﻿400 
  Sevkntji 
  Aknual 
  IvEroRT 
  ov 
  THE 
  

  

  wliich 
  combine 
  the 
  greatest 
  ease 
  with 
  the 
  best 
  accord 
  wdth 
  pub- 
  

   lished 
  date, 
  that 
  the 
  gravity 
  should 
  be 
  determined 
  at 
  15°. 
  5 
  C, 
  water 
  

   at 
  the 
  same 
  temperature 
  being 
  taken 
  as 
  imity. 
  Almost 
  all 
  the 
  

   determinations 
  of 
  specific 
  gravity 
  given 
  in 
  this 
  report 
  were 
  mp.de 
  

   under 
  these 
  conditions. 
  

  

  The 
  specific 
  gra^^ty 
  of 
  linseed 
  oil 
  may 
  be 
  taken 
  with 
  the 
  greatest 
  

   accuracy 
  by 
  means 
  of 
  a 
  specific 
  gra\dty 
  bottle, 
  the 
  weight 
  of 
  which 
  

   ia 
  determined, 
  empty, 
  full 
  of 
  water 
  at 
  15°. 
  5 
  C, 
  and 
  filled 
  with 
  the 
  

   oil 
  to 
  bo 
  examined 
  at 
  the 
  same 
  temperature. 
  Another 
  very 
  con- 
  

   venient 
  lal)oratory 
  method 
  having 
  only 
  sKghtly 
  inferior 
  accuracy, 
  

   and 
  the 
  method 
  by 
  which 
  almost 
  all 
  the 
  determinations 
  given 
  in 
  

   this 
  report 
  were 
  obtained, 
  is 
  an 
  application 
  of 
  the 
  principle 
  of 
  

   Mohr's 
  hydrostatic 
  balance, 
  by 
  using 
  a 
  plummet 
  vdth 
  the 
  ordinary 
  

   analytical 
  balance. 
  For 
  rougher 
  work, 
  a 
  delicate 
  hydrometer 
  may 
  

   be 
  used. 
  

  

  The 
  specific 
  gravity 
  of 
  raw 
  linseed 
  oil 
  is 
  given 
  by 
  Allen's 
  Oomm. 
  

   Org. 
  Anal., 
  3d 
  ed., 
  Vol. 
  2, 
  Part 
  1, 
  p. 
  147, 
  as 
  generally 
  about 
  .935, 
  

   but 
  varying 
  from 
  .931 
  to 
  .937. 
  The 
  temperature 
  is 
  not 
  stated, 
  but 
  

   it 
  is 
  presimiably 
  15°. 
  5 
  C. 
  These 
  limits 
  are 
  the 
  same 
  as 
  those 
  set 
  

   in 
  Benedikt, 
  Analyse 
  der 
  Fette 
  und 
  Wachsarten, 
  3 
  Aufl., 
  p. 
  429, 
  

   and 
  no 
  oils 
  of 
  undoubted 
  purity 
  which 
  I 
  have 
  examined 
  have 
  fallen 
  

   outside 
  of 
  these 
  limits. 
  It 
  may, 
  therefore, 
  be 
  stated 
  as 
  an 
  estab- 
  

   lished 
  fact 
  that 
  if 
  an 
  oil 
  lias 
  a 
  specific 
  gravity 
  at 
  15°. 
  5 
  C, 
  water 
  at 
  

   the 
  same 
  temperature 
  being 
  unity, 
  that 
  is, 
  below 
  .931 
  or 
  above 
  

   .937, 
  is 
  not 
  pure 
  raw 
  linseed 
  oil. 
  

  

  The 
  lower 
  limit 
  to 
  the 
  specific 
  gravity 
  of 
  boiled 
  linseed 
  oil 
  may, 
  

   without 
  fear, 
  be 
  set 
  at 
  the 
  same 
  point, 
  .931, 
  because 
  a 
  linseed 
  

   oil 
  can 
  only 
  become 
  heavier 
  by 
  heating 
  vrith. 
  access 
  of 
  air 
  and 
  

   the 
  addition 
  of 
  metallic 
  oxides. 
  " 
  Bunghole 
  " 
  oils 
  made 
  with 
  

   driers 
  containing 
  benzine 
  may 
  have 
  lower 
  specific 
  gi'avities. 
  The 
  

   upper 
  limit 
  to 
  the 
  gravity 
  it 
  is 
  difiicult 
  and, 
  indeed, 
  impossible 
  to 
  

   set, 
  because 
  genuine 
  linseed 
  oil 
  may 
  be 
  raised 
  to 
  .950 
  or 
  higher 
  by 
  

   continued 
  heating, 
  though 
  it 
  is 
  not 
  commonly 
  above 
  .940. 
  

  

  