﻿90 
  

  

  Mr. 
  Gervaise 
  Le 
  Bus 
  

   1 
  T 
  s 
  

  

  on 
  

  

  While 
  the 
  values 
  of 
  ^ 
  ~ 
  are 
  very 
  similar 
  for 
  the 
  two 
  

  

  compounds 
  C 
  6 
  H 
  6 
  and 
  C 
  6 
  H 
  12 
  , 
  they 
  are 
  quite 
  different 
  from 
  

   the 
  value 
  attaching 
  to 
  5 
  H 
  12 
  . 
  The 
  difference 
  amounts 
  to 
  

   about 
  15 
  per 
  cent, 
  of 
  the 
  whole. 
  This 
  indicates 
  a 
  large 
  

   constitutive 
  effect 
  which 
  has 
  already 
  been 
  traced 
  to 
  ring- 
  

   structure. 
  

  

  In 
  order 
  to 
  show 
  the 
  great 
  probability 
  of 
  similar 
  additive 
  

   relations 
  being 
  observable 
  at 
  the 
  critical 
  point 
  as 
  at 
  the 
  

   boiling 
  point 
  in 
  the 
  case 
  of 
  the 
  homologues 
  of 
  benzene, 
  

   a 
  table 
  is 
  given 
  of 
  critical 
  coefficients 
  quoted 
  by 
  Guve 
  

   (Bull, 
  de 
  la 
  Soc. 
  Chim. 
  (3) 
  xiii. 
  p. 
  34). 
  These 
  are 
  shown 
  

  

  T 
  

  

  to 
  be 
  subject 
  to 
  a 
  nearly 
  constant 
  diminution 
  in 
  — 
  . 
  The 
  

  

  critical 
  temperatures 
  are 
  absolute 
  and 
  the 
  pressures 
  are 
  

   expressed 
  in 
  atmospheres. 
  

  

  Table 
  XXVI. 
  

   Table 
  of 
  Critical 
  Coefficients. 
  

  

  Compound. 
  

  

  

  Plus 
  2-1. 
  

  

  W. 
  

  

  (crit. 
  coeff.). 
  

  

  Hexane, 
  C 
  G 
  H 
  12 
  

  

  16-92 
  

  

  ... 
  

  

  38 
  

  

  •445 
  

  

  Octane, 
  C 
  S 
  H 
  18 
  

  

  22-58 
  

  

  

  50 
  

  

  •451 
  

  

  Decane, 
  C 
  T0 
  H 
  22 
  

  

  28-32 
  

  

  _ 
  

  

  62 
  

  

  •459 
  

  

  Benzene, 
  C\H 
  G 
  

  

  1125 
  

  

  13-35 
  

  

  30 
  

  

  •445 
  

  

  Toluene, 
  C 
  7 
  H 
  8 
  

  

  14-28 
  

  

  16 
  38 
  

  

  3(5 
  

  

  •455 
  

  

  o 
  Xylene, 
  O 
  H 
  H 
  10 
  

  

  17-091 
  

  

  

  

  

  m 
  ,, 
  

   P 
  

  

  g« 
  1707 
  

  

  1917 
  

  

  42 
  

  

  •45(5 
  

  

  Ethylbenzene 
  

  

  16-24 
  J 
  

  

  

  

  

  Propylbenzene, 
  C 
  H 
  J2 
  

  

  19-8 
  i 
  

  

  

  

  

  Mesitylene 
  

  

  193 
  il96 
  

  

  2170 
  

  

  48 
  

  

  ■452 
  

  

  Pseudocumene 
  C^Hti 
  

  

  19-7 
  1 
  

  

  

  

  

  Cyrnene 
  

  

  22-8 
  

  

  24-90 
  

  

  54 
  

  

  •461 
  

  

  When 
  the 
  number 
  attaching 
  to 
  benzene 
  and 
  its 
  homologues 
  

   is 
  augmented 
  by 
  2*10 
  and 
  the 
  sum 
  divided 
  by 
  the 
  valency 
  

   numbers, 
  the 
  quotients 
  are 
  found 
  to 
  be 
  about 
  equal 
  to 
  those 
  

   obtained 
  by 
  dividing 
  the 
  critical 
  coefficients 
  of 
  the 
  paraffin 
  

   hydrocarbons 
  by 
  their 
  respective 
  valency 
  numbers. 
  It 
  must 
  

  

  T 
  

  

  therefore 
  be 
  concluded 
  thai 
  2'3 
  represents 
  the 
  change 
  in 
  p 
  K 
  

  

  paraffins 
  to 
  the 
  aromatic 
  

  

  which 
  occurs 
  on 
  passing 
  from 
  tl 
  

  

  Compounds. 
  Since 
  Y 
  K 
  = 
  

  

  X 
  constant, 
  the 
  molecular 
  

  

  