years ago * the writer was engaged in some investigations on the chemical action of light , and he succeeded in producing all the ordinary phenomena of photography , even to the production of good photographs in the camera , by purely luminous rays of light free from any admixture with the violet and invisible rays . When the solar spectrum ( of sufficient purity to show the principal fixed lines ) is projected for a few seconds on to a sensitive film of iodide of silver , and the latent image then developed , the action is seen to extend from about the fixed line G to a considerable distance into the ultra-violet invisible rays . When the same experiment was repeated with a sensitive surface of bromide of silver instead of iodide of silver , the result of the development of the latent image showed that , in this case , the action commenced at about the fixed line 6 , and extended , as in the case of the iodide of silver , far beyond the violet . A transparent cell , with parallel glass sides one inch across , was filled with a solution of twenty-five parts of sulphate of quinine to one hundred parts of dilute sulphuric acid ; this was placed across the path of the ray of light , and photographs of the spectrum were again taken on iodide of silver and on bromide of silver , the arrangements being , in all cases , identical with those in the first-cited experiments , with the exception of the interposition of the quinine screen . The action of the sulphate of quinine upon a ray of light is peculiar ; to the eye it scarcely appears to have any action at all , but it is absolutely opaque to the ultra-violet , socalled chemical rays , and thus limits the photographic action on the bromide and iodide of silver to the purely luminous rays . On developing the latent images , it was now found that the action on iodide of silver was confined to a very narrow line of rays , close to the fixed line G , and in the case of bromide of silver , to the space between b and G. Designating the spaces of action by colours instead of fixed lines , it was thus proved that , behind a screen of sulphate of quinine , iodide of silver was affected only by the luminous rays about the centre of the indigo portion of the spectrum , whilst bromide of silver was affected by the green , blue , and some of the indigo rays . It is very likely that a continuance of these experiments would lead to the construction of a photometer capable of measuring the luminous rays ; for although bromide of silver behind quinine is not affected by the red or yellow rays , still it is by the green and blue ; and as the proportion of red , yellow , green , and blue rays is always invariable in white light ( or the light would not be white , but coloured ) , a method of measuring one set of the components of white light would give all the information we want-just as in an analysis of a definite chemical compound the chemist is satisfied with an estimation of one or two constituents only , and calculates the others . Methods based upon the foregoing considerations would supply us with what may be termed an absolute photometer , the indication of which would be always the same for the same amount of illumination , requiring no standard light for comparison ; and pending the development of experiments which the writer is prosecuting in this direction , he has been led to devise a new and , as he believes , a valuable form of relative photometer . A relative photometer is one in which the observer has only to determine the relative illuminating powers of two sources of light , one of which is kept as uniform as possible , the other being the light whose intensity is to be determined . It is therefore evident that the great thing to be aimed at is an absolutely uniform source of light . In the ordinary process of photometry the standard used is a candle , defined by Act of Parliament as a " sperm-candle of six to the pound , burning at the rate of 120 grains per hour . " This is the standard from which estimates of the value of illuminating gas are deduced ; hence the terms " 12-candle gas , " " 14-candle gas , " &c. In his work on ' Gas Manipulation , ' Mr. Sugg gives a very good account of the difficulties which stand in the way of 360 obtaining uniform results with the Act-of-Parliament candle . A true sperm-candle is made from a mixture of refined sperm with a small proportion of wax , to give it a certain toughness , the pure sperm itself being extremely brittle . The wick is of the best cotton , made up into three cords and plaited . The number of strands in each of the three cords composing the wick of a six-to the-pound candle is seventeen , although Mr. Sugg says there does not appear to be any fixed rule , some candles having more and others less , according to the quality of the sperm . Sperm-candles are made to burn at the rate of one inch per hour , and the cup should be clean , smooth , and dry . The wick should be curved slightly at the top , the red tip just showing through the flame , and consuming away without requiring snuffing . To obtain these results , the tightness of the plaiting and size of the wick require careful attention ; and as the quality of the sperm differs in richness or hardness , so must the plaiting and number of strands . A variety of modifying circumstances thus tend to affect the illuminating power of a standard sperm-candle . These difficulties , however , are small compared with those which have resulted from the substitution of paraffin &c. for part of the sperm ; and Mr. Sugg points out that candles can be made with such combinations of stearin , wax , or sperm , and paraffin , as to possess all the characteristics of sperm-candles and yet be superior to them in illuminating-power ; while , on the other hand , candles made from the same materials otherwise combined are inferior . When , in addition to this , it is found that candles containing paraffin require wicks more tightly plaited and with fewer strands than those suitable for the true sperm-candle , our readers will be enabled to judge of the almost insurmountable difficulties which beset the present system of photometry . But assuming that the true parliamentary sperm-candle is obtained , made from the proper materials , and burning at the specified rate , its illuminating-power will be found to vary with the temperature of the place where it has been kept , the time which has elapsed since it was made , and the temperature of the room wherein the experiment is tried . The Rev. W. R. Bowditch , in his work on ' The Analysis , Purification &c. of Coal-gas , ' enters at some length into the question of test-candles , and emphatically condemns them as light-measurers . One experiment quoted by this author showed that the same gas was reported to be 14'63 or 17'36 candle-gas , according to the way the experiment was conducted . The present writer has taken some pains to devise a source of light which should be at the same time fairly uniform in its results , would not vary by keeping , and would be capable of accurate imitation at any time and in any part of the world by mere description . The absence of these conditions seems to be one of the greatest objections to the sperm-candle . It would be impossible for an observer on the continent , ten or twenty years hence , from a description of the sperm candle now employed , to make a standard which would bring his photometric results into relation 361 with those obtained here . Without presuming to say that he has satisfactorily solved all difficulties , the writer believes that he has advanced some distance in the right direction , and pointed out the road for further improvement . Before deciding upon a standard light , experiments were made to ascertain whether the electric current could be made available . Through a coil of platinum wire , so as to render it brightly incandescent , a powerful galvanic current was passed , and its strength was kept as constant as possible by a thick wire galvanometer and rheostat . To prevent the cooling action of air-currents , the incandescent coil was surrounded with glass ; and it was hoped that by employing the same kind of battery , and by varying the resistance so as to keep the galvanometer-needle at the same deflection , uniform results could be obtained . In practice , however , it was found that many things interfered with the uniformity of the results , and the light being much feebler than it was advisable to work with , this plan was deemed not sufficiently promising , and it was abandoned . The method ultimately decided upon is the following:-Alcohol of sp. gr. 0'805 , and pure benzol boiling at 81 ? C. , are mixed together in the proportion of 5 volumes of alcohol and 1 of benzol . This burning fluid can be accurately imitated from description at any future time and in any country ; and if a lamp could be devised equally simple and invariable , the light which it would yield would , it is presumed , be invariable . This difficulty the writer has attempted to overcome in the following manner . A glass:lamp is taken of about two ounces capacity , the aperture in the neck being 0'25 inch diameter ; another aperture at the side allows the liquid fuel to be introduced , and , by a well-known laboratory device , the have of the fluid in the lamp can be kept uniform . The wick-holder consists of a platinum tube 1 81 inch long and 0 125 inch internal diameter . The bottom of this is closed with a flat plug of platinum , apertures being left in the sides to allow free access of spirit . A small platinum cup 0'5 inch diameter and 0'1 inch deep is soldered round the outside of the tube 0-5 inch from the top , answering the threefold purpose of keeping the wick-holder at a proper height in the lamp , preventing evaporation of the liquid , and keeping out dust . The wick consists of fifty-two pieces of hard-drawn platinum wire , each 0-01 inch in diameter and 2 inches long , perfectly straight , and tightly pushed down into the platinum holder , until only 01 inch projects above the tube . The height of the burning fluid in the lamp must be sufficient to cover the bottom of the wickholder : it answers best to keep it always at the uniform distance of 1175 inch from the top of the platinum wick ; a slight variation of level , however , has not been found to influence the light to an extent appreciable by our present means of photometry . The lamp with reservoir of spirit thus arranged , with the platinum wires parallel , and their projecting ends level , a light is applied , and the flame instantly appears , forming a perfectly shaped cone 1'25 inch in height , the point of maximum brilliancy being 0'56 inch from the top of the wick . The extremity of the flame is perfectly sharp without any tendency to smoke ; without flicker or movement of any kind , it burns when protected from currents of air at a uniform rate of 136 grains of liquid per hour . The temperature should be about 60 ? F. , although moderate variations on either side exert no perceptible influence . Bearing in mind Dr. Frankland 's observations on the direct increase in the light of a candle with the atmospheric pressure , accurate observations ought to be taken only at one height of the barometer . To avoid the inconvenience and delay which this would occasion , a table of corrections should be constructed for each 01 inch variation of barometric pressure . There is no doubt that this flame is very much more uniform than that of the sperm-candle sold for photometric purposes . Tested against a candle , considerable variations in relative illuminating-power have been observed ; but on placing two of these lamps in opposition , no such variations have been detected . The same candles have been used , and the experiments have been repeated at wide intervals , using all customary precautions to ensure uniformity . The results are thus shown to be due to variations in the candle , and not in the lamp . It is expected that whoever may be inclined to adopt the kind of lamp here suggested will find not only that its uniformity may be relied upon , but that , by following accurately the description and dimensions here laid down , each observer will possess a lamp of equivalent and convertible photometric value ; so that results may not only be strictly comparable between themselves , but , within slight limits of accuracy , comparable with those obtained by other experimentalists . The dimensions of wick &c. here laid down are not intended to fix the standard . Persons engaged in photometry as an important branch of their regular occupation will be better able to fix these data than the writer , by whom photometry is only occasionally pursued as a means of scientific research . Already many improvements suggest themselves , and several causes of variation in the light have been noticed . Future experiments may point out how these sources of error are to be overcome ; but at present there is no necessity to refine our source of standard light to a greater degree of accuracy than the photometric instrument admits of . The instrument for measuring the relative intensities of the standard and other lights next demands attention . The contrivances in ordinary use are well known . Most of them depend on the law in optics , that the amount of light which falls upon a given surface varies inversely with the square of the distance between the source of light and the object illuminated . The simplest observation which can be taken is made by placing two sources of light ( say , a candle and gas-lamp ) opposite a white screen a few feet off , and placing a stick in front of them , so that two shadows of the stick may fall on the screen . The strongest light will cast the strongest shadow ; and by moving this light away from the stick , keeping the shadows side by side , a position will at last be found at which the two shadows appear of equal strength . By measuring the distance of each light from the screen and squaring it , the product will give the relative intensities of the two sources of light . In practice this plan is not sufficiently accurate to be used except for the roughest approximations ; and from time to time several ingenious contrivances , all founded upon the same law , have been introduced by scientific men by which a much greater accuracy is obtained ; thus , in Ritchie 's photometer , the lights are reflected on to a piece of oiled paper in a box , and their distances are varied until the two halves of the paper are equally illuminated . In Bunsen 's photometer , which is the one now generally used , the lights shine on opposite sides of a disk of white paper , part of which has been smeared with melted spermaceti to make it more transparent . When illuminated by a front light , the greased portion of the paper will look dark ; but if the observer goes to the other side of the paper , the greased part looks the lighter . If , therefore , lights of unequal intensity are placed on opposite sides of a piece of paper so prepared , a difference will be observed ; but by moving one backwards or forwards , so as to equalise the intensity , the whole surface of the paper will appear uniformly illuminated on both sides . This photometer has been modified by many observers . By some the disk of paper is moved , the lights remailing stationary ; by others the whole is enclosed in a box , and various contrivances are adopted to increase the sensitiveness of the eye , and to facilitate calculation : but in all these the sensitiveness is not greatly augmented , as the eye cannot judge of very minute differences of illumination approximating to equality . In 1833 Arago described a photometer in which the phenomena of polarized light were employed . This instrument is fully described , with drawings , in the tenth volume of the ' ( Euvres completes de Frangois Arago ; ' but the description , although voluminous , is far from clear . The principle of its construction is founded on the law of the square of the cosines , according to which polarized rays pass from the ordinary to the extraordinary image . The knowledge of this law , he says , will not only prove theoretically important , but will further lead to the solution of a great number of very important astronomical questions . Suppose , for example , that it is wished to compare the luminous intensity of that portion of the moon directly illuminated , by the solar rays , with that of the part which receives only light reflected from the earth , called the party cendree . Were the law in question known , the way to proceed would be as follows : After having polarized the moon 's light , pass it through a doubly refracting crystal , so disposed that the rays , not being able to bifurcate , may entirely undergo ordinary refraction . A lens placed behind this crystal will therefore show but one image of our satellite ; but as the crystal , in rotating on its axis , passes from its original position , the second image will appear , and its intensity will go on augmenting . The movement of the crystal must be arrested at the moment when , in this growing extraordinary image , the segment corresponding to the part of the moon illuminated by the sun exhibits the intensity of the ashy part shown by the ordinary image . From these data it is easy to perceive , he says , that the problem is capable of solution . In another part of the same volume , after speaking of the polariscope which goes by his name , Arago writes:- " I have now arrived at the general principle upon which my photometric method is entirely founded . The quantity ( I do not say the proportion ) the quantity of completely polarized light which forms part of a beam partially polarized by reflection , and the quantity of light polarized rectangularly which is contained in the beam transmitted under the same angle , are exactly equal to each other . The reflected beam , and the beam transmitted under the same angle by a sheet of parallel glass , have in general very dissimilar intensities ; if , however , we examine with a doubly refracting crystal first the reflected and then the transmitted beam , the greatest difference of intensity between the ordinary and the extraordinary images will be the same in the two cases , because this difference is precisely equal to the quantity of polarized light which is mixed with the common light . " In Arago 's 'Astronomy , ' the author again describes his photometer in the following words:- " I have constructed an apparatus by means of which , upon operating with the polarized image of a star , we can succeed in attenuating its intensity by degrees exactly calculable after a law which I have demonstrated . " It is difficult to obtain an exact idea of this instrument from the description given ; but from the drawings it would appear to be exceedingly complicated and to be different in principle and construction from the one now about to Fig. be described . The present photometer has this in common with that of Arago , as well as with those deD c scribed in 1853 by Bernard * , and in 1854 by Babinet + , that the phenomena of polarized light are used for effect ing the desired end ; but it is believed that the present arrangement is quite new , and it certainly appears to answer the purpose in a way which leaves little to be e/ desired . The instrument will be better understood if )(ID the principles on whiGh it is based are first described . Fig. 1 shows a plan of the arrangement of parts , not . -drawn to scale , and only to be regarded as an outline sketch to assist in the comprehension of general principles . Let D represent a source of light . This may be a white disk of porcelain or paper illuminated by any artificial or natural light . C represents a similar ( white disk , likewise illuminated . It is required to com* Comptes Rendus , April 25 , 1853 . t Proceedings of the British Association , Liverpool Meeting , 1854 . 365 pare the photometric intensities of D and C. ( It is necessary that neither D nor C should contain any polarized light , but that the light coming from them , represented on each disk by the two lines at right angles to each other , forming a cross , should be entirely unpolarized . ) Let H represent a double refracting achromatic prism of Iceland spar ; this will resolve the disk D into two disks d and d ' , polarized in opposite directions ; the plane of d being , we will assume , vertical , and that of dt horizontal . The prism HI will likewise give two images of the disk C ; the image c being polarized horizontally , and c ' vertically . The size of the disks D , C , and the separating power of the prism H , are to be so arranged that the vertically polarized image d , and the horizontally polarized image c , exactly overlap each other , forming , as shown in the figure , one compound disk c d , built up of half the light from D and half that from C. The measure of the amount of free polarization present in the disk cd will give the relative photometric intensities of D and C. The letter I represents a diaphragm with a circular hole in the centre , just large enough to allow the compound disk cd to be seen , but cutting off from view the side disks c ' , d ' . In front of the aperture in I is placed a piece of selenite , of appropriate thickness for it to give a strongly contrasting red and green image under the influence of polarized light . K is a doubly refracting prism , similar in all respects to H , placed at such a distance from the aperture in I that the two disks into which I appears to be split up are separated from each other , as at g , r. If the disk cd contains no polarized light , the images g , r will be white , consisting of oppositely polarized rays of white light ; but if there is a trace of polarized light in c d , the two disks g , r will be coloured complementarily , the contrast between the green and the red being stronger in proportion to the quantity of polarized light in c d. The action of this arrangement will be readily evident . Let it be supposed , in the first place , that the two sources of light , D and C , are exactly equal . They will each be divided by I into two disks d ' d and c ct , and the two polarized rays of which cd is compounded will also be absolutely equal in intensity , and will neutralize each other , and form common light , no trace of free polarization being present . In this case the two disks of light , g , r , will be colourless . Let it now be supposed that one source of light ( D , for instance ) is stronger than the other ( C ) . It follows that the two images d ' , d will be more luminous than the two images c , cr , and that the vertically polarized ray d will be stronger than the horizontally polarized ray c. The compound disk cd will therefore shine with partially polarized light , the amount of free polarization being in exact ratio with the photometric intensity of D over C. In this case the image of the selenite plate in front of the aperture I will be divided by K into a red and a green disk . Fig. 2 shows the instrument fitted up . A is the eyepiece ( shown in enlarged section at fig. 3 ) ; GB is a brass tube , blacked inside , having a 366 piece ( shown separate at D C ) slipping into the end B. The sloping sides , D B , B C , are covered with a white reflecting surface ( white paper or finely Fig. 2 . _ I ? ground porcelain ) , so that when DC is pushed into the end B , one white surface DB may be illuminated ( as in fig. 2 ) by the candle , and the other surface BC by the lamp , If the eyepiece A is removed , the observer , looking down the tube G B , will see at the end a luminous white disk divided vertically into two parts , one half being illuminated by the candle E , and the other half by the lamp F. By moving the candle E , for instance , along the scale , the illumination of the half DB carl be varied at will , the illumination of the other half remaining stationary . The eyepiece A ( shown enlarged at fig. 3 ) will be understood by reference to fig. 1 , the same letters representing similar ig . 3 . parts . At L is a lens to collect the rays from DBCL ( fig. 2 ) , and throw the image into the proper part | of the tube . At M is another lens so adjusted as to give a sharp image of the two disks into which I is divided by the prism K. The part N is an adaptation of Arago 's polarimeter ; it consists of a series of thin plates of glass capable of moving round the axis of the tube , and furnished with aI pointer and graduated arc ( shown at A G , fig. 2 ) . By means of this pile it is possible to partially polarize the rays coming from the illuminated disks in one or the other direction , and thus bring to the neutral state the partially polarized beam cd ( fig. 1 ) , i so as to get the images g , r free from colour . It is so adjusted that when at the zero-point it produces an : K equal effect on both disks . The action of the instrument is as follows . The M --:--standard lamp being placed on one of the supporting pillars which slide along the graduated stem ( fig. 2 ) , it is adjusted to the proper height , and moved 367 along the bar to a convenient distance , depending on the intensity of the light to be measured : the whole length being a little over 4 feet , each light can be placed at a distance of 24 inches from the disk . The flame is then sheltered from currents of air by black screens placed round , and the light to be compared is fixed in a similar way on the other side of the instrument . The whole should be placed in a dark room , or surrounded with nonreflecting screens ; and the eye must also be protected from the direct rays of the two lights . On looking through the eyepiece two bright disks will be seen , probably of different colours . Supposing F represents the standard flame , and E the light to be compared with it , the latter must now be slid along the scale until the two disks of light , seen through the eyepiece , are about equal in tint . Equality of illumination is easily obtained ; for as the eye is observing two adjacent disks of light , which pass rapidly from redgreen to green-red through a neutral point of no colour , there is no difficulty in hitting this point with great precision . It has been found most convenient not to attempt to get absolute equality in this manner , but to move the flame to the nearest inch on one side or the other of equality . The final adjustment is now effected at the eye-end by turning the polarimeter one way or the other up to 45 ? , until the images are seen without any trace of colour . This will be found more accurate than the plan of relying entirely on the alteration of the distance of the flame along the scale ; and by a series of experimental adjustments the value of every angle through which the bundle of plates is rotated can be ascertained once for all , when the future calculations will present no difficulty . Squaring the number of inches between the flames and the centre will give their approximate ratios ; and the number of degrees the eyepiece rotates will give the number to be added or subtracted in order to obtain the necessary accuracy . The delicacy of the instrument is very great . With two lamps , each about 24 inches from the centre , it is easy to distinguish a movement of one of them to the extent of 0'1 inch to or fro ; and by using the polarimeter an accuracy considerably exceeding this can be attained . The employment of a photometer of this kind enables us to compare lights of different colours with one another , and leads to the solution of a problem which , from the nature of their construction , would be beyond the powers of the instruments in general use . So long as the observer , by the eye alone , has to compare the relative intensities of tint-surfaces , respectively illuminated by the lights under trial , it is evident that , unless they are of the same tint , it is impossible to obtain that equality of illumination in the instrument which is requisite for a comparison . By the unaided eye one cannot tell which is the brighter half of a paper disk , illuminated on one side with a reddish , and on the other with a yellowish light ; but by using the above-described photometer the problem becomes practicable . For instance , on reference to fig. 1 , suppose the disk D were illuminated with light of a reddish colour , and the disk C with greenish 368 light , the polarized disks d ' , d would be reddish and the disks c , c1 greenish , the central disk cd being of the tint formed by the union of the two shades . The analyzing prism K , and the selenite disk I , will detect free polarization in the disk c d , if it be coloured , as readily as if it were white ; the only difference being that the two disks of light , g , r , cannot be brought to a uniform white colour when the lights from D and C are equal in intensity , but will assume a tint similar to that of c d. When the contrasts of colour between D and C are very strong-when , for instance , one is bright green and the other scarlet-there is some difficulty in estimating the exact point of neutrality ; but this only diminishes the accuracy of the comparison , and does not render it impossible , as it would be according to other systems . No attempt has been made in these experiments to ascertain the exact value of the standard spirit-flame in terms of the Parliamentary spermcandle . Difficulty was experienced in getting two lots of candles yielding light of equal intensities ; and when their flames were compared between themselves and with the spirit-flame , variations of as much as 10 per cent. were sometimes observed in the light they gave . Two standard spiritflames , on the other hand , seldom showed a variation of 1 per cent. , and had they been more carefully made they would not have varied 01 per cent. This plan of photometry is capable of far more accuracy than the present instrument will give . It can scarcely be expected that the first instrument of the kind , made by an amateur workman , should possess equal sensitiveness with one in which all the parts have been skilfully made with special adaptation to the end in view .

112417

3701662

Addendum to Description of Photometer

369

370

Proceedings of the Royal Society of London

W. Crookes

fla

6.0.4

http://dx.doi.org/10.1098/rspl.1868.0070

proceedings

http://corpora.clarin-d.uni-saarland.de/surprisal/6.0.3/?id=112417

10.1098/rspl.1868.0070

http://www.jstor.org/stable/112417

Optics

Biography

Optics

ADDENDUM to description of Photometer . By W. CROOKES , F.R.S. Received December 17 , 1868 . When I wrote that other experimentalists had already made use of the phenomena of polarized light for measuring the intensity of light , I was not aware that a photometer already existed in which the principle of the one above described was adopted . By the kindness of Sir Charles Wheatstone I have , within the last few days , been enabled to experiment with a photometer devised by M. Jamin , founded on the same principle . I have not yet succeeded in finding a printed account of this instrument , but a written one was supplied with it , and having been allowed to take it to pieces its construction is evident . It consists , first , of a Nicol 's prism , then of an achromatized doubly refracting prism ; next , of two plates of quartz , cut oblique to the axis , reversed , and superposed ; and finally , at the eye-end , of a second Nicol 's prism . As in my instrument , each of the two lights to be compared split Prof. Maskelyne on the Mineral Constituents into two images ; the ordinary ray from one is superposed on the extraordinary ray from the other , and the compound beam so produced is examined further . The means adopted to effect the desired object are , however , very different , being much simpler in my method , whilst the results are superior . In Jamin 's photometer the light which eventually reaches the eye is comparatively feeble , and the field of view is very restricted ; the objects themselves under comparison are seen direct through the instrument without the interposition of a telescopic arrangement , and no means are taken to prevent extraneous light from entering . The deficiency of light makes observations by artificial light difficult , whilst when examining objects illuminated by diffused or direct sunlight the eye is fatigued and bewildered by the variations of shape , size , and colour assumed by the overlapping objects seen through the instrument . In the photometer described in the former part of this paper , there is abundance of light , and the observation is made upon two luminous disks , which are magnified by means of a lens , so as to appear close to the eye . It will be found much easier to detect differences of colour between these two adjacent disks than to observe the presence or absence of the coloured fringes in the central portion of the field of Jamin 's photometer . In the former case the eye has nothing to observe but two uniform and purely coloured disks , changing from redgreen to green-red through an intermediate stage of neutrality ; in the latter case the eye has to detect the stage of neutrality in the central portion of the field , where the two images under comparison overlap , the attention being distracted , and the sensitiveness of the eye weakened , by the brilliantly coloured fringes which cross the adjacent objects . A. direct comparison of the two instruments for sensitiveness shows that the present photometer will detect much more minute differences of intensity than Jamin 's will , whilst it will work with tolerable accuracy in a light too feeble to give any results with the latter instrument .

