THE  MANUFACTURE  OF  LIQUOR  AMMONIA.  363 
which  the  worm  containing  the  impure  solution  of  ammonia  pre- 
viously alluded  to  is  conducted  before  it  is  brought  into  contact 
with  cold  water,  and  thus  the  hot  vapor  is  made  to  concentrate 
the  liquor  already  produced.  After  attaining  a  considerable  de- 
gree of  density,  the  liquid  is  drawn  off  into  large  leaden  boilers 
set  in  fire  bricks,  and  completely  surrounded  by  a  flue,  where  it 
is  boiled  down  to  such  a  density  that  on  cooling  it  is  found  to 
become  nearly  a  mass  of  salts.  Four  stills,  capable  of  contain- 
ing two  hundred  gallons  each,  may  be  readily  worked  off  twice 
in  twenty-four  hours,  and  will  yield  about  eight  or  ten  cwt.  of 
ordinary  sulphate  of  ammonia,  depending  upon  the  strength  of 
the  gas  liquor  employed. 
This  rough  sulphate  of  ammonia  is  next  introduced  into  a  still 
containing  a  quantity  of  milk  of  lime,  and  heat  gently  applied ; 
a  rapid  evolution  of  gas  soon  takes  place,  which  is  conducted 
through  upright  iron  pipes  placed  in  a  cool  situation  over  the 
still,  when  the  whole  of  the  steam  in  combination  with  the  gas 
becomes  condensed,  and  falls  back  into  the  still,  while  the  pure 
gas  is  conducted  through  leaden  or  gutta  percha  tubes  into  a  set 
of  glass  carboys,  arranged  and  connected  like  a  series  of  Woulfe's 
bottles,  about  three  parts  filled  with  distilled  water,  into  which 
a  piece  of  glass  tube  connected  with  the  delivery  pipe  just  dips. 
Water  possesses  the  power  of  absorbing  this  gas  in  a  most  extra- 
ordinary degree ;  at  a  temperature  of  50Q  it  is  capable  of  con- 
densing from  600  to  700  times  its  bulk ;  by  this  absorption  the 
bulk  of  the  solution  becomes  gradually  increased,  until,  in  the 
end,  six  parts  of  water  become  increased  to  ten,  and  the  specific 
gravity  of  the  liquid  is  reduced  from  1.00  to  0.875.  In  apply- 
ing heat  to  the  still,  it  is  necessary  to  be  exceedingly  careful  in 
the  first  place  not  to  apply  it  too  strongly,  otherwise  the  gas 
will  be  evolved  so  rapidly  as  to  endanger  the  safety  of  the  re- 
ceivers by  the  liquid  becoming  too  hot ;  and  in  the  second,  to- 
wards the  latter  end  of  the  process,  especially,  to  maintain  a 
gradually  increased  heat,  otherwise,  a  vacuum  will  be  formed, 
and  you  will  thus  lose  a  large  amount  of  your  product.  A  still, 
containing  about  one  cwt.  of  sulphate  of  ammonia  will  require 
about  twenty  four  hours  to  work  off,  and  will  produce  from 
sixty  to  seventy  pounds  of  the  strongest  liquor  amnionic,  having 
a  sp.  gr.  of  0.875,  and  containing  32.5  per  cent,  of  dry  ammo- 
nia.— Pharm.  Jour*,  April,  1855. 
