EUCALYPTUS  OIL. 
465 
EUCALYPTUS  OIL. 
The  essential  oil  of  eucalyptus  now  being  introduced  into  use 
in  perfumery  by  Mr.  Rimmel,  has  lately  been  examined  by 
Cloetz.  He  took  the  product  of  Eucalyptus  globulus^  originally 
a  native  of  Tasmania,  where  it  was  discovered  by  Labillardiere, 
in  the  year  1792.  It  has  since  been  acclimatized  on  the  shores 
of  the  Mediterranean.  From  10  kilogrammes  of  fresh  leaves  of 
the  plant,  275  grammes  of  the  essential  oil  were  obtained  by 
distillation  with  water.  In  another  experiment  about  double 
the  quantity  of  oil  was  obtained.  The  oil  is  very  fluid,  almost 
devoid  of  color,  and  having  a  smell  analogous  to  that  of  camphor. 
It  begins  to  boil  at  170°  C,  and  rises  in  boiling  point  as  the 
distillation  proceeds,  until  above  200°.  The  more  volatile  liquid, 
after  purification  with  caustic  potash  and  with  fused  chloride  of 
calcium,  boils  regularly  at  175°  C.  ;  this  is  eucalyptol.  Its  spe- 
cific gravity  at  8°  C.  is  0-905  ;  it  deflects  the  ray  of  polarized 
light  to  the  right  ;  it  does  not  freeze ;  its  vapor,  mixed  with  air, 
is  fresh,  agreeable  when  inhaled,  and  has  been  employed  as  a 
therapeutic  agent ;  it  is  hardly  soluble  in  water,  but  very  soluble 
in  alcohol ;  its  alcoholic  solution,  when  highly  diluted,  is  said  to 
afford  a  perfume  equal  to  the  rose.  The  composition  of  euca- 
lyptol is  represented  by  the  formula  0  (vapor  density 
6-22).  By  the  action  of  anhydrous  phosphoric  acid  upon  it,  a 
liquid  hydrocarbon  of  the  formula  C12H18'  named  eucalyp- 
tene,  has  been  obtained.  This  liquid  boils  regularly  at  165°  C, 
and  has  a  sp.  gr.  of  0*835  at  12°  C.  Its  vapor  density  is  5*3. 
It  is  derived  from  eucalyptol  by  the  loss  of  the  elements  of 
water.  At  the  same  time  a  polymer  of  eucalyptene  is  pro- 
duced. This  liquid  boils  at  temperatures  above  300°  C.  De- 
composition of  the  substance  at  the  high  temperature  required 
for  the  determination  of  its  vapor  density,  prevented  a  deter- 
mination  of  that  important  datum.  The  name  eucalyptolene 
is  proposed  for  it.  The  behaviour  of  eucalyptol  towards  hy- 
drochloric acid  gas  is  very  interesting.  Cooled  to  zero  and 
then  treated  with  a  current  of  dry  hydrochloric  acid  gas,  it  ab- 
sorbs the  gas  abundantly  and  solidifies  to  form  a  mass  of  crys- 
tals.   Very  soon,  however,  these  crystals  undergo  spontaneous 
30 
