36 
MANUFACTURE  OF  AMMONIA,  ETC. 
becomes  red-hot.  By  this  means  the  ammonia  is  set  free,  and  the 
uric  acid  contained  in  the  guano  being  decomposed,  yields  ammo- 
nia also.  The  ammoniacal  gas  thus  given  off  is  absorbed  by  water 
in  a  condenser,  whilst  other  gases,  which  are  given  off  at  the  same 
time,  being  insoluble  in  water,  pass  off.  Solutions  of  carbonate, 
bicarbonate,  or  sesquicarbonate  of  ammonia  are  produced,  by  filling 
the  condenser  with  a  solution  of  ammonia,  and  passing  carbonic 
acid  through  it.  A  solution  of  sulphate  or  muriate  of  ammonia  is 
obtained  by  filling  the  condenser  with  diluted  sulphuric  or  muriatic 
acid,  and  passing  the  ammonia  through  it  as  it  issues  from  the  re- 
tort. 
Dr.  Wilton  Turner  took  out  a  patent,  March  11,  1844,  for  ob- 
taining salts  of  ammonia  from  guano.  The  following  is  his  method 
of  obtaining  muriate  of  ammonia  in  conjunction  with  cyanogen 
compounds  : — The  guano  is  subjected  to  destructive  distillation  in 
close  vessels,  at  a  low  red  heat  during  the  greater  part  of  the  ope- 
ration ;  but  this  temperature  is  increased  towards  the  end.  The 
products  of  distillation  are  collected  in  a  series  of  Woulfe's  bottles, 
by  means  of  which  the  gases  evolved  during  the  operation  may  be 
made  to  pass  two  or  three  times  through  water,  before  escaping 
into  the  air.    These  products  consist  of  carbonate  of  ammonia, 
hydrocyanic  acid,  and  carburetted  hydrogen,  the  first  two  of  which 
-are  rapidly  absorbed  by  the  water,  with  the  formation  of  a  strong 
solution  of  hydrocyanate  and  carbonate  of  ammonia.    After  the 
ammoniacal  solution  has  been  removed  from  the  Woulfe's  apparatus, 
a  solution  of  protomuriate  of  iron  is  added  to  it,  in  such  quantities 
as  will  yield  sufficient  iron  to  convert  the  latter  into  Prussian  blue, 
which  is  formed  on  the  addition  of  muriatic  acid  in  sufficient  quan- 
tity to  neutralize  the  free  ammonia  ;  the  precipitate  thus  formed 
is  now  allowed  to  subside,  and  is  carefully  separated  from  the  so- 
lution, and  by  being  boiled  with  a  solution  of  potash  or  soda,  will 
yield  the  ferro-cyanate  of  the  alkali,  which  is  obtained  by  crystal- 
lizing in  the  usual  way.    The  solution  (after  the  removal  of  the 
precipitate)  should  be  freed  from  any  excess  of  iron  it  may  contain, 
by  the  careful  addition  of  a  fresh  portion  of  the  ammoniacal  liquor, 
by  which  means  the  oxide  of  iron  will  be  precipitated,  and  a  neu- 
tral solution  of  [muriate  of]  ammonia  obtained.    When  the  pre- 
cipit:«leci  oxide  and  cyanide  of  iron  has  subsided,  the  solution  of 
muriate  of  ammonia  is  drawn  off  by  a  syphon,  and  the  "sal-ammo- 