112418

3701662

Preliminary Notice on the Mineral Constituents of the Breitenbach Meteorite

370

372

Proceedings of the Royal Society of London

N. Story Maskelyne

fla

6.0.4

http://dx.doi.org/10.1098/rspl.1868.0071

proceedings

http://corpora.clarin-d.uni-saarland.de/surprisal/6.0.3/?id=112418

10.1098/rspl.1868.0071

http://www.jstor.org/stable/112418

Chemistry 2

Geography

Chemistry

I. " Preliminary Notice on the Mineral Constituents of the Breitenbach Meteorite . " By Professor N. STORY MASKELYNE , M.A. Communicated by Professor WARINGTON W. SMYTH , F.R.S. Received March 2 , 1869 . This meteorite , which belongs to the rare class intermediate between meteoric irons or siderites and meteoric stones or anrolites ( a class to [ Apr. 8 , 370 which I applied some years since the term siderolites ) , was found in Breitenbach in Bohemia . It is a spongy metallic mass , very similar to the siderolite of Rittersgriin in Saxony , the hollows in the iron being filled by a mixture of crystalline minerals . These minerals are two in number ; and the present notice deals with these two minerals . 1 . One of them is of a pale-green colour , crystallizing in the prismatic system , and presenting at once the formula of an augitic mineral and a crystalline form nearly approximating to that of olivine . Dr. Viktor von Lang , when my colleague at the British Museum , measured some merohedral crystals of this mineral , and obtained for its elements a : : c=0-8757 : 0-8496:1 , 0/ 110.010 = 44 8 101.100 = 41 11 104.100 = 74 3 011.010 = 40 16 The analysis of this green mineral gave , from 0'4127 grm. , per cent. Oxygen-ratios . Equivalent ratios . Silica ... ... ... ... 0-2315 56-101 29-920 1-87 Magnesia ... ... . . 0-1247 30-215 12-087 1.51 1 88 Ferrous oxide ... . 00560 13-583 3-018 0-37J 0-4122 99-899 results which correspond very nearly with an Enstatite of the formula ( Mg , Fe ) SiO , . The specific gravity is 3'23 . It is remarkable that of the minerals presenting the general formula M SiO , , where M stands for one or more metals of the calcium and magnesium groups , we are acquainted with two anorthic types ( Rhodonite and Babingtonite ) ; three oblique types , those , namely , of Wollastonite , of Hornblende , and of Augite ; two prismatic types , those , namely , of Enstatite and Anthophyllite , homceomorphous with the oblique Augites and Hornblendes ; and to these we shall have now to add ( if the measurements of Dr. Lang shall prove to be distinct from those of Enstatite ) a third , in the green mineral under description . Of these , the prismatic types are essentially those of the magnesian group . The rest , with the exception of the calcium silicate ( Wollastonite ) , are types belonging to the mixed groups . 2 . The other mineral is one of very great interest . It is , in short , silica crystallized in forms and in a system distinct from quartz , and possibly is tridymite . In bulk it forms about a third part of the mixed crystalline mass . The crystals are very imperfect , and are twinned : but there are two cleavages parallel to the planes of a prism of about 119 ? ; and , on looking through a plane that is perpendicular to this zone , it is seen that the crystal is biaxial . The normal to this plane is parallel to the second mean line , the optical character being negative . A section made for examination in the microscope showed two small crystals in which light traverses the section with equal brilliancy during its rotation between crossed Nicol prisms . This , and possibly a similar case recorded by Vom Rath , seems to result from the section being cut parallel to a composite portion of the crystal . The analysis of the mineral gave , by distillation of the silica as silicic difluoride , and subsequent determination as potassic fluosilicate , 97'43 per cent. of silica , the remainder being oxide of iron and lime . Thus 0-3114 grm. gave : per cent. Silica ... . . 03034 97-43 Ferric oxide ... ... 0-0035 1-124 Lime ... ... ... 0'0018 0-578 0-3087 99'132 A second analysis gave 99*21 per cent. silica , 0'79 of residue . Its specific gravity , as determined from a very small amount of the mineral picked under the microscope , was 2-18 ; a second determination made on a larger amount gave the value 2-245 . That of tridymite is 2'295 to 2'3 . This may be taken as evidence that the mineral is not quartz , the specific gravity of which is 2-65 . Vom Rath 's experiments were made on a rather less pure form of tridymite . There can be no doubt from these results , further details of which shall be shortly laid before the Society , that this mineral is silica in the form of its allotropic condition and lower density . It may possibly be the mineral to which Vom Rath has given the name of Tridymite ; the crystalline system , however , of Tridymite , as given by Vom Rath , does not accord with the above facts .

112419

3701662

On the Derivatives of Propane (Hydride of Propyl)

372

376

Proceedings of the Royal Society of London

C. Schorlemmer

fla

6.0.4

http://dx.doi.org/10.1098/rspl.1868.0072

proceedings

http://corpora.clarin-d.uni-saarland.de/surprisal/6.0.3/?id=112419

10.1098/rspl.1868.0072

http://www.jstor.org/stable/112419

Chemistry 2

Thermodynamics

Chemistry

II . " On the Derivatives of Propane ( Hydride of Propyl ) . " By C. SCHORLEMMER . Communicated by Prof. STOKES , Sec. R.S Received March 5 , 1869 . At the time when I commenced this investigation , the existence of normal propyl alcohol was very doubtful . According to Chancel* , this body is found in the fusel-oil from the marc of grapes ; but Mendelegefft tried in vain to isolate it from a sample of this oil which he had obtained from Chancel himself . Several attempts to prepare the normal alcohol by synthesis failed . Thus Linnemann and Siersch* tried to obtain it by converting acetonitril into propylamine , by means of hydrogen in the nascent state , and decomposing the hydrochlorate of this base with silver nitrite ; but the alcohol thus formed was found to be the secondary one . The same compound was obtained by Butlerow and Ossokint , by acting upon ethylene iodohydrine , C , H , { I , with zinc methyl , in order to replace iodine by methyl . Now as in both cases , according to theory , the normal or primary alcohol ought to have been formed , and as we have no explanation why instead of this compound the secondary alcohol was obtained , Butlerow and Ossokin believe that the normal propyl-alcohol cannot exist . Not agreeing with this view , I was led to an investigation of this subject , the results of which I have the honour to lay before the Society . My reasoning was as follows:-It appears , as the most probable theory , and which is now accepted by most chemists , that the four combining powers of the carbon atom have the same value . If so , only one hydrocarbon having the composition C , H , can exist . This propane must be formed by replacing the iodine in the secondary propyl iodide , by hydrogen , and subjecting the hydrocarbon thus obtained to the action of chlorine , by which primary propyl chloride must be formed in accordance with the behaviour of other hydrocarbons of the same series . I soon found that my theory was correct ; and in a short note , which I published in ' Zeitschrift fur Chemie ' ( 1868 , p. 49 ) , I stated that I had obtained the normal propyl alcohol by this method . At the same time , Fittig proved that it was contained in fusel-oils+ , and lately Linnemann prepared it synthetically from ethyl-compounds by converting acetonitrile ( ethyl cyanide ) into propionic anhydride , and acting upon this body with nascent hydrogen ? . The propane which I used in my researches was obtained by acting upon isopropyl iodide with zinc turnings and diluted hydrochloric acid . A continous evolution of gas takes place if the flask containing the mixture is kept cold . If it is not cooled down a violent reaction soon sets in . The gas always contains vapour of the iodide , even if it has been evolved very slowly . In order to purify it as much as possible , it was washed with Nordhausen sulphuric acid , with a mixture of nitric and sulphuric acids and with caustic soda solution . As a gas-holder I used a tubulated bell-jar , which was suspended in a larger inverted one , filled with a concentrated solution of common salt . When a sufficient quantity of gas had collected , chlorine was passed into it , care being taken not to have it in excess . In diffused daylight substitution-products were formed , which collected as an oily layer on the salt solution . Alternately more propane and chlorine were passed into the apparatus , until it was nearly filled with the excess of propane and vapours of the most volatile substitution-products . The latter were condensed by passing the gas into a receiver surrounded by a freezing-mixture . To collect the liquid chlorides which were contained in the gasholder , the tubulus of the bell-jar was closed with cork , which was provided with a wide short glass tube , open at both ends , and so much salt solution put into the gas-holder that the chlorides entered this tube , from which they could easily be removed with a pipette . By repeating this process several times , a quantity of chlorine compounds , sufficient for further investigation , was obtained . This was washed with water , dried over caustic potash , and distilled . The liquid commenced to boil at 42 ? C. , the boiling-point rising towards the end above 200 ? C. By fractional distillation , a comparatively small quantity of a liquid was obtained , which boiled at 42 ? -46 ? , and consisted of the primary propyl chloride , C , H7 C1 . 0-0975 of this chloride gave 0-1730 silver chloride , and 0-005 silver , corresponding to 0'044 chlorine . Calculated for C3 17 C1 . Found . 45'2 per cent. Cl. 45'5 per cent. Cl. In order to prove that this body was really the normal chloride , it had to be converted into the alcohol . For this purpose I used that portion of the chlorides which , after repeated distillation , boiled below 80 ? C. It was heated in sealed tubes with potassium acetate and glacial acetic acid for several hours to 200 ? C. , and thus converted into the acetate , a light colourless liquid , possessing the characteristic odour of the acetic ethers . I did not endeavour to obtain this ether in the pure state , as this could have been effected only with great loss of material , but converted it at once into the alcohol , by heating it with a diluted solution of potash , in sealed tubes , up to 120 ? C. After cooling , the contents of the tubes were distilled and rectified . A portion of it was oxidized with a cold diluted solution of chromic acid . No gas was evolved , but a strong smell of aldehyde was perceived , which disappeared on adding more chromic acid . On distilling to dryness , an acid liquid was obtained , which was neutralized with sodium carbonate . The solution was evaporated to dryness , and the residue distilled with a quantity of sulphuric acid , sufficient to liberate about one-fourth of the acid . The residue in the retort was again distilled with the same quantity of sulphuric acid , and , by repeating this process , the acid was obtained in four fractions . Each of these was converted . into the silver-salt by boiling with silver carbonate . The silver-salts crystallized from the hot saturated solution in small shining needles , which were grouped in stars and feathers . These were dried , first , over sulphuric acid , afterwards in the steam-bath , and the silver determined by ignition . per cent. Fraction ( 1 ) 0*2350 gave 0-1404 silver=59'74 , ( 2 ) 0-2420 , , 0-1450 , , =59-91 , , ( 3 ) 0-1676 , , 0-1002 , , =59-78 , ( 4 ) 0-2124 , , 0-1264 , , =59-51 Mean ... ... 59-73 Silver propionate contains ... ... ... ... 59-67 I also prepared the lead-salt , which exhibited the properties of lead-propionate ; it did not crystallize , but dried up to an amorphous gum-like mass . As by oxidation no other acid besides propionic was found , it follows that the alcoholic liquid could only contain normal propyl alcohol . I tried to isolate this body from the remaining liquid , by adding potassium carbonate until it separated into two layers . The upper one was taken off and dried , first over fused potassium carbonate , and afterwards over anhydrous baryta . This liquid , however , proved to be a mixture ; it began to boil at 80 ? C. , and the boiling-point rose slowly to 96 ? C. By fractionating it could be separated into two portions-a smaller one boiling between 80u-850 , and a larger one boiling above 90 ? . The portion boiling between 92 ? -96 ? gave , by combustion , numbers agreeing with the composition of propyl alcohol . 0-2238 substance gave 0*4098 carbon dioxide and 0-2675 water . Calculated . Found . C3 36 60 59-81 H18 8 13-33 13-28 0 16 26-67 -60 100-00 I have not yet studied the properties of this alcohol , as I hope to obtain it soon in larger quantities . The liquid boiling between 800-850 appears to be an acetal ; it is not acted upon by sodium , and therefore can easily be obtained free from alcohol , by distilling it over this metal . The small quantity was just sufficient for two analyses , the results of which give C , H , , 0 , as the probable formula . ( 1 ) 0-2500 gave 0-2725 water and 0-5280 carbon dioxide . ( 2 ) 0'2755 gave 0-2950 water ; the determination of carbon was lost . Calculated . Found . I. II . C5 60 57-96 5760 H,2 12 11-53 12-11 11-93 02 32 30-78 104 100-00 How this body has been formed I cannot explain . As I have already mentioned , chloride of propyl forms only a small fraction of the products obtained by subjecting propane to the action of chlorine , the chief product of the reaction being a liquid which boils at 940-98 ? C. , and has the formula C3 H6 Cl , . 0-1600 gave 0-3970 silver chloride and 0-005 silver . Calculated for 03 H6 C12 . Found . 62-8 per cent. C1 . 62-4 per cent. This body is propylene dichloride ; for its boiling-point not only coincides with that of this compound , but also all its reactions are the same . Heated with potassium acetate and acetic acid in closed tubes , it is readily decomposed , a high boiling acetate being formed , which , on heating with concentrated potash solution and distilling , yields a liquid the last portion of which boils between 1800-190 ? C. , and possesses the sweet taste of propyl glycol . I did not isolate the glycol in the pure state , but proposed to establish its structure by oxidation . A diluted cold solution of chromic acid acts violently on it , carbon dioxide being evolved in abundance , and a strong odour of aldehyde being recognized , which , on further addition of the oxidizing liquid , was changed into that of acetic acid . By distillation an acid liquid was obtained , which , on boiling:with silver carbonate , yielded a silver-salt , which crystallized in the well-known needles of silver acetate . 0'3013 of this salt left on ignition 0-1935 silver . Silver acetate contains Found . 64'67 per cent Aq . 64'22 per cent. The oxidation-products ( carbon dioxide and acetic acid ) prove sufficiently that the structure of the glycol is expressed by the formula CHI--CH ( OH)--CH2 ( OH ) , which is that of the known propyl glycol . The foregoing researches establish a general reaction for converting secondary compounds of the alcohols into those of primary radicals . This is effected by replacing the iodine in secondary iodides by hydrogen , and subjecting the hydrocarbons thus obtained to the action of chlorine , by which the primary chlorides are formed . Of greater interest , perhaps , as possessing an important bearing on the theory of substitution , is the fact that the second substitution-product of propane consists of propylene dichloride , having the structure CH3--CH C1 -CHE C1 . This was the less to be expected , as ethane , C , HG , the hydrocarbon next lower in the series , yields , by acting on it with chlorine as second product , ethylidene dichloride , CH -CH Cl , . Whilst , therefore , in propane first one hydrogen atom in the methyl group is replaced by chlorine , and afterwards one which is combined with the adjoining carbon atom , in ethane the substitution takes place at one and the same carbon atom . The action of chlorine upon propane is certainly in contradiction to all theories of substitution which have been expounded . In a second communication I propose to describe the higher chlorinated substitiltion-products of propane .

112420

3701662

Researches in Animal Electricity. [Abstract]

