ON  COTTON-SEED  OIL,  ETC. 
31 
Mr.  Weatherley  made  some  experiments  in  substituting 
w  winter-bleached"  cotton-seed  oil  for  olive  or  almond  oils,  in 
various  pharmaceutical  preparations.  He  states  that  cold 
cream,  spermaceti  ointment,  citrine  ointment,  and  some  lini- 
ments were  so  prepared,  and  fully  equalled  the  results  of  the 
officinal  formulae. 
In  England,  Dr.  Adriani  has  studied  the  properties  of  this 
oil  (Chem.  News,  Jan.  7,  1865.)  He  states  that  the  crushed 
seed  is  heated  to  about  180°  Fahr.,  and  then  pressed,  when  15 
to  18  per  cent,  of  a  dark  brown-red  oil  is  obtained.  The  spe- 
cific gravity  is  "930  or  *931,  and  in  this  respect,  as  well  as  in 
taste,  odor,  and  drying  qualities,  it  has  much  resemblance  to 
linseed  oil,  from  which,  however,  it  differs  in  its  darker  color. 
Dr.  Adriani  has  shown  that  the  dark  brown-red  color  pos- 
sessed by  the  oil  does  not  pre-exist  in  the  seed,  but  that  it  is 
the  result  of  the  oxidation  of  a  yellowish-green  principle  that 
is  found  in  the  seed,  and  which  may  be  extracted  from  it  with 
unchanged  color,  if  precautions  to  exclude  the  air  be  adopted. 
Much  attention  has  been  given  in  some  quarters  to  the  utiliza- 
tion of  this  principle  as  a  dyeing  agent,  but  without  successful 
results. 
The  operation  of  refining  the  oil  consists  chiefly  in  heating 
it  with  a  weak  solution  of  caustic  potash  or  soda  (the  former 
by  preference.)  A  preliminary  treatment  of  the  oil  by  boiling 
water,  to  remove  mucilaginous  matters,  much  facilitates  the 
operation.  If  the  crude  oil  be  well  agitated  with  solution  of 
potash  without  the  application  of  heat,  the  mixture,  after  re- 
pose, will  yield  a  yellow  layer  of  "  refined  oil "  floating  upon 
an  aqueous  solution  that  is  nearly  black,  from  the  coloring 
matter  extracted  from  the  oil.  A  singular  purple-colored 
film  may  also  be  produced  upon  the  surface.  The  loss  in  re- 
fining is  stated  at  about  15  per  cent. 
I  have  only  to  add  a  few  remarks  upon  the  detection  of  this 
oil  when  mixed  with  olive  oil.  A  well-known  chemist,  whom 
I  regard  as  the  highest  authority  upon  the  subject  of  the  adul- 
teration of  oils,  tells  me  that  he  does  not  know  of  a  test  for 
this  purpose. 
