482  Chemical  and  Pharmacognostical  Notes.     { Am'septr'i884arm 
sulphured  wines.  Since  the  precipitate  produced  in  a  wine  distillate 
by  silver  nitrate  contains  carbon,  probably  from  the  presence  of  organic 
acids,  Kilicsan  considers  Wartha's  process  for  the  detection  of  sulphur- 
ous acid  in  wines  to  be  untrustworthy. 
J.  Nessler  and  M.  Barth  give  a  method  for  estimating  free  tartaric 
acid  in  wine  as  an  improvement  of  the  original  Berthelot-Fleurieu's 
process.  50  cc.  of  wine  are  evaporated  to  thin  syrup,  this  is  well 
shaken  with  70  cc.  of  96  per  cent,  alcohol,  and  allowed  to  stand  four 
hours  in  a  cool  place,  to  permit  the  tartrate  to  settle  out.  The  precipi- 
tate is  separated,  and  its  acidity  reckoned  as  tartrate.  The  nitrate  is 
freed  from  alcohol,  and  0*5  cc.  of  acidified  20  per  cent,  solution  of 
potassium  acetate  is  stirred  into  the  syrupy  residue,  and  the  newly 
formed  tartrate  is  estimated  as  before.  But  this  method  fails  in  case  of 
wines  strongly  plastered,  although  negative  values  cannot  be  obtained, 
as  are  sometimes  got  by  the  older  method. 
For  the  estimation  of  sugar  by  Fehling\s  solution,  the  tannin  must 
first  be  removed  by  lead  acetate,  the  excess  of  lead  being  removed  by 
sodium  carbonate.  Ordinary  fully  fermented  wine  usually  contains 
under  0*1  per  cent,  sugar,  and  may  be  decolorized  by  a  small  quantity 
of  animal  charcoal ;  after  rendering  it  alkaline  with  a  little  caustic 
alkali  or  carbonate,  5  cc.  is  warmed  with  2  cc.  Fehling,  in  a  water- 
bath.  If  the  blue  color  completely  disappears  the  wine  contains  over 
0*2  per  cent,  sugar.  If  the  blue  color  persists  5  cc.  more  wine  may 
be  added,  and  the  warming  repeated.  In  this  way  an  approximation 
to  the  amount  of  sugar  may  be  made. 
Decolorizing  action  of  ferric  salts  on  indigo. — L.  Margary  ("  Gazzetta  " 
[13],  pp.  374,  375).  In  experiments  on  certain  iron  mordants  for 
silk  containing  ferric  sulphate  and  nitric  acid,  it  was  necessary  to  deter- 
mine the  amount  of  nitric  acid  present.  This  was  done  by  means  of 
indigo  solution,  and  the  author  observed  that  the  results  were  invari- 
ably too  high.  This  he  attributed  to  the  oxidizing  action  of  the  ferric 
salt,  and  found  on  heating  the  indigo  solution  with  pure  ferric  sulphate 
that  it  was  rapidly  and  completely  decolorized,  the  ferric  being  reduced 
to  a  ferrous  salt. — Jour.  Chem.  Soc. 
Estimation  of  phenol  in  commercial  carbolic  acid. — Kleinert  ("  Anal. 
Zeitschr."  [23],  pp.  1  to  13)  has  compared  the  results  of  estimating 
phenol  by  Koppeschaar's  method  (titration  by  means  of  standard 
bromine  solution)  and  by  fractional  distillation.  He  finds  that  they  in 
nowise  agree,  the  bromine  titration  yielding  figures  which  are  far 
