MANUFACTURE  OP  COMMERCIAL  CARBONATE  OF  AMMONIA.  133 
ON  THE  MANUFACTURE  OF  COMMERCIAL  CARBONATE 
OF  AMMONIA. 
By  J.  Carter  Bell,  F.C.S.,  Associate  of  the  Royal  School  of  Mines. 
This  salt  must  have  been  known  even  to  the  alchemists,  as 
it  forms  one  of  the  chief  constituents  of  putrid  urine,  but  there 
seems  to  be  no  evidence  that  it  was  manufactured  previously  to 
this  century  ;  indeed,  one  would  hardly  think  that  they  knew 
the  difference  between  ammonia  and  its  carbonate.  The  real 
difference  was  first  pointed  out  by  Dr.  Black,  of  Edinburgh. 
Carbonate  of  ammonia  is  formed  by  the  putrefaction  of  ani- 
mal substances,  and  by  the  destructive  distillation  of  animal 
matter. 
In  the  destructive  distillation  of  bones,  carbonate  of  am- 
monia is  produced,  and  also  water  with  the  oil  called  "  Dippel's 
oil,"  with  some  incondensable  gases.  The  condensed  liquors 
from  the  carbonization  of  bones  separate  in  two  distinct  forms 
— the  oily  and  the  aqueous  products — the  latter  containing 
the  carbonate  of  ammonia ;  the  salt  can  be  separated  by  sub- 
limation. 
Many  processes  have  been  tried  for  the  manufacture  of  this 
compound.  I  am  informed  by  Mr.  John  Hogarth  (who  has 
been  engaged  in  this  chemical  operation  for  forty  years)  that  in 
the  year  1825  a  Mr.  Holmes  manufactured  this  salt  in  the  old 
Haymarket,  Liverpool ;  it  was  made  from  stale  urine,  and  the 
resulting  blocks  were  very  small,  weighing  about  six  pounds. 
At  the  present  time  the  weight  of  a  block  is  about  two  hundred- 
weight. 
On  March  11,  1844,  Dr.  Wilton  Turner  took  out  a  patent 
for  obtaining  salts  of  ammonia  from  guano.  The  guano  is 
subjected  to  a  destructive  distillation  in  close  vessels  at  a  low 
red  heat  during  the  greater  part  of  the  operation,  but  the  tem- 
perature is  increased  towards  the  end.  The  products  of  distilla- 
tion 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.  The  products  consist  of  carbonate  of  ammonia,  hydro- 
cyanic acid,  and  carburetted  hydrogen;  the  first  and  second 
