Pyrometry  and  Areometry , Bcc.  525 
There  would  be  little  advantage,  with  refpedt  to  exadl- 
nefs,  in  making  of  fpirit  of  wine  the  Thermometer  in 
tended  for  thefe  effays;  though  its  variation  would  be 
more  exactly  conformable  to  the  effects  of  heat  upon  li- 
quors of  the  fame  fpecies:  for  it  has  been  feen  how  far, 
by  the  method  I propofed,  the  differences  vanifh ; and, 
on  the  contrary,  there  would  be  a lofs  on  two  accounts : 
the  one,  that  this  Thermometer  would  be  much  lefs  fen- 
fible  than  the  quickfilver  one ; the  other,  that  it  is  much 
more  difficult  to  conftrucft  it,  when  one  wants  to  make  it 
upon  fixed  principles,  and  this  the  rather  as  good 
workmen  have  loft  the  habit  of  making  them. 
One  fees,  moreover,  that  the  fame  Areometer  may  ( mu- 
tatis  mutandis ) be  ufecl  to  meafure  the  faltnefs.  of  water. 
Upon  which  I fhall  only  obferve,  that  the  manner  indi- 
cated of  fixing  the  corre&ion  for  the  heat,  would  be  ftill 
more 
II  y auroit  peu  a gagner  pour  I’exa&itude,  a faire  d’efprit  de  vin  le  Thermo- 
metre  defline  a ces  epreuves,  quoique  fa  marche  ftitdans  le  fond  plus  conform e 
aux  effets  de  la  chaleur  fur  des  liqueurs  de  meme  efpece;  car  on  a vu  a quel  degre 
la  methode  queje  propofe  a fait  xdifparoitre  les  differences:  et  il  y auroit  a 
perdre  au  contraire  a deux  egards,  .l’un  que  ce  Thermometre  feroit  bien  moins 
fenfible  que  celui  de  mercure,  l’autre  qu’il.eft  bien  plus  difficile  a conftruire, 
lorfqu’on  veut  le  faire  fur  des  principes  certains;  cfautant  plus  que  les  bons 
cuvriers  ont  perdu  I’habitude  d’en  faire. 
On  voit  au  refte  que  le  meme  infirument  peut  etre  employe  a mefurer 
la  falure  de  l’eau,  mutatis  mutandis . Sur  quoi  je  ferai  remarquer  feule- 
ment,  que  la  maniire  indiquee  de  fixer  la  corre&ion  pour  la  chaleur  y feroit 
d’autant  plus  neceffaire,  qu’il  y a plus  de  difference  dans  la  marche  des  effets  de  la 
chaleur* 
