Am.  Jour.  Pharm.  ) 
Feb.  1, 1873.  / 
Sulphovinate  of  Soda. 
61 
lime,  and  add  the  washings  to  the  filtrate,  which  now  contains  sulpho- 
vinate of  lime.  Add  to  the  latter  a  solution  of  carbonate  of  soda, 
until  it  just  ceases  to  give  a  precipitate.  Instead  of  carbonate  of 
soda,  I  have  also  used  oxalate  of  soda,  which,  although  requiring  con- 
siderably more  water  for  solution,  and  consequently  a  longer  time  for 
the  final  evaporation,  has  this  advantage,  that  it  effectually  removes 
the  whole  of  the  lime  salts,  thus  making  filtration  during  evaporation 
unnecessary.  Filter  the  liquid  through  filtering  paper  free  from  iron, 
to  remove  the  precipitated  carbonate  of  lime ;  wash  the  latter,  and 
evaporate  the  filtrate  until  it  measures  about  70  fl.  oz.  Filter  again 
from  a  small  quantity  of  separated  sulphate  and  carbonate  of  lime, 
and  evaporate  until  a  pellicle  forms.  Then  set  it  aside  for  a  few  days, 
and  remove  the  crystals.  It  is  very  difficult  to  obtain  more  than  one 
or  perhaps  two  crops  of  well-defined  crystals  ;  the  last  mother-liquors 
deposit  a  number  of  hemispherical,  knob-like  crystalline  masses,  of  a 
pasty  consistence  and  exceedingly  difficult  to  drain.  I  now  prefer  to 
evaporate  the  liquid  at  once  to  a  syrupy  consistence,  and  then,  under 
-constant  stirring,  to  evaporate  to  dryness. 
The  product  is  a  white,  granular  salt,  of  a  faint  ethereal  odor,  and 
a  cooling,  somewhat  aromatic  taste ;  it  is  very  deliquescent,  soluble  in 
0-7  parts  of  water,  at  60°  F.,  also  soluble  in  alcohol,  with  which  it  is 
-capable  of  forming  a  crystalline  compound.  When  pure,  BaCl  solu- 
tion should  throw  down  no  precipitate,  or  at  least  produce  only  slight 
cloudiness. 
The  quantity  of  sulphovinic  acid  produced  depends  upon  the  speci- 
fic gravity  of  the  materials,  and  on  the  temperature  employed ;  a 
decrease  of  the  specific  gravity  and  an  increase  of  the  temperature 
diminishing  the  yield.  The  liquid  obtained  by  mixing  alcohol  and 
sulphuric  acid  of  the  above  indicated  densities,  precautions  having 
been  taken  to  guard  against  loss,  was  found,  after  being  cooled  down 
to  the  original  temperature,  to  have  shrunk  3*5  per  cent,  in  volume. 
The  amount  of  uncombined  sulphuric  acid  was  determined  volumetri- 
cally,  with  the  following  results  : 
Original  amount  of  sulphuric  acid  taken,  .  3458*90  gm. 
Containing  of  dry  S03,  .  .  2594*18  gm. 
Total  amount  of  free  S03  (dry),  found  in 
the  mixture,  mean  of  three  experiments,  1409-86  gm.,  or  54-3  p.  c. 
Hence  total  amount  of  SOt  in  combination,  1184*32  gm.,  or  45*7  p.  c. 
New  York,  Jan.  14,  1873. 
