AmJ^me'i8P87arm•}      BecM  s  Test  for  Cotton-Seed  Oil  283 
influence  upon  the  reaction,  so  characteristic  with  oil  of  cotton.  It  is 
sufficient  to  say,  that  the  results  show  that  they  have  none,  and  the 
Commission  find  that  the  test  is  therefore  limited  to  that  fixed  oil  alone. 
The  cotton  seed  oil  was  added  in  20  per  cent,  proportion,  when  used 
with  both  oils  of  olive  and  benne  (in  the  secondary  tests),  which  latter 
two  were  evenly  divided  (i.  e.  40  per  cent.),  while  the  oil  of  sesame 
was  added  in  equal  parts  to  olive  oil,  prior  to  the  application  of  the 
primary  tests. 
Series  E. — Rape  oil  of  different  origins,  alone,  and  mixed  with  cot- 
ton oil. 
The  Commission,  in  view  of  the  importance  that  oil  of  rape  obtains 
in  the  application  of  Bechi's  test,  examined  seven  oils  of  various 
qualities,  derived  from  different  provinces.  From  these  experiments, 
the  assertion  is  made,  that  while  several  of  the  finest  samples  in  the 
pure,  undiluted  state,  furnished  a  noticeable  change  in  the  formation 
of  a  reddish-brown  color,  this  was  always  made  very  much  darker  if 
20  per  cent,  of  cotton  seed  oil  wTas  previously  added ;  and,  on  the 
other  hand,  if  the  rape  oil  examined  was  previously  diluted  with  pure 
olive  oil  or  amylic  alcohol,  as,  for  example,  in  the  proportions  used  by 
Prof.  Bechi  in  his  test,  no  change  whatever  was  evinced. 
Finally  the  Commission  wishing  to  see  if  a  variation  of  the  propor- 
tion of  the  reagents  would  more  clearly  demonstrate  results,  used  a 
stronger  solution  of  silver  nitrate,  and  found  that  the  brownish  color 
could  be  made  to  vary  from  brown  to  black,  according  to  the  quantity 
of  the  silver  salt  added.  After  numerous  experiments,  they  decided 
that  the  original  proportions  wTere  the  best  ones  to  adopt,  in  that  the 
test  would  be  much  more  delicate,  and  would  not,  under  any  circum- 
stances, be  caused  by  the  rape  oil. 
To  examine  olive  oil  for  admixed  cotton  oil,  with  Bechi's  method, 
the  Commission  recommend  the  division  of  the  suspected  sample  into 
three  parts,  as  follows  : 
No.  1.  Tube  of  the  suspected  oil  and  reagents. 
No.  2.  Tube  of  the  suspected  oil  and  20  per  cent,  of  cotton  oil,  and 
the  reagents. 
No.  3.  Tube  of  the  suspected  oil  and  reagents. 
Now  expose  tubes  No.  1.  and  No.  2.  to  the  heat  of  boiling  water 
for  5  or  10  minutes,  but  do  not  heat  tube  No.  3;  use  it  simply  as  a 
guide  to  see  if  No.  1.  remains  unaffected  by  heat  or  becomes  colored.  If 
the  sample  is  pure,  the  oil  will  remain  unchanged,  that  is  the  same  in 
