﻿626 
  Prof. 
  Kuenen 
  and 
  Mr. 
  Robson 
  on 
  the 
  Thermal 
  

  

  There 
  are 
  no 
  direct 
  measurements 
  of 
  this 
  quantity 
  below 
  

   0° 
  C. 
  with 
  which 
  our 
  results 
  might 
  be 
  compared. 
  Our 
  result 
  

   at 
  0° 
  C. 
  agrees 
  with 
  the 
  number 
  obtained 
  by 
  Chappuis 
  *, 
  

   which 
  is 
  contained 
  in 
  Mathias's 
  table 
  f. 
  The 
  comparison 
  

   above 
  0° 
  between 
  calculated 
  and 
  observed 
  values 
  was 
  made 
  

   by 
  Mathias 
  himself 
  and 
  by 
  Tsuruta 
  J, 
  to 
  whose 
  paper 
  we 
  had 
  

   unfortunately 
  no 
  access. 
  Mathias 
  also 
  gives 
  a 
  formula 
  pro- 
  

   posed 
  by 
  Cailletet 
  and 
  himself 
  from 
  which 
  the 
  latent 
  heat 
  

   may 
  be 
  calculated 
  : 
  — 
  

  

  \ 
  2 
  =117-303(31-0--466(31-0 
  2 
  . 
  

  

  Above 
  0° 
  this 
  formula 
  agrees 
  very 
  well 
  with 
  experiment 
  ; 
  at 
  

   temperatures 
  below 
  0° 
  the 
  differences 
  between 
  our 
  results 
  and 
  

   the 
  calculated 
  values 
  ultimately 
  increase 
  in 
  magnitude, 
  as 
  

   shown 
  by 
  the 
  last 
  column 
  of 
  Table 
  II. 
  More 
  particularly 
  

   there 
  is 
  no 
  evidence 
  of 
  a 
  maximum 
  in 
  the 
  latent 
  heat 
  as 
  given 
  

   by 
  the 
  quadratic 
  formula. 
  Our 
  results 
  seem 
  to 
  show 
  that, 
  

   starting 
  from 
  the 
  critical 
  temperature, 
  the 
  latent 
  heat 
  first 
  

   rises 
  quickly, 
  then 
  more 
  slowly, 
  and 
  at 
  very 
  low 
  temperatures 
  

   more 
  quickly 
  again. 
  

  

  Latent 
  Meat 
  at 
  the 
  Triple 
  Point. 
  — 
  By 
  interpolation 
  in 
  

   Table 
  II. 
  we 
  are 
  now 
  able 
  to 
  obtain 
  the 
  value 
  of 
  the 
  latent 
  

   heat 
  of 
  evaporation 
  at 
  the 
  triple 
  point. 
  Our 
  result 
  is 
  

   86*1 
  calories. 
  

  

  Table 
  III. 
  

   Triple 
  Point 
  of 
  Carbon 
  Dioxide. 
  

  

  Temp. 
  Pressure. 
  Y 
  v 
  . 
  Yi. 
  V 
  s 
  . 
  lii 
  v 
  . 
  L 
  S 
  y. 
  JjsI. 
  

  

  -56^24 
  5-10 
  74 
  -850 
  -076 
  , 
  8(rl 
  129-9 
  43-8 
  

  

  % 
  =-224 
  -337 
  47-9 
  

  

  at 
  

  

  In 
  order 
  to 
  obtain 
  the 
  latent 
  heat 
  of 
  sublimation 
  of 
  the 
  

   solid 
  at 
  this 
  point 
  the 
  volume 
  of 
  the 
  solid 
  is 
  required. 
  Behn 
  § 
  

   finds 
  for 
  the 
  density 
  at 
  —78° 
  the 
  value 
  1*53. 
  Assuming 
  that 
  

   the 
  solid 
  expands 
  about 
  half 
  as 
  much 
  as 
  the 
  liquid, 
  the 
  

   density 
  at 
  the 
  triple 
  point 
  must 
  be 
  about 
  1*48. 
  For 
  the 
  latent 
  

   heat 
  of 
  sublimation 
  we 
  now 
  obtain 
  129'9 
  calories. 
  

  

  By 
  subtraction 
  the 
  latent 
  heat 
  of 
  fusion 
  is 
  found 
  to 
  be 
  

  

  • 
  ■ 
  * 
  do 
  

  

  43' 
  8 
  calories. 
  From 
  this 
  figure 
  we 
  may 
  now 
  deduce 
  -~- 
  for 
  

  

  * 
  Chappuis, 
  Ann. 
  de 
  CJiirn. 
  et 
  Phys. 
  [6] 
  xv. 
  p. 
  514. 
  

  

  t 
  Mathias, 
  /. 
  c. 
  p. 
  57. 
  

  

  X 
  Tsuruta, 
  Journal 
  der 
  Phys. 
  [3] 
  ii. 
  p. 
  272. 
  

  

  § 
  BeJm, 
  Ann. 
  der 
  Physik, 
  iii. 
  p. 
  733. 
  

  

  