BROMINE  AND  IODINE  IN  CHILI  NITRE. 
161 
Next  to  common  alum  antl  chrome  alum,  this  is  the  one  most 
easily  formed  of  the  whole  series.  It  forms  a  beautiful  salt,  being  ot 
a  pale  violet  color.  It  is  more  soluble  than  common  alum,  the 
solution  having  a  reddish  color.  It  may  be  distinguished  from  an 
alum  containing  protosulphate  of  iron,  by  the  color  of  the  precip- 
itate formed  on  the  addition  of  caustic  potash,  which,  with  the  salt 
under  notice,  will  be  brown,  while  with  the  other  it  will  be  green. 
Mr.  Davenport  stated  that  the  preparation  referred  to  in  the 
note  just  read,  under  the  name  of  Iron  Alum,  was  obtained  by  him 
quite  casually  from  a  solution  of  persulphate  of  iron.  It  presented 
the  octahedral  form  of  common  alum,  and  upon  examination,  was 
found  to  contain  sulphate  of  ammonia  and  sulphate  of  peroxide 
of  iron,  but  not  a  trace  of  alumina.  This  so-called  iron  alum  was 
now  introduced  as  a  successful  remedial  agent,  and  would  no  doubt 
be  classed  among  the  pharmaceutical  preparations  of  the  day.  He 
thought  the  name  Iron  Alum  an  objectionable  one  to  apply  to  this 
salt,  and  his  object  in  making  these  remarks,  was  principally  to 
suggest  the  adoption  of  a  more  distinctive  appellation.  It  had 
been  very  properly  shown  by  Mr.  Blyth,  not  only  that  there  are  a 
great  many  alums,  differing  entirely  in  composition,  but  also  that 
there  are  several  iron  alums.  It  was  important  that  the  substan- 
ces used  in  medicine  should  be  clearly  defined,  and  he  would  there- 
fore suggest  that  this  salt  when  ordered  in  medicine  should  be 
called  Ammonia-sulphate  of  peroxide  of  iron,  when  the  ammonia 
salt  was  intended,  or  Potassio -sulphate  of  peroxide  of  iron,  if  it 
were  intended  to  indicate  the  potash  salt. — Pharm.  Journ.,  Jan. 
1854. 
BROMINE  AND  IODINE  IN  CHILI  NITRE. 
From  the  daily  increasing  consumption  of  Chili  nitre,  it  is  adr 
visable  that  some  attention  should  be  paid  to  the  small  quantities 
of  iodine  and  bromine  present  in  it.  These  substances  would  be 
accumulated  in  the  mother-liquors  of  the  refining  operations,  and 
their  quantity  would  render  them  worth  extraction. 
Rebling  states,  that  in  the  liquors  from  the  purification  of  2o 
lbs.  of  Chili  nitre,  amounting  to  a  few  pounds,  he  obtained  by  the 
addition  of  a  solution  of  sulphate  of  copper  in  sulphurous  acid 
water,  a  precipitate  equivalent  to  4.5  grs.  iodide  of  sodium> 
10* 
