346 
BEHAVIOUll  OF  PALM  OIL  WHEN  HEATED. 
the  palm  oil  was  bleached  in  this  manner;  and  although  still  some- 
what brownish,  was  quite  as  white  as  the  best  palm  oil  bleached 
according  to  Payen's  method.  It  had  the  consistence  of  hog's 
lard,  an  empyreumatic  odor,  the  peculiar  odor  of  palm-oil  having 
entirely  disappeared,  and  a  wax-like  taste.  The  portion  of  the 
heated  palm-oil  which  had  not  been  poured  into  water  was  still 
fluid  after  standing  two  hours  at  72°-5  F.,  and  the  separation  of  a 
solid  body  only  commenced  in  three  hours.  After  nineteen  hours, 
a  third  part  was  still  fluid,  and  a  brownish-red  oil  flowed  sponta- 
neously from  the  fatty  mass,  amounting  to  about  one  twenty-fifth 
of  the  whole.  In  the  course  of  sixty  hours,  even  this  oil  solidi- 
fied into  a  brownish-white  mass.  The  bleaching  of  palm- 
oil  therefore  takes  place  under  the  above  circumstances  in  a  short 
time,  as  completely  as  by  Payen's  process  in  ten  or  twelve  hours. 
It  was  now  to  be  ascertained  whether  the  access  of  light  and 
air  was  necessary  for  the  bleaching  ;  and  to  settle  this  point,  palm- 
oil  was  heated  in  a  covered  vessel,  and  in  the  dark,  to  475°  F., 
and  left  to  cool  after  exposure  to  this  temperature  for  ten  minutes. 
The  palm-oil  was,  as  before,  completely  bleached.  At  this  high 
temperature,  therefore,  the  destruction  of  the  yellowish-red  color- 
ing matter  is  not  affected  either  by  the  action  of  light,  or  by  oxida- 
tion at  the  expense  of  the  atmospheric  oxygen. 
To  find  the  lowest  temperature  at  which  this  rapid  bleaching 
can  be  advantageously  effected,  palm-oil  was  heated  in  twenty- 
four  minutes  to  410°  F.,  and  kept  at  this  temperature  for  six  min- 
utes ;  on  cooling  it  was  certainly  lighter  in  color,  but  not  perfectly 
bleached.  Heated  in  fifteen  minutes  to  419°  F.,  and  kept  in  this 
temperature  for  fifteen  minutes  more,  the  palm  oil  was  lighter  in 
color  than  in  the  preceding  case,  but  still  not  sufficiently  bleached. 
When  kept  at  469°.4  F.  for  fifteen  minutes,  it  appeared  com- 
pletely decolorized.  Lastly,  when  palm  oil  was  heated  in  twelve 
minutes  to  464°  F.,  a  sample  drawn  at  once  still  retained  a  yellow 
color  ;  but  in  five  minntes  it  was  colorless.  From  the  above  ex- 
periments it  appears  that  when  palm-oil  is  quickly  heated  to  464° 
F.,  and  kept  for  a  few  minutes  at  this  temperature,  it  is  perfectly 
bleached  without  access  of  air  or  light.  The  author  has  not  only 
tried  this  mode  of  bleaching  on  a  large  scale,  but  it  has  been  car- 
fifed  out  for  three  years  in  a  manufactory.  The  heating  of  the 
palm-oil  is  effected  as  rapidly  as  possible  in  cast-iron  pans ;  it  is 
