Am.  Jour.  Pharm.  ) 
Sept.,  1921.  S 
Determination  of  Camphor. 
603 
The  values  indicated  by  *  are  probably  accounted  for  by  the 
oxidation  of  the  oils  proceeding  faster  in  presence  of  camphor  than 
when  heated  alone.  This  view  is  confirmed  by  the  iodine  values, 
above  obtained,  being  smaller  for  the  oils  from  which  camphor  had 
been  volatilized  than  for  the  oils  heated  alone  for  the  same  length  of 
time;  if  so,  it  would  follow  that  the  gains  recorded  under  (Blank 
Oil),  representing  the  increase  in  weight  of  the  oils  due  to  oxidation 
on  heating  the  oils  alone,  are  slightly  less  than  should  actually  be 
added  to  the  "apparent  loss"  to  give  the  actual  loss. 
From  these  determinations,  which  have  been  limited  to  the  ex- 
amination of  one  sample  of  each  oil,  camphor  in  camphorated  oil 
may  be  determined  from  the  loss  in  weight  on  heating  in  platinum' 
dishes  at  120°  C.  for  five  hours  in  the  case  of  cottonseed,  four  hours 
in  the  case  of  peanut  and  olive,  and  three  hours  in  the  case  of  sesame 
oil,  after  adding  0.35,  0.26,  0.27  and  minus  0.042  per  cent.,  re- 
spectively, of  the  four  grams  of  oil  taken  for  the  experiments. 
OPTICAL  ROTATIONS. 
The  optical  rotations  of  the  camphorated  oils  were  determined 
by  a  half-shadow,  single  wedge  compensatin  saccharimeter,  using  a 
nitrogen  lamp  as  source  of  light.  To  eliminate,  as  far  as  possibe,  the 
difference  in  the  colors  of  the  field  of  view  a  cell  containing  two 
centimeters  thickness  of  10  per  cent,  bichromate  solution  was  placed 
between  the  light  and  illuminating  lens.  An  appreciable  difference 
was  noted  when  observations  were  made  at  one  time  with  and  at 
other  times  without  the  dichromate  cell.  The  reading  recorded 
are  the  average  of  several  measurements  and  are  for  a  200  mm.  tube 
at  200  C. 
TABLE  VI. 
Oil. 
Cottonseed  . 
Peanut  
Olive  ...... 
Sesame  .... 
Rotation 
of  Oil, 
—0-45°  V. 
—0.1 
0.2 
2.85 
Rotation 
of  Campho- 
rated Oil 
56.6°  V. 
56.90 
574 
59.25 
Absolute 
Rotation.. 
57.05°  V. 
57.00 
57.20 
56.40 
Angular 
Rotation. 
19.79  ang. 
19.72 
19.82 
19.56 
Angular 
Rotation  for 
1%  Camphor. 
0.989  ang. 
0.986 
0.991 
0.978 
From  these  results  the  calculated  angular  rotation  for  a  200  mm. 
tube  is  about  0.98-0.99  for  each  per  cent,  of  camphor  for  solutions  of 
standard  pharmacopceial  strength. 
