fig1 illustrates the present invention in combination with a conventional musical instrument mouthpiece shown generally at 1 , of the type including a hollow member 2 having a mouth engaging end 3 terminating in a generally arcuate edge 4 . a lower face 5 extends forwardly of edge 4 and includes a centrally positioned opening 6 ( see fig7 ). the marginal area surrounding opening 6 as well as the area positioned rearwardly of opening 6 forms a flat lower face 7 configured to mount an elongated reed 8 . reed 8 has a generally arcuate front tip portion 9 which is positioned adjacent arcuate edge 4 , marginal edges 10 ( see fig2 ), and a rear edge surface 11 spaced rearwardly from tip 9 and extending downwardly from lower face 7 . the foregoing description is substantially conventional in nature . the improvement of the present invention includes means , shown generally at 12 , for accurately adjusting the longitudinal position of reed 8 on mouthpiece 1 to place the reed tip portion 9 at a desired location with respect to arcuate edge 4 . in a first preferred embodiment , adjustment means 12 includes an elongated channel - shaped ligature body 13 mounted on mouthpiece face 7 and having a generally planar horizontal web portion 14 bearing a downwardly depending boss 15 . a flange member 16 extends upwardly from each outer edge of web 14 adjacent the marginal edges 10 of reed 8 . the upper edges of flange members 16 are configured to abut the flat surface of mouthpiece face 7 . adjustment means 12 also includes ligature means for fixedly securing ligature body 13 to mouthpiece 1 . in the embodiment illustrated , the securing members comprise a pair of spaced flat straps 17 having upper ends fixedly attached to ligature body 13 , and lower arcuate portions which surround the body of mouthpiece 1 to hold the adjustment means securely in place . a micrometer adjusting screw 18 bearing a knurled grasping portion 19 extends in a direction parallel to reed 8 and threadedly engages boss 15 at 20 . a flat plate - like reed yoke 21 including a vertically extending arm 22 bearing a centrally located slot 23 is rotatably secured to micrometer adjusting screw 18 by a reduced portion 24 of the screw which nicely fits into slot 23 . the lower end of reed yoke 21 terminates in a forwardly extending threaded fastener portion 25 which pierces and threadedly engages the rear edge surface 11 of reed 8 as at 26 . as shown in fig1 rotation of the micrometer adjusting screw will cause longitudinal movement of the reed in order to move the reed tip toward and away from the arcuate edge 4 of the mouthpiece . means are also provided for uging the reed against the mouthpiece face . the urging means include a u - shaped roller harness 27 having a lower horizontal web section 28 overlying the ligature body web portion 14 , and an arm 29 extending upwardly from each side edge of web portion 27 adjacent ligature body flange members 16 . means slidably secure roller harness 27 to the ligature body 13 for vertical movement therebetween . the securing means comprises a vertical tab 30 extending outwardly from each of roller harness arms 29 which is configured to slidably engage a vertically extending slot or groove 31 formed in the inner wall surface of each of flange members 16 ( see fig3 and fig4 ). a cylindrical roller 32 is rotatably mounted between roller harness arms 29 within the roller harness . roller 32 is positioned and configured to bear against the outer surface of reed 8 as best shown in fig1 . a vertically extending pressure adjusting screw 33 having a flat graspable portion 34 threadedly engages ligature body web portion 14 as at 35 . the upper end 36 of pressure adjusting screw 33 bears against the lower surface of roller harness web portion 28 of the roller harness to urge roller 32 against the outer surface of reed 8 . it will be observed that this arrangement permits a transverse force to be applied against the reed to hold it against the mouthpiece face , while permitting longitudinal movement of the reed by means of the adjusting means . if desired , a second similar urging means shown generally at 37 , may be positioned between the urging means just described and boss 15 to provide a transverse pressure to reed 8 . in operation , reed yoke 21 is attached to reed 8 as illustrated in fig6 and the reed positioned against the flat face 7 of mouthpiece 1 as illustrated in fig1 with the yoke arm 22 projecting downwardly . the adjusting means 12 may then be positioned on the mouthpiece , and strap 17 secured to hold the means securely in place against the mouthpiece body . micrometer adjusting screw 18 may be rotated to move reed tip 9 toward and away from arcuate edge 4 as illustrated by the directional arrows 38 in fig7 and fig8 . pressure adjusting screw 33 may then be rotated to move roller 32 upwardly or downwardly in the direction illustrated by directional arrow 39 in fig3 to provide the desired amount of transverse pressure against the reed 8 . if necessary , micrometer adjusting screw 18 may then be manipulated to accurately position longitudinally the reed on the mouthpiece to place the reed tip at the