^""'o^riSs^™'}         ^'^^  ^/  Peppermint  and  Spearmint.  485 
disappeared,  a  peculiar  terebinthinous  odor  replacing  it.    The  supply 
of  this  being  exhausted,  the  natural  oil  was  fractioned,  the  light  portion 
treated  with  metallic  sodium  and  distilled  from  it  three  times. 
A  combustion  of  this  gave  the  following : 
Carbon  84*42 
Hydrogen   12-28 
Oxygen   3-30 
10000 
It  was  then  allowed  to  stand  over  sodium  for  two  weeks,  and  dis- 
tilled. The  first  portion  which  came  over  boiled  at  160°  to  167'5°C., 
and  had  a  specific  gravity  of  '861  at  15°C.  A  combustion  of  this 
gave : 
Carbon  8452 
Hydrogen  12  27 
Oxygen   3-21 
100-00 
According  to  Gladstone  the  pure  hydrocarbon  boils  at  160°C.,  and 
has  a  specific  gravity  at  20°C.  of  '860. 
Another  attempt  was  made  to  get  the  pure  hydrocarbon  by  treating 
the  oil  with  alcoholic  ammonium  sulphide,  to  remove  the  carvol,  and 
rectifying  the  filtrate.  But  a  decomposition  occurred  on  heating  this 
filtrate,  and  a  greenish  oil  containing  sulphur  distilled  over. 
The  second  fraction  in  the  distillation  of  the  volatile  oil,  consisting 
largely  of  carvol,  was  submitted  to  a  temperature  of  —  23°C.  No 
separation  of  crystals  occurred. 
There  remained  in  the  flask  after  distillation,  whether  by  direct 
heat  or  by  forcing  steam  through  the  oil,  a  thick,  dark  brown,  resinous 
substance,  almost  free  from  the  odor  of  spearmint,  and  apparently  a 
usual  constituent  of  the  oil.  This  will  be  referred  to  again  under 
pepi)ermint. 
Experiments  on  Oil  of  Peppermint. — The  oil  of  peppermint  exposed 
to  temperatures  varying  from  —  10°  to  —  23°C.  did  not  deposit 
crystals.  It  was  then  fractioned  under  reduced  pressure,  and  the 
heavy  portion  crystallized  by  exposure  to  a  low  temperature. 
For  experiments  on  the  light  product  of  the  oil,  I  used  a  sample 
sent  me  by  Mr.  Todd,  who,  at  my  request,  favored  me  with  about  4 
ounces  of  a  light  oil,  being  the  distillate  gotten  by  taking  120  pounds 
of  natural  oil,  distilling  5  pounds,  taking  28  ounces  of  this  and  dis- 
