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ORIGIN  OF  GRAPHITE. 
might  not  have  been  sufficiently  poisonous  to  cause  the  effects 
described.  MM.  Claude  Barnard,  Valpine,  and  Raynal  were 
examined  as  to  the  action  of  digitaline  on  the  heart,  and  de- 
scribed the  experiments  they  had  made  with  that  substance. 
The  jury  found  the  prisoner  guilty  of  poisoning  the  widow  De 
Pauw.  No  mention  of  extenuating  circumstances  having  been 
made,  La  Pommerais  was  condemned  to  death,  and  has  since 
suffered  the  penalty. — Lond.  Pharm.  Jour.,  July,  1864 
ORIGIN  OF  GRAPHITE. 
Report  of  M.  Haidinger  and  others. 
Iron,  after  remaining  long  buried  in  the  earth,  at  last  entire- 
ly decomposes,  leaving  a  black,  porous,  eminently  combustible 
residuum,  known  as  graphite  or  pure  carbon.  M.  Haidinger's 
report  on  the  ferruginous  masses  of  Kokitzan  and  Gotta,  near 
Dresden,  masses  of  uncertain  origin,  lends  support  to  this  gene- 
ral fact. 
One  word  on  the  formation,  still  so  little  known,  of  graphite 
(plumbago  pencil  lead).  The  presence  of  graphite  in  granite 
gneiss  and  diorite,  has  renewed  the  disputes  between  the  Neptun- 
ists  and  Plutonists.  Graphite  is  well  known  to  be  nearly  pure 
carbon,  for  it  leaves  in  burning  but  a  very  small  quantity  of  ash. 
Now,  if  these  primitive  crystalline  rocks  are  of  igneous  formation, 
it  is  impossible  to  explain  how  graphite  could  co-exist  with  sili- 
cates of  protoxide  of  iron  without  having  reduced  these  salts. 
Judging  merely  by  what  takes  place  in  blast  furnaces,  carbon 
reduces  all  oxides  of  iron  at  a  high  temperature.  It  must,  then, 
be  admitted  that  granite,  gneiss  and  diorite  did  not  contain 
graphite  when  the  mineral  elements  of  these  rocks,  such  as 
mica,  hornblende,  and  other  ferrous  silicates  were  in  a  state  of 
fusion.  Graphite,  then  must  have  been  subsequently  introduced 
into  these  rocks — but  when,  and  how?  Questions  such  as  these 
are  very  difficult  to  answer  satisfactorily.  The  most  plausible 
hypothesis  is  that  graphite  has  been  introduced  by  the  wet  way 
into  the  crystalline  rocks  and  substituted  for  one  of  the  mine- 
ral components.  Thus,  in  the  gneiss  of  Passau  (Bavaria),  it 
takes  the  place  of  mica. 
Graphite  is  frequently  to  be  met  with  in  granulated  lime- 