377

391

Proceedings of the Royal Society of London

Charles Bland Radcliffe

abs

6.0.4

proceedings

http://corpora.clarin-d.uni-saarland.de/surprisal/6.0.3/?id=112420

http://www.jstor.org/stable/112420

Nervous System

Electricity

Nervous System

III . " Researches in Animal Electricity . " By CHARLES BLAND RADCLIFFE , M.D. Communicated by C. BROOKKE , F.R.S. Received , Part 1 . , Feb. 18 ; Part II.-V . , March 11 , 1869 . ( Abstract . ) After a description of certain instruments , now employed for the first time in researches of this kind , the topics inquired into successively are:the electrical phenomena which belong to nerve and muscle in a state of rest ; the electrical phenomena which mark the passing of nerve and muscle from the state of rest into that of action ; the motor phenomena ascribed to the action of the " inverse " and " direct " voltaic currents ; and electrotonus . I. On certain Instruments now employedfor the first time in Researches in Animal Electricity . The instruments here referred to and described are Sir Wm. Thomson 's Reflecting Galvanometer , Mr. Latimer Clarke 's Potentiometer , and some new electrodes devised by the author . Sir Wm. Thomson 's Reflecting Galvanometer , which is the principal galvanometer made use of , is stated to be more manageable than the old galvanometer of Prof. Du Bois Reymond , and not less sensitive . Mr. Latimer Clarke 's " Potentiometer , " which is really a very ingenious adaptation of the idea upon which the Wheatstone 's Bridge is based , is the instrument employed for the measurement of tension . It is so delicate as to measure with certainty the 1i65 part of the tension of a Daniell 's cell . The new electrodes are simply pieces of platinum wire , flattened an( pointed at the free ends , and having these free ends freshly tipped with sculptor 's clay at the time of an experiment . The necessary homogeneity of the two is secured by pushing the clay a little further on one of the wires , or by pulling it a little further off ; for by a simple manipulation of this kind it is found that the clay tips of the two electrodes may be so adjusted as to allow them to be brought together without the development of the slightest current . After a very little practice it is found , indeed , that in a very few moments the two electrodes may be made perfectly homogeneous by thus covering or uncovering one of them . And , further , it is found that the secondary polarization arising from the passage of a current may be got rid of at once by simply bringing the clay tips of the two electrodes together so as exclude the polarizing current from the circuit of the galvanometer , and by leaving them in this position for a moment or two-by short-circuiting the galvanometer , that is to say , for a very brief period . It is found , in short , that these electrodes are infinitely more manageable , and not less effectual , than the electrodes commonly in use , in which enter zinc troughs filled with saturated solution of zinc , and pads of blotting-paper , the pads being kept sodden with this solution by having one of their ends dipping into it-electrodes which , to say the least , are not easily put in order or kept in order . II . On the Electrical Phenomena which belong to Living Nerve and Muscle during the state of rest . Living nerve and muscle supply currents to the galvanometer ( the nerve-current , and the muscular current , so called ) which are not supplied by dead nerve and muscle . These currents , when the tissues supplying them are fresh and at rest , show that the surface composed of the sides of the fibres , and the surface composed of the ends of the fibres , are in opposite electrical conditions , the former surface being positive , the latter negative . These currents , when the tissues supplying them are about to die , and , in some cases , when they are put in action , are wholly or partially reversed-are so changed in direction , that is to say , as to show that there is at this time a total or partial reversal in the electrical relations of the ends and sides of the fibres . The fact of a partial reversal , in which the fibres may be positive in some part of their sides and negative in others , or positive at one of their ends and negative at the other , is now pointed out for the first time . Nerve and muscle , and the animal tissues generally , oppose a very high resistance to the passage of a common voltaic current-so high , indeed , as to justify the inference that muscles and nerves may be looked upon as non-conductors rather than as conductors . The resistance in an inch of the sciatic nerve of a frog , for example , is about 40,000 B.A. units , or nearly seven times that of the whole Atlantic Cable . The mean tension of the nerve-current and the muscular current proves to be about half that of a Daniell 's cell . Moreover , negative and positive electricity , in equal amounts , are both found to be present . The case is not one in which only one kind of electricity is present , in which what appears to be negative is only a lower degree of positive , or vice versed ; it is one in which two electricities are present , one above the zero of the earth , the other below it-one as much above the zero of the earth as the other is below it . These facts are made out by means of the potentiometer . Looking at these facts , and especially at the comparative non-conductibility of nerve and muscle , wholly or in part , and at the presence in these tissues of positive and negative electricity in equal quantities , it is thought probableThat the comparative non-conductibility of nerve and muscle may allow certain parts of these tissues to act as dielectrics rather than as conductors , and that these parts may be the sheaths of the fibres . That the development of one kind of electricity ( by oxygenation , or in some other way ) on the exterior of the sheaths of the nerve and muscular fibres may lead , by induction , to the development of the other kind of electricity on the interior of these sheaths . That the exterior and interior of the sheaths of the fibres in nerve and muscle may be in opposite electrical conditions , because the sheath plays the part of a dielectric . That the surface composed of the ends of the fibres in nerve and muscle may be in an electrical condition opposed to that of the surface composed of the sides of these fibres , because there may be a communication at the ends of the fibres with the interior of the sheaths of the fibres . That the nerve-current and muscular current may be no more than accidental phenomena , depending upon the mere fact of the positive exterior and the negative interior of the nerve and muscular fibre being connected by a conductor . That the fundamental electrical condition of nerve and muscle during rest may be , not one of currents ever circulating in closed circuits around peripolar molecules , of which currents the nerve-current and the muscular current are only derived portions , but one of tension--a condition , not current in any sense , but static-a state which , as long as it lasts , must tend to keep the molecules acted upon in a state of mutual repulsion . III . On the Electrical Phenomena which mark the passing of Nerve and Musclefrom the state of Rest into that of Action . The fact of " induced contraction " so called , together with the analogies existing between the muscles and the electric organ of the torpedo as to the relation to the nervous system and the manner of acting in more cases than one , are cited as reasons for believing , with Matteucei , that a discharge , analogous to that of the torpedo , marks the passage of both muscle and nerve from the state of rest into that of action . And , further , the fact , well established by Prof. Du Bois Reymond , that the nerve-current and the muscular current are both alike greatly weakened when the nerve or muscle passes from the state of rest into that of action , is cited as corroborative evidence in support of Matteucci 's conclusion-as demonstrating , in short , the actual disappearance of electricity in the very cases in which Matteucci , from analogy solely , infers the existence of discharge . Again , the conclusion arrived at as to the electrical condition of muscle and nerve during the state of rest , is looked upon as another argument to the same effect ; for if it be true that this condition is one , not of current , but of-charge , then there is a substantial ground for supposing that the passing of nerve and muscle from the state of rest into that of action may be marked by discharge . In a word , the more the evidence is considered the more it seems to justify this conclusion , -that the passing of nerve and muscle from the state of rest into that of action is marked by a discharge of electricity analogous to that of the torpedo . IV . On the Motor Phenomena ascribed to the action of the " Inverse and Direct " Voltaic Currents . When a voltaic current is so made to pass through the two hind limbs of a prepared frog that the current is " s inverse " in one limb and " direct " in the other , it is found that the closing and opening of the circuit may or may not be attended by contraction , and that the presence or absence of contraction may or may not obey a similar rule in the two limbs . The facts admit of being arranged in three stages , thus : The limb in which the curThe limb in which the current is " Direct . " rent is " Inverse . " On closing On opening On closing On opening circuit . circuit , circuit . circuit . Stage I. When ( n ) With a Contraction . 0 . Contraction . 0 . the electricity acts weak battery . similarlyupon the -two limbs . ( ) Witl stron bt a tie Contraction . Contraction Contraction . Contraction . strong battery . Stage II . Vhen 1st period . Contraction . 0 . Contraction . Contraction . the electricity acts differenly upon '2nd period . Contraction . 0 . 0 . Contraction . the two limbs . 3rd period . 0 . 0 . 0 . Contraction . Stage III . When Wt the electricity is ( a ) With a Contraction . 0 . Contraction . 0 . again made to act weak battery . similarlyupon the two limbs by reversing the posi(b ) With a Contraction . Contraction . Contraction.ontraction . tion of the poles . battery . In seeking to account for these facts , the " direct " and " inverse " currents are not the only agencies which have to be taken into consideration . If the limbs were perfectly sufficient conductors , the sole agencies at work might be these currents ; but instead of being very good conductors , the limbs are , in fact , non-conductors rather than conductors , opposing a resistance to the current of about 40,000 B.A. units ( a resistance nearly seven times that of the whole Atlantic Cable ) ; and the result of closing the circuit with them is this-that each limb is found to be charged with the free electricity which is present at the poles when the circuit is open , and which would be entirely discharged if the place of the limbs were supplied by a perfectly sufficient conductor . The case is one in which , in accordance with the investigations of Mr. Latimer Clarke on the tension of the voltaic circuit , each limb is found to participate in the charge of the pole nearest to it , the charge being positive in the limb in which the current is inverse , and negative in the limb in which the current is direct , the tension of the charge in each limb diminishing regularly from the pole where it is highest , to some point midway between the poles , where it is at zero ; the case is one in which , supposing the value of the tension at each of the poles to be 10 , the state as to tension at different points between the poles is found to be that which is indicated by the figures in the accompanying sketch : Fig. 1 . o This , then , being the state of the limbs as to tension under these circumstances , it is plain that there must be definite changes in tension at the closing and opening of the circuit . It is plain that the limbs must be traversed by a discharge at the moment of closing the circuit ; for the charge of the poles must diminish in direct proportion to the freedom with which the current passes . It is plain also that the opposite electricities which are accumulated in the limbs while the circuit is closed must be discharged when the circuit is opened . It is possible also that the discharge at the : opening of the circuit may be less in amount than that which occurs at the closing of the circuit ; for immediately after the opening both the limbs may be supposed to receive a charge from the pole with which they happen to remain in connexion , which charge will to some degree counteract the discharge . How then ? Is it possible that these changes of tension may have to do with the motor phenomena which are ascribed to the action of the direct and inverse currents ? That the changes of tension in question are of themselves sufficient to tell upon the muscles in the requisite manner is proved by a new and very curious experiment . The two hind legs of a frog , prepared and arranged as in the experiment for exhibiting the action of the inverse and direct currents , are connected , time after time , first with one pole of the battery and then with the other , but never with the two poles at once . The result , for a time at least , is contraction in one or both of the limbs when they are thus carried from dne pole to the other . There is a succession of charges and discharges ; for before a charge can be received from either pole this charge must neutralize the charge carried away from the other pole . The contraction must have to do with changes of tension , and with changes of tension only ; for the circuit remains open from the beginning to the end of the experiment . The case , indeed , appears to be not remotely analogous to that in which the prepared limbs of a frog are made to hang from the prime conductor of an electrical machine , and then charged and discharged alternately ; for here the rule as to contraction is the same , namely this , that the limbs contract , not when they receive or while they retain the charge , but at the moment of discharge . That the changes of tension in question do actually affect the limbs as they are found to be affected under the action of the inverse and direct current appears to gain in probability as the matter is more fully inquired into . There is no difficulty in referring to changes of tension the phenomena belonging to the first stage ( vide Table ) . If the closing and opening of the circuit be attended by discharge , and if contraction be coincident , not with charge but with discharge , the presence of contraction in both limbs at the moments of opening and closing the circuit is in accordance with rule ; and if the discharge at the opening of the circuit be weaker than that which happens at the closing , it is easy to see that with a weak battery the stronger discharge at the moment of closing the circuit may be strong enough to tell upon the muscles when the weaker discharge at the opening of the circuit is not strong enough to do so . Indeed it is plain that the absence of contraction at the opening of the circuit in the case where a weak battery is used is merely a matter of wanting battery power , for the missing contraction is made to appear by simply supplying this want . Nor is there any difficulty in applying the same key to the explanation of the phenomena belonging to the second stage ( vide Table ) . It is a fact that the power of contracting is affected very differently in the two limbs by the action of the electricity . The limb in which the current is direct loses this power much more speedily than it does when left to itself ; the limb in which the current is inverse retains this power much longer than it does when left to itself ; the limb in which a direct current has been passed until the power of contracting is at an end recovers this power , and this , too , more than once , if the direction of the current be changed for a time . Of these facts- the impairment of the power of contracting in the limb in which the current is direct , the preservation and restoration of this power in the limb in which the current is inverse-there can be no question . There is also reason to believe that there are electrical differences in the two limbs which will , in some degree at least , account for the differences in the power of contracting , and for other differences which have yet to be considered . The conclusion already arrived at respecting the natural electricity of nerve and muscle is that the state during rest is one of charge-that , ordinarily at least , the sheaths of the fibres are charged positively at their exterior and negatively at their interior . The resistance of the animal tissues to electrical conducion , it is assumed , is sufficient to keep the two opposite electricities apart-an assumption , be it remarked , which is not a little borne out by the fact that the resistance which the voltaic current encounters in the hind limbs of a frog when its course is up one limb and down the other ( vide fig. 1 ) is sufficient to keep the two limbs in opposite electrical conditions as regards charge . In short , the natural electrical condition of nerve and muscle during rest may be assumed to be one in which the exterior of the sheath of the fibre is positive and the interior negative-a state of charge which , taking 5 as the value of the tension , and viewingthe sheath in longitudinal sectio-i from within , may be figured thus : Fig. 2 . The electrical condition of the fibres of the nerves and muscles of the limb in which the current is direct may be assumed to be one in which the exteriors of the sheaths are charged negatively from the negative pole , and the interiors positively by induction-a state in which the disposition of the two electricities forming the charge is the reverse of that which belongs to the natural charge-in which , before this reversal can take place , there must be a meeting of opposite electricities without and within the sheaths which must result in the discharge of the weaker natural charge and of an equivalent quantity of the artificial charge-which , assuming 10 as the value of the tension , and taking the figure already used to illustrate the state of things in the natural charge , may be represented thus : Fig. 3 ... ... ... ... ... ... ... ... ------.The case , indeed , is one in which the artificial charge of the fibres involves a reversal similar to that which happens naturally when these fibres , in some instances at least , have lost a great portion of their activity , in which there may be supposed to be a similar reason , whatever that may be , for failure in this activity : and hence it need not be altogether a matter of wonder that the limb in which the current is direct should lose its power of contracting more rapidly than the same limb when left to . itself . The electrical condition of the fibres of the nerves and muscles of the limb in which the current is inverse , on the other hand , may be taken as one in which the exteriors of the sheaths are charged positively from the positive pole , and the interiors negatively by induction-a state in which the sheaths are affected without and within similarly by the natural and artificial charges-in which the artificial may be added to the natural charge , causing , not discharge , as in the case of the limb in which the current is direct , but surcharge-in which , assuming the value of tension to be 10 for the artificial and 5 for the natural charge , and taking the figure used before in illustration , the result of this combination of charges may be set down thus : Fig. 4 . The case is one in which the artificial charge , by supplementing the natural charge , may be supposed to retard the disappearance of the natural charge , and with it the power of contracting ; for between this charge and this power there is , without question , a connexion which may not be severed . And if this be so , then it is not difficult to advance a step further and perceive how it is that this artificial charge may restore the natural power of contracting after it is lost , and how , in this way , after this power has disappeared from the limb in which the current is direct , it may be brought back again by reversing the position of the poles . In a word , it is not altogether unintelligible that there should be along with the inverse current an action which preserves and restores the power of contracting . And if the condition of the two limbs be thus different when the circuit is closed , a clue is found , by tracing which it is possible to arrive at an explanation of the different behaviour of the two limbs at the moment of closing and opening the circuit . In the second period of the second stage ( vide Table ) , the limb in which the current is direct contracts at the moment of closing and not at the moment of opening the circuit , and , contrariwise , the limb in which the current is inverse contracts at the moment of opening the circuit and not at the moment of closing it ; and most assuredly there is nothing anomalous in these differences . In the limb in which the current is direct , as will appear on comparing the two figures 2 & 3 , there must be at the moment of closing the circuit a conflict between the natural and artificial charges of the fibres before the stronger artificial charge can have the victory which it gains in the end , -a conflict in which the neutralization of the natural charge by an equivalent quantity of the artificial charge , must issue in discharge ; and hence the presence of contraction at this moment , if contraction be coincident , not with charge , but with discharge . Indeed there is a double reason for contraction at this moment ; for in addition to this discharge is the discharge of the opposite electricities of the poles which attends upon the closing of the circuit in any case . Nor is the absence of contraction at the opening of the circuit unintelligible ; for it is easy to see that the loss in the power of contracting which the limb in which the current is direct has experinced by this time , may have rendered the limb incapable of responding to the weaker discharge which attends upon the opening of the circuit . In the limb in which the current is inverse , as will appear on comparing the figures 2 & 4 , there must be the addition of the artificial charge to the natural charge-a surcharge-a state which may nullify the discharge attending upon the closing of the circuit ; and hence the absence of contraction at the closing of the circuit ; for , according to the premises , there will be no contraction if there be no discharge , or , rather , there will be no contraction if there be no sufficient discharge . Nor is a reason wanting for the presence of contraction at the opening of the circuit in this case ; for if the action of the electricity be to preserve and restore the power of contracting in the limb in which the current is inverse , it is easy to suppose that in the case in question this power is so far preserved as to allow the limb to respond to the discharge which attends upon the opening of the circuit . Nor need there be any difficulty in dealing with the phenomena belonging to the other periods of the second stage . The presence of contraction at the closing as well as at the opening of the circuit , in the case of the limb in which the current is inverse ( second stage , first period , in Table ) , would seem to imply no more than this , that the conditions present in the first stage have not yet come to an end . The absence of contraction at the closing as well as at the opening of the circuit in the limb in which the current is direct ( second stage , third period , in Table ) , may merely be due to the electricity having now so far destroyed the power of contracting as to make the limb incapable of responding to the stronger no less than to the weaker of the discharges acting upon it . The differences in question are merely transitional , nothing more . A few words will suffice for all that need be said respecting the phenomena which remain to be considered ( third stage in Table ) . For if the charges of the poles play the part which has been ascribed to them , it is to be expected that , by reversing the position of the poles , what was done in either limb by either pole may be undone by the other pole , and that at a certain moment after this reversal the two limbs may be restored to that state of similarity in which they will , as at first , contract similarly on closing and opening the circuit , one or both-at the opening as well as at the closing if the battery power be strong , at the closing only if the battery power be feeble . It would seem , then , as if the changes of tension , to which attention has been directed , supplied an explanation of the motor phenomena ascribed to the action of the " inverse " and " direct " currents , which , to say the least , is more intelligible than any which can be found in the action of the currents themselves , and that in fact it is a gain rather than a loss to discard altogether the " inverse " and " direct " currents from the field of operation in which they have hitherto been supposed to play so allimportant a part . It would seem , in fact , that the evidence in this section agrees with that supplied in the two previous sections in leading to the conclusion that muscular relaxation is associated with a state of charge , and muscular contraction with a state of discharge . It would even seem as if all the evidence so far gave countenance to the conclusion that the state of charge may cause muscular relaxation by keeping the molecules of the muscle in a condition of mutual repulsion , and that the state of discharge may lead to muscular contraction by doing away with that state of electrical tension which prevents the molecules of the muscle from yielding to the attractive force , inherent in their physical constitution , which is ever striving to bring them together . V. On Electrotonus . It is not enough to be content with repeating , after Professor Du Bois Reymond , that the nerve-current and voltaic current are in the same direction in anelectrotonus and in opposite directions in cathelectrotonus , or , after Professor Eckhard , that the activity of the nerve is paralyzed in the former of these states and exalted in the latter . In fact , the subject of electrotonus requires complete revision . The direction of the nerve-current and voltaic current is found to agree in anelectrotonus and to disagree in cathelectrotonus , if , as is commonly the case , the direction of the former current is from the end to the side of the fibres ; but not so if , as may happen , the course of the nerve-current is the reverse of this . In this case the direction of the two currents will agree in cathelectrotonus and disagree in anelectrotonus . Nay , more , there are movements of the needle , corresponding perfectly to those which happen in the two electrotonic states , when the experiment is made upon dead nerve and upon other bodies too , provided these bodies are sufficiently bad conductors of electricity . If a piece of wire be placed as the piece of nerve is placed in an experiment on electrotonus and dealt with in the same manner , the needle of the galvanometer remains motionless ; and so likewise if a piece of cotton or hempen thread moistened with water be substituted for the wire ; but not so if the nerve be represented by silk or gutta percha moistened with water . In the latter case , indeed , the needle is found to move as it moves in anelectrotonus and cathelectrotonus when the voltaic poles are placed in the way necessary to produce these two electrotonic conditions . The needle may be at zero before these movements are manifested , or it may not . It is at zero if the electrodes of the galvanometer are homogeneous ; it is on this or that side of the zero-point if , as commonly happens , there is some accidental heterogeneity in these electrodes . Still no serious complication in the problem is introduced by the presence of this purely accidental current ; for all that it does is to shift in one direction or the other the point from which the electrotonic movements of the needle have to be reckoned . Be this accidental current present or absent , indeed , the degree and direction of the electrotonic movements of the needle remain the same , and it is only the starting-point of the movement which is shifted . These , then , being the facts , it is difficult to regard the electrotonic phenomena in nerve which are exhibited in the galvanometer as modifications of the nerve-current . The nerve-current , if present , is undoubtedly modified , just as is the accidental current depending upon the heterogeneity of the electrodes of the galvanometer to which attention has just been directed ; but the essential workings in electrotonus must be deeper than the nerve-current , deeper even than the nerve . It would seem , indeed , that the nerve-current must in reality play as accidental a part in the phenomena of electrotonus as does the current depending upon heterogeneity in the electrodes of the galvanometer in the experiment in which gutta percha or silk moistened with water is substituted for the nerve . It would seem , indeed , that a given degree of resistance between the voltaic poles is in reality all that is essential to the manifestation of the galvanometric phenomena of electrotonus-a resistance sufficient to pen up free positive electricity at the positive pole and free negative electricity at the negative pole ; and that the movements of the needle may be owing to the outflowing or inflowing of this free electricity through the coil of the galvanometer from or to the pole which happens to be nearest to the coil ; for it is found that similar movements to those which happen in electrotonus are witnessed when the part of the nerve acted upon ordinarily by the voltaic current is charged alternately with positive and negative electricity from a frictionmachine . In an experiment on electrotonus , as commonly conducted , the insulation of the circuits of the galvanometer and the battery is sufficient to prevent any passage of the voltaic current proper into the coil , but it is not sufficient to hem in electricity of a higher tension ; it is not sufficient to prevent the flowing of a stream of free electricity from the positive pole , and to the negative pole , of which stream a part may pass through the coil of the galvanometer , and so act upon the needle . And hence the movements of the needle of the galvanometer in anelectrotonus and cathelectrotonus ; for the movement in anelectrotonus is only that which happens when free positive electricity is passed through the coil , and the movement in cathelectrotonus is only that which happens when free negative electricity is so passed . Instead of the activity of nerve being paralyzed in anelectrotonus and exalted in cathelectrotonus , a very different conclusion appears to be necessary . Taking the prepared limbs of a frog , and placing the middle portion of the connecting band of nerve belonging to them across the poles of a voltaic battery of which the circuit is open , a drop of salt water is applied on each side to the portion of nerve beyond the pole . Then , having waited until the salt has set up a state of tetanus in both limbs , the voltaic circuit is closed and opened in turn , with the poles first in one position and then in the other . On closing the circuit , anelectrotonus is set up on the side of the positive pole , cathelectrotonus on the side of the negative pole ; and what has to be done is to notice the behaviour of the limb before , during , and after the setting up of these states . In this experiment are four steps , of which the particulars may be tabulated thus : Step 1 . Poles arranged so as to cause cathelectrotonus in limb A , anelectrotonus in limb B. Fig. 5 . Cathelectrotonus Action of salt , Anelectrotonus Action of salt , on the side of causing in on the side of causing in himb A imb A limb B. limb B Before . Tetanus . Before . Tetanus . During . 0 . During . 0 . Momentary After . Momentraction . After . Tetanus . After , contraction . Step 2 . Poles transposed so as to cause anelectrotonus in limb A , cathelectrotonus in limb B. Limb A+ -Limb B Anelectrotonus Cathelectrotonus after Action of salt , after Action of salt , Cathelectrotonus causing in Anelectrotonus causing in on the side of limb A on the side of limb B limb A. limb B. Rest at first , then twitchings , Semi-tetanus During , progressively enduring , at first , creasing in frethen rest . quency and force After . Tetanus . Aftr . Momentary contraction . Step 3 . Poles arranged as at first , so as to cause cathelectrotonus in limb A , anelectrotonus in limb B. Limb A+ Limb B Cathelectrotonus Anelectrotonus after Action of salt , after Action of salt , Anelectrotonus causing in Cathelectrotonus causing in on the side of limb A on the side of limb B limb A. limb B. Rest at first , then Semi-tetanus twitchings , proDutring . at then rest During . gressively i n't first , then rest , creasing in frequency andforce . After . O. After . Tetanus ... ... . , , Step 4 . Poles transposed again , so as to cause anelectrotonus in limb A , cathelectrotonus in limb B. Limb A+ -Limb B Anelectrotonus Cathelectrotanus after Action of salt , after Action of salt , Cathelectrotonus causing in Anelectrotonus causing in on the side of limb A on the side of limb B limb A. limb B. Rest at first , then twitchings , Semi-tetanus at During . progressively enduring . first , then creasing in fre . rest . quency and force . After . Semi-tetanus . After . 0 . In order to explain this experiment , all that is necessary is to realize the fact ( for fact it is ) that anelectrotonus has to do with a charge from the positive pole , and cathelectrotonus with a charge from the negative pole , and to suppose that these charges react with the natural charge of the animal tissues precisely as they do in the case of the limbs in which inverse and direct currents are passing-in similar cases , that is to say ; for , as regards the hen p en a of tension , the state in anelectrotonus is identical with that which is present in the limb in which the current is inverse ( see fig. 4 ) , and in cathelectrotonus with that which is present in the limb in which the current is direct ( see fig. 3 ) . 3In the first stage of the experiment the facts are-suspension of the tetanus caused by the salt during cathelectrotonus and anelectrotonus alike , return of tetanus after anelectrotonus , momentary contraction only after cathelectrotonus ; and these facts are not inexplicable . The tetanus after anelectrotonus , and the nlomentary contraction only after cathelectrotonus , show , as it would seem , that the power of responding to the action of the salt has been preserved in anelectrotonus , as in the case of the limb in which the current is inverse , and lost in cathelectrotonus , as in the case of the limb in which the current is direct . It is quite intelligible also that the tetanus caused by the salt should be suspended during the continuance of the electrotonic state , if this state be based upon charge , and if this charge have that power of counteracting contraction which would seem to belong to it . In the other steps of the experiment the two topics which have to be considered are ( 1 ) what happens when anelectrotonus follows cathelectrotonus , and ( 2 ) what happens when cathelectrotonus follows anelectrotonus . In the case in which anelectrotonus follows cathelectrotonus the facts are these:-during anelectrotonus , rest at first , then twichings progressively increasing in frequency and force ; and after anelectrotonus , tetanus ; and so it should be . If , indeed , the power of contracting is impaired in cathelectrotonus and preserved in anelectrotonus , it may be supposed , when anelectrotonus is made to follow cathelectrotonus , that the power of contracting has been so far impaired by the previous state of cathelectrotonus as to oblige the muscles to remain in a state of rest until this power is to a certain degree restored by the state of anelectrotonus ; and that the rest at first , and the twitchings progressively increasing in force and frequency afterwards , when anelectrotonus is made to follow cathelectrotonus , may be accounted for in this way . Moreover the tetanus upon the cessation of anelectrotonus may be supposed to receive its explanation also , if the action of the anelectrotonus has been to preserve and restore the power of contraction , and if the state of charge upon which that of anelectrotonus is based , has , in some degree at least , the effect of counteracting contraction . In the case of cathelectrotonus after anelectrotonus , also , what happens is intelligible enough when the same principles of interpretation are applied to the facts . The facts themselves are these:-during cathelectrotonus , first tetanus , then rest ; after cathelectrotonus , momentary contraction . Now when cathelectrotonus follows upon anelectrotonus , as a comparison of figs. 3 & 4 will show , there must be discharge . And , further , when either electrotonic state is established , there must be that discharge which attends upon the closing of the circuit in any case ; and hence the tetanus which happens when cathelectrotonus is made to follow anelectrotonus ; for in addition to being acted upon by the salt , the muscles ( the power of contracting is preserved in anelectrotonus ) are at this time acted upon by the two discharges which have been mentioned . Nor is it difficult to find a reason for the rest which follows the tetanus when cathelectrotonus is established , and the momentary contraction which happens when cathelectrotonus passes off . The rest which follows the tetanus under these circumstances is intelligible ; for the cathelectrotonus may be supposed to do away with the power of responding to the action of the salt ; and the momentary contraction which happens when the cathelectrotonus passes off is intelligible also ; for , according to the premises , the cessation of the state of electrotonus implies the cessation of a state which counteracts that action of the salt which causes contraction . Moreover , it is intelligible enough that there should be tetanns after anelectrotonus , and momentary contraction only after cathelectrotonus , if the power of contracting be impaired in the one case and preserved in the other . Nor is it otherwise with other experiments on electrotonus when care is taken to eliminate what is fallacious . One and the same explanation , indeed , would seem to apply to the motor phenomena connected with anelectrotonus and cathelectrotonus , and to the motor phenomena connected with the inverse and direct currents ; and this explanation is to be found , as it would seem , in the workings , not of the constant current , but of statical electricity . The electrotonic variations in the conductibility of nerve detected by Professor von Bezold are reserved for future investigation .

112421

3701662

On the Source of Free Hydrochloric Acid in the Gastric Juice

391

395

Proceedings of the Royal Society of London

E. N. Horsford

fla

6.0.4

http://dx.doi.org/10.1098/rspl.1868.0074

proceedings

http://corpora.clarin-d.uni-saarland.de/surprisal/6.0.3/?id=112421

10.1098/rspl.1868.0074

http://www.jstor.org/stable/112421

Chemistry 2

Biology 3

Chemistry

I. " On the Source of Free Hydrochloric Acid in the Gastric Juice . " By Professor E. N. HORSFORD , Cambridge , U. S. A. Communicated by T. GRAIIAM , F.R.S. Received January 18 , 1869 . The long-disputed position of Prout that the gastric juice contains free hydrochloric acid , was at length established by C. Schmidt , who , in an absolute quantitative analysis of the juice , found about twice as much hydrochloric acid as was required to neutralize all the bases presenlt . The prolonged discussion of this subject ( now since 1823 ) has brought to light , through the researches of Lassaigne , Tiedemann and Gmelin , Berzelius , Blondlot , Claude Bernard , Schwann , and numerous others , the unmistakeable evidence of the presence of lactic acid and of acid phosphates in the gastric juice , which latter might or might not be due to the presence of lactic or hydrochloric acid . A point of special interest to the chemist and physiologist still remained , and was this : How couldfree hydrochloric acid be secretedfrom the blood , which is an alkaline luid ? The blood freshly drawn consists of a fluid ( the plasma ) in which there are swimming myriads of exceedingly minute irregularly spheroidal bodies ( the corpuscles ) . The plasma consists of two bodies , one of which , the fibrine , spontaneously separates from the other , the serum . The corpuscles are little sacs of delicate animal membrane enclosing a fluid . This fluid has an acid reaction , and its ash contains a monobasic alkaline phosphate . The fibrine of the plasma contains , according to Virchow , a glycero-phosphate of lime , though the plasma , as a whole , has an alkaline reaction , and contains in its ash a great measure ( 11 per cent. ) of chloride of sodium . The moist corpuscles constitute about one-half of the blood . I assume that in healthy digestion , as a consequence of increased flow of blood to the gastric mucous membrane and of the normal elasticity of the walls of the capillaries , there exists in the membrane a condition which is the equivalent of engorgement . Under the pressure which attends this condition , the corpuscles in contact with the walls of the capillaries would discharge a portion of their acid contents , which , with the adjacent plasma , would pass through the walls of the capillaries . This mixture would contain acid phosphates and chlorides . The mucous membrane of the stomach presents on its inner surface the mouths of numerous microscopic tubes , which , like stockings , are sometimes single blind sacs , or , like gloves , terminate in several blind sacs like the glove fingers . In the bottoms of these tubes , and along their sides , are several closed spherical sacs or cells , containing other lesser sacs and fluid within . The tubes , as a whole , dip down into the spongy tissue that underlies the mucous coat , where they are surrounded by the fluid poured from the network of nutritive capillaries , which fluid , as remarked above , contains acid phosphates and chlorides . Now by pressure and osmosis a portion of this fluid will pass through the walls of the gastric tubes , and the question is : Whether thefluid that goes through will contain free hydrochloric acid ? The experiments I have made are conclusive on the principal point . By employing acid phosphate of lime and common salt I had this advantage , that as increased acidity on the one hand is a just inference from increased alkalinity on the other , and as increased alkalinity would be shown by the precipitation of phosphate of lime ( a visible white powder ) I could determine the qualitative fact without the difficulties and delay attending on accurate quantitative analysis of the solutions , before and after the experiments on both sides of the membrane . I employed an acid phosphate of lime of specific gravity 1l ' 17 , of a constitution of 3(CaO a0 P)+ 2P , 0 with an amount of phosphate of peroxide of iron present as one to twenty-eight of the acid phosphate of lime . The various other solutions employed were the ordinary laboratory reagents . On adding ammonia in small quantities to the solution of acid phosphate , with alternate agitation , it required , as might be inferred , several repetitions before the peroxide with its phosphoric acid became a permanent precipitate , and still several more before the precipitate of phosphate of lime became permanent . In my earlier experiments , in which I employed parchment-paper , I was embarrassed with the presence of sulphate of limle in the precipitated powder ; so that what was at first supposed to be phosphates of lime and iron was found to be in part sulphate of lime . This sulphate was due to imperfectly washed parchment-paper , which still contained sulphuric acid . This difficulty overcome , the experiments were made with parchment-paper prepared from German and Swedish filter-paper , as well as with goldbeater 's skin ( animal membrane ) . I employed acid phosphate of the formula above , with ( each by itself ) chloride of sodium , chloride of ammonium , chloride of potassium , chloride of calcium , and chloride of magnesium . I also experimented with acetate of potassa and acid phosphate of lime . With all of these there was obtained the same kind of evidence of increased acidity on one side and of increased alkalinity on the other , to wit , the powder thrown down from the mixture of acid phosphate and chloride . What successive additions of ammonia had been required to effect , had been accomplished by dialysis . The same effect took place from a mixture of acid phosphate of soda and chloride of calcium . It follows from the above , if these experiments fairly represent the case , and from the known composition of the blood , its condition in the walls of the stomach , and the structure of the gastric tubules , that free or uncombined hydrochloric acid must find its way into the bottoms of the gastric tubules , and thence into the cavity of the stomach . It may be urged that I should show that the acid phosphate pressed from the corpuscles more than neutralizes the alkalinity of the plasma present . In reply it may be said that I present a condition of things in which there is the kind of physical change required going on , namely , relative augmentation of the corpuscles , under pressure , the concomitant of increased supply of blood to the gastric mucous membrane . Its degree must be inferred from the effects on the secretions , which I have endeavoured to point out , by conducting an experiment under what I conceive to be essentially like conditions , and obtaining the result due to identical conditions . The secretion of hydrochloric acid is of course mixed with acid phosphates and alkaline chlorides . That such a result as I have arrived at would follow experiment might have been predicted from Graham 's researches on dialysis . Phosphates of lime and soda are colloidal relatively to more crystalloidal hydrochloric acid . Graham found that bisulphate of potassa , by dialysis , was resolved into two salts or mixtures of greater and lesser acidity than the original bi sulphate . So he found that acetate of peroxide of iron was resolved by dialysis into hydrated peroxide of iron and free acetic acid . It is possible and probable that the albuminoid bodies present take part in determining the contrast between colloid and crystalloid bodies . Graham found that by dialysis he could separate free hydrochloric acid from the gastric juice thrown up in vomiting . It may be further objected that anatomists are not agreed as to the structure of the corpuscles . But it will be seen that there is no more required than may be regarded as established . The corpuscles act in many particulars , if not in all , as if they were membranous sacs more or less distended with fluid . They may be swollen by immersion in a thinner ( less colloid ) fluid , and reduced by immersion in a more colloid fluid-that is , they are susceptible of endosmosis and exosmosis as membranous sacs would be . In their ordinary condition as seen under a microscope , they present the appearance of collapsed spherical or oval sacs or cells . They appear as double concave disks . In swelling ( by endosmosis ) the lowest part of each concavity is the last to take on the spherical contour , just as it would do if the corpuscles were membranous sacs . The corpuscles sometimes so collapse ( by exosmosis ) that one-half of the hollow sphere is reversed , while the other half retains its form unchanged , the former sitting like a cup in the latter-a conformation inconceivable on the theory of homogeneity of the corpuscles as a whole . Crystallizable substances may be extracted from the corpuscles by pressure and by endosmosis . They must have been in solution in order to crystallization , and solution involves a fluid . The liquid expressed from the corpuscles has an acid reaction , and contains an organic acid and acid phosphates . It contains , among other bodies , the haematoidin of Virchow . The ash of these crystals consists almost wholly of metaphosphates* , which point directly to tribasic phosphoric acid in solution , combined with one atom of fixed base , which is inconceivable unless separated by membrane from the plasma , which is always alkaline . In fine , whatever other peculiarities the blood-corpuscles may possess , they have the requisites for furnishing acid phosphates in solution under pressure , such as must attend engorgement of the capillaries in the walls of the stomach . Let us glance at what takes place in all probability as the acid fluid enters the gastric tubules . They are surrounded by a mixture of hydrochloric acid , acid salts , * neutral salts , and albuminoid bodies . Dialysis must be repeated , and a stronger acid solution pass into the sacs or cells contained in them . The sacs swelling by endosmosis , and corroded by the acid , must at length burst , and the liquid contents , together with the disintegrated and partially digested membrane of the sacs , pass out into the stomach , to constitute the gastric juice , the free hydrochloric acid , acid phosphates and chlorides , and the albuminoid bodies and disintegrated tissue ( the pepsine ? ) to act in the liquefaction of food .

