MANUFACTURE  OF   AMMONIA,  ETC, 
33 
ON  THE  MANUFACTURE  OF  AMMONIA  AND  AMMONIACAL 
SALTS. 
During  the  last  twenty-five  years,  the  manufacture  of  liquid  am- 
monia and  of  ammoniacal  salts  (more  especially  the  sulphate  of 
ammonia)  has  received  considerable  development,  insomuch  that 
in  nearly  all  the  principal  towns  of  the  kingdom,  manufactories  of 
these  articles  are  now  to  be  met  with.  The  development  of  this 
manufacture  has  arisen  from  the  immense  increase  in  the  production 
of  the  raw  ammonia  furnished  by  the  continued  extension  of  gas- 
lighting,  the  low  prices  at  which  it  is  obtainable  from  this  source 
rendering  the  application  of  liquid  ammonia,  and  of  ammoniacal 
salts,  accessible  to  various  useful  purposes  in  the  arts,  manufac- 
tures, and  agriculture,  to  which  previously  the  cost  of  these  articles 
formed  an  impediment,  Liquid  ammonia  is  usually  obtained  in  the 
commercial  scale  by  submitting  a  mixture  of  sulphate  or  muriate 
of  ammonia  and  lime  to  the  action  of  heat,  in  a  closed  iron  pan  or 
still ;  the  ammonia  passes  off  in  the  state  of  vapor,  and  is  condensed 
by  passing  through  water  contained  in  a  series  of  Woulfe's  bottles, 
formed  of  lead  or  earthen  ware,  whence  the  solutions  of  ammonia 
may  be  drawn  off,  of  any  required  strength  or  density.  The  res'i-, 
duum  in  the  still  is  either  sulphate  or  muriate  of  lime,  according 
to  the  salt  employed. 
Carbonate  of  ammonia  is  obtained  by  exposing  a  mixture  of 
sulphate  or  muriate  of  lime  to  the  action  of  heat  enclosed  in  a  re- 
tort ;  carbonate  of  ammonia  and  sulphate  or  muriate  of  lime  are 
thus  obtained  ;  the  former  passes  off  into  large  leaden  chambers, 
called  balloons,  where  it  is  condensed  in  solid  masses,  whilst  the 
latter  remains  as  a  residuum  in  the  retort.  The  impure  carbonate 
of  ammonia  thus  obtained  is  then  placed  in  iron  pots,  and  heated, 
by  which  means  the  pure  salt  is  volatilized  and  collected  in  suita- 
ble receiving  or  subliming  vessels. 
The  sulphate  and  muriate  of  ammonia  may  be  obtained  by  the 
action  of  sulphuric  or  muriatic  acid  on  certain  sulphates  and  mu- 
riates in  the  carbonate  of  ammonia  contained  in  the  ammoniacal 
waters  of  the  gas-works  or  other  sources,  the  sulphuretted  hydrogen 
contained  in  these  waters  being  got  rid  of  by  the  assistance  of  the 
metallic  oxides,  &c.  The  solutions  of  these  salts  are  then  evapo- 
rated and  crystallized.    The  sublimed  muriate  of  ammonia  (sal 
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