ON  THE  CAMPHENIC  SERIES. 
73 
ON  THE  CAMPHENIC  SERIES. 
By  M.  Berthelot. 
The  relations  which  exist  between  the  formula  of  the  camphor 
of  Borneo,  or  camphol,  C20H18O2,  that  of  ordinary  camphor 
C20H16O2,  and  that  of  the  insomeric  carburets,  C20H16,  and  the 
artificial  formation  of  ordinary  camphor  by  means  of  Borneo 
camphor  realised  by  M.  Pelouze,  have  led  me  to  try  the  inverse 
experiments,  and  to  form  these  substances  with  each  other. 
I  have  followed  up  this  attempt  not  in  relying  on  approxima- 
tions of  formulae,  which  are  too  frequently  fruitless,  but  on 
considerations  relative  to  the  similitude  of  molecular  states. 
Indeed,  if  camphol  and  ordinary  camphor  are  comparable  as 
regards  their  physical  properties,  it  is  not  the  same  with  the 
carburets,  C20H16.  None  of  these  bodies  at  present  known  ef- 
fects the  solid  state  or  the  physical  properties  so  characteristic 
of  camphors.  But  several  of  these  carburets,  if  not  all,  and 
especially  essence  of  turpentine,  may  form  a  crystallised  hydro- 
chlorate,  C20H16HC1,  endowed  with  the  general  properties  of  the 
camphors,  and  often  designated,  on  account  of  this  fact,  by  the 
improper  denomination  of  artificial  camphor.  It  is  this  hydro- 
chlorate  which  I  have  taken  as  a  starting  point.  Although  my 
researches  are  not  yet  concluded,  I  have  already  obtained  a  cer- 
tain number  of  results,  which  I  think  useful  to  indicate  briefly. 
I  have  decomposed  the  solid  hydrochlorate  C20H16HC1  in 
special  and  proper  conditions  for  preventing  all  molecular  mod- 
ifications, which  had  not  hitherto  been  done,  and  I  obtained  a 
carburet  of  hydrogen  of  the  formula  C20H16,  endowed  with  the 
rotatory  power,  volatile  towards  160°  C-  (320°  F.),  crystallisa- 
ble  and  fusible  at  46°  C.  (114°  8'  F.)  quite  similar  to  the  cam- 
phors properly  so  called:  this  was  true  camphene.  Hydrochloric 
acid  changes  it  entirely  into  solid  hydrochlorate. 
This  camphene,  oxidised  under  the  influence  of  platinum 
black,  is  metamorphosed  into  a  volatile  and  crystalline  matter, 
with  the  odor  and  appearance  of  ordinary  camphor,  and  pro- 
bably identical  with  it ;  I  have  not  yet  completed  the  study  of  it. 
Finally,  ordinary  camphor,  G20H16O2,  was  heated  between 
180°  and  200°  C.  (356°  and  392Q  F.)  with  an  alcoholic  solution 