112422

3701662

Contributions to the History of Explosive Agents. [Abstract]

395

397

Proceedings of the Royal Society of London

F.A. Abel

abs

6.0.4

proceedings

http://corpora.clarin-d.uni-saarland.de/surprisal/6.0.3/?id=112422

http://www.jstor.org/stable/112422

Chemistry 1

Fluid Dynamics

Chemistry

II . " Contributions to the History of Explosive Agents . " By F. A. ABEL , F.R.S. , For . Sec. C. S. Received March 9 , 1868 . ( Abstract . ) The degree of rapidity with which an explosive substance undergoes metamorphosis , as also the nature and results of such change , are , in the greater number of instances , susceptible of several modifications by variation of the circumstances under which the conditions essential to chemical change are fulfilled . Excellent illustrations of the modes by which such modifications may be brought about are furnished by gun-cotton , which may be made to burn very slowly , almost without flame , to inflame with great rapidity , but without development of great explosive force , or to exercise a violent destructive action , according as the mode of applying heat , the circumstances attending such application of heat , and the mechanical condition of the explosive agent , are modified* . The character of explosion and the mechanical force developed , within given periods , by the metamorphosis of explosive mixtures such as gunpowder , is similarly subject to modifications ; and even the most violent explosive compounds known ( the mercuric and silver fulminates , and the chloride and iodide of nitrogen ) behave in very different ways , under the operation of heat or other disturbing influences , according to the circumstances which attend the metamorphosis of the explosive agent ( e.g. the position of the source of heat with reference to the mass of the substance to be exploded , or the extent of initial resistance opposed to the escape of the products of explosion ) . Some new and striking illustrations have been obtained of the susceptibility to modification in explosive action possessed by these substances . The product of the action of nitric acid upon glycerine , known as nitroglycerine or glonoine , which bears some resemblance to chloride of nitrogen in its power of sudden explosion , requires the fulfilment of special conditions for the development of its explosive force . Its explosion by the simple application of heat can only be accomplished if the source of heat be applied , for a protracted period , in such a way that chemical decomposition is established in some portion of the mass , and is favoured by the continued application of heat to that part . Under these circumstances , the chemical change proceeds with very rapidly accelerating violence , and the sudden transformation , into gaseous products , of the heated portion eventually results , a transformation which is instantly communicated throughout the mass of nitroglycerine , so that confinement of the substance is not necessary to develope its full explosive force . This result can be obtained more expeditiously and with greater certainty by exposing the substance to the concussive action of a detonation produced by the ignition of a small quantity of fulminating powder , closely confined and placed in contact with , or proximity to , the nitroglycerine . The development of the violent explosive action of nitroglycerine , freely exposed to air , through the agency of a detonation , was regarded until recently as a peculiarity of that substance ; $ it is now demonstrated that gun-cotton and other explosive compounds and mixtures do not necessarily require confinement for the full development of their explosive force , but that this result is attainable ( and very readily in some instances , especially in the case of gun-cotton ) by means similar to those applied in the case of nitroglycerine . The manner in which a detonation operates in determining the violent explosion of gun-cotton , nitroglycerine , &c. , has been made the subject of careful investigation . It is demonstrated experimentally that the result cannot be ascribed to the direct operation of the heat developed by the chemical changes of the charge of detonating material used as the exploding agent . An experimental comparison of the mechanical force exerted by different explosive compounds , and by the same compound employed in different ways , has shown that the remarkable power possessed by the explosion of small quantities of certain bodies ( the mercuric and silver-fulminates ) to accomplish the detonation of gun-cotton , while comparatively very large quantities of other highly explosive agents are incapable of producing that result , is generally accounted for satisfactorily by the difference in the amount of force suddenly brought to bear in the different instances upon some portion of the mass operated upon . Most generally , therefore , the degree of facility with which the detonation of a substance will develope similar change in a neighbouring explosive substance may be regarded as proportionate to the amount of force developed within the shortest period of time by that detonation , the latter being , in fact , analogous in its operation tQ that of a blow from a hammer , or of the impact of a projectile . Several remarkable results of an exceptional character have been obtained , which indicate that the development of explosive force under the circumstances referred to is not always simply ascribable to the sudden operation of mechanical force . These were especially observed in the course of a comparison of the conditions essential to the detonation of guncotton and of nitroglycerine by means of particular explosive agents ( chloride of nitrogen , &c. ) , as well as in an examination into the effects produced upon each other by the detonation of those two substances . The explanation offered of these exceptional results is to the effect that the vibrations attendant upon a particular explosion , if synchronous with those which would result from the explosion of a neighbouring substance in a state of high chemical tension , will , by their tendency to develope those vibrations , either determine the explosion of that substance , or at any rate greatly aid the disturbing effect of mechanical force suddenly applied , while , in the instance of another explosion , which developes vibratory impulses of different character , the mechanical force applied through its agency has to operate with little or no aid , greater force , or a more powerful detonation , being therefore required in the latter instance to accomplish the same result . Instances of the apparently simultaneous explosion of numerous distinct and even somewhat widely separated masses of explosive substances ( such as simultaneous explosions in several distinct buildings at powder-mills ) do not unfrequently occur , in which the generation of a disruptive impulse by the first or initiative explosion , which is communicated with extreme rapidity to contiguous masses of the same nature , appears much more likely to be the operating cause , than that such simultaneous explosions should be brought about by the direct operation of heat and mechanical force . A practical examination has been instituted into the influence which the explosion of gun-cotton through the agency of a detonation , exercises upon the nature of its metamorphosis , upon the character and effects of its explosion , and upon the uses to which gun-cotton is susceptible of application .

112423

3701662

Results of Magnetical Observations Made at Ascension Island, Latitude 7\lt;sup\gt;\#x26AC;\lt;/sup\gt;55\lt;sup\gt;\#x2032;\lt;/sup\gt; 20\lt;sup\gt;\#x2032;\#x2032;\lt;/sup\gt; South, Longitude 14\lt;sup\gt;\#x26AC;\lt;/sup\gt; 25\lt;sup\gt;\#x2032;\lt;/sup\gt; 30\lt;sup\gt;\#x2032;\#x2032;\lt;/sup\gt; West, from July 1863 to March 1866

397

400

Proceedings of the Royal Society of London

Lieut. Rokeby

fla

6.0.4

proceedings

http://corpora.clarin-d.uni-saarland.de/surprisal/6.0.3/?id=112423

http://www.jstor.org/stable/112423

Meteorology

Tables

Meteorology

III . " Results of Magnetical Observations made at Ascension Islanid , Latitude 7§ 55 ' 20 " South , Longitude 14§ 25 ' 30 " West , from July 1863 to March 1866 . " By Lieut. ROKEBY , R.M. Reduced by G. M. WHIPPLE , Magnetical Assistant at the Kew Observatory . Communicated by B. STEWART , LL. D. Received March 11 , 1869 . On leaving England for Ascension Island in May 1862 , Lieut. Rokeby was supplied by General Sabine with the following instruments for the purpose of making observations of magnetical variation and intensity , viz. A portable declinometer and unifilar for absolute observations of declination and horizontal intensity , a Barrow 's dip-circle ( No. 24 ) , a differential declinometer , and a differenitial bifilar . The differential declinometer and the bifilar were erected at George Town , Ascension , in August 1862 , and bihorary observations commenced ; but in consequence of instability in the supports of the instruments , caused probably by the shifting of the volcaniic cinders which formed the ground at the observing-station , the observations made exhibit frequent discrepancies . The whole of the bifilar observations , and all the differential declinometer observations prior to June 1864 , have therefore been omitted from the present discussion . These observations were discontinued in June 1866 , when Lieut. Rokeby left the Island . Observations of absolute horizontal force and dip were made on the Green Mountain , Ascension , once every motuth from July 1863 to March 1866 , two months in 1865 excepted . Observations were not made with the portable declinometer . Observations of Horizontal Force and Dip . The horizontal , vertical , and total forces ( Table No. 1 ) are calculated to English measure ; one foot , one second of mean solar time , and one grain being assumed as the limits of space , of time , and of mass . The vertical and totalforces are obtained from the absolute measures of the horizontal force and the dip . The observations of dip ( Table No. 1 ) were made in every instance save one with the needle marked A 2 . For the observations of deflection and vibration taken each month for absolute measure of horizontal force , the same magnet ( collimator 5 ) has always been employed . The moment of inertia of the magnet , with its stirrup for different degrees of temperature , and the coefficients in the corrections required for the effects of temperature and of terrestrial magnetic induction on the magnetic moment of the magnet , were determined in 1858 at the Kew Observatory by the late Mr. Welsh . That these corrections held good in 1862 was proved by the agreement of the horizontal force obtained at Kew with this instrument previous to its departure , with the value of the force determilned by the observatory unifilar . The moment of inertia of the magnet with its stirrup is 5 3828 at 60 ? Fahr. The induction-coefficient , =0-000252 . The correction for error of graduation of the deflection-bar at 10 foot is 0 00000 foot , and at 1P3 foot 0-00003 foot . The formula used for determining the temperature correction was q ( t0-350)+q ' ( t_350)2 , where to is the observed temperature , 35 ? F. being the adopted standard temperature . The values of q and q ' for the magnet used are respectively 0 0001 1035 and 0G000000581 . The observed times of vibration have been corrected for rate of chronometer when it has exceeded five seconds per day . A correction has also been applied for the effect of torsion on the suspending thread . The initial and terminal semiares of vibration have always been less than 30 ' , consequently no correction was requisite on this account . The time of one vibration is derived from the mean of twelve observations of the time of 100 vibrations . & kn to tz t. ti U)~~~U ( 4 , , HXS ij~~~~~~~~~~~~~~~~~~~~c 44AL < SSt IL ; ) t E0SX3TTf to . t1 SL r1 vASs1III LX1 111 X11g+S w~~~~~~~~~~~~ a qWd d0|]Xk W~~~~~~~~~~ QJ EIr__ JII_1E 1 , e S\\ A / UlUlliSlll T SScll/ I\ljlllr]]]].t_ % % t ? t. _ u_ The angles of deflection given are each the mean of two determinations . In deducing from these observations the ratio and product of the magnetic moment m of the magnet , and the earth 's horizontal magnetic intensity X , the inductionand temperature-corrections have always been applied . m In calculation of the ratio Xv thi-e third and subsequent terms of the PQ series 1+ 2-+ + &c. have always been omitted . The value of the constant P was fouind to be -0 00291 , by the mean of ten determinations obtained each from six pairs of deflection-observations at distances 1P0 and 13 foot . The mean of the values of m derived from deflection-observations at the distances 10 foot and 1P3 foot has been used in calculating the measure of horizontal force . Observations made with the Diff'erential Declinomete2 . Observations were made of the scale-reading of the differeiitial declinometer at 3 A.m. , and hourly from 6 A.M. to midnight , daily , from December 1863 to June 1865 , from which date to the conclusion of the series the 3 A.M. observations were discontinued . The observations from the commencement until May 1864 were found on inspection to be valueless for the purposes of reduction , for the reason assigned in the introduction . The two years ' records , June 1864 to 1866 , were treated according to the method employed by General Sabine in the reduction of declination-observations . In the first place , hourly means were taken for each month . All observations which vary from these means to a greater extent than 4'0 were then rejected , and new means taken of the unrejected observations . The mean reading for each month was then computed ; finally , the hourly means were subtracted from the monthly means . Table 2 shows these differences as derived from the meani of two years ' observations , excepting in the case of 15 hours , which is the result of one year only . In the Table , the sign + represents the north pole of the magnet to the east of the mean position , and the sign that it was to the west of the mean . At the bottom of the Table semiannual and annual means are given , and these means are exhibited in the form of curves in the diagram accompanying the paper . Figure 1 shows the differences of the semiannual and annual means from the normal position , which is represented by the straight horizontal line . In figure 3 the annual mean is represented as a straight liie , and the curves show the deviations of the semiannual means from it . In both figures the curves between twelve and fifteen hours and fifteen and eighteen hours are interpolated . Figures 2 and 4 are copied from General Sabine 's St. Helena Observations , vol. ii . , and show the similarity between the movements of the magnet at Ascension and St. Helena . The Tables ainnexed to this Paper are preserved for reference in the Archives .

112424

3701662

Description of Parkeria and Loftusia, Two Gigantic Types of Arenaceous Foraminifera. [Abstract]

400

404

Proceedings of the Royal Society of London

Dr. Carpenter|H. B. Brady

abs

6.0.4

proceedings

http://corpora.clarin-d.uni-saarland.de/surprisal/6.0.3/?id=112424

http://www.jstor.org/stable/112424

Paleontology

Biography

Paleontology

I. ' " Description of Parkeria and Loftusia , two gigantic Types of Arenaceous Foraminifera . " By Dr. CARPENTER , V.P.R.S , and H. B. BRADY , F.L.S. Received March 18 , 1869 . ( Abstract . ) The Authors of this Memoir commence by referring to the separation of the series of Arenaceous Foraminifera from the Imperforate or Porcellanous , and from the Tubular or Vitreous , first distinctly propounded in Dr. Carpenter 's ' Introduction to the Study of the Foraminifera ' ( 1862 ) , on the basis of the special researches of Messrs. Parker and Rupert Jones ; who had pointed out that whilst there are several genera in some forms of which a cementation of sand-grains into the substance of the calcareous shell is a common occurrence , there are certain genera in which a " test " formed entirely of an aggregation of sand-grains takes the place of a calcareous shell ; and that these genera constitute a distinct Family , to which important additions might probably be made by further resenarch . The propriety of this separation of the Arenaecea from the calcareous . shelled Foraminifera has been fully recognized by Prof. Reuss , the highest Continental authority upon the group ; who had come to accept the principle laid down in Dr. Carpenter 's successive Memoirs ( Phil. Trans. 18561860 ) , that the texture of the shell is a character of fundamental importance in the classification of this group , the plan of growth ( taken by M. d'Orbigny as his primary character ) being of very subordinate value ; and who had , on this basis , independently worked out a Systematic Arrangement of the entire group , which presents a most remarkable correspondence with that propounded by Dr. Carpenter and his coadjutors . And their anticipation of important additions to the Arenaceous series has been fully borne out , on the one hand by the discovery of several most remarkable new forms at present existing at great depths in the Ocean , which has been made by the dredgings of M. Sars , Jun. , and those of the 'Lightning ' Expedition , and on the other by the determination of the real characters of two fossils , one of the Cretaceous , and the other probably of the earlier Tertiary period , which prove to be gigantic examples of the same type . The first of these , discovered by Prof. Morris more than twenty years ago in the Upper Greensand near Cambridge , was long supposed to be a Sponge ; but his more recent discovery of two specimens which had been but little changed by fossilization , led him to suspect their Foraminiferal character ; and this suspicion has been fully confirmed by the carefill examination made of their structure by Dr. Carpenter , to whom he committed the inquiry , and by whom , with his concurrence , the name Parkeria was assigned to the genus . The second , which was obtained by the late Mr. W. K. Loftus from " a hard rock of blue marly limestone " between the N.E. corner of the Persian Gulf and Ispahan , bears so strong a resemblance in its general form and mode of increase to the genus Alveolina , that its Foraminiferal character was from the first recognized by the discoverer ; but as all the specimens brought by Mr. Loftus had undergone considerable alteration by fossilization , their minute structure , though carefully studied by means of transparent sections , could not in the first instance be satisfactorily made out . When , however , Dr. Carpenter 's investigation of Parkeria , with the full advantage of specimens but little changed by fossilization , revealed the very remarkable plan of its structure , the investigation of this type was resumed by Mr. Brady ( who assigned to it the name Loftusia ) , with the new light thence derived : for as transparent sections of infiltrated Parkerie3 furnish a middle term of comparison between specimens of the same type which retain their original character , and transparent sections of infiltrated Loftusice , the last-mentioned can now be interpreted by reference to the preceding ; so that the obscurities which previously hung over their minute structure have been almost entirely dissipated.-The description of the structure of Parkeria in this Memoir is by Dr. Carpenter , and that of the structure of Loftusia by Mr. H. B. Brady ; but each has gone over the work of the other , and can testify to its correctness . The specimens of Parkeria which have been collected by Prof. Morris* are spheres varying in diameter from about 3-4ths of an inch to about 14 , Since this Memoir was completed , the Author has learned that Mr. Harry Seeley , of Cambridge , has collected several specimens of this type , and has been studying it independently with a view to publication . And Mr. Henry Woodward has placed in his hands a specimen from the Upper Greensand in the Isle of Wight , which is not less than 21 inches in diameter . It is interesting to remark that the " nucleus " of a smaller specimen from the same locality consists of a considerable number of chambers arranged in a spire , the structure of its concentric spherical layers being exactly the same as in the specimens described in the text . The character of their external surface differs considerably in different individuals ; but the Author gives reason for believing that it was originally tuberculated , like a mulberry , and that the departures from this have been the result of subsequent abrasion . The entire sphere is composed of a great number of concentric layers , all of which , except the innermost , are arranged with very considerable regularity around a central " nucleus , " which consists of five chambers , disposed in rectilineal sequence , thus unmistakeably indicating the Foraminiferal character of the organism , which might otherwise have remained in doubt , on account of the entire divergence from any known type presented in the structure of the concentric layers . The first of these layers is moulded ( as it were ) on the exterior of the nucleus , and partakes of its elongated form ; but the parts of every additional exogenous layer are so arranged as to bring about a gradual approximation to the spherical form , which is afterwards maintained with great constancy . Each layer may be described as consisting of a lamella of " labyrinthic structure " ( that is , of an assemblage of minute chamberlets , whose cavities communicate freely with one another ) , separated from the contiguous lamellae by an " interspace , " which is traversed by " radial tubes , " that pass from each lamella to the one external to it . All these structures , in common with the chamber-walls and septa of the " nucleus , " are built up by the aggregation of sand-grains of very uniform size . These sand-grains are found to consist of Phosphate of lime ; and they seem to be united by a cement composed of Carbonate of lime , which was probably exuded by the animal itself . Although there is a very general uniformity in the thickness of the successive layers , the proportion of their several components varies considerably in different parts of the sphere . In those which immediately surround the nucleus , the solid lamellae , which are composed of labyrinthic structure , are comparatively thin ; whilst the interspaces which separate them from one another are very broad , so that the radial tubes which traverse these interspaces are very conspicuous . As we pass outwards , we find the labyrinthic lamelle increasing in thickness , whilst the breadth of the interspaces diminishes in the same degree , until we meet with layers in which the interspaces are almost entirely replaced by labyrinthic structure . With this increased development of the labyrinthic structure in the concentric lamelle thenmselves , we find it extending between one lamella and another , as an investment to the radial tubes ; thus forming " radial processes " of a subconical form , which occupy a considerable part of what would otherwise be the interspaces between the successive lamellae . Still every lamella is separated from that which invests it(except where brought into connexion with it by its radial processes ) by a system of cavities , which are in free communication with each other , and which may be collectively designated the " interspace-system ; " and from this system the labyrinthic structure of the investing lamella is entirely cut off by an impervious wall , which bounds it upon its inner side ; whilst its chamberlets open freely upon the outer side of the lamella , into what , when it is newly formed , is the surrounding medium , but , when it has itself been invested by another layer , into its " interspace-system."- In the larger of the two non-infiltrated specimens which have furnished the materials for the present description , the number of concentric layers is 40 , and their average breadth about 1-65th of an inch . The Author discusses the mode in which this composite structure was formed ; and comes to the conclusion that the production of each new layer was probably accomplished by the instrumentality of the sarcodic substance , which not only filled the chamberlets of the preceding layer , but projected beyond it ; that the radial processes were first built up like the columns of a Gothic cathedral , and that their impervious investing wall spread itself from their summits , so as to form a continuous lamella over the sarcodic layer , in the manner that the summits of such columns extend themselves to form the arched roof of the edifice ; and that on the floor of the new layer thus laid the partitions of the chamberlets were progressively built up by the agency of the sarcodic substance conveyed to the outer surface of that floor through the radial tubes . The author further argues , from the analogy of living Foraminifera , that notwithstanding the indirectness of the communication between the cavitary system of the inner layers and the external surface , the whole of that system ( consisting of the labyrinthic structure of the successive lamellae , and of the interspaces which separate them ) was occupied during the life of the animal by its sarcode-body . The plan of growth in Loftusia is stated by Mr. Brady to differ extremely from that of Parkeria , whilst its intimate structure , on which its physiological condition must have depended , is essentially the same ; thus affording a conspicuous example of the validity of the principle of Classification already referred to . This difference is indicated by its shape , which closely resembles that of many Alveolince and Fusulince ; being a long oval , frequently tapering almost to a point at either end , though sometimes obtusely rounded at its extremities . Of two large and perfect examples in the collection of the late Mr. Loftus , one measures 34 inches by 1 inch , the other 24 inches by 1-4 inch . A transverse section at once indicates that the plan of growth is a spiral , formed by the winding of a continuous lamina around an elongated axis ; the general disposition of the chambered structure being very similar to that which would be produced if one of the simple Rotalians were thickened and drawn out at the umbilici . The space enclosed by the primary lamina is divided into chambers by longitudinal septa , which may be regarded as ingrowths from it , extending , nor perpendicularly ( asin Alveolina ) , but very obliquely . The chambers , separated by these principal or secondary septa , are long and very narrow , and extend from one end of the body to the other . Their cavities are further divided into chanberlets by tertiary ingrowths , which are gene rally at right angles to the septa or nearly so , but are otherwise irregular in their arrangement . No large primordial chamber , such as is common among Foraminifera , has been yet discovered in Loftusia ; but its absence cannot be certainly affirmed . In fully grown specimens the turns of the spire , which succeed each other with tolerable regularity at intervals of from 1-50th to 1-30th of an inch , are usually from twelve to twenty in number ; but as many as twenty-five have been counted in one instance , and a yet larger number might not improbably be met with . The spiral lamina and its prolongations , forming the accessory skeleton , are all constructed of almost impalpable grains of sand , which is proved by analysis to have consisted of Carbonate of Lime , united by a cement of the same material . The Author then describes in detail the several components of the fabric of Loftusia , and compares them with the corresponding parts of Parkeria . The continuity of increase of the spiral lamina always leaves an open fissure between its last-formed margin and the surface of the previous whorl ; and through this aperture the whole system of chambers included within its successive laminae communicates with the exterior , through the passages between their cavities , which are left in the building up of the septa . As already explained , the labyrinthic structure takes its origin from the inner surface of the impervious spiral lamina , the septa being directed towards the central axis . These ingrowths have in many instances the form of tubular columns , which traverse the chambers in a radial direction ( i. e. perpendicular to the spiral lamina ) , terminating either on the septum of the previous chamber , or on the exterior wall of the preceding whorl of chambers . But these tubes do not seem to be homologous with the " radial tubes " of Parkeria , whose relations differ in important particulars . The range of variation in a number of specimens , as to the amount of the " secondary " and " tertiary " ingrowths which divide and subdivide the chambers in Loftusia is very great . The principal office fulfilled by this accessory skeleton seems to be that of a support to the primary spiral lamina , imparting the necessary solidity to the organism . The degree of subdivision of the chambers into chamberlets seems to have little bearing on the general economy of the animal . The Author attempts to determine from the other Foraminifera , of which the remains are found associated in the same Limestone with those of Loftusia , what was its probable Geological age , and under what conditions it was deposited ; and he thence draws the conclusion that the rock belongs to the lowest portion of the Tertiary period , presenting a microzoic Fauna very similar to that of some of our Miliolite Limestones , but richer in the small arenaceous Rhizopods ; and that the sea-bottom was a soft Calcareous mud lying at a depth of from 90 to 100 fathoms .

