﻿588 
  

  

  MR 
  W. 
  J. 
  M. 
  RANKINE 
  ON 
  THE 
  

  

  /^ 
  v 
  =-/]?f^ 
  D 
  =- 
  p 
  .MT7 
  h 
  ^ 
  ,0 
  s 
  D 
  4/D 
  dI) 
  ) 
  ' 
  < 
  u3) 
  

  

  For 
  carbonic 
  acid, 
  the 
  first 
  of 
  these 
  formulae 
  becomes 
  simply 
  

  

  ♦p.y.rS-ft-a)^-*)} 
  

  

  and 
  the 
  second, 
  > 
  . 
  . 
  (113 
  A.) 
  

  

  Glasgow, 
  27th 
  December 
  1852. 
  

  

  APPENDIX. 
  

  

  Note 
  A 
  (to 
  Article 
  58). 
  Since 
  this 
  section 
  was 
  read, 
  the 
  theoretical 
  views 
  

   relative 
  to 
  the 
  relation 
  between 
  heat 
  and 
  temperature 
  contained 
  in 
  it 
  and 
  the 
  

   previous 
  sections 
  of 
  this 
  paper, 
  have 
  received 
  a 
  strong 
  confirmation 
  by 
  the 
  publi- 
  

   cation 
  by 
  M. 
  Regnault 
  of 
  the 
  fact, 
  that 
  he 
  has 
  found 
  the 
  specific 
  heat 
  of 
  air 
  to 
  

   be 
  sensibly 
  constant 
  at 
  all 
  temperatures 
  from 
  -30° 
  centigrade 
  to 
  +225°, 
  and 
  at 
  

   all 
  pressures 
  from 
  one 
  to 
  ten 
  atmospheres 
  (Comities 
  Rendus, 
  18th 
  April 
  1853); 
  

   so 
  that 
  equal 
  lengths 
  on 
  the 
  scale 
  of 
  the 
  air 
  thermometer 
  represent 
  equal 
  quanti- 
  

   ties 
  of 
  heat. 
  

  

  Note 
  B 
  (to 
  Article 
  62). 
  Until 
  very 
  recently, 
  there 
  existed 
  no 
  exact 
  experi- 
  

   mental 
  determination 
  of 
  the 
  specific 
  heat 
  of 
  any 
  gas. 
  The 
  specific 
  heat 
  of 
  air 
  at 
  

   constant 
  pressure, 
  as 
  compared 
  with 
  that 
  of 
  water, 
  was 
  calculated 
  theoretically 
  

   in 
  the 
  previous 
  part 
  of 
  this 
  paper, 
  from 
  Joule's 
  equivalent 
  and 
  the 
  velocity 
  of 
  

   sound, 
  and 
  found 
  to 
  be 
  0*24. 
  This 
  value 
  has 
  since 
  been 
  confirmed 
  very 
  closely 
  

   by 
  Mr 
  Joule's 
  experiments, 
  whose 
  mean 
  result 
  was 
  0-23, 
  and 
  still 
  more 
  exactly 
  

   by 
  M. 
  Regnault's 
  experiments, 
  already 
  referred 
  to, 
  which 
  give 
  the 
  value 
  23 
  79. 
  

   The 
  following 
  table 
  shews 
  the 
  results 
  of 
  the 
  application 
  of 
  the 
  formulae 
  of 
  this 
  

   paper 
  to 
  the 
  specific 
  heats 
  of 
  five 
  different 
  gases 
  at 
  constant 
  pressure, 
  selected 
  

   from 
  M. 
  Regnault's 
  table 
  (Comptes 
  Rendus, 
  18th 
  April), 
  as 
  being 
  those 
  in 
  which 
  

   the 
  velocity 
  of 
  sound 
  can 
  be 
  computed, 
  and 
  has 
  been 
  determined 
  experimentally. 
  

   The 
  table 
  shews 
  also 
  a 
  comparison 
  of 
  the 
  calculated 
  and 
  observed 
  velocities 
  of 
  

   sound. 
  This 
  table 
  appeared 
  originally, 
  in 
  French 
  measures, 
  in 
  the 
  Philosophical 
  

   Magazine 
  for 
  June 
  1853 
  : 
  the 
  metres 
  are 
  here 
  reduced 
  to 
  feet. 
  Kp, 
  K 
  v 
  , 
  and 
  K„, 
  

   are 
  expressed 
  in 
  feet 
  of 
  fall 
  per 
  centigrade 
  degree. 
  K 
  w 
  (Joule's 
  equivalent) 
  

   = 
  1389-6. 
  

  

  