250        The  Production  and  Uses  of  Cotton-seed  Oil.  {^iSS^StT^' 
seed  will  yield  two  gallons  of  oil.  There  are  four  qualities  of  oil 
made.  The  crude  oil  is  of  a  dirty  yellow  to  reddish  color;  on  stand- 
ing it  deposits  a  slimy  sediment.  The  second  quality  has  a  pale 
orange  color,  and  is  obtained  by  refining  the  crude  oil  with  a  solu- 
tion of  caustic  soda.  The  yellow  oil  resulting  from  this  process  is 
further  purified  by  being  heated  and  allowed  to  settle  again,  or  by 
filtration,  and  is  called  "yellow  summer  oil."  "Winter  yellow  oil"  is 
made  from  the  above  material  by  chilling  it,  until  it  partially  crys- 
tallizes, and  separating  the  stearin  (about  25  per  cent.)  in  presses, 
similar  to  those  used  for  lard. 
This  is  then  treated  with  fuller's  earth  in  a  tank,  which  holds 
back  the  coloring  matter,  and  the  oil  which  issues  from  the  filter 
press  is  almost  white. 
In  1893,  there  were  probably  1,250,000  tons  of  cotton  seed 
crushed  in  the  United  States.  From  this  seed  there  were  obtained 
1,000,000  barrels  of  oil.  It  is  estimated  that  300,000  barrels  were 
used  in  Chicago  for  making  oil  lard  ;  and  St.  Louis,  Kansas  City 
and  Omaha  took  200,000  for  the  same  purpose.  About  250,000 
barrels  went  to  Holland  for  making  margarine,  and  large  quantities 
to  Southern  Europe  for  mixing  with  olive  oil. 
Cotton-seed  oil  appears  to  be  useful  for  table  purposes,  and  it  is 
desirable  that  its  use  in  the  pure  state,  rather  than  as  a  mixture, 
should  be  encouraged.  It  ought,  however,  to  be  sold  on  its  merits, 
and  with  the  addition  of  some  qualifying  term,  which  will  indicate 
its  origin. 
This  oil  has  entirely  replaced  olive  oil  in  America,  and  there  is 
scarcely  a  restaurant  in  London  or  Paris  in  which  this  new  "  salad 
oil "  has  not  taken  the  place  of  the  old  Lucca  product.  In  Portugal 
every  means  are  now  taken  to  prevent  the  sophistication  of  olive  oil 
with  cotton-seed  oil,  or  passing  it  off  as  a  food  oil  of  the  same  value 
as  olive  oil. 
For  pharmaceutical  purposes  cotton-seed  oil  cannot  be  regarded 
as  a  good  substitute  for  olive  oil.  It  saponifies  with  difficulty  as  a 
drying  oil,  and  the  coloration  which  it  gives  with  nitric  acid  shows 
that  if  used  for  any  preparation  liable  to  oxidation  it  may  give 
curious  results.  The  density  of  crude  cotton-seed  oil  is  0  920  to 
o  933,  and  when  refined  0-925  to  0.930. 
To  distinguish  cotton-seed  oil  from  olive  oil,  take  pure,  colorless 
nitric  acid  of  the  density  of  1-40  and  mix  it  with  half  the  quantity 
