﻿630 
  Thermal 
  Properties 
  of 
  Carbon 
  Dioxide 
  and 
  Ethane. 
  

  

  Table 
  Y. 
  contains 
  the 
  values 
  of 
  the 
  latent 
  heats 
  thus 
  found. 
  

   It 
  will 
  be 
  noticed 
  that 
  the 
  change 
  of 
  this 
  quantity 
  with 
  tem- 
  

   perature, 
  except 
  at 
  the 
  lowest 
  temperature, 
  follows, 
  on 
  the 
  

   whole, 
  the 
  same 
  law 
  as 
  for 
  carbon 
  dioxide. 
  From 
  the 
  critical 
  

  

  Table 
  Y. 
  

   Latent 
  Heat 
  of 
  Ethane. 
  

  

  Temperature. 
  

  

  Vapour 
  

   Volume. 
  

  

  Liquid 
  

   Volume. 
  

  

  dp 
  

   df 
  

  

  L. 
  

   Ill 
  

  

  c 
  

  

  -74 
  7 
  

  

  256 
  

  

  1-9 
  

  

  •091 
  

  

  -57-0 
  

  

  133 
  

  

  20 
  

  

  •169 
  

  

  110 
  

  

  -42:9 
  

  

  81-1 
  

  

  21 
  

  

  •224 
  

  

  99 
  

  

  -31-75 
  

  

  57-8 
  

  

  21 
  

  

  •301 
  

  

  98 
  

  

  -19-4 
  

  

  39-6 
  

  

  22 
  

  

  •390 
  

  

  90 
  

  

  - 
  3-65 
  

  

  25-3 
  

  

  2-4 
  

  

  •548 
  

  

  82 
  

  

  + 
  7-8 
  

  

  178 
  

  

  2-60 
  

  

  •678 
  

  

  70 
  

  

  + 
  17-7 
  

  

  1287 
  

  

  286 
  

  

  •772 
  

  

  54-5 
  

  

  +22-9 
  

  

  1050 
  

  

  305 
  

  

  •855 
  

  

  45-7 
  

  

  + 
  26-17 
  

  

  910 
  

  

  322 
  

  

  

  

  +29-3 
  

  

  7-84 
  

  

  345 
  

  

  

  

  +32-05 
  

  

  4-84 
  

  

  4-84 
  

  

  

  

  point 
  downwards 
  it 
  first 
  rises 
  quickly, 
  then 
  more 
  slowly, 
  and 
  

   ultimately 
  begins 
  to 
  rise 
  more 
  quickly 
  again, 
  the 
  last 
  value 
  

   being, 
  however, 
  smaller 
  than 
  the 
  last 
  but 
  one. 
  The 
  irregu- 
  

   larities 
  are 
  doubtless 
  due 
  to 
  the 
  irregularities 
  in 
  the 
  value 
  

  

  of 
  -~. 
  When 
  we 
  compare 
  with 
  each 
  other 
  the 
  slopes 
  as 
  

  

  read 
  from 
  the 
  curves 
  for 
  carbon 
  dioxide 
  and 
  ethane 
  at 
  corre- 
  

   sponding 
  temperatures, 
  we 
  find 
  that 
  the 
  ratio 
  of 
  the 
  slopes 
  

   varies 
  from 
  1°59 
  to 
  1*74, 
  the 
  average 
  being 
  1*65- 
  Irregu- 
  

   larities 
  of 
  an 
  amount 
  up 
  to 
  5 
  per 
  cent, 
  are 
  thus 
  accounted 
  for. 
  

   It 
  need 
  not 
  be 
  explained 
  how 
  difficult 
  it 
  is, 
  even 
  by 
  means 
  of 
  

   a 
  flexible 
  rule, 
  to 
  draw 
  a 
  perfectly 
  satisfactory 
  curve 
  through 
  

   a 
  comparatively 
  small 
  number 
  of 
  experimental 
  points, 
  and 
  

   again 
  how 
  easily 
  the 
  slope 
  of 
  the 
  curve, 
  especially 
  near 
  its 
  

   end, 
  may 
  be 
  slightly 
  over- 
  or 
  under-estimated. 
  Our 
  chief 
  

   object 
  was 
  to 
  obtain 
  a 
  rough 
  idea 
  of 
  the 
  value 
  of 
  the 
  latent 
  

   heat 
  of 
  ethane, 
  for 
  the 
  sake 
  of 
  comparison 
  with 
  carbon 
  dioxide 
  

   and 
  mixtures 
  of 
  the 
  two 
  substances. 
  

  

  University 
  College, 
  Dundee. 
  

  

  