202 
ME.  C.  GEEVILLE  WILLIAMS  ON  THE  CONSTITUTION 
The  first  of  these  experiments  yielded  the  same  number  as  that  found  by  Gerhaedt. 
It  is  somewhat  remarkable  that  the  vapour-density  did  not  induce  him  to  adopt  a formula 
with  22  instead  of  20  equivalents  of  carbon. 
The  specific  gravity  of  the  fluid  was  0-8497  at  15°.  During  a cold  night  the  aldehyde 
was  converted  into  a solid  crystalline  mass,  resembling  camphor.  Agitation  will  cause 
it  to  solidify  when  the  temperature  is  as  high  as  7°. 
Gerhaedt  made  four  analyses  and  one  vapour-density  determination  of  oil  of  rue,  and 
it  is  worthy  of  notice  that  two  of  his  analyses  and  the  vapour-density  agree  better  mth 
the  view  now  proposed  of  its  constitution  than  with  his  o-^vn.  His  analyses  were  as 
follows : — 
a. 
b. 
C. 
d. 
Carbon . . 
. . 77-65 
77-69 
76-95 
77-10 
Hydrogen  . 
. . 12-80 
12-87 
12-85 
12-95 
Oxygen 
. . 9-55 
10-44 
10-20 
9-95 
100-00 
100-00 
100-00 
100-00 
The  analysis  a was  made  on  the  first  portion  of  the  distillate,  h and  c on  the  last  third, 
and  d by  treating  an  alcoholic  solution  of  oil  of  rue  with  gaseous  hydrochloric  acid,  and 
reobtaining  the  aldehyde  by  the  addition  of  water.  It  would  appear  that  this  last  opera- 
tion (supposed  by  him  to  yield  an  isomeric  modification  of  the  capric  aldehyde)  was  in 
fact  to  some  extent  a process  of  purification,  the  liquid  so  prepared  haring  a fruity  odour, 
different  from  the  oil  merely  purified  by  distillation,  and  therefore  resembling  the  pui-e 
and  fragrant  aldehyde  obtained  by  me. 
Although  the  experiments  detailed  scarcely  permit  a doubt  of  the  true  natm-e  of  the 
substance  (especially  when  the  mode  of  purification  is  considered),  still  it  was  -wished  to 
place  the  matter  beyond  dispute.  With  this  intention,  the  aldehyde  obtained  from  the 
crystalline  bisulphite  was  again  treated  with  bisulphite  of  ammonia,  and  the  whole  pro- 
cess of  purification  repeated.  The  annexed  analysis  was  made  upon  the  aldehyde  so 
obtained. 
•2112  gramme  gave  -6015  carbonic  acid  and  -2458  water. 
Experiment. 
Calculation. 
Carbon  . 
. . . 77-67 
77-65 
Hydrogen  . 
. . . 12-93 
12-94 
Oxygen  . 
. . . 9-40 
9-41 
100-00 
100-00 
The  existence  of  margaritic  acid  having  been  disproved,  and  it  having  been  rendered 
certain  that  cocinic  acid  does  not  contain  22  equivalents  of  carbon,  it  follows  that  this  is 
the  first  substance  yet  isolated  belonging  to  the  eleventh  series  of  bodies  homologous 
with  the  derivatives  of  the  fatty  acids.  It  is  the  hydruret  of  the  negative  radical  euodyle  * 
homologous  with  acetyle.  When  carefully  purified  by  distillation,  it  distils  at  213°  C. 
* Erom  ev6)^r)s. 
