AmAJu°gu,ri8>76arm'}  Contributions  from  the  School  of  Pharmacy^  etc.  357 
and  the  last  three  prepared  for  the  purpose  according  to  the  U.  S.  P., 
but  in  smaller  quantities  : 
One  fluidounce  of  No.  1  gave  12*69  grains  ferric  oxide, 
cc  cc         cc       2    u    1 1  *99    "       u  cC 
cc  cc         cc       2    u    16*93    "       c'  tc 
cc  cc  cc  m      cc     11*28     tc         "  cc 
5    "  8-46 
CC  CC  CC  r        CC  W.,.A       "  CC  CC 
An  attempt  was  made  to  prepare  the  solution  of  nitrate  of  iron  by 
adding  solution  of  tersulphate  to  an  alcohol  solution  of  potassium 
nitrate,  but  it  was  found  that  with  the  precipitate  of  potassium  sulphate 
was  a  precipitate  of  basic  ferric  nitrate.  This,  on  warming  to  expel 
the  alcohol,  became  so  basic  as  to  be  insoluble  in  water.  The  experi- 
ment was  repeatedly  varied,  without  full  success. 
The  following  process  was  then  devised  by  calculation  and  experi- 
ment, and  in  repeated  trials  it  made  a  satisfactory  liquor,  one  fluidounce 
of  which,  in  each  instance,  gave  very  nearly  ten  grains  of  dry  ferric 
oxide : 
Take  of    solution  of  tersulphate  of  iron,       .  .    7  fluidounccs 
water  of  ammonia,    .  .  .8^  fluidounces 
nitric  acid,       .  .  3  troyounces  and  145  grains 
distilled  water,         .  .  .a  sufficient  quantity 
To  the  water  of  ammonia,  mixed  with  twelve  fluidounces  of  water, 
add,  stirring  constantly,  the  solution  of  tersulphate  of  iron,  previously 
mixed  with  twelve  fluidounces  of  water.  Filter  and  wash  the  pre- 
cipitate until  the  washings  render  solution  of  chloride  of  barium  only 
slightly  turbid.  Let  the  precipitate  drain  and  dry  till  it  can  be  removed 
from  the  filter  without  loss.  To  two  troyounces  and  250  grains  of 
the  nitric  acid,  mixed  with  an  equal  volume  of  distilled  water,  add, 
without  heat  and  stirring  constantly,  the  precipitate  of  ferric  hydrate 
until  it  no  longer  dissolves.  Filter  the  solution,  and  wash  the  filter 
with  repeated  small  portions  of  distilled  water,  adding  the  washings  to 
the  filtrate.  Then  add  to  the  solution  the  remainder  of  the  nitric  acid 
and  (after  it  has  attained  a  pale  amber  color)  add  enough  distilled  water 
to  make  the  liquid  measure  36  fluidounces. 
One  fluidounce  of  this  solution  should  furnish  10  grains  of  dry  ferric 
oxide. 
