PREPARATION  OF  SULPHATE  OF  AMMONIA.  229 
metal  in  powder,  with  a  concentrated  solution  of  caustic  potash, 
an  intensely  blue  liquid  is  obtained,  containing  cobaltate  of 
potash. 
The  proper  proportions  seem  to  be  one  part  of  metal  in 
a  spongy  state  (produced  by  the  reduction  of  protoxide  by 
means  of  hydrogen  or  starch,)  one  part  of  caustic  potash,  and 
three  of  water ;  the  boiling  is  continued  until  the  dark  blue  color 
is  produced,  after  which  the  mixture  is  filtered  through  asbestos. 
Cobaltate  of  potash  is  not  very  stable  ;  it  cannot  be  evaporated 
to  dryness ;  its  solution  decomposes  spontaneously,  and  the  more 
rapidly  the  more  it  is  diluted ;  acids  precipitate  from  it  hydrated 
protoxide  with  disengagement  of  oxygen,  a  part  of  which  dis- 
solves in  the  water,  forming  binoxide  of  hydrogen,  hydrochloric 
acid  is  decomposed,  and  its  chlorine  set  at  liberty.  Sulphurous 
acid  is  transformed  into  sulphuric  acid,  which  combines  with  the 
protoxide  of  cobalt.  By  estimating  the  cobalt  and  determining 
the  quantity  of  sulphuric  acid  formed  in  a  given  volume  of  co- 
baltate of  potash,  the  author  has  ascertained  the  composition  of 
cobaltic  acid ;  he  represented  it  in  his  first  paper  by  Co05,  and 
afterwards  by  C0O3.  It  would  be  interesting  to  compare  this 
compound  with  that  obtained  by  M.  Schwartzenberg  by  fusing 
oxide  of  cobalt  with  potash  in  contact  with  the  air. — Lond.  Chem. 
.News,  March  31,  1865. 
PREPARATION  OF  SULPHATE  OF  AMMONIA. 
MM.  Margueritte,  Lalouet,  de  Sourdeval,  and  Worms,  of  Ilo- 
milly,  have,  with  the  cooperation  of  the  able  director  of  the 
Compagnie  Richer,  established  at  Bondy  a  large  factory  of  sul- 
phate of  ammonia,  producing  daily  from  7000  to  8000  kilogs. 
The  raw  material  is  the  liquor  of  the  Bondy  basins,  which  is 
merely  the  liquor  of  cesspools  left  to  stand  for  a  time  sufficient 
to  exhaust  the  fermentation,  and  transform  the  urea  into  carbo- 
nate of  ammonia,  the  solution  of  which  is  decanted.  Ammonia 
exists  in  these  liquids  in  the  state  of  sesquicarbonate  or  bicarbo- 
nate. 
The  distilled  ammonical  liquid,  which  is  perfectly  limpid,  marks 
