68 
DETECTION  OF  A  CRUCIFEROUS  OIL,  ETC. 
assume  the  same  direction  in  the  whole  circumference  of  the  stem, 
as  they  are  apt  to  do?  the  wood-cells  would  assume  a  certain  ob- 
liquity ;  so  that  this  twist  of  the  wood  is  connected  with  the  in- 
timate nature  or  disposition  of  the  cells  themselves.  But  this  is 
not  sufficient  to  explain  the  higher  grades  of  the  obliquity,  which 
sometimes  reaches  an  angle  of  45  degrees.  It  would  here  be 
desirable  to  ascertain  whether  the  cambium  cells  divide  in  this  ob- 
lique direction  and  high  angle.  Any  one  who  may  take  an  in- 
terest in  these  investigations,  is  requested  to  institute  observa- 
tions and  make  memoranda,  noting  the  number  of  trees  observed, 
as  well  as  the  direction  and  angle  of  the  .twist  observed,  if 
any.— -G.  e.  Sillimans  Journal,  September,  1855. 
DETECTION  OF  A  CRUCIFEROUS  OIL,  WHEN  MIXED  WITH 
ANY  OTHER  FRUIT  OR  SEED  OIL. 
By  M.  Mailho. 
The  difficulty  of  distinguishing  the  different  fatty  oils  of  com- 
merce, in  a  state  of  mixture,  has  been  the  subject  of  various  re- 
searches for  a  length  of  time,  and  yet  the  indicated  tests  do  not 
always  lead  to  an  easy  detection  ;  especially  when  the  mixture 
is  the  result  of  fraud,  and  the  inferior  oils  added  are  in  such  pro- 
portion as  to  preserve  to  the  adulterated  article  its  physical  cha- 
racters. In  such  case  Lefebre's  oleometer,  which  is  usually  used 
in  commerce,  does  not  indicate  the  true  nature  of  the  oil ;  and 
even  when  it  indicates  fraud,  it  cannot  tell  us  what  oil  has  been 
added.  For  olive  oil,  the  nitrate  of  mercury  test,  proposed  by  Pou- 
tet,  and  the  hyponitric  acid  of  M.  Felix  Boudet,  are  sufficiently 
accurate  reagents.  Oils  used  for  burning,  find  in  chlorine  (as 
proposed  by  M.  Faure*)  a  delicate  test  for  indicating  the  presence 
of  an  animal  oil,  but  no  method  has  yet  been  published  for  indi- 
cating the  presence  of  a  cruciferous  oil  in  other  fatty  oils,  such 
as  linseed,  nut,  or  olive  oil. 
Having  been  called  upon  to  examine  a  certain  quantity  of 
linseed  oil,  in  order  to  decide  a  dispute  between  buyer  and  seller, 
I  subjected  the  oil  to  the  different  reagents  as  indicated  by  those 
Chemists  who  have  principally  studied  this  branch  of  analysis, 
and  although  they  proved  to  me  that  the  oil  could  not  be  pure,  I 
was  at  a  loss  to  specify  the  adulteration.    After  many  futile  ex- 
