﻿228 
  

  

  Mr. 
  J. 
  Rose-Innes 
  on 
  Lord 
  Kelvin* 
  s 
  Absolute 
  

  

  very 
  well 
  in 
  the 
  case 
  of 
  air. 
  For 
  carbonic 
  acid, 
  however, 
  

   the 
  results 
  furnished 
  by 
  this 
  rule 
  are 
  not 
  so 
  satisfactory, 
  as 
  

   may 
  be 
  seen 
  by 
  inspecting 
  the 
  table 
  given 
  by 
  him 
  comparing 
  

   the 
  actual 
  with 
  the 
  theoretical 
  cooling 
  effect 
  (loc. 
  cit. 
  p. 
  429). 
  

   Moreover 
  in 
  the 
  case 
  of 
  hydrogen 
  it 
  is 
  found 
  that 
  there 
  is 
  a 
  

   heating 
  effect, 
  which 
  increases, 
  if 
  anything, 
  when 
  the 
  tempe- 
  

   rature 
  rises, 
  so 
  that 
  here 
  the 
  law 
  of 
  the 
  inverse 
  square 
  of 
  the 
  

   temperature 
  is 
  wholly 
  inapplicable. 
  It 
  seemed 
  to 
  me 
  that 
  it 
  

   might 
  be 
  possible 
  to 
  hit 
  upon 
  some 
  simple 
  algebraic 
  expres- 
  

   sion 
  which 
  should 
  reproduce 
  the 
  experimental 
  results 
  rather 
  

   better 
  than 
  Lord 
  Kelvin's 
  rule 
  does 
  ; 
  and 
  in 
  fact 
  it 
  was 
  found 
  

   that 
  a 
  satisfactory 
  agreement 
  between 
  observation 
  and 
  calcu- 
  

   lation 
  might 
  be 
  obtained 
  by 
  putting 
  

  

  cooling 
  effect 
  = 
  m—ft, 
  

  

  where 
  a 
  and 
  f3 
  are 
  constants 
  characteristic 
  of 
  the 
  gas, 
  and 
  T 
  

   is 
  the 
  absolute 
  temperature. 
  

  

  The 
  following 
  values 
  of 
  a 
  and 
  ft 
  were 
  found 
  from 
  the 
  

   experimental 
  data 
  : 
  — 
  

  

  Air 
  441*5 
  

  

  Carbonic 
  acid 
  . 
  . 
  2615 
  

   Hydrogen 
  . 
  . 
  . 
  64*1 
  

  

  A 
  comparison 
  of 
  the 
  actual 
  results 
  with 
  those 
  calculated 
  by 
  

   the 
  new 
  formula 
  is 
  given 
  in 
  the 
  following 
  table 
  : 
  — 
  

  

  /3- 
  

  

  •697 
  

   4-98 
  

   •331 
  

  

  Name 
  of 
  

   Gas. 
  

  

  Temp. 
  

  

  Actual 
  cooling 
  

   effect. 
  

  

  Calculated 
  cooling- 
  

   effect 
  

   (Kelvin's 
  formula). 
  

  

  Calculated 
  cooling 
  

  

  effect 
  

  

  (New 
  formula). 
  

  

  Air 
  

  

  o 
  

   

  

  71 
  

  

  P 
  92 
  

  

  •88 
  

  

  o 
  

   •92 
  

  

  •87 
  

  

  •920 
  

   •879 
  

  

  

  

  39-5 
  

  

  •75 
  

  

  •70 
  

  

  •716 
  

  

  

  92-8 
  

  

  •51 
  

  

  •51 
  

  

  •510 
  

  

  Carbonic 
  

  

  

  

  4-64 
  

  

  4-64 
  

  

  4-60 
  

  

  

  7-4 
  

  

  4-37 
  

  

  4-40 
  

  

  4-35 
  

  

  

  35-6 
  

  

  341 
  

  

  363 
  

  

  3-49 
  

  

  

  54-0 
  

  

  295 
  

  

  3-23 
  

  

  3-02 
  

  

  

  93-5 
  

  

  2-16 
  

  

  2-57 
  

  

  2-16 
  

  

  

  97-5 
  

  

  2-14 
  

  

  2-52 
  

  

  2-08 
  

  

  Hydrogen 
  . 
  

  

  4-5 
  

  

  -o-ioo 
  

  

  

  -•100 
  

  

  

  910 
  

  

  - 
  -155 
  

  

  

  -•155 
  

  

  It 
  will 
  be 
  seen 
  that 
  the 
  formula 
  proposed 
  in 
  this 
  paper, 
  

   regarded 
  simply 
  as 
  an 
  empirical 
  formula, 
  is 
  more 
  efficient 
  

  

  