6o2 
Practical  Notes. 
\nri.  Jour.  Pharr  . 
Dec,  1880. 
coated,  while  the  latter  is  externally  cooled  with  water.  The  thin 
deposit  is  washed  with  water  and  sulphuretted  hydrogen  is  conducted 
into  the  vessel,  producing  antimony  sulphide  of"  a  golden  color  with  a 
green  reflection.  In  a  similar  manner  a  black  coating  of  lead  sulphide 
may  be  obtained  by  mixing  in  the  glass  vessel  solution  of  lead  acetate 
with  a  little  phosphoric  acid  and  an  equal  bulk  of  a  mixture  of  water 
with  a  volatile  oil  (oil  of  turpentine),  and  passing  sulphuretted  hydrogen 
into  it.  It  is  advisable  to  form  this  coating  upon  a  thin  film  of  anti- 
mony sulphide,  when  it  will  adhere  more  firmly  to  the  glass.  —  Phar, 
Centralhalle.,  1880,  p.  381,  from  Chem.  Ztg..,  No.  42. 
Preparation  of  Tincture  of  Litmus. — Kretzschmar  gives  the  following 
directions  :  Finely  powdered  litmus  is  exhausted  with  cold  water  and 
the  solution  mixed  with  fine  sand  and  evaporated,  sufficient  hydro- 
chloric acid  being  added  during  the  evaporation  to  impart  a  red  color. 
The  dry  residue  is  powdered  and,  upon  large,  plain  filters,  washed  with 
hot  and  afterwards  with  cold  water.  The  residue  contains  Kane's 
azolitmin,  which  is  the  really  valuable  principle,  and  is  nearly  insoluble 
in  pure  water;  it  is  dissolved  upon  a  filter  by  hot  water  containing  a 
few  drops  of  ammonia,  the  filtrate  is  acidulated  with  sulphuric  acid  and 
accurately  neutralized  by  ammonia.  If  the  solution  be  largely  diluted 
and  then  acidulated,  nearly  pure  i:Zolitmin  is  deposited,  while  a  body 
remains  in  solution  imparting  to  the  liquid  a  faint  wine-red  color.  The 
precipitate  may  subsequently  be  dissolved  in  water  containing  a  trace 
of  ammonia,  when  a  brilliantly  blue  solution  wi!l  be  obtained  ;  but 
such  a  degree  of  purity  is  scarcely  necessary  for  the  use  of  litmus  as 
an  indicator.  —  Zeitschr.  f.  Anal.  Chem. — Chemiker  Zeitung. 
Liquor  Arsenicalis  Bromati  dementis. — Dissolve  pure  potassium  car- 
bonate and  arsenious  acid,  of  each  3-75  grams,  in  sufficient  distilled 
water  to  obtain  360  grams  of  liquid;  add  7*5  grams  of  bromine,  and 
set  aside  until  colorless.  The  solution,  which  is  said  to  improve  by 
age,  is  given  in  epilepsy  in  doses  of  one  or  two  drops  once  or  twice 
daily. — Pharm.  Zeitschr.  f.  Russl.,  1880,  p.  573. 
The  Detection  of  Free  Acid  in  Acetic  Ether  is  best  accomplished,  accor- 
ding to  Bouvier,  by  agitating  in  a  small  vial  20  or  25  grams  of  the  ether 
with  3  or  4  grams  of  litharge,  and  setting  aside  for  a  day.  If  free  acid 
was  present,  the  litharge  will  be  covered  with  a  white  layer.  By  wash- 
ing the  sediment  well  with  water,  drying  and  weighing  it  again,  the 
loss  in  weight  of  the  litharge  will  give  the  amount  which  has  been 
conveited  into  lead  acetate,  and  from  this  the  amount  of  free  acetic 