112425

3701662

On Remains of a Large Extinct Lama (Palauchenia magna, Owen) from Quaternary Deposits in the Valley of Mexico. [Abstract]

405

406

Proceedings of the Royal Society of London

Professor Owen

abs

6.0.4

proceedings

http://corpora.clarin-d.uni-saarland.de/surprisal/6.0.3/?id=112425

http://www.jstor.org/stable/112425

Anatomy 2

Biography

Anatomy

II . " On Remains of a large extinct Lama ( Palauchenia magna , Owen ) from Quaternary deposits in the Valley of Mexico . " By Professor OWEN , F.R.S. &c. Received March 22 , 1869 . ( Abstract . ) The author premises to his descriptions of these remains a summary of the evidence of Fossil Cameloid Quadrupeds in the memoirs and works of Lund , Pictet , De Blainville , Gervais , Burmeister , and Leidy , deferring the further analysis and comparison of the descriptions by the latter palaeontologist to the conclusion of the present paper . The subject of it consists of casts and photographs of fossils discovered by Don Antonio del Castillo , mining engineer , in a posttertiary deposit beneath volcanic tufa in the Valley of Mexico . The fossils include the dentition of the left ramus of the lower jaw , wanting the incisors ; also the series of cervical vertebrae , wanting the first or atlas . Assuming the incisors to be in number as in Ruminants , the dentition of this mandibular ramus is formularized as:-i 3 , c 1 , p 3 , m 3=10 . Of the grinding-teeth , the three molars , with the last two premolars , form a close-set or continuous series of five teeth , the first of which ( p 3 ) is small , simple , conical , and obtusely pointed . A still smaller or rudimental premolar ( p 2 or p 1 ) is situated in the long diastema between the series of five teeth and the canine ; the latter tooth is relatively smaller than in the Camel . Detailed descriptions are given , illustrated by drawings , of each of the teeth , from which the author shows that they have belonged to a Cameloid species , as large as the larger variety of existing Dromedary , but with modifications of the teeth , testifying to a closer affinity with the Lama and Vicugna . He then proceeds to give detailed descriptions , with figures , of the cervical vertebrEe ; they present the intraneural position of the vertebroarterial canals characteristic of the Camelidce , and of the extinct Perissodactyle genus Macrauchenia ; and the comparisons of the fossil vertebrae are made with the corresponding one of that extinct genus and of the existing species of Camelus and Auchenia . The result of the comparison concurs with that of the dental characters in demonstrating the former existence in America of a Cameline Ruminant as large as the largest variety of living Camrel or Dromedary , with closer affinities to the Lamas and Vicugnas , yet with such departures from the dental and osteological characters of Auchenia , Illig . , as justify the author in indicating them by the generic or subgeneric term Palauchenia , which he proposes for such extinct form of American Cameline quadruped . The author , in conclusion , refers more at large to Prof. Leidy 's descriptions of Procamelus occidentalis , Leidy , and Camelops Kansanus , Leidy , pointing out the more important particulars wherein they differ from Palau chenia magna , Owen , and dwelling on the evidences of a progress from a more generalized to a more specialized type of Ruminant dentition in the extinct Cameloid forms succeeding each other , from the old Pliocene of Nebraska to the new or Postpliocene of Mexico . Tables of dimensions of teeth and vertebrae of Palauchenia , Auchenia , and Camelus , and drawings arranged for one folding and three 4to plates , accompany the memoir .

112426

3701662

On the Proof of the Law of Errors of Observations. [Abstract]

406

407

Proceedings of the Royal Society of London

M. W. Crofton

abs

6.0.4

proceedings

http://corpora.clarin-d.uni-saarland.de/surprisal/6.0.3/?id=112426

http://www.jstor.org/stable/112426

Tables

Formulae

Tables

III . " On the Proof of the Law of Errors of Observations . " By M. W. CROFTON , F.R.S. Received March 24 , 1869 . ( Abstract . ) The object of this Paper is to give the mathematical proof , in its most general form , of the law of single errors of observations , on the hypothesis that each error in practice arises from the joint operation of a large number of independent sources of error , each of which , did it exist alone , would occasion errors of extremely small amount as compared generally with those actually produced by all the sources combined . This proof is contained in a process given for a different object , namely , Poisson 's generalization of Laplace 's investigation of the law of the mean results of a large number of observations , to be found in the 'Connaissance des Temps ' for 1827 , and also in his ' Recherches sir la Probabilite des Jugements ; ' it is also reproduced in Mr. Todhunter 's able ' History of the Theory of Probability . ' It is not therefore pretended that any new results are arrived at in the present Paper . Considering , however , the importance and celebrity of the question , and the refined and difficult character of Poisson 's analysis , it will not probably be deemed superfluous to show how the same law may be demonstrated with equal generality , in a much more simple and elementary manner . The difficulty of the general proof seems indeed to have been so extensively felt , that several attempts have been made to simplify it . However , so far as the present writer is aware , no proof has been given , except Poisson 's , which is not open to grave objection , as based upon unjustifiable assumptions , or as unduly limiting the generality of the investigation . The mathematical reasoning in this Paper is based entirely on the abovementioned hypothesis as to the causation of error , namely , that errors in rerum naturd result from the superposition of a large number of minuter errors arising from a , number of , independent sources . The laws of these elementary errors are supposed entirely unknown , no further restriction whatever being imposed on the generality of the investigation ; as would be the case , for instance , were we to assume ( as has sometimes been done ) that each independent source gives positive and negative errors with equal facility . To decide fully how far the above hypothesis ( which seems now to be generally accepted ) really agrees with facts , is an extremely subtle question in philosophy , -one which probably never can be more than partially resolved . Still , even a cursory and superficial examination of a few particular cases seems to show that , far from being a mere arbitrary assumption , it is at least a reasonable and probable account of what really does take place in nature , in many large classes of errors of observations . The history of practical astronomy , in particular , seems to prove that , whatever doubt may be entertained of its exactness as applied to the errors of rude and primitive observers , we may safely accept it in the case of the refined and delicate observations of modern astronomers . It would be scarcely possible in this Abstract to convey any clear idea of the mathematical analysis employed in reducing the above hypothesis to calculation . It will suffice to remark that , whereas in the processes given by Laplace and Poisson , when applied to the problem before us , the elementary component errors are at first supposed of finite magnitude , and finite in number , and the results are afterwards modified for the supposition that the magnitude of the errors becomes infinitesimal and their number infinite ; much simplicity is gained in this Paper by making these suppositions at the commencement . Also , instead of taking a simultaneous view of all the elementary errors , as affecting the actual or resultant error , the latter is considered as produced by the superposition of some one of the elementary errors upon the error produced by the combination of all the others . We are thus led to examine the infinitesimal change produced in a given finite error , as expressed by a given function , by the superposition of a new infinitesimal error ; and from the analytical expression arrived at , it is shown how to find the form of the function of error resulting from the combination of an infinite number of given infinitesimal errors . This form is found to be altogether independent of the nature or laws of the component errors . If we assume the following data as known , viz. m=sum of the mean values of the component errors , h=sum of the mean values of the squares of component errors , i=sum of squares of the mean values of component errors , it is proved that the probability of the actual resulting error being found to lie between x and x dv is 1 ( ' m)2 2(/ -i ) d : . 27r ( h-i ) This result will be found to agree with Poisson 's .

112427

3701662

On a Certain Excretion of Carbonic Acid by Living Plants. [Abstract]

407

408

Proceedings of the Royal Society of London

J. Broughton

abs

6.0.4

proceedings

http://corpora.clarin-d.uni-saarland.de/surprisal/6.0.3/?id=112427

http://www.jstor.org/stable/112427

Biography

Chemistry 2

Biography

I. " On a certain Excretion of Carbonic Acid by Living Plants . " By J. BROUGHTON , B.Sc. , F.C.S. , Chemist to the Cinchona Plantations of the Madras Government . Communicated by J. D. HOOKER , M.D. , F.R.S. Received March 31 , 1869 . [ Abstract . ] While the author was engaged in some experimental determinations of the changes that take place in the composition of the Cinchona barks after being taken from the tree , he noticed a somewhat singular circumstance , which induced him to institute a series of experiments , by which he discovered that the various parts of living plants excrete carbonic acid , not only in their normal condition , but after they have been deprived for days together of all access of oxygen . The experiments were mostly made on cut portions of the plants ; but experiments were also made , for control , on plants as they actually grow . The deprivation of oxygen was effected sometimes by Sprengel 's air-pump , sometimes by substituting for air an atmosphere of hydrogen or nitrogen ; while comparative experiments were made on plants supplied with air that had been freed from carbonic acid . The main conclusions to which he was led are those enunciated by the author:1st . That nearly all parts of growing plants evolve carbonic acid in considerable quantities , quite independently of direct oxidation . 2nd . That this evolution is connected with the life of the plant . 3rd . That it is due to two causes , namely , to previous oxidation , resulting after a lapse of time in the production of carbonic acid , and to the separation of carbonic acid from the proximate principles of the plant while undergoing the chemical changes incident to plant-growth .

112428

3701662

On the Causes of the Loss of the Iron-Built Sailing-Ship Glenorchy

408

415

Proceedings of the Royal Society of London

Archibald Smith

fla

6.0.4

http://dx.doi.org/10.1098/rspl.1868.0081

proceedings

http://corpora.clarin-d.uni-saarland.de/surprisal/6.0.3/?id=112428

10.1098/rspl.1868.0081

http://www.jstor.org/stable/112428

Meteorology

Measurement

Meteorology

II . " On the Causes of the Loss of the Iron-built Sailing-ship 'Glenorchy . " ' By ARCHIBALD SMITH , Esq. , M.A. , LL. D. , F.R.S. Received April 15 , 1869 . When the loss of an iron-built vessel has been caused by an error in the direction of her course by dead reckoning , as derived from her course by compass , it is a question of scientific interest whether the error has or has not arisen from an error in the assumed deviation of the compass . By careful consideration of all the circumstances of the case , and by piecing together the generally scanty fragments of information which can be obtained as to the magnetic state of the ship , a probable or certain answer to this question may be given more frequently than might be supposed possible by those who do not know how perfectly definite and well ascertained the laws of the deviation of the compass are , how small is the number of quantities involved which are peculiar to each particular ship , and from what apparently slight indications an approximate estimate of the numerical values of these quantities can be made . The case the circumstances of which I now propose to lay before the Royal Society , is one in which it appears to me that a positive answer to the question can be given . It will , I hope , be found to have some interest as an example of the manner in which such an answer can be elicited from the data . It may have some scientific interest as the first case in which any information as to the magnetic character of an English merchant-ship has been published since the publication of the Third Report of the Liverpool Compass Committee in 1861 ; and I think it will be found to have much practical interest , as bringing into prominence a particular error of great importance , not as yet , I believe , ascertained or corrected in the usual course of adjustment of compasses in merchant-ships , even by the most experienced and skilful compass-adjusters , but which , ever since the mode of ascertaining and correcting it without heeling the ship was given in . the 'Admiralty Manual for the Deviation of the Compass ' in 1862 , has been ascertained , and when necessary corrected , in the ships of the Royal Navy , viz. the Heeling Error . The case to which I refer is the loss of the ship 'Glenorchy ' of Glasgow , on the Kish Bank , in Dublin Bay , on the 1st of January 1869 , on which a court of inquiry was held under the direction of the Board of Trade in pursuance of the Merchant Shipping Act . In examining this case I have had the advantage , by the permission of the Board of Trade , of perusing the evidence taken before the Court of inquiry , and the report of the Court . I have also had the advantage of discussing the nautical as well as the magnetical circumstances of the case with Captain Evans , F.R.S. , the highest authority in all that relates to such an inquiry , and who permits me to state his concurrence in the conclusions at which I have arrived ; and above all , I have to express my obligations to Mr. William Fleming , compass-adjuster , James Watt Street , Glasgow , for the full particulars with which he has kindly furnished me of the deviations and correction of the compasses of the 'Glenorchy '-information without which the results of this inquiry would have been in a great measure conjectural . The 'Glenorchy ' was an iron-built sailing-ship of 1200 tons , having an iron poop , with a wooden deck laid upon iron beams , with iron bulwarks , except on the poop-deck , above which there was a light rail . She was built at Dumbarton in 1868 . Her head in building was about N.N.E. After being launched she was taken to Glasgow , where she lay for some time head N.W. taking in a cargo of about 1100 tons of iron railwaychairs and sleepers . She had two compasses on deck-a steering-compass and a standard compass . The card of each had two edge-bar needles 8inches long , the ends separated 50 ? . The steering-compass was near the stern , about 32 or 33 inches above the poop-deck , and 2 feet in front of the steering-wheel , which had an iron spindle . The standard compass was on a wooden pillar about 5 feet high , standing on a wooden platform laid from the poop to the mainmast , and about 15 feet abaft the mainmast , which was of iron . On the 18th of December the Glenorchy ' had her compasses adjusted in the Gareloch by Mr. Fleming in the usual way . The deviation of the steering-compass , as might have been expected from the combined effect of the position of the compass in the ship and of the ship in building , was enormous . Mr. Fleming says it was " as bad if not worse than any he ever saw . " Mr. Fleming informs me that before magnets were applied to the steering-compass , when the ship 's head bore N. ( magnetic ) it bore S. by the steering-compass ; when the ship 's head bore W. ( magnetic ) it bore about S.W , by S. by the steering-compass . In other words , at N. ( magnetic ) there was a deviation 180 ? , at W. ( magnetic ) a deviation of about 56 ? ? 15 ' E. The quadrantal deviation was about 10 ? . These data give , using the notation of the 'Admiralty Manual for the Deviation of the Compass , ' 3=--1'250 , C= 0 , or a force of the ship to the stern exceeding by one-fourth the whole directive force of the earth 's magnetism acting on the compass , a disturbing force about twice as great as that found at the steering-compass in any of the iron-built armour-plated ships in Her Majesty 's Navy . This enormous disturbing force was corrected by three large magnets one of 36 inches and two of 26 and 28 inches placed together , fore and aft , on the starboard side of the binnacle , and by two or three smaller magnets placed so as to correct as far as possible the residual error on the other cardinal points . The ship was then placed head N.W. ( magnetic ) , when a westerly deviation of three-fourths of a point 8 ? ? 26 ' was observed . This was of course approximately the amount of the quadrantal deviation , and it was corrected by a No. 12 iron jack-chain placed in the chain-boxes on each side of the compass . The ship was then swung on sixteen points and the following deviations of the steering-compass obtained ( + signifying that the N. point of the needle was drawn to the E. , to the W. ) . Glenorchy ' Steering-Compass , December 18 , 1868 . Magnetic Course . Deviation . Magnetic Course . Deviation . N. 0 , s. -2 N.N.E. +3 ? S.S.W. +3 N.E. +7 S.W. 0 E.N.E. +2 i.S.W.0 E. +3 W. +5 ; E.S.E. -3 WI . N.W. -3 S.E. -2 N.W. 0 S.S.E. -1 N.N.W. -2 410 From these I derive the following expression for the deviation ( I ) in terms of the azimuth of the ship 's head ( ( ) measured eastward from the magnetic N. =-30'+30 ' sin + 1 ? ? 2 ' cos 4+2 ? ? 37 ' sin 2 38 ' cos 24 . These values show that the semicircular deviation had been entirely corrected . Of the quadrantal deviation a small part appears to have been uncorrected . There are practical difficulties in the way of correcting very large amounts of this deviation by soft iron , and I have no doubt Mr. Fleming acted with judgment in not attempting to carry this correction further . We may probably assume the maximum quadrantal deviation to have been about 10 ? . The standard compass was not corrected by magnets , but its deviations were observed , and a Table of the deviations furnished . They were:'Glenorchy ' Standard Compass , December 18 , 1868 . Magnetic Course . Deviation . Magnetic Course . Deviation . N. +12 ? S. 5 ? N.N.E. 7 30 ' S.S.W. +7 30 ' N.E. -24 S.W. +16 E.N.E. -37 30 1 W.S.W. +22 30 E. -38 W. +33 E.S.E. -31 30 W.N.W. +35 30 S.E. -24 N.W. +35 S.S.E. -11 30 N.N.W. +20 30 These values give =0 , 33=--610 , f==+'105 , ==+ 100 , e=-0 . This Table and these values do not bear directly on the loss of the ship , because owing , as I collect , to the unsteadiness of the pillar the standard compass was found to be useless , and the ship was navigated by the steering-compass alone ; but it is interesting from the light it throws on the general magnetic character of the ship , and its confirmation of the results obtained from the steering-compass . The proportion of C to -33 exactly agrees with what we know of the direction in which the ship was built . The large value of --3 was no doubt owing to the original magnetism of the hull and not to the iron cargo , which in fact probably rather diminished than increased the -3B . Cards containing the deviations of both compasses were furnished to the captain . The question of the correction of the standard compass by magnets is one which has become of so much importance that I may be pardoned for interposing a digression on this subject and for inserting a passage from the third edition of the 'Admiralty Manual ' now in the press . " The question of the mechanical deviation of the compass has materially changed its aspect of late years . Before that time the deviation of a properly placed standard compass was of moderate amount , its maximum seldom exceeding 20 , and the directive force which acted upon it being generally comprised within the limits of two-thirds and four-thirds of the mean force . There was then no difficulty and some advantage in dispensing altogether with mechanical correction ; or , if mechanical correction was employed , it was possible , at least in vessels which did not change their magnetic latitude , to make the correction so complete that tabular correction might be dispensed with . But in the present day it is frequently impossible to find a position for the standard compass at which the deviation and the variation of directive force do not greatly exceed these limits . In such . cases the application of magnets for the purpose of equalizing the directive force on different azimuths becomes a matter of necessity ; while at the same time the danger of trusting to mechanical correction alone without ascertaining and applying the residual errors is increased . 'This change of the condition of the question has produced a corresponding change in the practice in the Royal Navy . ' The same care as before is still used in the selection of a place for the standard compass ; but a magnet is frequently or generally introduced for the purpose of equalizing the directive force on different azimuths , and at the same time diminishing the semicircular deviation . The quadrantal deviation is not often corrected mechanically , but is generally left for tabular correction . " The heeling deviation is always ascertained , and is sometimes corrected mechanically . " After the 'Glenorchy ' was swung she took in an additional quantity ( about 120 tons ) of iron . I do not , however , think it possible that this quantity could have altered the deviations sensibly . The 'Glenorchy ' sailed from Greenock on the 25th of December . She had on board a pilot accustomed to the navigation of the Irish Channel . She was towed to Lamlash Harbour , in the Island of Arran , where she lay till 3 A.M. on the 31st of December . She then got under way , the wind blowing moderately from the N.W. , and steered a course down midchannel , sighting the Copeland , the Mull of Galloway , the North and South Rock , St. John 's Point , and the Calf of Man lights . The wind gradually heading her , she tacked about 6.15 A.M. on the 1st of January . At 7.10 A.M. her position was determined by a bearing and distance of the South Stack Light , which then bore S. by W. , distant nive miles . Till the ship tacked she had been on the starboard tack , on courses from S.W. to S. , on which the deviation-card gave small deviations for the steering-compass , The bearing of the lights sucoessively passed had , however , been carefully taken by the captain , and from these he found that the compass had a westerly deviation of one point not shown by the deviation-card . From 7.10 A.M. till 3 P.M. the ship was on the port tack , sailing by the wind but kept good full , her course by the steering-compass being about S.W. by W. During the whole of this time a gale of wind was blowing from S.S.E. , gradually increasing in intensity , with thick weather and rain , which cleared only for a little about 1.30 , when land was seen in the distance bearing W.N.W. The lead was cast and 35 fathoms found . The captain and pilot consulted the chart , and making what they considered a proper allowance for tide and leeway , came to the conclusion that the land was Wicklow Head , bearing W.N.W. , distant twenty-two miles . The ship then stood on the same course till 3 P.M. , when soundings were again taken and 25 fathoms found . Orders were then given to wear , but in wearing , and when nearly before the wind , the ship struck and remained fixed on the Kish Bank , about four miles S. of the Kish Lightship . The point at which the ship so unexpectedly found herself was about twenty geographical miles to leeward of that at which the captain and pilot supposed themselves to be . In other words , the ship 's actual course was about 28 ? or 24 points to the right of her supposed course . To what , then , was the error due ? In the first place , it seems impossible to attribute any large part of the error to an insufficient allowance for the effects of tide and leeway . It is true that from 7 to 1 o'clock a spring flood-tide , assisted by a southerly gale , had been running , but this was known to the captain and pilot . They had watched with great care throughout the day the courses , the leeway , and the rate , and , if we may judge from their estimate of the distance run , had estimated them with great exactness . The next cause that suggests itself is a deviation of the compass not allowed for . The steering-compass by which the ship was navigated was , we have seen , carefully adjusted in the Clyde , and was then nearly correct on a S.W. by W. course . Is it possible that any change in the magnetism of the ship had taken place , as has sometimes been found or supposed in new ships , which would account for the error ? The answer to this must be in the negative . It is certain that any such change in the 'Glenorchy ' would have had the effect of producing an error of the opposite kind , and , had it operated , she would have been found to the south , not to the north , of her supposed course . Is there , then , any other cause adequate to produce an easterly deviation on a S.W. by W. . course which might lurk concealed and undetected in the process of adjustment and only emerge during the voyage ? To this the answer is emphatically Yes The Heeling Error . From the combined effects of the position of the steering-compass in the ship and of the ship in building , it is certain that there must have been a very large heeling error drawing the north point of the compass to the weather side of the ship . This error was probably not less than 3 ? or 4 ? for each degree of heel on a N. or S. course , before the chaincorrectors were applied . The chain-correctors would reduce it about 50 ' , leaving 2 ? or 3 ? for each degree of heel . On a S.W. by W. course this error would be reduced to five-ninths of its maximum amount , or would be from 1 ? to 1 ? for each degree of heel . Hence if the 'Glenorchy ' was heeling 10 ? , she would certainly have an easterly deviation of a point to a point and a half , or possibly more , introduced . But it may be asked , if the ship had this large amount of heeling deviation , how did it escape detection in the earlier part of the voyage , when the ship was on a southerly course and the bearings of the lights were taken ? and if detected , how was it not allowed for on the st of January ' The answer to these questions is remarkable ; it is shortly this . The error was detected and was allowed for correctly when the ship was on the starboard tack . Afterwards , and when the ship was put on the port tack , it was still allowed for , but in the same direction as before , and therefore in the wrong direction . It was allowed for as a westerly deviation , although it had become an easterly deviation ; and consequently the heeling error instead of being corrected , was doubled . And of this the cause was as follows . Between Greenock and Lamlash , the ship being towed and on even keel , there were no means of detecting the error . Between Lamlash and the Calf of Man , when the ship was on the starboard tack and on a southerly course , an error of a point of westerly deviation was , as we have seen , detected and allowed for by the captain . This error I think there cannot be a doubt was heeling error . But when on the morning of the 1st of January the ship tacked and was put on the port tack , the heeling deviation changed from being a westerly deviation to being an easterly deviation . The captain not being aware that there would be this change , and having no opportunity of verifying his course , continued to make the same allowance as before , and consequently made it , as I have said , in the wrong direction . As to the fact I think I cannot be mistaken . The captain 's words are:-- " Our observations of the different lights all the way down Channel showed the compasses were inaccurate , and during the whole course on the starboard tack we had to steer one point more to the west than the proper course . " Then , speaking of the ship 's supposed position at 1.30 , he says:"The courses I had observed , and the rate we were going , allowing for the tide and the leeway , and the point the compass was in error while on the starboard tack , should have brought us to a point with Wicklow Head , lying W. by N. , twenty-one miles distant . " It is clear from this that the captain made an allowance for the point of error he had discovered . Had he applied it in the opposite direction , he would undoubtedly have mentioned that he did so and why he did so . The particular conclusions , then , which I draw from the facts of the case are these:1 . There must have been a large heeling error affecting the steeringcompass of the ' Glenorchy , ' which , on the courses steered , would be a westerly deviation on the starboard tack , an easterly deviation on the port tack . 2 . The westerly deviation detected on the starboard tack was this heeling error . 3 . The true construction to be put on the captain 's statement is , that when on the port tack he allowed for the point of deviation which he had detected on the starboard tack as a point of westerly deviation , not as a point of easterly deviation , as he would have done had he known the cause and the law of the deviation which he had detected . 4 . That , in consequence , his supposed course was in error one point plus the heeling deviation , which , on a S.W. by W. course , was probably about one point more . The general conclusions to be drawn from the history of the shipwreck seem to me to be:1 . The great importance of selecting a position for the navigatingcompass where the force of the ship 's magnetism is moderate and uniform . 2 . The importance of extending the usual process of " adjustment " of a compass to the ascertaining and ( if necessary ) the correcting of the heeling error . This is a matter of no difficulty if the compass-adjuster is duly instructed and supplied with the requisite instruments .