optimum location with respect to the arcuate edge of the mouthpiece . a second embodiment of the present invention is illustrated in fig9 - fig1 , where elements similar to those perviously described have been similarly designated . as in the previous embodiment , means , shown generally at 112 , are provided for urging the reed against the mouthpiece and for accurately adjusting the longitudinal position of reed 8 on mouthpiece 1 to place the reed tip portion in a desired location with respect to arcuate edge 4 . adjustment means 112 includes an elongated channel or u - shaped ligature body 113 mounted on mouthpiece face 7 and having a generally planar horizontal web portion 114 . a flange member 116 extends upwardly from each outer edge of web portion 114 adjacent the marginal edges 10 of reed 8 . as best shown in fig1 , the longitudinally extending upper edges of flange members 16 are beveled as at 116a to abut the arcuate outer surface of mouthpiece 1 . ligature body 113 is secured to mouthpiece 1 by a pair of spaced arcuate straps 117 having lower edges fixedly secured to the upper ends of flange members 116 . straps 117 may be adjusted as described hereinabove in connection with the embodiment of fig1 - fig8 to securely hold adjustment means 112 in position on the instrument mouthpiece . a pair of spaced inwardly directed guides 118 are fixedly secured to the inner surface of flange members 16 near the upper edge thereof , and at positions adjacent the forward and rearward edges thereof . the inner surfaces of guides 118 are tapered so as to make sliding contact with the outer edges of reed 8 as it is adjusted longitudinally in order to laterally restrain the reed . flange members 116 are each provided with a longitudinally extending elongated slot 119 which rotatably support the ends of a cylindrical shaft 120 having an enlarged cylindrical central portion or roller 121 bearing a plurality of circumferentially spaced axially extending ridges , as at 122 . each outermost end of shaft 120 terminates in a generally downwardly extending lever arm 123 . the lowermost ends of lever arms 123 terminate in inwardly directed support members 124 as best shown in fig1 . a plate - like member 125 is gimballed at each end as at 126 to opposing inner ends of members 124 as best shown in fig1 . gimballed plate 125 is provided with an aperture 127 for threadedly accepting an adjustment screw 128 . the uppermost end 129 of adjustment screw 128 bears against the lowermost surface of web portion 114 . in operation , ridged roller 121 is positioned so as to engage the lowermost surface of reed 8 and bear inwardly thereagainst so as to urge the reed securely but slidingly against the mouthpiece . as adjustment screw 128 is rotated , a slight pivoting motion is imparting to pivot arms 123 which tends to rotate ridged roller 121 and thereby longitudinally move reed 8 . for example , when adjustment screw is rotated in a clockwise direction as viewed from below , lever arms 123 and ridged roller 121 will be rotated in a counter - clockwise direction to retract reed 8 . conversely , when adjustment screw 128 is rotated in a counter - clockwise direction when viewed from below , lever arms 123 and ridged roller 121 rotate in a clockwise direction to advance reed 8 . to facilitate the insertion and removal of reed 8 , the forwardmost end of each of slots 119 is provided with an enlarged portion 130 . as best shown in fig1 , thumb screw 128 may be loosened permitting ridged roller 121 to be moved forwardly and downwardly to the position illustrated . this places the outer surface of the ridged roller out of contact with the underside of reed 8 to facilitate insertion or removal of the reed . after the reed is in place , the entire structure may be moved upwardly and rearwardly to urge the ridged roller 121 against the underside of the reed . the longitudinal position of the reed may be maintained or adjusted by thereafter rotating thumb screw 128 . a third embodiment of the adjustment means of the present invention is illustrated in fig1 - fig1 , where parts similar to those previously described have been similarly designated . in this arrangement , the cylindrical shafts 120 extending outwardly from ridged roller 121 are rotatably supported in arcuate slots 219 positioned in each of flange members 116 . in the embodiment illustrated best in fig1 , ridged roller 121 may be rotated by means of a thumb wheel 251 secured to the end of shaft 252 extending outwardly from one of flange members 116 which has connected to its innermost end a first spur gear 253 . gear 253 is arranged to mesh with a larger spur gear 254 which is non - rotatably affixed to one of shafts 120 . consequently , rotation of thumb wheel 251 will cause rotation of ridged roller 121 , which in turn will provide longitudinal movement for reed 8 in a manner similar to that described in connection with the embodiment of fig9 - fig1 . a coil spring 255 is wrapped about shafts 252 and fixedly secured to flange member 116 as at 256 . the opposite end of spring 255 bears against the underside of shaft 120 to urge roller 121 upwardly against the reed 8 . similarly , a boss 257 extends outwardly from the opposite flange member 116 and supports a similar coil spring 255 which also operates to urge the other one of shaft 120 upwardly . if desired , gears 253 and 254 may be eliminated , and thumb wheel 251 connected directly to shaft 120 as illustrated in fig1 . in this arrangement , shaft 252 is replaced by an outwardly extending boss 257 which supports the first of springs 255 . it will be understood , however , that the geared arrangement of fig1 provides for finer adjustment of the longitudinal motion of the reed . in some instances , it may be desirable to provide better frictional engagement between reed 8 and ridged roller 121 . this may be accomplished as illustrated in fig1 and fig1 by providing , on the lower surface of reed 8 in the area adjacent ridged roller 21 , a ridged portion 300 having transversely extending ridges or grooves configured to engage corresponding ridges on roller 121 to create a rack - like gear . ridged portion 300 may be provided as an integral part of reed 8 by scoring or the like , or may be provided as a separate member as illustrated in fig1 which is secured by an adhesive or the like 301 to the appropriate surface of reed 8 . it will be understood that this arrangement provides a rack and pinion - like effect for longitudinally moving reed 8 . in some instances , it may further be desirable to vary the force with which the reed 8 is pressed against the mouthpiece . this may be accomplished as illustrated in fig1 and fig1 by providing auxiliary means for urging the reed against the mouthpiece face in the form of one or more thumb screws 400 which are threadedly engaged in a corresponding threaded aperture in horizontal web portion 114 . the uppermost end of the thumb screw is rounded as at 401 to be urged against the underside of the reed and thereby provide an upward pressure against the mouthpiece lay . it will be especially observed that in each of the embodiments described the performer may vary the longitudinal position of the reed while the instrument is being played in order to select the reed location producing the best results . consequently , the position of the reed may be quickly changed without the need to disassemble the entire ligature . it will be understood that each of the embodiments illustrated includes a rotatably mounted roller which operates to urge the reed against the adjacent mouthpiece surface , as well as means for longitudinally adjusting the position of the reed . furthermore , it will be understood that various changes in the details , materials , steps and arrangements of parts , which have been herein described and illustrated in order to explain the nature of the invention , may be made by those skilled in the art within the principle and scope of the invention as expressed in the appended claims . for example , alternate embodiments of the u - shaped ligature body 113 are illustrated in fig1 a and fig1 b . in the first of these figures , means are provided on the left - hand flange member 116 &# 39 ; for adjusting the spacing between the underside of the mouthpiece face ( not shown ) and a beveled surface 116a . these means are in the form of a threaded set screw 500 which is threadedly engaged within a threaded bore 501 extending longitudinally within flange member 116 &# 39 ;. it will be understood that such an adjustment mechanism may be provided on both sides of the ligature body , and may also be provided at several locations along the length of the ligature body . the adjustment means comprising said adjustment set screw 500 enable the performer to adjust the positioning of the ligature body with respect to the mouthpiece to account for variations in the mouthpiece surfaces . another embodiment is illustrated in the right - hand portion of fig1 a and comprises means for varying the horizontal position of guide 118a , which is similar in constructure and operation to fixed guide 118 described previously . in the embodiment illustrated in fig1 a , guide 118a rides within a horizontally extending groove 502 in a vertically extending flange member 116 . the horizontal position of guide 118a may be moved inwardly or outwardly by means of set screw 503 which is threadedly engaged in a cooperating bore 504 extending through the side of flange member 116a into groove 502 . this adjustment permits guide 118a to make sliding contact with the outer edges of reed 8 ( not shown ) in order to laterally restrain the reed , and also permits the present invention to be used with a wide variety of reed shapes and sizes . it will be understood that the adjustment mechanism including guide 118a may be included in either or both of vertical flange members 116 &# 39 ; or 116 &# 34 ; at one or more points along the length of ligature body 113 . an enlarged version of the guide member adjusting means is illustrated in fig1 b . in this arrangement , set screw 503 has been replaced by a compression spring 505 which urges the guide member 118a inwardly against the side edges of the reed . spring 505 is housed within a counterbore 506 extending horizontally within vertical flange member 116 &# 34 ;.