The  Dodor  proceeds  analytically  diroug)i  the  pinumnm  o£  thia
laft-  mentioned  experiment,  and  argues  thus :

*  If  the  quantity  of  fir^,  fays  he,  before  contained  or  diffuM
in  the  fnow  and  fsJt,  was  expelled  in  the  uniting  of  the  two
matters,  it  notuft  be  driven  away,  either  thro'  the  air,  or  the  vefiel
containing  them.     If  it  is  driven  off  through  the  air^  it  muft

.    warm  the  air  -,  and  a  thernuuneter  held  over  the  mixture,  witb^
^    oyt  touching  it,  would  diicover  the  heat,,  by  the  rifing  of  tho
■lercury,.  as  it.muft  and  always  does  in  warm  air.
'*  This,  indeed,,  I.  have  not*  tried*;  but  I  fliould  gocfs  it
would  rather  be  dxivea  off;  throMgb  the  veflcl,.  efpedally-  if  tho
— *-^ 1 : , -.
*  We  ihall  ftop  to  take  notice  that  M.  Geoffi-oy  long  ago  ob£rve4
Chatg  in  the  fngorific  mixtare  of  oil  of  vitriol  with  fal  ammpniac,
the-copioM  fimes,  whtch  arife  during  die  ell^rvelcenoe,  ieniibif
raiTe  the  thermometer  faljpeoded  above  the  mixture.  We  fhall  not
enquire  whether,  in  this  inftancey  the  e§h€t  is  produced  by  the  par*
tides  of  firs  flying  off  fimn  the  mixtuie,  or  anfes  horn  other  cauies

7  whiclf


304  PraiiklinV  E^irimeftiSy  i^c.  oH  EUffrtclty.
