﻿Properties 
  of 
  C 
  avion 
  Dioxide 
  and 
  of 
  Ethane. 
  G27 
  

  

  the 
  third 
  line 
  which 
  passes 
  through 
  the 
  triple 
  point, 
  the 
  

   solid-vapour 
  line 
  or 
  fusion 
  curve. 
  The 
  result 
  is 
  that 
  

  

  — 
  =47 
  , 
  9 
  atmospheres 
  per 
  degree 
  centigrade. 
  The 
  dotted 
  

  

  line 
  which 
  we 
  drew 
  in 
  the 
  triple-point 
  diagram 
  contained 
  in 
  

   our 
  former 
  paper* 
  is 
  thus 
  seen 
  to 
  be 
  much 
  less 
  steep 
  than 
  it 
  

   ought 
  to 
  have 
  been 
  : 
  our 
  only 
  object 
  at 
  the 
  time 
  was 
  to 
  show 
  

   clearly 
  which 
  way 
  it 
  slopes. 
  According 
  to 
  Tammann's 
  mea- 
  

   surements 
  referred 
  to 
  above, 
  the 
  fusion 
  curve 
  rises 
  with 
  a 
  

   slight 
  curvature, 
  concave 
  towards 
  the 
  ^-axis, 
  starting 
  at 
  the 
  

   triple 
  point 
  with 
  a 
  rise 
  of 
  50 
  atmospheres 
  per 
  degree, 
  which 
  

   is 
  in 
  fair 
  agreement 
  with 
  the 
  result 
  of 
  our 
  calculation. 
  

  

  It 
  is 
  impossible 
  to 
  make 
  similar 
  calculations 
  with 
  regard 
  

   to 
  the 
  transformation 
  on 
  the 
  solid-vaponr 
  curve 
  owing 
  to 
  our 
  

   ignorance 
  of 
  the 
  volume 
  of 
  the 
  vapour. 
  Neither 
  the 
  law 
  of 
  

   corresponding 
  states 
  nor 
  the 
  diameter 
  law 
  is 
  applicable 
  to 
  

   this 
  curve. 
  An 
  approximate 
  result 
  may 
  be 
  obtained 
  by 
  using 
  

   the 
  gaseous 
  bvvs 
  and 
  assuming 
  the 
  volume 
  to 
  be 
  slightly 
  

   smaller 
  than 
  that 
  thus 
  obtained. 
  At 
  the 
  boi 
  ling-point 
  the 
  

   theoretical 
  gaseous 
  volume 
  is 
  362. 
  It 
  appeared 
  above 
  that 
  

   the 
  deviation 
  from 
  the 
  gaseous 
  laws 
  was 
  diminishing 
  as 
  the 
  

   temperature 
  fell 
  along 
  the 
  liquid-vapour 
  line 
  : 
  it 
  is 
  thus 
  

   unlikely 
  that 
  at 
  the 
  boiling-point 
  the 
  actual 
  volume 
  should 
  be 
  

   more 
  than 
  2 
  or 
  3 
  per 
  cent, 
  smaller 
  than 
  the 
  calculated 
  value. 
  

   If 
  we 
  assume 
  355 
  as 
  the 
  volume 
  w 
  T 
  e 
  cannot 
  be 
  very 
  far 
  wrong. 
  

   Calculating 
  the 
  latent 
  heat 
  of 
  sublimation 
  in 
  the 
  same 
  way 
  as 
  

   before, 
  we 
  find 
  at 
  the 
  boiling-point 
  — 
  78°*32, 
  121 
  calories. 
  

   This 
  result 
  is 
  not 
  in 
  good 
  agreement 
  with 
  the 
  number 
  found 
  

   experimentally 
  by 
  Behn, 
  — 
  112-1 
  -j\ 
  It 
  * 
  s 
  improbable 
  that 
  the 
  

   calculated 
  value 
  is 
  at 
  fault 
  ; 
  it 
  cannot 
  be 
  assumed 
  that 
  the 
  gas 
  

   volume 
  as 
  calculated 
  is 
  too 
  small, 
  and 
  the 
  only 
  other 
  experi- 
  

   mental 
  quantity 
  in 
  the 
  calculation 
  is 
  the 
  slope 
  of 
  the 
  vapour- 
  

   pressure 
  curve 
  at 
  the 
  boiling-point. 
  We 
  have 
  adopted 
  for 
  

   this 
  quantity 
  the 
  number 
  obtained 
  by 
  du 
  Bois 
  and 
  Wills 
  J, 
  

   our 
  own 
  readings 
  not 
  being 
  numerous 
  enough 
  near 
  that 
  point 
  

   to 
  determine 
  the 
  slope 
  with 
  sufficient 
  accuracy. 
  Our 
  curve, 
  

   as 
  far 
  as 
  it 
  went, 
  gave 
  a 
  number 
  agreeing 
  with 
  that 
  obtained 
  

   by 
  du 
  Bois 
  and 
  Wills. 
  We 
  must 
  therefore 
  conclude 
  that 
  

   Behn's 
  value 
  is 
  too 
  large, 
  although 
  we 
  cannot 
  say 
  why 
  it 
  

   should 
  be 
  so. 
  

  

  The 
  latent 
  heat 
  at 
  - 
  78°-32 
  being 
  121 
  and 
  at 
  -56°*24 
  

  

  * 
  Kuenen 
  and 
  Ttobson, 
  Phil. 
  Mag. 
  [6] 
  iii. 
  p. 
  149. 
  

  

  t 
  Behn, 
  Ann, 
  der 
  Phys. 
  i. 
  p. 
  272. 
  Favre 
  and 
  Silbermann 
  {Ann. 
  de 
  

   Chimie 
  et 
  de 
  Phys. 
  [3] 
  xxxvii. 
  p. 
  170) 
  found 
  142-2 
  calories, 
  

   \ 
  du 
  Bois 
  and 
  Wills. 
  /. 
  c. 
  

  

  