178  Abietene,  a  New  Hydrocarbon.  {^Afcl^""' 
unaltered  abietene,  showing  only  a  trifling  opalescence  when  tested  with 
silver  nitrate,  after  previous  addition  of  a  little  nitric  acid,  while  a  small 
quantity  of  a  brownish  oil  remained  which  did  not  distill  over  at  1600. 
While  this  was  probably  the  same  as  the  oil  which  separated  out  at 
first,  it  was  put  to  one  side,  and  the  latter  was  examined  for  itself. 
After  standing  it  in  contact  with  precipitated  calcium  carbonate  for  a 
short  time,  to  free  it  from  any  adhering  HC1,  it  was  filtered  and  pre- 
pared for  analysis.  A  combustion  was  first  made  :  '2495  gram 
substance  gave  -2261  gram  H20,  corresponding  to  10*07  Per  cent«  H., 
and  *6n8  gram  C02,  corresponding  to  66*88  per  cent.  C. 
A  chlorine  determination  was  next  made,  decomposing  the  oil  by 
heating  with  nitric  acid,  diluting,  and,  after  filtration,  adding  silver 
nitrate.  It  was  found,  however,  that,  unfortunately,  the  nitric  acid 
had  not  effected  a  complete  decomposition,  and  so  the  determination 
was  lost.  Too  little  then  remained  for  a  chlorine  determination  by  a 
combustion  with  quick-lime  or  soda-lime,  which  would  certainly  have 
been  effectual  in  decomposing  the  chlorhydrate. 
The  carbon  and  hydrogen  percentages  only  remained  for  comparison. 
Now  the  formula  C10H16.HC1  requires  C  =  69*56  and  H  =  9*85, 
and  the  formula  C10H16.2(HC1)  requires  C  =  57*41  and  H  =8*6i. 
The  found  results,  C  =  66*88  and  H  =  10*07,  render  it  probable, 
therefore,  that  the  oil  in  hand  was  a  mono-chlorhydrate  of  the  abietene. 
Still,  a  careful  analysis  of  larger  amounts  of  this  oil  is  needed  before 
its  composition  can  be  asserted  with  certainty. 
Formation  of  a  Hydrate. — Common  turpentine  oil  left  in  contact  with 
water  forms  a  crystallized  hydrate,  C10H16.3H2O.  It  is  best  obtained  by 
mixing  8  parts  turpentine  oil,  2  parts  nitric  acid  of  specific  gravity  1*25, 
and  1  part  alcohol,  and,  after  thorough  agitation  for  some  hours, 
allowing  the  mixture  to  stand  exposed  to  the  air  in  shallow  vessels. 
This  procedure  was  carried  out  with  abietene,  but  with  purely  negative 
results.  It  does  not  form  any  crystallized  or  well-defined  hydrate. 
After  a  week's  standing,  all  that  remained  was  a  few  drops  of  a  dark- 
brown  resinous  substance,  which  was  too  small  in  amount  to  investigate. 
Action  of  Sulphuric  Acid  upon  Abietene. — Wenzell  had  stated  that  con- 
centrated sulphuric  acid  was  absolutely  without  action  upon  abietene. 
However,  turpentine  oil,  when  repeatedly  distilled  with  a  small  amount 
of  strong  sulphuric  acid,  is  converted  into  two  distinct  varieties,  tere- 
bene,  C10H16,  and  a  polymer,  colophene,  C20H32,  both  optically  inactive. 