112429

3701662

Spectroscopic Observations of the Sun.--No. IV

415

418

Proceedings of the Royal Society of London

J. Norman Lockyer

fla

6.0.4

http://dx.doi.org/10.1098/rspl.1868.0082

proceedings

http://corpora.clarin-d.uni-saarland.de/surprisal/6.0.3/?id=112429

10.1098/rspl.1868.0082

http://www.jstor.org/stable/112429

Atomic Physics

Astronomy

Atomic Physics

III . " Spectroscopic Observations of the Sun.-No . IV . " By J. NORMAN LOCKYER , F.R.A.S. Communicated by Dr. SHARPEY , Sec. R.S. Received April 14 , 1869 . I beg to lay before the Royal Society very briefly the results of observations made on the 11th instant in the neighbourhood of a fine spot , situated not very far from the sun 's limb . I. Under certain conditions the C and F lines may be observed bright on the sun , and in the spot-spectrum also , as in prominences or in the chromosphere . II . Under certain conditions , although they are not observed as bright lines , the corresponding Fraunhofer lines are blotted out . III . The accompanying changes of refrangibility of the lines in question 1869 . ] 415 show that the absorbing material moves upwards and downwards as regards the radiating material , and that these motions may be determined with considerable accuracy . IV . The bright lines observable in the ordinary spectrum are sometimes interrupted by the spot-spectrum , i. e. they are only visible in those parts of the solar spectrum near , and away from , spots . V. The C and F lines vary excessively in thickness over and near a spot , and on the 1lth in the deeper portion of the spot they were much thicker than usual . IV . Stars , in the spectrum of which the absorption-lines of hydrogen are absent , may either have their chromospheric light radiated from beyond the limb just balanced by the light absorbed by the chromosphere on the disk , or they may come under the condition referred to in ( II . ) , either absolutely or on the average . ADDENDUM.-Received April 29 , 1869 . Since the date on which the foregoing paper was written , I have obtained additional evidence on the points referred to . I beg therefore to be permitted to make the following additions to it . The possibility of our being able to determine the velocity of movements of uprush and downrush taking place in the chromosphere depends upon the alterations of wave-length observed . It is clear therefore that a mere uprush or downrush at the sun 's limb will not affect the wave-length , but that if we have at the limb cyclones , or backward or forward movements , the wave-length will be altered ; so that we may have:1 . An alteration of wave-length near the centre of the disk caused by upward or downward movements . 2 . An alteration of wave-length close to the limb , caused by backward or forward movements . If the hydrogen-lines were invariably observed to broaden out on both sides , the idea of movement would require to be received with great caution ; we might be in presence of phenomena due to greater pressure , both when the lines observed are bright or black upon the sun ; but when they widen out sometimes on one side , sometimes on the other , and sometimes on both , this explanation appears to be untenable , as Dr. Frankland and myself in our researches at the College of Chemistry have never failed to observe a widening out on both sides the F line when the pressure of the gas has been increased . On the 21st I was enabled to extend my former observations . On that day the spot , observations of which form the subject of the paper , was very near the limb ; as this was the first opportunity of observing a fine spot under such circumstances I had been able to utilize , I at once commenced work upon it . The spot was so near the limb that its spectrum and that of the chromosphere were both visible in the field of view . The spot-spectrum was very narrow , as the spot itself was so greatly foreshortened ; but the spectrum of the chromosphere showed me that the whole adjacent limb was covered with prominences of various heights all blended together . Further , the prominences seemed fed , so to speak , from , apparently , the preceding edge of the spot ; for both C , F , and the line near D , were magnificently bright on the sun itself , the latter especially striking me with its thickness and brilliancy . In the prominences C and F were observed to be strangely gnarled , knotty , and irregular , and I thought at once that some " injection " must be taking place . I was not mistaken . On turning to the magnesium lines I saw them far above the spectrum of the limb and unconnected with it . A portion of the upper layer of the photosphere had in fact been lifted up beyond the usual limits of the chromosphere , and was there floating cloud-like . The vapour of sodium was also present in the chromosphere , though not so high as the magnesium , or unconnected with the spectrum of the limb , and , as I expected , with such a tremendous uplifting force , I saw the iron lines ( for the first time ) in the spectrum of the chromosphere . My observations commenced at 7.30 A.M. ; by 8.30 there was comparative quiet . At 9.30 the action had commenced afresh ; there was now a single prominence . At the base of the prominence I got this appearance : Higher up this : . Here I may be permitted to recall the observation made on March 14 , in which a slight movement of the slit gave me first , then , and finally -i , all these appearances being due to cyclonic action . 1869 . ] Observations of the Sun . On the following side of the spot , at about 10 A.M. , I observed that the F line had disappeared ; at the point of disappearance there appeared to be an elongated brilliantly illuminated lozenge lying across it at right angles , as if the spectroscope were analyzing the light proceeding from a cyclone of hydrogen on the sun itself , but so near the limb that the rotatory motion could be detected . The next observations I have to lay before the Royal Society were made on the 27th inst . Careful observations on the 25th and 26th revealed nothing remarkable except that the chromosphere was unusually uniform . On the 27th a fine spot with a long train of smaller ones and faculhe was well on the disk . The photosphere in advance of the spot , and the large spot itself , showed no alteration from the usual appearance of the hydrogenlines ; but in the tails of the spot the case was widely different . The F line , at which I worked generally , as the changes of wave-length are better seen , was as irregular as on the former occasions . I. It often stopped short of one of the small spots , swelling out prior to disappearance . II . It was invisible in a facula between two small spots . III . It was changed into a bright line , and widened out on both sides two or three times IN THE VERY SMALL SPOTS . IV . Once I observed it to become bright near a spot , and to expand over it on both sides . V. Very many times near a spot it widened out , sometimes considerably , on the less refrangible side . VI . Once it extended as a bright line without any thickening over a small spot.i ! l VII . Once it put on this appearance bright . VIII . I observed in it all gradations of darkness . IX . When the bright and dark lines were alongside , the latter was always the less refrangible .

112430

3701662

On Some of the Minor Fluctuations in the Temperature of the Human Body When at Rest, and their Cause

419

426

Proceedings of the Royal Society of London

A. H. Garrod

fla

6.0.4

http://dx.doi.org/10.1098/rspl.1868.0083

proceedings

http://corpora.clarin-d.uni-saarland.de/surprisal/6.0.3/?id=112430

10.1098/rspl.1868.0083

http://www.jstor.org/stable/112430

Biology 2

Thermodynamics

Biology

I. On some of the minor Fluctuations in the Temperature of the Human Body when at rest , and their Cause . " By A. H. GARROD , St. John 's College , Cambridge . Communicated by Dr. BEALE . Received April 16 , 1869 . The author 's object in the following communication is to show that the minor fluctuations in the temperature of the human body , not including those arising from movements of muscles , mainly result from alterations in the amount of blood exposed at its surface to the influence of external absorbing and conducting media . In the following Tables , when not otherwise mentioned , all the temperatures are taken under the tongue , the thermometer remaining in the mouth for five minutes , except when the observations were made each twoand-a-half minutes , on which occasions the temperature of the bulb was not allowed to fall below 85 ? F. It may be remarked that in no case mentioned below was the temperature of the air above 65 ? F. , and that on all occasions the skin was dry , whereby any complications from the presence of perceptible moisture were avoided ; and the arguments based on the facts necessitate an approximation to those conditions . The Tables have been selected from a great number of observations ; and no results have been obtained which are not easily explained on the theory given . The temperatures were taken on one subject , aged 22 , male , thin . No. 1.-From 10.30 P.M. till 12 n ? i#ht . 97§ 980 990 1000 10.30 10.4U o.o*10 , , g * , l Sitting in a room ( temp. of air 660 F. ) 11 *all the time . Fully clad till 11 , when I~~~ ~f1.5 l stripped in a minute , therefore nude at 11.10 eI_ I *l 11.1 . WTarm when dressed , but got cold 11,15i gli f when nude . At 11.40 covered body all 11l20 over with a thick blanket , soon followed 11.25 by a slight skin-glow . In the blanket until 11.30 a|s|112 night . W35hen body covered , pulse much more 11.4035 , EE bounding than when not covered . 11.40 45 EE* ! 3iX 11.45 11.50 11.55 111111 970 980 990 1000 No. II.-From 11.15 P.M. till 12.30 night . 970 980 990 1000 11.20 Standing from 11 till 12.5 in a 11.2305 * roomlwith the thermometer at 470 1135 * . warmly clad till 11.30 , when 11.3540 * stripped in two minutes , so nude at 11.40 * 1132 . Fairly warm all the while . 11 . 45 * , * Got to bed at 12.6 , and lay closely 11.50 wrapped by bedelothes for the rest *11 . , , of the time . A decided glow came 12.5 on at 12.11k , lasting a minute , after 12.50 lSRllX1-ll lj ; 1|which feet beca.me a little cold , but 12.15 0| ** skin of body quite warm . 12.1*5 , Whilst standing nude pulse small , 12.20 iilii* but bounding when dressed and when 12.23 No. III.-From 11 P.M. till 1 A.M. 970 98§ 990 1000 11.5 11.12 11.15 11.25 *** *|j Standing in room ( temp. of air 520 11.3C * " " |* ** F ) from 11 until 12 . Fully clad r11.801 ~ffiW II until 11.30 , and then stripped in two 11.3 40 minutes , so nude at 11.32 . Warm 1140 ** in body all the while . At 12.2 got 11.45g *Efl Ej I flffilIG to bed , and there the rest of the **1 *fll | ll flfl time , closely wrapped . A glow came 11.52 Iii i on at 12.81 , lasting half a minute , 12 after which feet became coldish . 12.5 l _a:=_=_ 12.510 *m***** *fli Pulse not so bounding when nude 12.12 n** as when body covered . lO Indicates the temperature of 1225 l the pectoral region , found by placing a spiral fiat thermometer on it , 12.30 123 EHE_ *f lflf llfl and keeping it there five minutes . 12.35 12.45 E ... i ln , . 12.50 / lr 970 90 99o 1000 NTo . IV.-Froin 11 P.M. till 12.45 night . 97O 980 99O 10 ? 0 11 ** EU EHEE __Nude at 11.11 in a room 11.10 l ( temp. of air 560 ) . Standing from 10.50 until 12.20 nude . At 11.20 Ni ; liliiiii5liii 12.21 got to bed , and remained there re/ st of time . At 11.45 beo""in nn ' ? 11.30 gan moving about and stooping , and whenever stooped felt a chill . 11.40 *i m , m E. . , , , , , , Quite shivering from 11.57till 11.45 12.72 , when , leaving off moving , ll/ 11/ 111X.1O l/ l^^l the shivering ceased . 1* *,11/ l,.i iIn When in bed had no marked 12j giil..ow , and feet continued to be 12.510 l.11.1 warm ; skin of thighs not warm . 12.10 12.15 ll 2 Tho following is the sphygm012.20 mmEm*q graphic curve of radial airtery at wrist : when in bed at 12.40 , pulse 12.30 / I * E.1 . , ; ; ; 5 same as at 11 ( the same pressure 12 3 11.20 11.35 11.51 10.30 10.35 10.40.0.45 10.50 10.55 11 11.5 11.10 11.15 11.20 11.25 11.30 11.35 11.40 11.45 11.50 11.55 12 Mr. A. H. Garrod on some of the Minor [ May 13 , No. V.--From 10.30 P.M. till 12 night . 97§ 980 99§ 1000 Sitting in a room ( temp. of air 58 ? F. ) all the time . Warmly clad till 11 , when stripped in two minutes , so nude at 11.2 . At 11.20 went for half a minute into a colder room . At 11.45 put on several flannel things , which had been warmed by the fire , and sat in front of a warm fire . Took sphygmograph-trace from right superficialis vola3 at 10.40 and at 11.10 . Tried to do so at 11.40 , but could not get any indication , from the smallness of its pulsation . At 12 the pulsation was as great as at 10.40 . 10.40 . 11.10 . No. VI.-From 10.30 P.M. till 11.45 P.M. 970 98§ 99§ 10.30 Sitting in'a room ( temp. of air 59 ? F. ) from 9.30 until 10.40 , quiet , cool , and warmly clad . From 10.40 till 10.55 moving about in the same room . Stripped at 10.55 , and nude in two minutes . Remained nude until 11.24 , when got to bed , and remained there for the rest of the time . 422 11 10.45 11 11.15 11.30 11.45 No. VII , -From 11.10 P.M. till 11.55 P , M. Standing in a room ( temp. of 970 98§ 990 ? 000 air 530 F. ) from 11 until 11.25 . ll11.10 lI Flully clad until 11.9 , when stripped , and nude at 11.10 . r11.20 HEEHE EE s *-----Continued nude until 12 . At 11.25 H--__ElIUM -----11.25 seated , and remained so 11.30 HUE until 12 , on a bed . At 11.40 11,35 E*-U EURIIII put feet in water from 110 ? 11.40 Ul lU EU 1140 , above ankles , and re11.45 * mained thus rest of time , main11.50 #| ! | _| -r taining the heat of the water . 11.55 No. X.-Fromn 11.10 A , M. till 12.40 P.M. 99§ 1n00 " 990 100 ? Temperature of air 62 ? F. A cloudy , breezy day . At 11.10 11 walked about 200 yards on to a beach , and sat down on 11.20 ~Iii[ the shingle at 11.5 , where there was a slight side breeze..1ao30 ra mil/ Hands an feet a little cold . 11.40 5imlm m* Sun covered by clouds until 11.35 , after which it began 11.50 to shine ; immediately after which began to feel warm , 12.0l and continued to get warmer until 12.7 , when at 12.7 a^ 12.1^^20 ~1 cloud covered sun until 12.11 . During time sun covered , several chills came over body . 1240 Walking in sun from 12.16 onward . 990 1000 Clad in thin merino next skin and summer clothes . 99§ 100o No. XI.-From 3 P.M. till 6 P.M. 980 99§ 100§ 3o _ T3.15 Tcll temperature of air 66 F. , slowly diminishing 3.30 ElI to 64 ? F. Sitting on a beach from 3 until 5 , after 3.45 HUE Of a dinner at 2.15-2.45 . A slight face breeze . In 4 of U1 teaIo11u the shacde . Warm until 4.15 , when feet began 4.15 s to get a little cold , and by 5 so cold that 4.30 obliged to move abotut . At 5 began to walk 4.45 0 slowly , and had to go ap several steps . At 5 U2 bn 5.20 began to walk briskly . B3egan to perspire 530 *elie at 5.25 . Conitinued walking , p erspiring untr5.30 wh~if~cl-hnnn'~ e , til 6 . 5.45 A.|| , MU||g Clad as in last , 980 990 100 ? To explain these Tables:-The actual temperature of the body at any given moment must be the resultant of ( 1 ) the amount of heat generated in the body , and ( 2 ) the amount lost by conduction and radiation . ( 1 ) The source of heat in the body is not considered in this paper ; and no more will be now said of it , except that there is every reason to believe that it is not in the skin itself , and that , for the short periods through which each observation was made , it is approximately uniform . ( 2 ) The loss of . heat from the body is modified by changes in the skill and by changes in the surrounding media ; and these two are mutually dependent . It has long been known that cold contracts and heat dilates the small arteries of the skin , respectively raising and lowering the arterial tension , and thus modifying the amount of blood in the cutaneous capillaries . But modifications in the supply of blood to the skin must alter the amount of heat diffused by the body to surrounding substances ; and so we should expect that by increasing the arterial tension , thus lessening the cutaneous circulation , the blood would become hotter from there being less facility for the diffusion of its heat , and that by lowering the ten[May 13 , 424 sion , thus increasing the cutaneous circulation , the blood would become colder throughout the body , from increased facility for conduction and radiation . That such is the case is proved by Tables I. , II . , III . , IV . , V. , and VI . , where , by stripping the warm body of clothing , in a cold air , when the tensiona was low ( as in Tables IV . , V. , shown by the sphygmnograph-trace ) , the temperature and tension rose , at the same time that the surface became colder . In Tables I. , II . , III . , IV . , V. , and VI . , by covering the nude body with badly conducting clothing , when the tension was high , the surface-heat soon accumulated sufficiently to cause a sudden reduction of arterial tension , commonly called a glow , and a rapid fall in the temperatures , from the larger amount of blood exposed at the surface of the body to the influence of colder media . Changes in the arterial tension are easily recognized by the subject of experiment , from the sensations they produce ; a feeling of warmth followed by a shiver , or a shiver itself , generally shows that the tension is lowered , while the opposite effect follows a rise in the tension ; and this can be generally confirmed by the sphygmograph-trace . A bounding weak pulse shows a low , and a small thready one a high tension . We know , from the observations of Davy and others , that by reducing , the tension in one part of the body the tension of other parts is lowered ; thus by placing one hand in hot water , a thermometer in the other rises . In Tables VII . and VIII . it is shown that by putting the feet in hot water ( at 110 ? to 115 ? ) the lowering of the tension was so great that the amount of heat lost into the air considerably exceeded that gained to the body from the water , so that the temperature of the body began to fall directly , and decreased considerably ; and it was noticed that on adding more hot water chills were produced , which was the same as the effect of first putting the feet in the water . By covering a small part of the body with a bad conductor , the tension of the whole body soon falls , from the accumulation of heat in the covered parts causing a lowering in the tension generally , and a consequent greater carrying away of heat . In this way the fall after sitting down on a bad conductor when nude can be explained ( Table VII ; ) . A glow is felt in the skin directly upon short muscular movement , as stooping , and the temperature falls at the same time , as in Table IV . , between 11.45 and 12.20 , and in Table XI . , between 5.0 and 5.15 . In the latter case the muscular movement was carried to suoh an extent that the loss was made up for by the increase of heat from the muscular movement . Simply heating the feet lowers the tension and temperature together , as in Table IX . and in Table X. The passage of a cloud before the sun seems to have acted by reducing the loss of heat , as the temperature rose at the time . Further confirmation of the facts stated as to the modification of arterial tension may be found in Marey 's work , ' De la Circulation du Sang , ' published in Paris in 1863 . In that book the author ascribes the uniformity of the heat in the internal parts to the same cause as the author of the present paper ascribes the variations . The fact observed by Dr. W. Ogle in the St. George 's Hospital Reports for 1866 , and by Drs. Ringer and Stewart in a paper read before the Royal Society this year , that the temperature falls at night , and is lowest at from 12 to 1 A.M. , and begins to rise after that time , is simply explained on the theory given above ; for it depends on the custom of Englishmen going to bed at about that hour , and thus giving a large amount of heat to the cold bedclothes , which at first is expended in warming the sheets &c. , while later on in the night the bedclothes are warm , and therefore the body has only to make up for the heat diffused . Other natural phenomena can be similarly explained . Thus , on a cold day , the effect of sitting with one side of the body in the direct rays of a fire is to cause the other side to feel much colder than if there was no fire at all , because the fire lowers the tension over the whole body , and supplies heat to the full cutaneous vessels of one side , while the other side , being equally supplied with blood in the skin , does not receive heat , but has to distribute it rapidly to the cold clothes &c.

112431

3701662

Observations of the Absolute Direction and Intensity of Terrestrial Magnetism at Bombay. [Abstract]

426

427

Proceedings of the Royal Society of London

Charles Chambers

abs

6.0.4

proceedings

http://corpora.clarin-d.uni-saarland.de/surprisal/6.0.3/?id=112431

http://www.jstor.org/stable/112431

Meteorology

Tables

Meteorology

II . " Observations of the Absolute Direction and Intensity of Terrestrial Magnetism at Bombay . " By CHARLES CHAMBERs , Esq. , Superintendent of the Colaba Observatory . Communicated by Lieut-General SABINE , R.A. , President . Received April 5 , 1869 . ( Abstract . ) The observations made by the author were of the three usual elements the Dip , Declination , and Intensity of the Horizontal Component of the Force . They were taken with instruments supplied to the Colaba Observatory in the year 1867 through the Kew Committee of the British Association , after having been tested at the Kew Observatory . The dip-circle was made by Barrow of London , and is furnished with two needles ; the other instrument , the unifilar magnetometer , which serves both for observations of declination and horizontal force , was made by Elliott Brothers of London . The results of the observations for dip only have as yet been received from the author . A complete observation consists of thirty-two readings , each end of the needle being read twice in each different position of the needle and circle ; and the mean of the thirty-two is taken as the result of the observation . The observations were 178 in number , commencing on the 29th of April 1867 , and extending to the 29th of December 1868 . They were generally taken , with the two needles alternately , on particular days of the week . Up to August 17 , 1867 , the observations commenced with either end ( A or B ) of the needle dipping , and without remagnetizing the needle ; i. e. the magnetization for the latter half of one observation was made to serve for the first half of the next observation with the same needle , the two needles having been kept during the interval with contrary poles adjacent in a zinc box ; but after August 17 , 1867 , the needle was always remagnetized , so as to make the end A dip during the first half of the observation . The effect of this change of practice was to produce a marked increase in the accordance of successive observations . Tables are given containing every complete observation made up to the end of 1868 , and showing , as well as the mean dip , the partial results in each position of the circle , and with each end of the needle dipping , and also the mean weekly and mean monthly values . The mean dip obtained for the months April to December 1867 was 19§ 2'`00 , and for the year 1868 was 19§ 3'87 . The period embraced by the observations is too limited to allow of an exact determination of the rate of secular change ; nevertheless the observations show distinctly that the dip is increasing . The author takes + 1'"3 as the rate of annual change . For the probable error of a single weekly determination , including the effect of actual magnetic disturbance of an irregular character , the author obtains for the period from April 29 to August 16 , 1867 , 0'-67 ; from August 23 to December 31 , 1867 , 0'26 ; from January 1 to December31 , 1868 , 0'`24 . Notwithstanding the extreme smallness of these probable errors , the indications of needle No. 2 exceeded those of needle No. 1 by quantities ranging , in the means of periods of a few months , from about 0 to +5'.0 . An endeavour is made in another communication to explain a possible cause of these differences .

