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IACTS  RELATING  TO  MAGNESIUM. 
Slightly  acidulated  solutions  of  proto-  and  sesqui-salts  of  iron, 
of  zinc,  of  protoxide  of  cobalt  and  of  nickel,  placed  in  contact 
with  pure  magnesium,  cause  an  escape  of  hydrogen,  and  precipi- 
tation, in  a  metallic  state,  of  the  metals  of  these  solutions. 
All  these  metals,  freed  by  washing  from  saline  liquid,  dried  and 
then  compressed,  possesses  great  metallic  brilliancy,  and  entirely 
dissolve  in  acids.  Iron,  cobalt,  and  nickel  so  obtained  are 
highly  magnetic  ;  zinc  takes  the  form  of  a  large  spongy  mass, 
which  the  least  compression  renders  brilliant. 
Magnesium  precipitates  equally  silver,  gold,  platinum,  bis- 
muth, tin,  mercury,  copper,  lead,  cadmium,  and  thallium. 
Aluminium  is  not  precipitated  in  a  metallic  state  from  its  saline 
solutions. 
Salts  of  chromium  and  of  manganese  form  deposits  by  their 
contact  with  plates  of  magnesium,  which  have  the  characteristics 
of  oxides  of  these  substances,  and  which  we  reserve  for  further 
study*. 
Arsenic  and  antimony  are  not  precipitated  from  their  acid 
solutions  by  contact  with  magnesium  ;  they  combine  with  the 
hydrogen  gas  whicji  is  formed  in  this  reaction,  and  pass  off  as 
arseniuretted  or  antimoniuretted  hydrogen. 
Magnesium  very  readily  decomposes  water ;  in  a  very  weak 
solution  of  common  salt,  of  sal  ammoniac,  of  some  acid,  &c,  the 
metal  will  be  oxidized,  and  a  considerable  disengagement  of 
hydrogen  take  place.  This  gas  is  extremely  pure,  for  the  mag- 
nesium contains  no  silicium. 
The  foregoing  qualities  encouraged  the  hope  that  a  substitu- 
tion of  magnesium  for  zinc  in  ordinary  piles  would  offer  a  great 
*  I  have  recently  observed  that  a  sodium  amalgam  shaken  up  with 
acidulous  salts  of  chromium  and  manganese  changes  to  an  amalgam  of 
chromium  and  manganese.  The  last  two  amalgams,  purified  by  washing 
in  acidulated  water,  then  distilled  in  a  current  of  hydrogen,  leave  the  pure 
metals  in  the  form  of  a  pulverulent  sponge.  The  amalgam  of  manganese 
is  opalescent  and  crystalline  ;  that  of  chromium  is  more  fluid  and  less 
variable  at  the  ordinary  temperature.  If  the  latter  is  heated  in  a  small 
porcelain  capsule  in  the  air,  the  vapors  of  mercury  mechanically  carry 
away  particles  of  chromium,  which  produce,  whilst  burning  in  a  darkened 
room,  a  singular  scintillation  which  ends  in  the  sudden  incandescence  of 
the  rest  of  the  metallic  chromium. —Z,  R. 
