MANUFACTURE  OF    AMMONIA,  ETC. 
133 
dried,  may  be  brought  into  the  market  without  further  purification 
or  they  may  be  sublimed  into  sal  ammoniac. 
The  other  mode  of  manufacturing  sal  ammoniac  consists  in  ta- 
king a  quantity  of  liquid  containing  ammonia,  either  in  the  caus- 
tic state  or  combined  with  carbonic,  hydrosulphuric,  and  hydrocy- 
anic acids  (as  in  the  case  of  the  ammoniacal  liquor  of  the  gas  worksj 
and  rectifying  it  by  distillation  until  the  distilled  portion  contains 
from  twenty  to  twenty-five  per  cent,  of  carbonate  of  ammonia.  If 
the  liquid  contain  any  other  acids  than  those  above  mentioned,  a 
sufficient  quantity  of  lime  is  used  in  the  distillation  to  decompose 
the  ammoniacal  salt.  The  distilled  liquid  being  now  mixed  with  as 
large  a  quantity  of  powdered  common  salt  as  it  will  dissolve,  is  agi- 
tated for  several  hours,  and  as  much  carbonic  acid  gas  is  passed 
into  it  as  it  will  absorb.  The  remainder  of  the  operation  is  the 
same  as  before  described  in  the  method  of  manufacturing  muriate 
of  ammonia. 
In  1841  Mr.  Laming  took  out  a  patent  for  manufacturing  car- 
bonate of  ammonia  by  mixing  together  its  separate  acid  and  alka- 
line constituents  instead  of  by  the  decomposition  of  an  ammoniacal 
salt.  One  of  the  processes  used,  is  to  cause  ammonia  and  carbonic 
acid  gas,  obtained  separately  from  any  convenient  sources,  to 
traverse  a  succession  of  leaden  chambers,  maintained  at  as  cool  a 
temperature  as  may  be  conveniently  practicable,  and  so  contrived 
as  to  favor  the  admixture  of  the  dissimilar  gases.  In  this  process 
it  is  not  essential  that  the  two  gases  be  present  in  their  combining 
proportions;  it  is  preferable  that  the  carbonic  acid  be  in  greater 
abundance  than  will  combine  with  the  ammonia  which  is  present. 
Sometimes  a  stratum  of  water,  or  of  water  impregnated  with  am- 
monia, is  placed  in  one  or  more  of  the  leaden  chambers,  and  car- 
bonic acid  and  ammonia  in  the  form  of  gas  are  then  introduced  ;  in 
wThich  case,  it  is  stated,  a  larger  proportion  of  carbonic  acid  gas  is 
found  in  the  resulting  salt  or  saline  solution  than  when  only  the 
hygrometric  moisture  of  the  aeriform  fluids  is  present.  In  Mr. 
AslleyTs  process  of  manufacturing  muriate  of  ammonia,  the  bittern 
or  muriate  of  magnesia,  obtained  from  the  sea-salt  works,  was  em- 
ployed as  the  source  of  muriatic  acid,  and  the  parings  of  skins, 
horns,  and  other  animal  matters,  furnished  the  ammonia.  The  ani- 
mal matters  were  saturated  with  the  bittern  in  stone-rooms  heated 
by  brick  flues,  and  being  afterwards  subjected  to  a  red  heat  in  a 
close  kiln,  muriate  of  ammonia  was  obtained. 
