MANUFACTURE  OF   AMMONIA,  ETC. 
137 
solved  in  the  liquid  may  be  used.  If  muriate,  sulphate  or  carbon- 
ate of  ammonia  be  required,  the  vapors  may  be  condensed  in  suita- 
ble vessels  containing  muriatic,  sulphuric,  or  carbonic  acids. 
For  the  purpose  of  obtaining  ammonia  sufficiently  pure  for  many 
purposes  in  the  arts  from  gas  water,  Mr.  Laming  patented,  July 
14,  1843,  the  substitution  of  a  solution  of  muriate  of  lime  for  the 
mineral  acids  usually  employed.  This  process  is  as  follows  :  he 
first  mixes  with  gas  water  a  sufficient  quantity  of  muriate  of  lime 
in  solution  to  convert  the  carbonate  of  ammonia,  which  is  present, 
into  muriate  of  ammonia,  and,  after  having  separated  the  carbon- 
ate of  lime  which  forms,  the  remaining  solution  is  exposed  for  an 
hour  to  a  boiling  temperature.  This  solution,  after  having  been 
cooled,  is  first  agitated  with  enough  hydrated  oxide  of  iron  to 
combine  with  all  its  sulphuretted  hydrogen  ;  secondly,  with  lime 
enough  to  saturate  the  muriatic  acid  which  is  present ;  and,  finally, 
it  is  distilled.  The  ammonia  will  be  found  in  the  water  which 
comes  over,  in  a  tolerably  pure  state. 
In  Watson's  patent  of  January  16,  1844,  the  following  descrip- 
tion of  apparatus  for  manufacturing  sulphate  of  ammonia  is  given. 
An  iron  boiler  capable  of  holding  a  charge  of  about  260  gallons 
of  ammoniacal  gas  liquor  is  provided,  furnished  with  a  bent  pipe  or 
tube  connecting  the  boiler  with  a  leaden  vessel  open  at  the  top. 
Into  the  boiler  a  quantity  of  slaked  lime  may  be  placed  with  the 
ammoniacal  liquor,  which  has  the  effect  of  hastening  the  opera- 
tion, and  producing  a  salt  of  a  purer  quality.  The  leaden  vessel 
is  partly  filled  with  sulphuric  acid  (if  sulphate  of  ammonia  be  re- 
quired) in  the  proportion  of  about  one  pound  weight  of  sulphuric 
acid,  sp.  gr.  1.700  to  every  gallon  of  water.  The  acid  must  be  di- 
luted with  from  three  to  four  times  its  weight  of  water.  When 
heat  is  applied  to  the  boiler,  the  ammonia  is  driven  off,  and  in  com- 
ing into  contact  wu'th  the  acid  in  the  leaden  vessel  combines  with 
it  with  the  formation  of  solution  of  sulphate  of  ammonia,  which  is 
afterwards  drawn  off  and  crystallized.  By  the  use  of  muriatic  acid 
on  muriate  of  lime,  a  solution  of  muriate  of  ammonia  may  be  ob- 
tained. 
Johnson's  process  (patented  1845)  for  obtaining  sulphate  of  am- 
monia is  to  put  the  ammoniacal  liquor  of  the  gas  works  into  a 
boiler  similar  to  a  steam-engine  boiler,  having  a  pipe  passing 
from  the  top  of  the  vessel  containing  a  solution  of  alkali,  lime,  or 
