AmMarch\i89ifm,}^^^w  °f  a  Substance  from  Sesame  Oil.  145, 
here  state  certain  precautions  which  I  found  it  necessary  to  take  in 
order  to  obtain  crystals  of  a  constant  melting-point.  The  acetic 
acid  extract  may  be  said  to  be  satisfactory  when  it  is  firm,  gela- 
tinous and  dark  brown.  If  the  extract  is  liquid,  too  much  glacial 
acetic  acid  has  been  used.  It  may  be  mentioned  .in  passing,  how- 
ever, that  the  extracts  from  cotton  seed  and  olive  oils  are  liquid  and 
yellow  in  color.  Regarding  the  precautions  to  be  taken  after  the 
deposit  has  been  collected,  it  was  found  that  after  treating  with 
HC1,  washing  and  drying,  an  oily  stain  had  been  imparted  to  the 
filter  paper,  indicating  the  presence  of  oleic  or  other  acids,  as  the 
substance  does  not  melt  at  the  boiling-point  of  water.  In  that  case^ 
the  substance  had  to  be  repeatedly  treated  with  KHO,  etc.,  in  order 
to  remove  the  last  trace  of  foreign  matter,  and  less  trouble  was 
experienced  in  crystallizing. 
The  combustions  were  performed  in  the  usual  way  with  CuO> 
using  a  filter  pump  as  an  aspirator  at  the  close  of  the  operations, 
taking  the  precaution,  of  course,  of  inserting  an  apparatus  for  drying, 
etc.,  the  air  previous  to  being  used.    The  following  are  the  results :. 
No.  1.  Amount  of  substance  taken,  -2483  gram.  Result,  -2781 
gram  C02  =  -0758  C.  -1239  H20—  -0137  H.  No.  2.  Amount 
taken,  -1851  gram.  Result,  -2028  gram  C02  =  o555  C.  -0890  gram 
H20  —  0099  H.  No.  3.  Amount  taken,  -2065  gram.  Result,. 
•2355  gram  C02  =  -0642  C,  and  -ioio  gram  H20  =0112  gram  H.. 
The  following,  therefore,  are  the  percentages  found  : 
II. 
III. 
Mean. 
c,  
...  .    -  .  30-50 
30-02 
31-08 
30-53 
H  
5  "35 
5-42 
5-43 
O  (by  diff.),  .... 
 63-96 
64-63 
63-50 
64-04 
100*00 
IOO'OO 
100.00 
IOO'OO 
The  hydrogen  has  been  pretty  constant,  but  the  carbon  rather 
variable  (maximum  has  been  1  per  cent.),  but  the  results  are  con- 
stant enough  to  warrant  one  in  saying  that  the  substance  does  not 
correspond  to  any  known  constituent  in  sesame  oil.  To  arrive  at  its 
formula,  it  only  remained  for  me  now  to  determine  the  molecular 
weight  of  the  substance,  which  I  tried  by  one  method,  but  owing  to 
the  small  quantity  remaining  at  my  command,  I  did  not  obtain  con- 
cordant results.  Time  has  also  been  against  me,  having  only  had 
five  days  at  my  disposal  after  the  completion  of  the  above  experi- 
ments, that  time  being  quite  inadequate  to  commence  anew  to  pre- 
