356 
METALLIC  HYDROGEN. 
(Ci4Hjo04)+H20,  because  the  11  fi  of  crystallization  is  only 
driven  off  at  115°  ;  it  should  be  kept  in  view  that  emodine  is 
very  difficult  to  separate  from  chrysophanic  acid,  and  M.  Roch- 
leder  suspects  that  the  statements  of  Messrs.  Graebe  and  Lei- 
bermann  about  the  action  of  pulverized  zinc  upon  chrysophanic 
acid  are  vitiated  by  the  presence  of  emodine  in  the  acid  used  for 
these  experiments. — Chemical  News,  London,  Jan.  7,  1870. 
METALLIC  HYDROGEN. 
At  a  recent  meeting  of  the  Lyceum  of  Natural  History,  in 
New  York,  a  paper  was  read  by  Dr.  Loew,  assistant  in  the  Col- 
lege of  New  York,  On  the  Preparation  of  Hydrogen  Amal- 
gam." 
The  researches  of  Graham  went  to  show  that  hydrogen  could 
be  alloyed  with  palladium,  and  that  it  was  also  contained  in  me- 
teoric iron.  He  condensed  the  hydrogen  in  the  palladium,  and 
came  nearer  proving  its  metallic  character  than  any  other  person 
had  done.  Schoenbein  in  his  search  for  ozone,  found  a  method 
for  making  the  peroxide  of  hydrogen,  which  brought  him  to  the 
very  threshold  of  discovering  hydrogenium.  Schoenbein's  ex- 
periment was  this — An  amalgam  of  zinc  and  mercury  is  violently 
agitated  in  water ;  the  water  is  then  filtered,  and,  on  being  ex- 
amined with  iodide  of  starch  and  protosulphate  of  iron,  will  be 
found  to  contain  peroxide  of  hydrogen  or  oxygenated  water. 
Dr.  Loew  has  carried  the  investigation  further,  and  has,  instead 
of  oxidising  the  hydrogen,  succeeded  in  combining  it  with  the 
mercury.  He  takes  an  amalgam  composed  of  not  more  than  3 
or  4  per  cent,  of  zinc,  and  shakes  it  with  a  solution  of  bichloride 
of  platinum  ;  the  liquid  becomes  black,  and  a  dark  powder  settles 
to  the  bottom.  The  contents  of  the  flask  are  then  thrown  into 
water,  and  hydrochloric  acid  added  to  dissolve  the  excess  of 
zinc.  The  amalgam  of  hydrogen  and  mercury  at  once  forms  in 
a  brilliant  voluminous  mass,  resembling  in  every  way  the  well- 
known  ammonium  amalgam.  It  is  soft  and  spongy,  and  rapidly 
decomposes,  but  without  any  smell  of  ammonia.  The  hydrogen 
escapes,  and  soon  nothing  but  pure  mercury  is  left  in  the  dish. 
The  experiment  appears  to  show  conclusively  that  an  amalgam  of 
