204 
ON  THE  CONSTITUTION  OE  THE  ESSENTIAL  OIL  OF  EUE. 
The  fluids  accompanying  the  aldehydes  in  oil  of  rue  were  found  not  to  be  of  much 
interest.  That  portion  boiling  at  154°  was  the  most  volatile.  It  evidently  belongs  to 
the  already  too  numerous  groups  of  bodies  isomeric  with  oil  of  turpentine.  It  was  not 
obtained  quite  free  from  an  oxygenated  oil.  By  repeated  rectifications  a portion  was 
obtained  yielding, — 
I. 
II. 
Carbon  . 
. . 84-63 
84-88 
Hydrogen 
. . II-9I 
11-90 
Oxygen  . 
, . 3-46 
3-22 
100-00 
100-00 
By  cohobation  over  a fluid  alloy  of  potassium  and  sodium,  a portion  of  oxygen  was 
removed  without  decomposition  of  the  oil.  Thus  purified,  a combustion  gave — 
Carbon  . . 
. . 86-20 
Hydrogen 
. . 12-16 
Oxygen 
. . 1-64 
100-00 
But  it  was  impossible  to  remove  the  whole  of  the  oxygen  in  this  manner ; and  although 
the  object  could  have  been  attained  by  other  methods,  the  trouble  would  have  been  out 
of  proportion  to  the  result. 
Oil  of  rue  contains,  in  addition  to  the  aldehydes  and  terebinthinate  oils,  fluid  hydrates 
of  oil  of  turpentine.  There  even  appeared  to  be  fluids  present  homologous  with  boineol, 
but  (although  higher  in  the  series)  having  a lower  boiling-point  than  borneol  itself,  and 
probably,  therefore,  isomeric  with  the  borneol  series.  The  substance  was  obtained  from 
the  fluid  refusing  to  combine  with  the  alkaline  bisulphites.  One  fluid  boiling  at  191° 
contained, — 
Carbon  . . 
. . 78-7 
C22  JJ20  Q2  requires 
78-6 
Hydrogen 
, . II-7. 
II-9 
Oxygen  . 
, . 9-6 
9-5 
100-0 
100-0 
Little  attention  was  paid  to  these  bodies,  partly  because  they  appeared  to  difier  in 
difierent  samples  of  oil,  but  chiefly  because  no  positive  guarantee  of  their  puiity  could 
be  obtained.  The  fact,  however,  was  observed,  that  the  above  fluid,  like  borneol,  yielded 
camphor  when  boiled  with  nitric  acid. 
