﻿462 
  Seventh 
  Annual 
  Report 
  of 
  the 
  

  

  (2) 
  rosin 
  oil; 
  (3) 
  excessive 
  heating 
  or 
  unusual 
  addition 
  of 
  metallic 
  

   oxides. 
  

  

  2. 
  The 
  Action 
  of 
  Bkomine 
  or 
  Iodine 
  on 
  the 
  Oil. 
  

  

  Linseed 
  oil 
  ia 
  largely 
  composed 
  of 
  constituents 
  wliich 
  ai*e 
  un- 
  

   saturated, 
  and 
  -wliicli 
  can, 
  therefore, 
  combine 
  by 
  direct 
  addition 
  

   with 
  2, 
  4, 
  or 
  G 
  atoms 
  of 
  bromine 
  or 
  iodine. 
  Of 
  the 
  adulterants 
  

   of 
  linseed 
  oil, 
  mineral 
  and 
  rosin 
  oils 
  and 
  rosin 
  itself 
  ix)ssess 
  thi^ 
  

   power 
  only 
  to 
  a 
  slig-ht 
  degi-ee, 
  and 
  none 
  of 
  the 
  other 
  adulterants 
  

   except 
  menhaden 
  oil 
  ix)esess 
  it 
  in 
  as 
  high 
  a 
  degree 
  as 
  linseed 
  oil. 
  

   Beside 
  the 
  principle 
  action 
  of 
  bromine 
  or 
  iodine 
  upon 
  linseed 
  oil, 
  

   i. 
  e., 
  direct 
  addition 
  of 
  halogen, 
  another 
  action 
  takes 
  place 
  by 
  

   which 
  one-half 
  of 
  the 
  lialog'en 
  which 
  disappears 
  enters 
  into 
  oombiiia- 
  

   tion 
  with 
  the 
  oil, 
  and 
  the 
  other 
  half 
  combines 
  with 
  hydrogen 
  which 
  

   the 
  fii*st 
  half 
  has 
  supplanted 
  in 
  the 
  oil. 
  

  

  The 
  substitution 
  of 
  bromine 
  or 
  iodine 
  for 
  hydrogen 
  goes 
  on 
  to 
  

   only 
  a 
  slight 
  extent 
  ■^^ith 
  seed 
  oils 
  and 
  with 
  glycerides 
  in 
  general, 
  

   but 
  with 
  rosin, 
  rosin 
  oil, 
  and 
  mineral 
  oils, 
  the 
  case 
  is 
  very 
  different. 
  

   It 
  has 
  been 
  proved 
  by 
  the 
  author 
  that 
  when 
  bromine 
  acts 
  upon 
  

   rosin 
  and 
  uiX)ii 
  rosin 
  oil, 
  although 
  a 
  large 
  amount 
  of 
  bromine 
  is 
  

   changed 
  from 
  the 
  free 
  into 
  the 
  combined 
  state, 
  almost 
  all 
  of 
  the 
  

   bromine 
  is 
  taken 
  up 
  by 
  the 
  rosin 
  or 
  oil 
  by 
  substitution, 
  and 
  not 
  

   by 
  addition, 
  and 
  in 
  the 
  case 
  of 
  ordinary 
  American 
  mineral 
  oUs, 
  that 
  

   taken 
  up 
  by 
  substitution 
  is 
  a 
  large 
  projx>rtion 
  of 
  the 
  total 
  absorp- 
  

   tion. 
  

  

  The 
  process 
  in 
  most 
  common 
  use 
  for 
  detennining 
  the 
  percentage 
  

   of 
  halogen 
  absorbed 
  by 
  oils 
  is 
  kno^^^l 
  as 
  the 
  Hubl 
  process, 
  and 
  

   though, 
  by 
  its 
  use, 
  valuable 
  indications 
  as 
  to 
  the 
  purity 
  and 
  value 
  

   of 
  linseed 
  oil 
  are 
  obtained, 
  it 
  unfortunately 
  does 
  not 
  distinguish 
  

   between 
  the 
  ]x>wer 
  of 
  the 
  oil 
  to 
  absorb 
  halogen 
  by 
  addition 
  and 
  

   the 
  power 
  it 
  likewise 
  possesses 
  of 
  absorbing 
  halogen 
  by 
  substitu- 
  

   tion. 
  The 
  Hubl 
  process, 
  on 
  this 
  account, 
  fails 
  to 
  discriminate 
  

   closely 
  l>etween 
  rosin, 
  which 
  is 
  one 
  of 
  the 
  likeliest 
  constituents 
  of 
  a 
  

   linseed 
  oil 
  substitute, 
  and 
  linseed 
  oil 
  itself, 
  as 
  the 
  Hubl 
  figures 
  for 
  

   both 
  substances 
  are 
  nearlv 
  the 
  same. 
  

  

  