112432

3701662

On the Uneliminated Instrumental Error in the Observations of Magnetic Dip. [Abstract]

427

429

Proceedings of the Royal Society of London

Charles Chambers

abs

6.0.4

proceedings

http://corpora.clarin-d.uni-saarland.de/surprisal/6.0.3/?id=112432

http://www.jstor.org/stable/112432

Meteorology

Formulae

Meteorology

III . " On the Uncliminated Instrumental Error in the Observations of Magnetic Dip . " By CHARLES CHAMBERS , Esq. , Superintendent of the Government Observatory , / Bombay . Communicated by Lieut.-General SABINE , R.A. , President . Received April 15 , 1869 . ( Abstract . ) A single reading of one end of a dipping-needle placed in a dip-circle provided with microscopes for observing is liable to a variety of instrumental errors , which are eliminated by taking the mean of the sixteen readings of the two ends in the eight different positions included in a complete observation . Nevertheless it is found that with the best modern instruments a mean value results from these sixteen observations different for each different needle , and that the difference between the results obtained with two different needles is not the same at all times . The irregularities in the values of the dip observed at Bombay with two needles of excellent character made by Barrow of London , led the author to investigate the effect of a hypothetical irregularity in the shape of the axle of the needle , such that a section of the axle by a plane perpendicular to its axis would be elliptical instead of circular in form . Another source of error , which was brought to the notice of the Royal Society many years ago in a paper published in the Proceedings , is the displacement of the centre of gravity of the needle from the centre of the axle , combined with inequality in the magnetization of the needle when the poles are direct and reversed . Experience has led the author to the conclusion that the usual method of magnetization , by a definite number of passes of the same pair of bar-magnets , communicates magnetism to the needle very unequally when the one end of the needle is made north and when the other end is made north . Consequently it is advisable to investigate the effects of ellipticity of the axle and of displacement of the centre of gravity at the same time , which the author proceeds to do . As each of these errors depends upon two independent unknown quantities , suppose the excentricity and the azimuth of the major axis of the elliptic section of the axle for the first , and the two coordinates of the centre of gravity , referred to axes in the plane of motion of the needle and passing through the centre of the axle , for the second , the equation connecting the true and apparent dip , in any one position of the needle and of the face of the dip-circle , will involve four unknown quantities depending on the above errors . If we suppose the instrumental errors small , so that the apparent dip does not much differ from the true dip , these four unknown quantities will appear as coefficients respectively of the sine and of the cosine of twice the dip for the elliptic error , and of the sine and the cosine of the dip for the error of excentricity of the centre of gravity , and will be divided in each case by the magnetic moment of the needle . On taking the mean of the apparent dips in the four usual positions of the needle and of the dip-circle before the magnetism of the needle is reversed , two of the terms , one for each error , disappear , and there results for the difference between the true dip 0 and the mean of the four apparent dips ( 0 ' ) an equation of the form n'(-B ) = ( ')- , ... ... . ( 1 ) where n ' is the reciprocal of the magnetic moment of the needle , and A and B are the constants depending on the errors of the pivot and of the centre of gravity respectively . These two quantities are constant only for the same place , the first involving as a factor the sine of twice the dip divided by the total force , the second the cosine of the dip divided by the total fo:rce . Now let the poles be reversed in the usual way , and let n " be the reciprocal of the magnetic moment , and ( 0 " ) the mean apparent dip in the four positions after remagnetization ; then n"(A+tB)-=(0")--0 ... ... . . ( 2 ) The equations ( 1 ) , ( 2 ) contain three unknown quantities A , B , 0 ; but if we repeat the observations with the difference that this time the needle is magnetized as weakly as is consistent with the condition that the apparent shall not greatly differ from the true dip , we shall obtain two more equations of the form n " ' ( A-B)=(0 ' " ) -0 , n".(A + B)=(0'd"")--0 ; and these four equations , when suitably combined , will determine the values of the three unknown quantities A , B , 0 . The magnetic moments involved in these equations may be determined with little trouble , and with sufficient accuracy , by placing the needle as a deflector on a unifilar magnetometer , and observing the angle of deflection produced thereby upon the suspended magnet . A series of observations has been commenced by the author with the view of testing whether the true dip can be determined exactly with a single needle by the method above described , the results of which he hopes to communicate to the Royal Society hereafter .

112433

3701662

On the Laws and Principles Concerned in the Aggregation of Blood-Corpuscles Both within and without the Vessels. [Abstract]

429

436

Proceedings of the Royal Society of London

Richard Norris

abs

6.0.4

proceedings

http://corpora.clarin-d.uni-saarland.de/surprisal/6.0.3/?id=112433

http://www.jstor.org/stable/112433

Fluid Dynamics

Biology 3

Fluid Dynamics

magnetized as weakly as is consistent with the condition that the apparent shall not greatly differ from the true dip , we shall obtain two more equations of the form n " ' ( A-B)=(0 ' " ) -0 , n".(A + B)=(0'd"")--0 ; and these four equations , when suitably combined , will determine the values of the three unknown quantities A , B , 0 . The magnetic moments involved in these equations may be determined with little trouble , and with sufficient accuracy , by placing the needle as a deflector on a unifilar magnetometer , and observing the angle of deflection produced thereby upon the suspended magnet . A series of observations has been commenced by the author with the view of testing whether the true dip can be determined exactly with a single needle by the method above described , the results of which he hopes to communicate to the Royal Society hereafter . fact , many theories have been advanced to explain its nature ; but all of them , without exception , have laboured under the disadvantage of being purely hypothetical in their character , and quite incapable of demonstration by an appeal to experiment . Thus , while some writers have attributed the effect to an imaginary law of vital attraction , others have more correctly referred it to the operation of some unexplained physical cause . Professor Lister ( son of the original observer already mentioned ) , who has devoted much attention to this subject , says , in a paper submitted to the Royal Society , June 18 , 1857 , and published in the Philosophical Transactions for 1858 , p. 648:- " For my own part , I am satisfied that the rouleaux are simply the result of the biconcave form of the red disks , together with a certain though not very great degree of adhesiveness , which retains them pretty firmly attached together when in the position most favourable for its operation , viz. when the margins of their concave surfaces are applied accurately together , but allows them to slip upon one another when in any other position . There is never to be seen anything indicating the existence of an attractive force drawing the corpuscles towards each other : they merely stick together when brought into contact by accidental causes . Their adhesiveness does not affect themselves alone , but other substances also , as may be seen when blood is in motion in an extremely thin film between two plates of glass , when they may be observed sticking for a longer or shorter time to one of the surfaces of the glass , each one dragging behind it a short tail-like process . " Again , at the end of section I. , p. 652 of the same paper , Lister says , " From the facts detailed in this section , it appears that the aggregation of the corpuscles of blood removed from the body depends on their possessing a certain degree of mutual adhesiveness , which is much greater in the colourless globules than in the red disks , and that in the latter this property , though apparently not dependent upon vitality , is capable of remarkable variations in consequence of very slight chemical changes in the liquor sanguinis . " From these quotations it is apparent that Mr. Lister ignores altogether the idea of the aggregation of the corpuscles being due to an attractive force or energy , and refers it to adhesiveness or stickiness of the corpuscles ; in his own words , " they merely stick together when brought into contact by accidental causes . " At the same time he states that this adhesiveness is liable to great variations , both in the way of increase and diminution , by very slight changes in the chemical qualities of the plasma . Dipping deeper into the writings of Lister , we find that this idea of adhesiveness or stickiness of the corpuscles is retained in his explanation of the nature of inflammatory stasis . And his views upon the subject generally may be summed up in three propositions:1 . The blood-corpuscles exhibit no tendency to unite together in healthy blood within the vessels , although such blood may be in a state of rest . 2 . The corpuscles become suddenly adhesive ( in 10 seconds ) when , by being shed , the blood is brought into contact with ordinary matter . 3 . Irritation , by reducing the vitality of the surrounding tissues , causes them to bear the same relation to the blood within the vessels in their immediate vicinity as ordinary matter does to that which has been shed , inducing adhesiveness of the corpuscles , and thus bringing about inflammatory stasis . These effects upon the blood-corpuscles are assumed by Lister to depend upon chemical changes induced by ordinary matter or by vitally degraded tissues upon the plasma of the blood ; but inasmuch as chemical changes cannot occur without corresponding physical modifications , it is quite as rational to refer the increased aggregating-tendency displayed by the corpuscles to physical as to chemical changes in the liquor sanguinis ; and this view has the advantage of not requiring us to believe that the functional activity of the tissues is depressed by mild forms of irritation-an idea which is opposed to all we know of the increased nutritive and formative changes which follow in the wake of irritation . Having now briefly reviewed the existing position of the subject , we will proceed to consider the real causes at work in the production of the phenomenon under consideration . Many years since , having familiarised myself with the behaviour of , and the appearances presented by blood-corpuscles under almost every conceivable condition , both within and without the vessels , I became profoundly impressed with the conviction that these phenomena had their origin in some physical law of attraction , and at the same time felt not the less certain that , if this view proved to be correct , the behaviour of the blood-corpuscles would be found to be no isolated exhibition of this law , and that , provided conditions similar to those which exist in the case of the blood-corpuscles could be obtained , many illustrative examples of the operation of the law would be immediately forthcoming . That such attractive force did not exert its influence through distances readily appreciable was obvious , and this fact at once indicated that it must be sought for among those forms of attraction which have been designated molecular . After much experiment and reflection I came , in 1862 , to the conclusion that these phenomena were due to no less universal a law than that of cohesive attraction ; and I embodied the views I then held upon the subject in a paper which was read before the Royal Society , and published in the Proceedings , entitled " The Causes of various Phenomena of Attraction and Adhesion as exhibited in Solid Bodies , Films , Vesicles , Liquid Globules , and Blood-corpuscles . " Since that time other departments of physiology have occupied my attention ; and I have only been induced to recur to the old theme because I find that , in some recent references to the history of this subject , my observations have not been mentioned , from which I am led to infer either that my views had not been sufficiently put forward , or that my experiments had failed to produce conviction in others . I therefore now present the result of a renewed investigation , in which believe I have established , by conclusive experiments , the correctness of my explanation of the phenomena . Among the various modes of aggregation which the blood-corpuscles undergo , two typical forms stand prominently forward , of which all others are merely modifications . The one appears to be dependent upon the normal disk-shape , the other upon the globular or spherical form which the corpuscles assume on the addition of various substances to the blood , such as gum , gelatine , linseed mucilage , potash , &c. With the first of these modes of aggregation , viz. into rouleaux , we are all sufficiently familiar ; and an excellent notion of the character of the second form may be obtained by a careful examination of microphotographs of the blood-corpuscles which have been obtained instantaneously by exploding magnesium in heated oxygen* . In order to leave as little as possible to hypothesis , it was desirable as a preliminary step to make sure that these differences in form of the corpuscles were the real cause of the diverse modes of arrangement-whether , in fact , we could safely predicate that disk-shaped bodies having an attraction for each other would arrange themselves so as to form rolls or cylindrical masses , and whether , on the other hand , attracting spheres of soft material would attach themselves together in such a fashion as to cause plane surfaces to be opposed to each other-in a word , to convert themselves by mutual attraction into polyhedral bodies just as they might do under mutual compression . In the first place , we had to ascertain experimentally how disk-shaped bodies , having the utmost freedom of movement , and possessing an attraction for each other , would arrange themselves . In casting about for the conditions to make such an experiment , I remembered a very familiar phenomenon which had often excited my curiosity , viz. the rapidity with which a bubble or a small floating fragment upon the surface of a cup of tea or other liquid rushes to the side of the containing vessel , or with which two such bubbles or fragments rush together , the moment they approach within a certain range . I determined to see if I could not make use of this attraction , the true nature of which I at the time imperfectly understood , and with this object prepared a number of circular disks of cork , which I accurately poised so that they should assume and maintain the vertical position when partially immersed in liquid . On throwing these disks into liquid , I had the satisfaction of seeing them run together and form themselves into the most perfect rouleaux after the fashion of the blood-disks . This experiment has the value of demonstrating that if the blooddisks attracted each other , their shape would determine the formation of rouleaux . As regards the behaviour of spherical vesicles or globules which attract each other , it is found that the moment any point in their convex surfaces is made to touch , these surfaces become flattened , and consequently bubbles in a group convert each other into polyhedral-shaped bodies . This effect is not due to compression , but to a progressive mutual attraction of the surfaces of these bodies for each other . As soap-bubbles are vesicles with airial contents , and are therefore physically unlike the blood-corpuscles , it became desirable to ascertain how vesicles with liquid contents would behave in regard to each other . This was accomplished by placing in a large test-tube a solution of soap , and upon its surface a stratum of petroleum an inch or so in depth ; the petroleum does not mix with or injure the soap solution , which is the case with most other substances . A glass tube is now passed through the petroleum into the solution of soap below . On blowing down the tube , we succeed in forming innumerable small bodies or corpuscles of a spherical form , which are very plastic , and the contents of which consist of petroleum , and the external envelope or vesicle of soap . Corpuscles so produced float in the upper stratum of petroleum , and are found to unite themselves into groups and masses in precisely the manner of the air-bubbles , although they are entirely submerged in liquid . These experiments show that disk-shaped bodies , having an attraction for each other , will arrange themselves in rolls or cylindrical masses , and that spherical bodies of a plastic character and vesicular structure , be their contents aerial or liquid , will attach themselves together in such a fashion as to cause plane surfaces to be opposed to each other-in a word , convert themselves by a progressive attraction , which commences at their points of mutual contact , into groups of polyhedral bodies . The question now remaining is , do the blood-corpuscles possess such attractions for each other as those displayed by the objects with which we have been dealing ? The reply is that their physical nature being analogous , if the same conditions exist , they cannot escape the influence of the same law . An examination of the photographs and of the drawings of blood-corpuscles exhibited will serve to show that these bodies are amenable to the law which is concerned in grouping together the bubbles and liquid vesicles . But in the cases we have heretofore been considering , the disks , bubbles , and other factitious objects are not in precisely the same conditions as the blood-corpuscles the former being only partially , or not at all submerged in liquid , while the latter are entirely so , and nevertheless they run together into rouleaux and groups . It may fairly be asked if the artificial bodies will do the same . The answer obtained by experiment is , that the moment these disks or bubbles are entirely submerged , they lose at once their attraction for each other and fall apart . For several years I unceasingly asked myself the cause of this difference in behaviour . I at length found that when small bodies , such as disks of cork or gelatine , are first wetted with water , and then submerged in a liquid with which water will not mix , such as oil of turpentine or petroleum , they will run together in piles or rouleaux , very much in the same way as the blood-disks . To understand this result , a few simple primary principles must be called to mind . In the first place , the particles which compose any liquid have a mutual attraction for each other ; but between the particles which compose different liquids a mutual repulsion may exist , e. g. water and oil , or chloroform and water . It is likewise true that there is a mutual attraction between certain liquid and rigid bodies , and also a mutual repulsion between others . Any rigid body which can be wetted by a liquid is regarded as having a cohesive attraction for it , while one which cannot be wetted is said to have no such attraction , or to exert a repulsive influence , as the case may be . These phenomena therefore depend upon what might be justly termed double cohesion-cohesion in the first place between the rigid body and the liquid , and in the second place between the particles of the liquid itself . If , now , we examine into the cases in which we have complete submergence , viz. the blood-rolls , the gelatine disks , and the loaded cork disks , we find the same law to be in operation . These bodies must all be regarded as localizers of liquids , either by their cohesive attraction for liquids , or , as in the case of the blood-corpuscles , by being receptacles containing liquids . If the cork disks , bubbles , or other bodies are entirely submerged in water , all attraction ceases , and this because a cohesive equilibrium is established ; there is no longer any differentiation such as exists between water and air . If , however , after having wetted these bodies in water , we completely submerge them in a liquid which has a cohesive antagonism to water , or even a liquid which has simply no cohesion for water , which may be known by the insolubility and immiscibility of one liquid in the other , such as turpentine or petroleum , we get the phenomena of attraction precisely as in the atmosphere . This fact is illustrated by taking the cork disks from the water in which they are non-adherent , and placing them in the vessel of petroleum , in which they become instantly attractive of each other . This principle is further illustrated by the gelatine disks , which are first made to absorb as much water as possible , and are then submerged in petroleum . In all these cases there are present , therefore , two dissimilar or antagonistic liquids ; and upon the presence of these the phenomena depend . My idea of the blood-corpuscle is that its contents are something essentially different , so far as cohesive attraction is concerned , from the liquor sanguinis-that is to say , not readily miscible with liquor sanguinis . This is of course self-evident , if , according to some modern views , we regard the corpuscles " as tiny lumps of a uniformly viscous matter , " inasmuch as such matter must be insoluble in and immiscible with the liquor sanguinis . The explanation is equally easy if we accept the old and , I believe , the true view , of the vesicular character of these bodies , as we have only to assume that the envelope is so saturated with the corpuscular contents as practically to act as such contents would themselves act , i. e. to exhibit a greater cohesive attraction for their own particles than for those of the contiguous liquid . The cohesive power of the blood-corpuscles varies with varying conditions of the liquor sanguinis ; and this is doubtless due to the law of osmosis ; for we can readily imagine that when the exosmotic tendency is in excess , the corpuscles will become more adhesive , and , on the contrary , when the endosmotic current prevails , less so . In any case the increased cohesiveness will be due to the increased extrusion of the corpuscular contents upon the surface . All , then , that is required in the case of the blood-corpuscles , is a difference between their liquid contents and the plasma in which they are submerged . That this difference is not so great as between the liquids used in these experiments is probable ; but it must also be remembered that the attraction is , not so powerful . The power required to attach the bloodcorpuscles together is , on account of their exceeding minuteness , extremely small , as they are thus so much more removed from the influence of gravitation , and brought under that of molecular attraction . I shall conclude this paper by a brief reference to inflammatory stasis . In one of my papers(communicated to the Royal Societyin 1862 ) I described no less than four distinct forms of stasis . I proposed to designate that induced by irritation homogeneous stasis , because the blood-corpuscles become so blended together as to entirely lose their outlines and present the appearance of a uniform and continuous plug filling up the capillaries . This peculiar blending of the corpuscles is dependent upon the law I have been describing , viz. that of double cohesion , and is brought about by diminished quantity of liquor sanguinis in a part in proportion to the corpuscles , and by loss of fluidity in that which remains . One of the primary effects of irritation is neural paralysis of the minute arteries which supply capillary tracts ; and this paralysis gives rise to increased diosmotic action , in fact to exudation of liquor sanguinis ; consequently there is a lagging behind of the corpuscles , and an increase of their numbers in the capillaries ; the plasma , too , which still surrounds the corpuscles in the capillaries , is modified ; and when a certain relation has been reached between the corpuscles and the plasma , the former blend together precisely in the same manner as the soap-bubbles , or as the blood-corpuscles exhibited in the photographs . This completely arrests the passage of blood through the capillaries , which become as much occluded as if blocked up by solid fibrin . I have frequently had opportunities of watching in the transparent webs of frogs the mode in which this homogeneous stasis is resolved . In these creatures the restoration of the circulation commences some hours after the application of the irritant . When the circulation is about to be resumed , the stagnating mass in the vessel appears to thaw as it were . The corpuscles are not pushed onwards in mass as a coherent plug ; but the homogeneity of appearance is suddenly lost by the resumption of their normal form by the corpuscles and the reappearance of their differentiating outlines , which were previously obscured by their blending with one another and with the walls of the vessels . Before this takes place , the vessel very gradually assumes a lighter tint , passing in some instances from a deep red to a pale orange . This appears to be due to a washing away of extruded colouringmatter . When this change from homogeneity to heterogeneity commences , although sufficiently progressive in its character as it traverses the vessel , it nevertheless takes place with considerable rapidity . It is evidently brought about by the gradual permeation of new liquor sanguinis among the corpuscles , and the contemporaneous abolition of their cohesive attraction for each other in accordance with the principles previously established .

112434

3701662

Researches on Turacine, an Animal Pigment Containing Copper

436

436

Proceedings of the Royal Society of London

A. W. Church

fla

6.0.4

http://dx.doi.org/10.1098/rspl.1868.0087

proceedings

http://corpora.clarin-d.uni-saarland.de/surprisal/6.0.3/?id=112434

10.1098/rspl.1868.0087

http://www.jstor.org/stable/112434

Chemistry 2

Biology 1

Chemistry

II . " Researches on Turacine , an Animal Pigment containing Copper . " By A. W. CHURCH , M.A. Oxon . , Professor of Chemistry in the Royal Agricultural College , Cirencester . Communicated by Dr. W , A. MILLER , Treas . R.S. Received May 4 , 1869 . ( Abstract . ) From four species of Touraco , or Plantain-eater , the author has extracted a remarkable red pigment . It occurs in about fifteen of the primary and secondary pinion feathers of the birds in question , and may be extracted by a dilute alkaline solution , and reprecipitated without change by an acid . It is distinguished from all other natural pigments yet isolated , by the presence of 59 per cent. of copper , which cannot be removed without the destruction of the colouring-matter itself . The author proposes the name turacine for this pigment . The spectrum of turacine shows two black absorption-bands , similar to those of scarlet cruorine ; turacine , however , differs from cruorine in many particulars . It exhibits great constancy of composition , even when derived from different genera and species of Plantain-eater ; as , for example , the Musophaga violacea , the Corythaix albo-cristata , and the C. porphyreolopha .

112435

3701662

On the Radiation of Heat from the Moon. [Abstract]

