458 
ORIGIN  OF  GRAPHITE. 
explanation  is  inadmissible.  If  it  be  maintained  that  graphite 
is  an  organic  product,  it  must  be  admitted  that  in  the  case  of 
newly-fallen  meteorites  it  can  proceed  only  from  organic  mat- 
ters belonging  to  another  world  than  our  own. 
In  his  report  on  Alibert  graphite,  M.  Dumas  presents  some 
considerations  on  the  probable  origin  of  graphite  and  of  the  di- 
amond. M.  Despretz  and  others  ascribe  to  fire  the  change  of 
carbon  into  diamond  ;  Newton  ascribed  it  to  the  coagulation  of 
a  fatty  or  oily  body;  Liebig  says  the  diamond  is  slowly  formed 
by  processes  which  determine  the  prolonged  putrefaction  of  a 
liquid  body  rich  in  carbon  and  in  water  ;  then,  contrary  to  M. 
Despretz's  method,  a  high  temperature  would  be  unfavorable  to 
a  successful  attempt.  Adopting  Newton's  hypothesis,  M.  Gcep- 
pert  states,  in  "  a  memoir  on  the  solid  bodies  entering  into  the 
composition  of  the  diamond,  and  considered  with  regard  to  their 
organic  or  inorganic  origin,"  that  he  is  disposed  to  class  the 
diamond  among  the  products  of  the  decomposition  of  organic 
matters.  All  these  hypotheses  M.  Dumas  rejects ;  according 
to  him  the  diamond  is  crystallized  carbon,  at  the  moment  of  its 
production  and  in  the  midst  of  a  mass  which  has  been  exposed 
merely  to  the  heat  necessary  to  soften  it,  provided  this  condi- 
tion is  sufficiently  prolonged. 
Finally,  M.  Dumas  frankly  admits  that  nothing  positive  is 
known  as  to  the  true  origin  of  the  diamond,  though  the  sub- 
stance most  allied  to  it,  silicum,  is  perfectly  known,  and  very 
beautiful  specimens  of  it  are  obtained. 
However,  it  is  positively  ascertained  that  the  diamond  and 
graphite  have  not  the  same  origin,  and  that  the  residue  of  every 
carboniferous  substance,  treated  at  a  high  temperature,  proves 
to  be  but  a  variety  of  graphite.  The  new  carbon  found  by  M. 
Alibert  in  the  mines  of  Marinski,  situated  at  the  summit  of 
Batougol,  on  the  Siberian  frontiers,  is,  then,  a  graphitoid  car- 
bon of  the  most  beautiful  kind,  formed  by  volcanic  phenomena. 
M.  Jaquelain,  after  carefully  comparing  the  external  charac- 
teristics of  Alibert  graphite  with  that  obtained  by  hi3  process, 
concludes  that  the  conditions  under  which  they  are  produced 
must  be  analogous. 
In  fact,  on  comparing  the  texture  of  the  two  carbons,  they 
will  be  found  sometimes  of  a  metallic,  mirror-like  lustre ;  at 
