MANUFACTURE  OF  AMMONIA,  ETC. 
129 
ON  THE  MANUFACTURE  OF  AMMONIA  AND  AMMONIACAL 
SALTS. 
(Continued  from  page  38.) 
Ammonia  from  the  Ammoniacal  Waters  of  Coal  Gas-works. — 
The  chief  source  whence  ammonia  is  ?now  obtained,  is  the  am- 
moniacal  waters  produced  in  the  distillation  of  coal,  as  per- 
formed at  gas-works.  A  great  number  of  processes  have 
been  devised  for  the  purpose  of  obtaining  ammonia  ana 
ammoniacal  salts  from  these  waters  in  the  most  convenient 
and  economical  way,  the  principal  of  which  we  now  proceed 
to  notice.  As  most  of  these  processes  have  for  their  object  the  ob- 
taining of  more  than  one  of  these  salts,  we  have  found  it  prefera- 
ble to  describe  them  in  the  order  of  priority  of  invention,  rather  than 
under  the  head  of  each  particular  salt.  Mr.  Ledsom  took  out  a 
patent,  March  2nd,  1827,  for  improvements  in  the  manufacture  of 
muriate  of  ammonia.  In  this  process,  a  quantity  of  the  ammonia- 
cal liquor  obtained  from  the  distillation  of  coal  is  converted  iato 
muriate  of  ammonia  by  saturating  it  with  muriatic  acid.  When 
this  has  been  done,  the  liquor  is  to  be  evaporated  and  the  salt  re- 
duced to  a  crystalline  state.  The  crystals  are  then  to  be  dissolved 
in  water,  and  lime  added  to  the  liquor  in  the  proportion  of  fifty 
pounds  of  lime  to  100  pounds  of  muriate  of  ammonia.  The  gas 
passed  off  from  the  retort  in  the  process  of  distillation,  having 
been  conducted  through  water  for  the  purpose  of  cooling  it  and 
separating  the  tar,  is  now  to  be  passed  through  ihis  liquor,  when 
the  sulphurretted  hydrogen  which  it  contains,  uniting  with  the 
ammonia,  for  which  it  has  a  great  affinity,  becomes  soluble  in  the 
water,  and  remains  principally  in  the  purifier.  But  if  any  portion 
of  the  sulphuretted  hydrogen  happens  to  pass  over,  it  is  arrested 
by  another  vessel  of  water  containing  the  mixture  above  des- 
cribed. When  the  muriate  of  ammonia  in  the  liquor  has  become 
spent,  the  liquor  is  to  be  drawn  off  from  the  purifier,  and  a  fresh 
supply  introduced,  and  the  spent  liquors  may  be  restored  by 
another  quantity  of  muriatic  acid.  Messrs.  Midgley  and  Kyan 
patented,  November  4,  1837,  the  following  process  for  obtain- 
ing ammoniacal  salts,  and  at  the  same  time  preventing  the 
usual  nuisance  arising  from  the  vapors  evolved  from  manu- 
factories when  the  ammonia  is  extracted  from  ammonia- 
cal liquor  according  to  the  modes  of  manufacturing  it  previ- 
9  " 
