ON  THE  PREPARATION  OF  MANGANESE. 
173 
by  the  steam,  and  kept  in  solution  in  a  peculiar  state,  analogous 
to  that  of  essences.  Chemist,  Jan.  1858,  from  Jour,  de  Pharm., 
Nov.  1857. 
ON  THE  PREPARATION  OF  MANGANESE. 
By  C.  B RUNNER. 
In  continuing  his  experiments  on  the  reduction  of  manganese, 
the  author  has  made  some  further  observations,  which  he  pub- 
lishes as  a  supplement  to  his  previous  memoirs. 
He  first  describes  the  preparation  of  protochloride  of  manga- 
nese. When  this  can  be  obtained  as  a  residue  of  manufacture, 
of  course  such  crude  solutions  of  protochloride  of  manganese  may 
be  made  use  of  directly.    Otherwise  it  is  prepared  as  follows  : 
Powdered  black  oxide  of  manganese,  moistened  w^ith  a  very 
small  quantity  of  water,  is  calcined  in  an  earthen  crucible.  The 
residue,  when  cold,  is  treated  in  a  retort  with  three  times  its 
weight  of  common  muriatic  acid,  and  the  mixture  is  digested 
gently  for  24  hours.  It  is  then  evaporated  to  dryness  in  an 
earthen  capsule  ;  the  brown  saline  mass  obtained  is  broken  up, 
and  roasted  at  a  bare  red  heat,  during  which  operation  it  is  fre- 
quently stirred  with  an  iron  spatula. 
The  gray  powder  thus  obtained  is  then  extracted  with  water. 
The  pale  rose-colored  solution  produced  contains  no  trace  of 
iron,  but  retains  some  zinc  and  cobalt ;  the  presence  of  the  latter 
is  shown  by  the  fact,  that  a  small  portion,  when  evaporated  in  a 
porcelain  capsule,  acquires  a  bluish  color  immediately  before  it 
becomes  perfectly  dry. 
To  get  rid  of  these  impurities  some  acetate  of  soda  is  added 
to  the  solution,  which  is  then  treated  with  sulphuretted  hydrogen 
gas.  A  precipitate  is  formed,  which  is  at  first  dingy  white,  and 
afterwards  becomes  brownish  ;  by  the  aid  of  heat  this  separates 
more  completely  and  falls  to  the  bottom  in  black  flakes.  A 
filtered  portion  of  the  fluid  is  then  again  tested  for  cobalt  by 
evaporation.  If  a  bluish  color  still  occurs,  the  addition  of  ace- 
tate of  soda  and  the  treatment  with  sulphuretted  hydrogen  must 
be  repeated. 
If  cobalt  be  no  longer  shown  by  testing,  the  fluid  is  examined 
for  sulphuric  acid ;  and  if  this  be  present,  it  is  thrown  down  by 
