188 
The  Origin  of  Petroleum. 
/Am.  Jour.  Pharm. 
\      April,  1888. 
Od  the  other  hand,  in  investigating  the  structure  of  the  earth  we 
find  it  is  in  itself  what  I  may  designate  as  an  automatic  historical  re- 
corder of  the  various  epochs  which,  judging  from  the  various  strata, 
have  succeeded  one  another  since  its  earliest  formation.  A  record  of 
events  formed  in  this  way  we  are  bound  to  consider  as  the  most  truth- 
ful and  accurate  historical  record  that  we  have,  and  where  we  find  in 
it  phenomena  which  we  cannot  completely  explain,  we  may  pretty 
safely  assign  the  cause  to  our  own  inability,  and  rest  assured  that  what 
we  leave  undetermined  will  be  solved  by  subsequent  generations. 
Now  the  subject  of  my  paper  is  one  which  an  ordinary  observer 
might  think  should  be  determined  without  any  great  difficulty,  con- 
sidering the  vast  supplies  of  petroleum  that  are  daily  brought  forth 
from  the  interior  of  the  earth  to  its  surface  in  all  four  quarters  of  the 
globe.  The  fact  remains,  however,  that  up  to  the  present  the  origin 
of  the  formation  of  this  product,  now  invaluable  to  the  wants  of  man- 
kind, is  still  in  the  realms  of  scientific  speculation. 
As  ardent  lovers  of  scientific  truth,  we  would  prefer  not  to  leave  the 
solution  of  this  problem  to  posterity,  but  rather  endeavor  ourselves  to 
bring  the  causes  of  its  origin  completely  within  the  range  of  absolute 
certainty.  Whether  our  scientific  knowledge  of  the  earth^s  crust  and 
interior  is  sufficiently  advanced  to  accomplish  this  is  an  open  question, 
and  my  purpose  in  the  remarks  I  shall  make  to  you  will  be  confined 
mainly  to  placing  before  you  as  well  and  concisely  as  I  can  the  reason- 
ing of  those  who  have  put  forward  the  most  reliable  theories  on  the 
question. 
These  may  be  considered  as  follows  : — 
1st. — The  theory  that  regards  petroleum  as  a  distillate  produced  by 
natural  causes. 
2d. — The  theory  that  regards  petroleum  as  indigenous  to  the  rocks 
in  which  it  is  formed. 
3d. — The  theory  that  regards  petroleum  as  the  result  of  a  purely 
chemical  action  on  purely  mineral  or  inorganic  materials. 
The  first  two  above  mentioned  are  comprised  under  what  is  under- 
stood as  the  organic  theory,  and  the  latter  as  the  inorganic  theory. 
Now  it  will  be  readily  conceived  by  those  who  are  accustomed  to 
analyze  the  merits  of  conflicting  theories  that  that  theory  which  seem- 
ingly admits  of  the  most  actual  proofs  is  the  more  likely  to  be  the  cor- 
rect one,  and  may  be  said  to  emerge  out  of  the  realm  of  theory  into 
that  of  comparative  certainty.    In  this  respect,  in  the  present  inquiry, 
