226 
MANUFACTURE  OF  AMMONIA,  ETC. 
Mr.  Hills,  in  his  patent  of  Nov.  28,  1849,  claims  the  use  of 
the  sub-sulphates,  the  oxychlorides,  and  the  hydrated  or  precipi- 
tated oxides  of  iron  (which  he  prefers  to  use  in  a  rather  damp 
state),  either  by  themselves  or  mixed  -with  sulphate  of  lime,  or 
sulphate  or  muriate  of  magnesia,  baryta,  strontia,  potash,  or  soda ; 
and  he  causes  them  to  be  absorbed  into  or  mixed  with  sawdust  or 
peat  charcoal  in  coarse  powder,  or  breeze,  or  other  porous  or  ab- 
sorbent material,  so  as  to  make  a  very  porous  substance  easily 
permeable  by  the  gas.  This  material  is  to  be  put  into  a  purifier 
(a  dry  lime  purifier  will  answer  the  purpose)  and  the  gas  is  to  be 
passed  through  it ;  by  this  means  the  ammonia  and  other  products 
are  absorbed.  By  the  admission  of  air  and  application  of  heat 
to  the  material  so  saturated  with  ammonia,  this  substance  is 
driven  off  and  collected  by  passing  it  through  a  condenser,  or  the 
ammonia  may  be  fixed  by  an  acid  and  converted  directly  into 
sulphate  or  muriate  of  ammonia.  If  sulphate  of  lime  or  sulphate 
of  magnesia  be  present  in  the  purifying  material,  these  salts  will 
be  decomposed  with  the  formation  of  sulphate  of  ammonia,  which 
may  then  be  washed  out  of  the  purifying  material,  concentrated 
by  evaporation,  and  crystallized. 
Mr.  Laming,  in  his  patent  of  April  23,  1850,  claims  the  use  of 
muriate  of  iron,  of  muriate  of  iron  decomposed  by  lime  into 
chloride  of  calcium  and  oxide  of  iron,  of  sulphate  of  iron  decom- 
posed by  its  equivalent  quantity  of  chloride  of  sodium,  adding  to 
the  solution  of  muriate  of  iron  thus  produced,  enough  hydrate  of 
lime  to  decompose  it  into  chloride  of  calcium  and  precipitated 
oxide  of  iron.  In  these,  and  in  various  modified  forms  of  the 
same  process,  muriate  of  ammonia  may  be  obtained  from  the 
purifying  material  when  it  has  served  its  purpose,  and  has  been 
removed  from  the  purifying  vessel.  Mr.  Laming  also  claims  the 
use  of  a  mixture  of  sulphate  of  lime  and  sulphate  of  iron,  of  a 
mixture  of  hydrated  or  precipitated  oxide  of  iron  with  carbonate 
of  lime,  magnesia,  carbonate  of  magnesia,  or  magnesian  lime- 
stone, or  chloride  of  magnesium  or  sulphate  of  magnesia  and 
water,  phosphate  of  lime  dissolved  in  hydrochloric  acid,  and, 
lastly,  of  a  mixture  containing  sulphate  of  magnesia  or  chloride 
of  magnesium  or  calcium,  or  one  or  more  of  them  in  combination 
with  oxide  of  copper,  and  mixed  or  not  with  lime  or  magnesia, 
or  both  or  either,  or  both  of  the  carbonates  of  those  earths.  In 
