46        PROPERTIES  OF  FRESHLY  CALCINED  WOOD  CHARCOAL. 
equivs.  of  water,  which  is  still  serviceable  for  some  purposes.  In 
these  two  operations  the  quantity  of  salt  precipitated  will  be 
64-65  kilogrms.  This  is  theoretical ;  but  if  we  consider  the 
quantity  of  salt  reproduced  as  50  per  cent,  only,  this  valuation 
will  not  appear  exaggerated  when  we  consider  the  efficacy  of  the 
means  and  the  simplicity  of  the  operation. 
The  principle  of  this  operation  consists  in  the  employment  of 
a  volatile  agent,  which,  after  serving  to  precipitate  the  salt,  may 
be  driven  off  by  heat,  without  leaving  any  impurity  behind 
it.  Upon  the  same  principle  several  other  salts  may  be  elimin- 
ated from  their  solutions,  although  in  a  less  complete  manner. 
Carbonate  of  soda  may  be  precipitated  in  a  state  of  great  purity 
by  ammonia  from  a  solution  of  common  soda ;  the  crystalline 
salt  obtained,  when  dried  upon  a  stove,  does  not  retain  the  small- 
est trace  of  ammonia.  Moreover,  the  same  quantity  of  ammonia 
will  serve  almost  for  an  indefinite  period,  as  it  is  sufficient  to 
heat  the  ammoniacal  liquid  to  recover  all  the  gas  which  it  had 
dissolved.  Ferrocyanide  of  potassium,  and  some  other  salts,  are 
also  precipitated  by  ammonia. — Chemical  Gazette,  Sept.,  1856, 
from  Oomjrtes  Rendus,  July,  1856. 
ON  SOME  NEW  PROPERTIES  OF  FRESHLY  CALCINED  WOOD 
CHARCOAL. 
By  M.  Moride. 
The  deoxidising  power  of  wood  charcoal  is  well  known,  when 
used  in  the  dry  state  and  under  the  influence  of  an  elevated 
temperature;  but  I  do  not  know  that  any  one  has  mentioned  it 
as  reducing  metals  in  the  midst  of  neutral,  alkaline,  or  acid 
liquors,  neither  am  I  aware  that  any  one  has  observed  that  in 
contact  with  a  dilute  and  alcoholised  acid,  freshly  calcined  wood 
charcoal  caused  the  formation  of  ether.  I  am  continuing  this 
study,  but  I  have  determined  to  make  known  the  results  of  my 
first  experiments. 
Coke,  charcoal  from  lignites,  animal  and  bone  charcoal,  do  not 
produce  the  effects  of  which  I  am  about  to  speak. 
1st.  When  incandescent  wood  charcoal  is  plunged  directly,  or 
after  being  extinguished  with  cold  water,  into  an  acid  solution  of 
sulphate  of  copper,  the  metal  is  gradually  deposited  upon  the 
