A^Yeb^imaTm'}^s^ma^on  of  Sugar  and  Tannin  in  Wines.  95 
an  unpowdered  condition  and  mixed  with  pieces  of  wood.  The 
others  were  in  powder  of  various  degrees  of  fineness.  All  were 
reduced  to  the  same  powdered  condition,  interfering  in  no  other 
way  by  removing  the  wood  or  otherwise.  As  a  rule  those  samples 
which  were  in  broken  lumps  and  appeared  most  inferior,  yielded  the 
best  results.  We  have  brought  the  samples  with  us,  and  it  will  be 
seen  that  they  vary  very  much  in  color. 
The  insoluble  matter  was  not  examined,  but  it  appeared  to  con- 
sist mainly  of  woody  tissue,  and  left  a  little  ash  on  burning.  From 
the  above  results  it  is  evident  that  the  statements  as  to  the  defi- 
ciency of  commercial  Goa  powder  at  the  present  time  are  not  well 
founded,  but  that  the  present  .supply  compares  favorably  with  the 
drug  originally  imported. — Phar.  Jour,  and  Trans.,  January  2,  1892, 
P-  543.   
ESTIMATION  OF  SUGAR  AND  TANNIN  IN  WINES.1 
By  J.  H.  Vogel. 
The  author  has  proved  by  several  experiments  that  it  is  abso- 
lutely necessary  to  first  remove  the  tannin  and  coloring  matters 
before  attempting  to  estimate  the  sugars  by  Fehling's  solution.  25 
cc.  of  a  1  per  cent,  solution  of  tannin  gave  an  amount  of  metallic 
copper  corresponding  with  0-91  per  cent,  of  sugar.  As  the  amount 
of  tannin  in  Portuguese  wines  often  is  as  high  as  3  per  cent.,  the 
importance  of  fully  removing  the  tannin  will  be  readily  understood. 
After  a  short  treatment  with  an  insufficient  amount  of  animal  char- 
coal, the  tannin  is  removed  before  the  coloring  matters  are  precipi- 
tated, and  this  fact  enabled  the  author  to  prove  that  these  coloring 
matters  exercise  a  powerful  reduction  on  Fehling's  solution,  as 
the  yield  of  copper  became  greater  as  the  solution  was  more  colored. 
Their  removal  is  best  effected  either  with  animal  charcoal  or  basic 
lead  acetate,  but  the  author  has  made  several  important  observa- 
tions. As  to  the  use  of  lead  solution,  3  cc.  is  supposed  to  be  suffi- 
cient for  60  cc.  of  Rhine  wine,  whilst  for  red  wines  the  amount  must 
be  doubled.  But  in  the  case  of  Portuguese  wines,  this  amount  is 
far  too  small,  and  the  author  has  met  with  a  sample  which  required 
three  times  its  bulk  of  liquor  plumbi  before  it  was  completely  decol- 
orized. The  excess  of  lead  must  be  removed,  according  to  Barth, 
by  sodium  carbonate,  but  the  lead  separates  slowly,  causing  after- 
1  Zeit.  ang.  Cheni.,  1891,  44-69;  Jour.  Chem.  Soc,  1891,  p.  1557. 
