﻿478 
  Seventh 
  .V.nmal 
  liKi'oirr 
  oi- 
  the 
  

  

  oil. 
  Refractive 
  index. 
  

  

  Linseed 
  oil 
  1.484 
  to 
  1.488 
  at 
  15° 
  C. 
  

  

  Cottonseed 
  oil 
  1 
  . 
  475 
  at 
  15° 
  C. 
  

  

  Rosin 
  oil 
  1 
  . 
  5:J5 
  to 
  1 
  . 
  549 
  at 
  18° 
  C. 
  

  

  Mineral 
  oil 
  1 
  . 
  438 
  to 
  1 
  . 
  507 
  • 
  

  

  Turix-ntine 
  oil 
  1 
  , 
  4G4 
  to 
  1 
  . 
  474 
  

  

  Rosin 
  (eolopliony) 
  1 
  . 
  548 
  

  

  Com 
  oil 
  1 
  . 
  478 
  at 
  20° 
  

  

  The 
  Action 
  on 
  Polaeized 
  Light. 
  

   The 
  nse 
  of 
  the 
  polariscope 
  is 
  very 
  limited 
  in 
  tci-ting 
  linseed 
  oil. 
  

   Little 
  has 
  been 
  done 
  with 
  it, 
  and 
  its 
  value 
  in 
  this 
  connection 
  seems 
  

   to 
  be 
  confined 
  to 
  the 
  detection 
  of 
  rosin 
  oil, 
  which 
  is 
  dextro-rotiiiy. 
  

   Valenta 
  finds 
  its 
  rotaiy 
  power 
  to 
  bo 
  30°-40°, 
  and 
  Demski 
  and 
  

   Morawski 
  find 
  it 
  to 
  be 
  50°. 
  American 
  oil 
  of 
  turpentine 
  deviates 
  

   polarized 
  light 
  to 
  the 
  rig-ht, 
  while 
  the 
  French 
  oil 
  of 
  tnrjientine 
  de- 
  

   viates 
  to 
  the 
  left. 
  Mineral 
  oils 
  have 
  no 
  rotatory 
  |X)wer, 
  or 
  only 
  

   a 
  slight 
  one, 
  and, 
  according 
  to 
  Bishop, 
  vegetable 
  oils, 
  A\ith 
  the 
  ex- 
  

   ception 
  of 
  sesame 
  oil, 
  rotate 
  to 
  the 
  left. 
  Therefore, 
  a 
  right-handed 
  

   rotation 
  in 
  a 
  sample 
  of 
  linseed 
  oil 
  is 
  indicative 
  of 
  rosin 
  oil. 
  

  

  The 
  Best 
  Tests 
  to 
  Apply 
  in 
  Analyzing 
  Linseed 
  Oils. 
  

   In 
  examining 
  linseed 
  oil 
  for 
  adulteration 
  it 
  will 
  ii^nallv 
  be 
  foimd 
  

   adA'isable 
  to 
  make 
  the 
  following 
  determinations: 
  

  

  1. 
  Determine 
  the 
  specific 
  gra\aty 
  at 
  15°. 
  5 
  C, 
  water 
  at 
  the 
  same 
  

   temperature 
  being 
  taken 
  as 
  1.000. 
  This 
  should 
  be 
  between 
  .931 
  

   and 
  .937 
  for 
  raw 
  oil, 
  and 
  between 
  .931 
  and 
  .950 
  for 
  boiled 
  oil. 
  

  

  2. 
  Determine 
  the 
  bromine 
  addition 
  figure 
  and 
  the 
  bromine 
  sub- 
  

   stitution 
  figTire. 
  The 
  former 
  should 
  be 
  between 
  100 
  and 
  110 
  and 
  

   the 
  latter 
  should 
  not 
  be 
  higher 
  than 
  5, 
  though 
  it 
  may 
  rarely, 
  in 
  a 
  

   pure 
  oil, 
  be 
  as 
  hig-h 
  as 
  7, 
  probably 
  from 
  the 
  presence 
  of 
  an 
  unusual 
  

   amount 
  of 
  nonfatty 
  matter 
  extracted 
  with 
  the 
  oil 
  from 
  the 
  seed. 
  

   The 
  figures 
  to 
  be 
  expected 
  are 
  the 
  same 
  for 
  raw 
  oil 
  and 
  boiled 
  oil 
  

   as 
  now 
  made. 
  

  

  3. 
  Test 
  for 
  volatile 
  oil 
  by 
  the 
  odor 
  and 
  determine 
  the 
  amount 
  

   present 
  by 
  distillation 
  with 
  steam. 
  There 
  should 
  be 
  none. 
  

  

  4. 
  Determine 
  the 
  amount 
  of 
  nonvolatile 
  unsaponifiable 
  material. 
  

   There 
  should 
  be 
  less 
  than 
  2.5 
  per 
  cent 
  in 
  either 
  raw 
  or 
  boiled 
  oil. 
  

  

  5. 
  Determine 
  the 
  acid 
  figure. 
  It 
  should 
  be 
  less 
  than 
  5 
  in 
  either 
  

  

  