Am.  .Tour,  Pharm. 
July,  1892. 
Rapid  Solution  in  the  Cold. 
375 
to  be  done  since  the  black  spots  may  not  disappear  again — Prof. 
Emmerich,  Pharm.  Ztg.,  1892,  317. 
Gravimetric  standardization  of  normal  acids. — This  depends  upon 
adding  to  a  definite  volume  of  the  acid  an  excess  of  ammonia  water 
and  evaporating  to  dryness ;  in  determining  hydrochloric  acid  the 
residue,  NH4C1,  is  dried  at  ioo°  C.  to  constant  weight ;  multiply  by 
0-68224  for  weight  of  HC1 ;  with  sulphuric  acid  the  dry  residue 
(NH4)2S04  is  finally  heated  for  one-half  hour  to  1200  C;  multiply  by 
0742  for  weight  H2S04;  with  oxalic  acid  the  residue,  (NH4)C204,  is 
dried  at  100-1050  C;  multiply  by  roi6  for  weight  of  oxalic  acid. 
This  method  gives  perfectly  accurate  results  if  a  pure  ammonia* 
which  should  leave  no  residue  upon  evaporation  is  used. — Dr.  H. 
Eckenroth,  Pharm.  Ztg.,  1S92,  317. 
Test  for  veratrine. — Instead  of  sugar,  as  used  by  Weppen  in  his 
color  test  for  veratrine,  E..  Laves  uses  furfurol,  the  colors  obtained 
being  much  purer.  In  a  test  tube  3-4  drops  of  a  I  per  cent, 
aqueous  furfurol  solution  is  mixed  with  1  cc.  pure  sulphuric  acid. 
Of  this  solution  3-5  drops  are  placed  in  a  capsule  and  the  substance 
to  be  tested  applied  to  the  edge  of  the  liquid ;  a  dark  blue  streak 
which  changes  to  a  green  as  it  traverses  across  the  acid  ;  upon  mix- 
ing the  liquid  a  uniform  dark  green  color  results,  which,  only  after 
some  time  changes  to  a  blue  or  violet. — Pharm.  Ztg.,  1892,  338. 
RAPID  METHOD  OF  SOLUTION  IN  THE  COLD.1 
By  J.  B.  Coleman. 
The  author  found  that  by  simply  passing  a  current  of  air  through 
the  coarsely  powdered  solid  suspended  in  water  complete  solution  is 
obtained,  in  some  cases  in  the  space  of  ic  minutes,  and  in  most 
cases  before  the  expiration  of  an  hour.  The  solid  is  put  into  a  glass 
cylinder  half  filled  with  distilled  water.  The  mouth  of  the  jar  is 
tightly  stoppered  with  an  india-rubber  cork  through  which  pass  two 
glass  tubes.  One  tube  has  inserted  in  the  upper  end  a  plug  of 
cotton  wool  to  keep  out  dust,  whilst  the  lower  end  is  drawn  out  and 
bent,  and  passes  to  the  bottom  of  the  cylinder;  the  other  tube  just 
passes  through  the  cork.  Before  use,  the  cylinder  is  surrounded  by 
a  vessel  containing  water  of  the  temperature  at  which  the  solubility 
XJ.  Soc.  Chem.  Ind.,  10,  231-233  ;  Jour.  Chem.  Soc,  1892,  397. 
