﻿442 
  

  

  MR 
  W. 
  J. 
  M. 
  RANKINE 
  ON 
  THE 
  COMPUTATION 
  

  

  The 
  first 
  term 
  of 
  this 
  expression 
  corresponds 
  to 
  the 
  formula 
  employed 
  by 
  

   M. 
  Regnault. 
  To 
  correct 
  the 
  results 
  given 
  in 
  his 
  table 
  of 
  experiments, 
  we 
  must, 
  

   therefore, 
  subtract 
  from 
  each 
  of 
  them 
  the 
  quantity 
  

  

  (P-ct)p 
  

  

  K 
  1>2( 
  T 
  3 
  - 
  T 
  2) 
  

  

  As 
  T 
  x 
  and 
  T 
  2 
  were 
  always 
  low 
  temperatures, 
  I 
  have 
  treated 
  K 
  15 
  2 
  as 
  a 
  con- 
  

   stant 
  quantity 
  in 
  computing 
  the 
  corrections, 
  its 
  value 
  being 
  

  

  In 
  feet 
  per 
  degree 
  of 
  Fahrenheit, 
  . 
  

  

  In 
  feet 
  per 
  centigrade 
  degree, 
  

  

  In 
  metres 
  per 
  centigrade 
  degree, 
  . 
  

  

  Number. 
  

  

  772 
  

   1389-6 
  

   423-54 
  

  

  Common 
  

   Logarithm. 
  

  

  2-8876173 
  

   3-1428898 
  

   2-6268944 
  

  

  In 
  the 
  following 
  table, 
  the 
  numbers 
  in 
  the 
  first 
  column 
  refer 
  to 
  certain 
  groups 
  

   of 
  experiments 
  in 
  M. 
  Regnault's 
  table, 
  the 
  mean 
  results 
  of 
  which 
  are 
  given 
  in 
  

   the 
  succeeding 
  columns. 
  

  

  The 
  correction, 
  which 
  is 
  scarcely 
  appreciable 
  for 
  temperatures 
  near 
  the 
  ordi- 
  

   nary 
  boiling 
  point, 
  increases 
  rapidly 
  as 
  the 
  temperature 
  in 
  the 
  boiler 
  rises. 
  

  

  The 
  temperatures 
  are 
  all 
  stated 
  according 
  to 
  the 
  scale 
  of 
  a 
  centigrade 
  ah* 
  ther- 
  

   mometer. 
  

  

  Table 
  I. 
  

  

  Reference 
  to 
  

  

  M. 
  Regnault's 
  

  

  Experiments. 
  

  

  T, 
  

  

  T 
  2 
  

  

  T 
  3 
  

  

  E-2, 
  3 
  

   Kl,2 
  

  

  as 
  computed 
  by 
  

   M. 
  Regnault. 
  

  

  Correction 
  to 
  

   be 
  subtracted. 
  

  

  K2, 
  3 
  

   El, 
  2 
  

  

  Corrected. 
  

  

  1,2,3. 
  

  

  11-97 
  

  

  20-77 
  

  

  10f-79 
  

  

  100384 
  

  

  0-00009 
  

  

  1-00375 
  

  

  4, 
  5, 
  6, 
  7. 
  

  

  8-39 
  

  

  17-70 
  

  

  109-29 
  

  

  1-00665 
  

  

  0-00010 
  

  

  1-00655 
  

  

  26, 
  27, 
  28, 
  29. 
  

  

  12-96 
  

  

  26-31 
  

  

  159-74 
  

  

  1-00871 
  

  

  0-00092 
  

  

  1-00779 
  

  

  30, 
  31, 
  32, 
  33. 
  

  

  8-95 
  

  

  23-94 
  

  

  172-69 
  

  

  1-01140 
  

  

  0-00121 
  

  

  1-01019 
  

  

  36, 
  37, 
  38. 
  

  

  12-97 
  

  

  28-69 
  

  

  18651 
  

  

  101581 
  

  

  0-00162 
  

  

  1-01419 
  

  

  Empirical 
  Formulae. 
  

  

  The 
  results 
  of 
  experiment, 
  as 
  thus 
  corrected, 
  agree 
  very 
  nearly 
  with 
  those 
  of 
  

   the 
  following 
  empirical 
  formula, 
  in 
  which 
  K 
  is 
  the 
  apparent 
  specific 
  heat 
  of 
  liquid 
  

   water 
  at 
  the 
  temperature 
  T, 
  and 
  K 
  , 
  its 
  apparent 
  specific 
  heat 
  at 
  the 
  tempera- 
  

   ture 
  T 
  , 
  which 
  is 
  that 
  of 
  the 
  maximum 
  density 
  of 
  water 
  ; 
  viz., 
  4°-l 
  centigrade, 
  

   or 
  39°-4 
  Fahr. 
  

  

  a 
  is 
  a 
  constant 
  coefficient, 
  whose 
  value 
  is, 
  

  

  For 
  the 
  centigrade 
  scale, 
  

   For 
  Fahrenheit's 
  scale, 
  . 
  

  

  0000001 
  

   0-000000309 
  

  

  