436

443

Proceedings of the Royal Society of London

Earl of Rosse

abs

6.0.4

proceedings

http://corpora.clarin-d.uni-saarland.de/surprisal/6.0.3/?id=112435

http://www.jstor.org/stable/112435

Astronomy

Optics

Astronomy

III . " On the Radiation of Heat from the Moon . " By the EARL OF ROSSE , F.R.S. Received May 27 , 1869 . The following experiments on Lunar Radiant Heat were undertaken with the view of ascertaining whether with more powerful and more suitable means than those previously employed by others , with little or no success , it would be possible to detect and estimate the amount of heat which reaches the earth 's surface from the moon . 436 [ May 27 , Professor Piazzi Smyth had conducted a series of experiments on the Peak of Teneriffe with a thermopile , but apparently without any means of concentrating the moon 's heat beyond the ordinary polished metal cone . Melloni had employed a glass lens of considerable diameter ( I believe about three feet ) ; but as glass absorbs rays of low refrangibility , it was not so well adapted to concentrate heat as a metallic mirror . In the following experiments the point sought to be determined was , in what proportions the moon 's heat consists of ( 1 ) That coming from the interior of the moon , which will not vary with the phase . ( 2 ) That which falls from the sun on the moon 's surface , and is at once reflected regularly and irregularly . ( 3 ) That which , falling from the sun on the moon 's surface , is absorbed , raises the temperature of the moon 's surface , and is afterwards radiated as heat of low refrangibility . The apparatus consisted of a thermopile of four elements , the faces half an inch square , on which all the moon 's heat which falls on the large speculum of the 3-foot telescope is concentrated , by means of a concave mirror of 31 inches aperture , 2'8 inches focal length . As it was found difficult to compensate the effects of unequal radiation on the anterior face of the pile , by exposing the posterior face also of the same pile to radiation from the sky , during the later experiments ( beginning with March 23rd ) two piles were used , and the following was the form of apparatus adopted . DE is the large mirror of the telescope ; FG the two small concave mirrors of 3k inches aperture , and 2'8 inches focal length , fixed in the plane of the image formed by the large mirror D E. The two thermopiles are placed respectively in the foci of F and G , their anterior faces shielded from wind and other disturbing causes by polished brass cones , and their posterior faces kept at a nearly uniform temperature by means of brass caps filled with water . The thermopiles and accompanying mirrors are supported by a bar screwed temporarily on the mouth of the tube . Two wires are connected with the two poles of each pile ; and the ends of the wires are connected , two and two , close to the galvanometer , in such a manner that a given amount of heat on the anterior face of one pile will produce a deviation equal in amount , and opposite in direction , to that produced by an equal amount of heat on the anterior face of the other pile . Thomson 's Reflecting Galvanometer was the one used . 2K This apparatus has not yet had a fair trial , as I was unable to obtain from Messrs. Elliot a pile ready made of similar dimensions to that which I already possessed . That which they sent had only one-fourth the required area of face . The following is a summary of the results:-8 Id ? I^ '8 I000 o. ? r 0 0W , 0j bj0 a0o & D prii __ __i 2 a.s 110 99-2 0 19 33 92-1 47 81-1 79 85'8 84-2115 117 15 57 5 16 35 30 40 15 49 27-7 58 18 31 79 96 68 88-2 88-8 123 110 85 72 45 18 4 27 65 25 35 30 6 25 14 51 15 29 66 Occasional clouds . ( White frost . Mirrors became dewed ; but the readings taken after this took place have been rejected . Occasional clouds . f Occasional clouds , strong gusts of wind . No note of cloud , very little breeze , generally calm . t Moon low , sky covered with hazy clouds , through which the moon was seenwith much diminished brilliancy . Very clear and calm , but moon low ; no perceptible impulse imparted to the needle . { Wind blowing strong into the mouth of the tube nearly the whole time . No note of cloud till just at the end of these observations . A very little wind ; occasional clouds . Halo with hazy clouds ; J oon seen through them with much-diminished brilliancy . Frequent passing clouds during the latter part of these observations . { No cloud visible , but haziness suspected , as it existed both at sunset and at sunrise . 23 I. II . III . IV . V. VI . VII . VIII . IX . 1868 . Dec. 30 . , , 31 . 1869 . Jan. 1 . , , 21 . , 26 . Mar. 23 . , , 27 . , , 28. . 31 . 103-7 85-1 67-5 34 83 57 115 113 17 94-1 85'8 73-1 41-9 96-7 67-7 99'6 96-1 62-8 34 49 35 X. April 14.1 ... 8-3 ... ... XI . XlI . XIII . XIV . XV . XVI . , , 17 . , , 19 . 20 . 22 . , , 24 . , , 25 . 27 43 85 38 28 45 13-1 35.5 33 12-1 84 88-4 16-6 36-3 48-8 7565 95-3 99-4 I456789 1 In column 3 is given the mean of the deviations of all the single differences from the mean difference of all the readings taken with the moon on and with the moon off the apparatus . In column 4 the arithmetic mean of all the observed deviations . In column 5 the calculated deviation for each night at midnight , on the assumption that the deviation corresponding to fill moon =100 , and that the moon is a smooth sphere . We have then Q ( quantity of heat coming from the moon 's surface ) =C 2 cos 0 . cos ( e-0 ) dO -2 C= { rr-e . cos e+ sin e}* , where e= 7r-apparent distance between the centres of the sun and moon . C When e=O ( full moon ) , Q= . 7- , when e-= 2 ( half moon ) , Q= , when e-=7r ( new moon ) , Q=0 ; ' . if full moon = 100 , Q in general 100(lecose + sin e ... ( a ) In column 6 we have the deviation for full moon calculated from the observed mean deviation for each night . In column 7 the supplement of the apparent distance betweal the centres of the sun and moon . In column 8 the approximate mean altitude of the moon . In column 9 the number of times the telescope was put on or off the moon during the observations included in the mean result . In all these observations the deviations which have been measured are those due to the difference between the radiation from a circle of sky containing the moon 's disk , and that from a similar circle of sky close to it not containing the moon 's disk . The annexed diagram will show approximately the rate at which the moon 's light increases and diminishes with its phases as deduced from formula ( a ) ; and the ringed dots with the accompanying Roman figures ( for reference ) give the quantity of the moon 's heat as determined by observation on different nights . Although there is considerable discordance between some of the observed NEW 1%OON . FIRST QUARTER . FULL MIOON . LAST QUARTER . NEW MOON . 180 ? ? 160 ? ? 140 ? ? 120 ? ? 100 ? ? 80 ? ? 60 ? ? 400 20 ? 00 20 ? ? 400 600 800 1000 120 ? ? 140 ? ? 160 ? ? 1800 sm}i ; nfvinnI I___ __I -IDeviation . 120 10C 80 0 100 ^ 80 120 0 80 O 40 60 ? t 20 t0rp *- . uvs ruuvu ? 'no and calculated quantities of heat , the results suggest to us that the law of variation of the moon 's heat will probably be found not to differ much from that of the moon 's light . It therefore follows that not more than a small part of the moon 's heat can come from the first of the three sources already mentioned . With the view of ascertaining what proportion of the sun 's heat does not leave the moon 's surface until after it has been absorbed , some readings of the galvanometer were taken on four different nights near the time of full moon , with a disk of thin plate glass in front of the face of each pile ; and the deviation was about six or eight divisions . As the glass screens were examined with care for dew after removal on each night , and none was perceived except on one occasion , the probable percentage of the moon 's heat which passes through plate glass is 8 , or rather less . Few experiments appear to have been made on the absorptive power of glass for the sun 's rays ; but , from the best data that I have been able to obtain , I find that probably about 80 per cent. pass through glass . The greater part of the moon 's heat which reaches the earth appears , therefore , to have been first absorbed by the lunar surface . It now appeared desirable to verify this result , as far as possible , by determining by direct experiment the proportion which exists between the heat which reaches the earth from the sun and from the moon . If we start with the assumption that the sun 's heat is composed of two portions , the luminous rays , whose amount = L , and the non-luminous , , , , , = 0 , also that the moon 's light consists of two corresponding portions , L ' , 0f , the luminous not being absorbed , and the non-luminous being entirely absorbed in their passage through glass , then L. L+o 0. . L+O 10 . L+0 L+O -'.08 ; L'+0 ; O ' Substituting for , its generally received value ( 800,000 ) , we have L'+O ' I L+O 80(,000b ) Owing to the extremely uncertain state of the weather , only one series of eighteen readings was obtained for the determination of the sun 's heat . A beam of sunlight was thrown , by means of a plane mirror , alternately on and off a plate of polished metal with a hole 175 inch in diameter . At a short distance behind this the pile was placed . The deviation thus found was connected with that previously found for Full Moon by using the deviation produced by a vessel of hot water as a term of comparison . The relative amount of solar and lunar radiation thus found was 89819 : 1 , ... ... ( c ) which is quite as near that given by ( b ) as we could expect when we consider the roughness of the data . As a further confirmation of the correctness of the two rough approximations to the value of the ratio existing between the sun 's and the moon 's radiant heat already given , the subject was investigated from a purely theoretical point of view . It was assumed ( 1 ) That the quantity of heat leaving the moon at any instant may without much error be considered the same as that falling on it at that instant . ( 2 ) That the absorptive power of our atmosphere is the same for lunar and solar heat . ( 3 ) That , as was already assumed in obtaining formula ( a ) , the moon is a smooth sphere not capable of reflecting light regularly . Then the heat which leaves the moon in all directions = quantity which falls on the moon = , -55 of the quantity which falls on the earth from the sun *o =K . OJ(r-e).'cose+sine sine.de= K 37r . The part which falls on the earth 1 =K . | { 9 B4(r-e ) cos + sin e sin. de 0K { -X . versin ( 1 ? ? 55')+ osin(1 ? ? 55 ) 4-X~~ / ~~ 59'964 = . E suppose ; 4 therefore ( if we may be allowed the expression ) sun-heat 1355 x 37r moon-heat E 79,000 7900 ( quam proxim ) ... . ( d ) In the above , the proportion between the areas of surface presented by the moon and earth to the sun is taken = 13'55 , and the angle subtended by the earth at the moon ==1 ? ? 55 ' . The value of the readings of the galvanometer was determined by comparison with those obtained by using a vessel of hot water coated with shellac and lampblack varnish as a source of heat . The vessel was of tin , circular , and subtended the same angle at the small concave reflectors as the large mirror of the telescope . It was thus found that ( the radiating power of the moon being supposed equal to that of the lampblack surface and the earth 's atmosphere not to influence the result ) a deviation of 90 for full moon appears to indicate an elevation of temperature through 500 ? Fahr.* In deducing this result allowance has been made for the imperfect absorption of the sun 's rays by the lunar surface . In the present imperfect state of these observations it would be premature to discuss them at greater length ; but as some months must elapse before any more complete series can be obtained , and the present results are sufficient to show conclusively that the moon 's heat is capable of being detected with certainty by the thermopile , I have thought it best to send this account to the Royal Society ; and I shall be most happy to receive suggestions as to improvements in the method of working , and as to the direction in which it may be most desirable to carry on future experiments .

112436

3701662

On a New Arrangement of Binocular Spectrum-Microscope

443

448

Proceedings of the Royal Society of London

William Crookes

fla

6.0.4

http://dx.doi.org/10.1098/rspl.1868.0089

proceedings

http://corpora.clarin-d.uni-saarland.de/surprisal/6.0.3/?id=112436

10.1098/rspl.1868.0089

http://www.jstor.org/stable/112436

Optics

Measurement

Optics

IV . " On a New Arrangement of Binocular Spectrum-Microscope . " By WILLIAM CROOKES , F.R.S. &c. Received April 23 , 1869 . The spectrum-microscope , as usually made , possesses several disadvantages : it is only adapted for one eyet ; the prisms having to be introduced over the eyepiece renders it necessary to remove the eye from the instrument , and alter the adjustment , before passing from the ordinary view of an object to that of its spectrum , and vice versed ; the field of view is limited , and the dispersion comparatively small . I have devised , and for some time past have been working with , an instrument in which the above objections are obviated , although at the same time certain minor advantages possessed by the ordinary instrument , such as convenience of examining the light reflected from an object , and comparing its spectrum with a standard spectrum , are not so readily associated with the present form of arrangement . The new spectrum-apparatus consists of two parts , which are readily attached to an ordinary single or binocular microscope ; and when attached they can be thrown in or out of adjustment by a touch of the finger , and may readily be used in conjunction with the polariscope or dichrooscope ; object-glasses of high or low power can be used , although the appearances are more striking with a power of 4-inch focus or longer ; and an object as small as a single corpuscle of bloodcan be examined audits spectrum observed . * This may seem a very large rise of temperature ; but it is quite in accordance with the views of Sir John Herschel on the subject ( Outlines of Astronomy , section 432 and preceding sections ) , where he says that , in consequence of the long period of rotation of the moon on its axis , and still more the absence of an atmosphere , " The climate of the moon must be most extraordinary , the alternation being that of unmitigated and burning sunshine , fiercer than that of an equatoreal noon ; and the keenest severity of frost , far exceeding that of our polar winters , for an equal time . " And again , " ... . the surface of the full moon exposed to us must necessarily be very much heated , possibly to a degree much exceeding that of boiling water . " t Mr. Sorby in several of his papers ( Proc. Roy . Soc. 1867 , xv . p. 433 ; ' How to Work with the Microscope , ' by L. Beale , F.R.S. , 4th edition , p. 219 ) refers to a binocular spectrum-microscope ; but he gives no description of it , and in one part says that it is not suited for the examination of any substance less than ? $ of an inch in diameter . The two additions to the microscope consist of the substage with slit &c. , and the prisms in their box . The substage is of the ordinary construction , with screw adjustment for centring , and rackwork for bringing it nearer to or withdrawing it from the stage . Its general appearance is shown in fig. 1 , which represents it in position . AB is a plate of brass , Fig. 1 . sliding in grooves attached to the lower part of the substage ; it carries an adjustable slit , C , a circular aperture , D , 0-6 inch in diameter , and an aperture , 0 , inch square . A spring top enables either the slit or one of the apertures to be brought into the centre of the field without moving the eye from the eyepiece . Screw adjustments enable the slit to be widened or narrowed at will , and also varied in length . At the upper part of the substage is a screw of the standard size , into which an object-glass of high power is fitted . E represents one in position . I generally prefer a --inch power ; but it may sometimes be found advisable to use other powers here . The slit C and the object glass E are about 2 inches apart ; and if light is reflected by means of the mirror along the axis of the instrument , it is evident that the object-glass E will form a small image of the slit C , about 0'3 inch in front of it . The milled head F moves the whole substage up or down the axis of the microscope , whilst the screws G and H , at right angles to each other , will bring the image of the slit into any desired part of the field . If the slide AB is pushed in so as to bring the circular aperture D in the centre , the substage arrangement then becomes similar to the old form of achromatic condenser . Beneath the slit C is an arrangement for holding an object , in case its surface is too irregular , or substance too dense , to enable its spectrum to be properly viewed in the ordinary way* . Supposing an object is on the upper stage of the microscope ( shown in fig. 2 ) and viewed by light transmitted from the mirror through the large aperture D and the condenser E , by pushing in the slide AB so as to bring the slit C into the field , and then turning the milled head F , it is evident that a luminous image of the slit C can be projected on to the object ; and by proper adjustment of the focus , the object and the slit can be seen together equally sharp . Also , since the whole of the light which illuminated the object has been cut off , except that portion which passes through the slit , all that is now visible in the instrument is a narrow luminous line , in which is to be seen just so much of the object as falls within the space this line covers . By altering the slit-adjustments the length or width of the luminous line can be varied , whilst by means of the rackwork attached to the upper stage , any part of the object may be superposed on the luminous line . The stage is supplied with a concentric movement , which permits the object to be rotated whilst in the field of view , so as to allow the image of the slit to fall on it in any direction . During this examination a touch with the finger will at any time bring the square aperture 0 , or the circular aperture D into the field , instead of the slit , so as to enable the observer to see the whole of the object ; and in the same manner the slit can as easily be again brought into the field . The other essential part of this spectrum-microscope consists of the prisms . These are enclosed in a box , shown at K ( fig. 2 ) . The prisms are of the direct-vision kind , consisting of three flint and two crown , and are altogether 16 inch long . The box screws into the end of the microscope-body at the place usually occupied by the object-glass ; and the object-glass is attached by a screw in front of the prism-box . It is shown in its place at L. The prism-box is sufficiently wide to admit of the prisms being pushed to the side when not wanted , so as to allow the light , after passing through the object-glass , to pass freely up the tube K. A pin at M enables the prisms to be thrown either in or out of action by a movement of the finger . As the prisms are close above the object-glass , the usual sliding box , carrying the binocular prism and the Nicol 's prism ( shown at N ) , may be employed as usual , and the spectrum of any substance may thus be examined by both eyes simultaneously , either by ordinary light , or when it is under the influence of polarized light . The insertion of the prism-box between the object-glass and the body of the microscope does not interfere with the working of the instrument in the ordinary manner . The length of the tube is increased 1 or 2 inches , and a little additional rackwork may in some instruments be necessary when using object-glasses of low power . The stereoscopic effect when the Wenham prism is put into action does not appear to be interfered with . Fig. 2 . For ordinary work both these additions may be kept attached to the microscope , the prisms being pushed to the side of the prism-box , and the large aperture D being brought into the centre of the substage . When it is desired to examine the spectrum of any portion of an object in the field of view , all that is necessary is to push the slit into adjustment with one hand , and the prisms with the other . The spectrum of any object which is superposed on the image of the slit is then seen . The small square aperture at O ( fig. 1 ) is for the examination of dichroic substances . When this is pushed into the field , by placing a double-image prism P between AB and E , two images of the aperture are seen in juxtaposition , oppositely polarized ; and if a dichroic substance is on the stage , the differences of colour are easily seen . When the spectrum of any substance is in the field and the double-image prism P is introduced , two spectra are seen , one above the other , oppositely polarized , and the variations in the absorption-lines , such as are shown by didymium , jargonium , &c. , are at once seen . A Nicol 's prism , Q , as polarizer , is also arranged to slip into the same position as the double-image prism , and another , R , as analyzer , above the prism-box . The spectra of the brilliant colours exhibited by certain crystalline bodies , when seen by polarized light , can then be examined . Many curious effects are then produced , a description of which I propose to make the subject of another paper . Both the prisms P and Q are capable of rotation . If the substance under examination is dark coloured , or the illumination is not brilliant , it is best not to divide the light by means of the Wenham prism at N , but to let the whole of it pass up the tube to one eye . If , however , the light is good , a very great advantage is gained by throwing the Wenham prism into adjustment and using both eyes . The appearance of the spectrum , and the power of grasping faint lines , are incomparably superior when both eyes are used ; whilst the stereoscopic effect it confers on some absorption and interference spectra ( especially those of opals ) seem to throw entirely new light on the phenomena . No one who has worked with a stereoscopic spectrum-apparatus would willingly return to the old monocular spectroscope* . If the illuminatitn in this instrument is taken from a white cloud or the sky , Fraunhofer 's lines are beautifully visible ; and when using direct sunlight they are seen with a perfection which leaves little to be desired . The dispersion is sufficient to cause the spectrum to fill the whole field of the microscope , instead of , as in the ordinary instrument , forming a small portion of it , the dispersion being four or five times as great ; whilst , owing to the very perfect achromatism of the optical part of the microscope , all the lines from B to G are practically in the same focus . As tht only portion of the object examined is that part on which the image of the slit falls , and as this is very minute ( varying from 0'01 to 0'001 inch , according to the actual width of the slit ) , it is evident that the spectrum of the smallest objects can be examined . If some blood is in the field , it is easy to reduce the size of the image of the slit to dimensions covered by one blood-disk , and then , by pushing in the prisms , to obtain its spectrum . If the object under examination will not transmit a fair image of the slit ( if it be a rough crystal of jargoon for instance ) , it must be fixed in the universal holder beneath the slit and the light concentrated on it before it reaches the slit . If the spectra of opaque objects are required , they can also be obtained in the same way , the light being concentrated on them either by a parabolic reflector or by other appropriate means . By replacing the illuminating lamp by a spirit-lamp burning with a sodaflame , and pushing in the spectrum-apparatus , the yellow sodium-line is seen beautifully sharp ; and by narrowing the slit sufficiently it may even be doubled . Upon introducing lithium or thallium compounds into the flame , the characteristic crimson or green line is obtained ; in fact so readily does this form of instrument adapt itself to the examination of flame-spectra , that for general work I have almost ceased to use a spectroscope of the ordinary form . The only disadvantage I find is an occasional deficiency of light ; but by an improved arrangement of condensers I hope soon to overcome this difficulty .

112437

3701662

On Some Optical Phenomena of Opals

448

453

Proceedings of the Royal Society of London

William Crookes

fla

6.0.4

http://dx.doi.org/10.1098/rspl.1868.0090

proceedings

http://corpora.clarin-d.uni-saarland.de/surprisal/6.0.3/?id=112437

10.1098/rspl.1868.0090

http://www.jstor.org/stable/112437

Optics

Atomic Physics

Optics

V. " On some Optical Phenomena of Opals . " By WILLIAM CROOKES , F.R.S. &c. Received April 23 , 1869 . When a good fiery opal is examined in day- , sun- , or artificial light , it appears to emit vivid flashes of crimson , green , or blue light , according to the angle at which the incident light falls , and the relative position of the opal and the observer ; for the direction of the path of the emitted beam bears no uniform proportion to the angle of the incident light . Examined more closely , the flashes of light are seen to proceed*from planes or surfaces of irregular dimensions inside the stone , at different depths from the surface and at all angles to each other . Occasionally a plane emitting light of one colour overlaps a plane emitting light of another colour , the two colours becoming alternately visible upon slight variations of the angle of the stone ; and sometimes a plane will be observed which emits crimson light at one end , changing to orange , yellow , green , &c. , until the other end of the plane shines with a blue light , the whole forming a wonderfully beautiful solar spectrum in miniature . I need scarcely say that the colours are not due to the presence of any pigment , but are interference colours caused by minute striae or fissures lying in different planes . By turning the opal round and observing it from different directions , it is generally possible to get a position in which it shows no colour whatever . Viewed by transmitted light , opals appear more or less deficient in transparency and have a slight greenish yellow or reddish tinge . In order to better adapt them to the purposes of the jeweller , opals are almost always polished with rounded surfaces , back and front ; but the flashes of coloured light are better seen and examined when the top and bottom of the gems are ground and polished flat and parallel . A good opal is not injured by moderate heating in water , soaking in turpentine , or heating strongly in Canada balsam and mounting as a microscopic slide . By the kindness of Mr. W. Chapman , of Frith Street , Soho , and other friends , I have been enabled to submit some thousands of opals to optical examination ; and from these I have selected about a dozen which appeared worthy of further study . If an opal which emits a fine broad crimson light is held in front of the slit of a spectroscope or spectrum-microscope , at the proper angle , the light is generally seen to be purely homogeneous , and all the spectrum that is visible is a brilliant luminous line or band , varying somewhat in width and more or less irregular in outline , but very sharp , and shining brightly on a perfectly black ground . If , now , the source of light is moved , so as to shine into the spectrum-apparatus through the opal , the above appearance is reversed , and we have a luminous spectrum with a jet-black band in the red , identical in position , form of outline , and sharpness with the luminous band previously observed . If instead of moving the first source of light ( the one which gave the reflected luminous line in the red ) another source of light be used for obtaining the spectrum , the two appearances , of a coloured line on a black ground , and a black line on a coloured ground , may be obtained simultaneously , and they will be seen to fit accurately . Those parts of the opalwhich emit red light are therefore seen to be opaque to light of the same refrangibility as that which they emit ; and upon examining in the same manner other opals which shine with green , yellow , or blue light , the same appearances are observed , showing that this rule holds good in these cases also . It is doubtless a general law , following of necessity the mode of production of the flashes of colour . Having once satisfied myself that the above law held good in all the instances which came under my notice , I confined myself chiefly to the examination of the transmitted spectra , although the following descriptions will apply equally well , mutatis mutandis , to the reflected spectra . The examinations were made by means of the spectrum-microscope a description of which I have just had the honour of sending to the Society . This instrument is peculiarly adapted to examinations of this sort , both on account of the small size of the object which can be examined in it , and also as it permits the use of both eyes in viewing the spectrum . The following is a brief description of some of the most curious transmission spectra shown by these opals . The accompanying figures , drawn with the camera lucida , convey as good an idea as possible of the different appearances . The exact description will of course only hold good for one portion of the opal ; but the general character of each individual stone is well marked . No. 1 shows a single black band in the red . When properly in focus this has a spiral structure . Examined with both eyes it appears in decided relief , and the arrangement of light and shade is such as to produce a striking resemblance to a twisted column . No 2 . gives an irregular line in the orange . Viewed binocularly , this exhibits the spiral structure in a marked manner , the different depths and distances standing well out ; upon turning the milled head of the stageadjustment , so as to carry the opal slowly from left to right , the spiral line is seen to revolve and roll over , altering its shape and position in the spectrum . It is not easy to retain the conviction that one is looking merely at a band of deficient light in the spectrum , and not at a solid body , possessing dimensions and in actual motion . No. 3 has a line between the yellow and green , vanishing to a point at the top , and near the bottom having a loop , in the centre of which the green appears . Higher up , in the green , is a broad green band , indistinct on one side and branching out in different parts . No. 4 has a broad , indistinct , and sloping band in the blue , and another , still more indistinct , in the violet . No. 5 has a band in the yellow , not very sharp on one side , and somewhat sloping . Upon moving the opal sideways , it moves about from one part of the yellow field to another . In one position it covers the line D , and is opaque to the sodium-flame of a spirit-lamp . No. 6 shows a curiously shaped band in the red , very sharp and black , and terminating in one part at the line D. In the yellow there is a black dot . The spectrum of this opal showed by reflected light intensely bright red bands , of the shape of the transmission bands . On examining this opal with a power of 1 inch , in the ordinary manner , the portion giving this spectrum appeared to glow with intense red light , and was bounded with a tolerably definite outline . Without altering any other part of the microscope , the prisms were then pushed in so as to look at the whole surface of the opal through the prisms , but without the slit . The shape and appearance of the red patch were almost unaltered ; and here and there over other parts of the opal were seen little patches of homogeneous light , which , not having been fanned out by the prisms , retained their original shape and appearance . No. 7 shows a black patch in the red , only extending a little distance , and a line in the yellow . On moving the opal the line in the red vanishes , and the other line changes its position and form . No. 8 shows the most striking example of a spiral rotating line which I have yet met with . On moving the opal sideways the line is seen to start from the red and roll over , like an irregularly shaped and somewhat hazy corkscrew , into the middle of the yellow . The drawing shows the appearance of this band in two positions . C 013~~~~0 tr . : " " b rn " y ^ ? _= ^^W g~~~~~~~~~~~~~~~~~ ^~ " y y"^~^ __ -y~--y ~~-.-1 _Y , 1 . 1 ; 11 - ... ... 1 , ^^_ _1 1 '1 ' ... ... , = IE E-b _e|I d < oyI -^cr II[| I*^ *y 1L ^^ r^ z : t ? o z. ; ... t0^ No. 9 is one of the most curious . A broad black and sharp band stretches diagonally across the green , touching the blue at the top and the yellow at the bottom . No. 10 gives a diagonal band , wide , but straight , and tolerably sharp across the green . By rotating these opals , 9 and 10 , in azimuth , whilst in the field of the instrument , the lines can be made to alter in inclination until they are seen to slope in the opposite direction . No. 11 gives another illustration of a diagonal line , across the yellow and green , not extending quite to the top . No. 12 is one of the best examples I have met with of a narrow , straight , and sharply cut line . It is in the green , and might easily be mistaken for an absorption-band caused by an unknown chemical element . Other opals are exhibited which show a dark band travelling along the spectrum , almost from one end to the other , as the opal is moved sideways . It is scarcely necessary to say that the colour of the moving luminous line varies with the part of the spectrum to which it belongs . The appearance of a luminous line , slowly moving across the black field of the instrument , and assuming in turn all the colours of the spectrum , is very beautiful . All these black bands can be reversed , and changed into luminous bands , by illuminating the opal with reflected light . They are , however , more difficult to see ; for the coloured light is only emitted at a particular angle , whilst the special opacity to the ray of the same refrangibility as the emitted ray holds good for all angles . The explanation of the phenomena is probably as follows : In the case of the moving line , the light-emitting plane in the opal is somewhat broad , and has the property of giving out at one end , along its whole height and for a width equal to the breadth of the band , say , red light ; this merges gradually into a space emitting orange , and so on throughout the entire length of the spectrum , or through that portion of it which is traversed by the moving line in the instrument , the successive pencils ( or rather ribbons ) of emitted light passing through all degrees of refrangibility . It is evident that if this opal is slowly passed across the slit of the spectrum-microscope , the slit will be successively illuminated with light of gradually increasing refrangibility , and the appearance of a moving luminous line will be produced ; and if transmitted light is used for illumination , the reversal of the phenomena will cause the production of a black line moving along a coloured field . A diagonal line will be produced if an opal of this character is examined in a sloping position . The phenomenon of a spiral line in relief , rolling along as the opal is moved , is doubtless caused by modifying planes at different depths and connected by cross planes ; I can form a mental picture of a structure which would produce this effect , but not clear enough to enable me to describe it in words . It is probable that similar phenomena may be seen in many , if not all , bodies which reflect coloured light after the manner of opals . A magnificent specimen of Lumacelli , or Fiery Limestone , from Italy , kindly presented to me by my friend David Forbes , shows two sharp narrow and parallel bands in the red . I have also observed similar appearances in mother-of-pearl . The effects can be imitated to a certain extent by examining " ( Newton 's rings , " formed between two plates of glass , in the spectrum-instrument .

112438

3701662

Anniversary Meeting

453

453

Proceedings of the Royal Society of London

fla

6.0.4

proceedings

http://corpora.clarin-d.uni-saarland.de/surprisal/6.0.3/?id=112438

http://www.jstor.org/stable/112438

Biography