288        THE  PREPARATION  OF  HYPOCHLORITE  OP  SODA. 
2.  The  solution  of  the  precipitate  in  pure  ammonia.  Before 
the  appearance  of  Mr.  Bartlett's  communication,  a  mixture  of 
citrate  of  ammonia  with  free  ammonia  was  used,  and  heat  was 
applied. 
3.  The  highly  important  addition  of  a  quantitative  analysis. 
A  margin  was  formerly  left  to  allow  for  loss  (which  is  not  con- 
siderable) in  the  manufacture,  and,  as  above  stated,  the  nitrate 
of  bismuth  was  used  as  a  more  uniform  salt  than  the  carbonate. 
The  weak  points  in  Mr.  Bartlett's  process  appear  to  be  the 
following  :— 
1.  The  great  acidity  of  the  solution  from  which  the  citrate  of 
bismuth  is  ultimately  separated,  causes  the  precipitation  to  be 
extremely  imperfect ;  there  is  consequently  great  waste  of 
material  and  labor.  * 
2.  The  extreme  dilution  of  each  portion  of  the  acid  bismuth 
solution,  in  the  act  of  addition  to  the  solution  of  citrate  of  pot- 
ash, seems  to  determine  the  precipitation  of  basic  nitrate,  in- 
soluble in  ammonia,  before  the  double  decomposition  necessary 
to  the  formation  of  the  citrate  can  take  place. 
I  am,  Sir,  your  obedient  servant, 
Thomas  P.  Blunt,  F.  C.  S. 
— London  Pharm.  Jour.,  May,  1865. 
THE  PREPARATION  OF  HYPOCHLORITE  OF  SODA. 
By  substituting  a  solution  of  bicarbonate  of  soda  for  one  of 
carbonate  in  the  preparation  of  hypochlorite  of  soda,  a  precipi- 
tate of  carbonate  of  lime  is  obtained  in  the  form  of  a  crystalline 
powder,  depositing  itself  very  easily,  whilst,  when  a  solution  of 
ordinary  carbonate  of  soda  is  employed,  a  kind  of  magma  forms, 
which  it  is  difficult  to  separate  from  the  liquid  by  decantation. 
A  small  excess  of  bicarbonate  of  soda  in  the  liquid  is,  as  has 
been  proved  by  experiment,  very  advantageous  in  some  respects. 
With  hypochlorite  of  soda  thus  prepared,  hardly  a  minute  is 
required  to  bleach  any  kind  of  engraving  or  printing  without 
in  the  least  degree  damaging  the  paper,  especially  if  it  be  im- 
mediately afterwards  plunged  for  a  few  seconds  in  water  in 
which  a  little  acid  sulphate  of  soda  has  been  dissolved. — Qhem. 
News,  (Lond.),  March  17,  1865,  from  Journal  de  Pharmacie  et 
de  Chimie. 
