Pyrometry  and  Areonietry,  Etc.  517 
mon  ufe,  and  in  which  it  is  not  neceffary  that  the  branch 
lhould  be  fo  long,  divide  the  fundamental  interval  into 
1 5 parts,  which  will  then  be  double  degrees. 
Having  in  this  manner  fixed  points  and  determined 
degrees  upon  the  Areometer,  the  next  thing  is  to  chufe  a 
convenient  place  for  the  o of  its  fcale;  and  the  belt  will 
be  that  by  which  all  the  cffays  of  the  liquors  Inall  be  ex- 
preffed  with  the  fame  fign.  To  effedt  this,  one  may  take 
one  of  the  wines  of  which  brandy  is  moft  commonly 
made,  and,  reducing  it  to  the  temperature  of  water  in  ice, 
dip  the  Areometer  in  it,  obferving  how  much  higher  it 
will  Hand  than  the  inferior  fixed  point.  This  excefs  of 
emerfion,  compared  with  the  fundamental  fcale,  anci  xe- 
duced  to  the  neareft  number  of  degrees  which  will  be  an 
aliquot  part  of  it,  will  be  a proportional  quantity  fixed 
for  ever,  which  will  be  added  to  the  fcale  below  tne  in- 
ferior 
delicat,  et  ou  Ton  ne  voudra  pas  la  branche.  fi  longue,  divifer  l’intervalle  fonda- 
mental  en  15  parties,  qui  feront  alors  des  doubles  degres.  . _ 
Avant  ainfi  des  point  fixes  et  des  degres  determines  fur  1 Areometie,  faut 
choifirune  place  commode  pour  fon  zero;  etle  mieux  eft  de  le  placer  de  mamere 
oue  toutes  les  epreuves  des  liqueurs  puiffent  etre  expnmees  avec  le  meme  figne. 
Jour  cet  eftet  on  pourra  prendre  un  des  vins  done  on  fait  le  plus  communement 
1’eau  devie,  etle  reduifant  a la  temperature  de  l’eait  dans  la  glace,  y plongei  1 _ >s- 
ometre,  obfervant  decombien  il  s’enfoncera  de  moms  que  le  point  fixe  mfeneur. 
Ce  furplus  d’emerfion,  compare  i l’intervalle  fondamental,  et  redmt  au  nombie 
le  plus  prochain  de  degres  qui  fotrouvera  une  partie  al.quote  de  cet  mtervalle 
feraunequantite  fixeepourtoujours,  qu’il  faudra  ajouter  a l’echelle  au 
