﻿the 
  Porous 
  Plug 
  Experiment, 
  

  

  Table 
  III. 
  

   Constant 
  Temperature 
  Experiments. 
  

  

  167 
  

  

  Time. 
  

  

  Temperature. 
  

  

  i 
  

  

  

  

  31-6 
  

   34-42 
  

   33-23 
  

   G340 
  

   34-0 
  

   G, 
  34-0 
  

   34-65 
  

  

  5m 
  

  

  lOm 
  

  

  15m 
  

  

  20m. 
  15s 
  

  

  24m 
  lOs 
  

  

  29m. 
  10s. 
  

  

  

  The 
  average 
  rate 
  of 
  rise 
  of 
  temperature 
  during 
  the 
  escape 
  

   of 
  the 
  gas 
  was 
  0°'142 
  per 
  minute. 
  

  

  G 
  and 
  Gi 
  mark 
  the 
  commenoement 
  and 
  cessation 
  of 
  flow 
  

   o£ 
  the 
  gas. 
  

  

  Table 
  IY. 
  

   Constant 
  Temperature 
  Experiments. 
  

  

  Weight 
  

   of 
  gas. 
  

  

  Time 
  of 
  

   escape. 
  

  

  Heat 
  

   absorbed. 
  

  

  Calculated 
  

   fall 
  of 
  T. 
  

  

  Pressure 
  

   of 
  gas. 
  

  

  Cooling 
  per 
  

   atmosphere. 
  

  

  4-52 
  

  

  7m. 
  45s. 
  

  

  260 
  

  

  267-5 
  

  

  473 
  

  

  1-128 
  

  

  4o2 
  

  

  7m. 
  55s 
  

  

  296 
  

  

  312 
  

  

  473 
  

  

  1-31 
  

  

  4-67 
  

  

  9m. 
  303. 
  

  

  308 
  

  

  314 
  

  

  487 
  

  

  1-20 
  

  

  4-53 
  

  

  5m. 
  20s. 
  

  

  249 
  

  

  262 
  

  

  474 
  

  

  1103 
  

  

  The 
  numbers 
  in 
  the 
  last 
  column 
  do 
  not 
  agree 
  very 
  well, 
  

   but 
  the 
  values 
  are 
  very 
  much 
  of 
  the 
  same 
  order 
  as 
  those 
  of 
  

   the 
  other 
  experiments, 
  and 
  the 
  variations 
  indicate 
  the 
  order 
  

   of 
  the 
  differences 
  met 
  with 
  in 
  about 
  50 
  experiments. 
  

  

  iSo 
  very 
  great 
  accuracy 
  can 
  be 
  claimed 
  for 
  these 
  experi- 
  

   ments, 
  especially 
  for 
  those 
  conducted 
  below 
  the 
  critical 
  

   temperature, 
  as 
  there 
  is 
  some 
  uncertainty 
  as 
  to 
  the 
  correct 
  

   value 
  to 
  be 
  taken 
  for 
  the 
  latent 
  heat, 
  and 
  also 
  the 
  value 
  of 
  

   the 
  specific 
  heat 
  must 
  be 
  continually 
  changing 
  under 
  the 
  

   great 
  changes 
  in 
  pressure 
  ; 
  but 
  the 
  method 
  seems 
  promising 
  

   if 
  carried 
  out 
  with 
  more 
  refined 
  apparatus 
  than 
  is 
  at 
  present 
  

   at 
  the 
  author's 
  disposal. 
  A 
  piece 
  of 
  apparatus 
  is 
  now 
  under 
  

  

  