﻿926 
  Dr. 
  J. 
  W. 
  McBain 
  on 
  the 
  Meclianism 
  of 
  the 
  

  

  amount 
  of 
  hydrogen 
  was 
  71 
  c.c. 
  (corr.) 
  of 
  which 
  19 
  c.c. 
  (corr.) 
  

   was 
  removed. 
  

  

  Table 
  IX. 
  

  

  Eemarks. 
  

  

  Time. 
  

  

  Pressure. 
  

  

  Difference. 
  

  

  Eemoved 
  gas 
  

  

  0-7i 
  minutes. 
  

  

  

  

  

  8 
  

  

  8-43 
  mm. 
  

  

  

  

  

  10 
  

  

  8-51 
  „ 
  

  

  + 
  008 
  mm. 
  

  

  

  12 
  ., 
  

  

  8-55 
  „ 
  

  

  + 
  012 
  „ 
  

  

  , 
  

  

  14 
  „ 
  

  

  8-60 
  „ 
  

  

  + 
  0-17 
  „ 
  

  

  ! 
  

  

  19 
  ., 
  

  

  8-68 
  „ 
  

  

  + 
  0-25 
  „ 
  

  

  i 
  

  

  26 
  

  

  8-76 
  „ 
  

  

  + 
  0-33 
  „ 
  1 
  

  

  i 
  

  

  60 
  „ 
  

  

  8-88 
  „ 
  

  

  4-0M5 
  „ 
  ! 
  

  

  1 
  

  

  5 
  hours. 
  

  

  9-22 
  „ 
  

  

  + 
  0-79 
  ,, 
  1 
  

  

  ! 
  

  

  21 
  

  

  1016 
  „ 
  

  

  + 
  1-73 
  „ 
  

  

  i 
  

  

  As 
  expected, 
  the 
  sign 
  of 
  the 
  pressure-change 
  is 
  constant. 
  

  

  Surface 
  Equilihrium. 
  

  

  It 
  is 
  clear 
  that 
  adsorption 
  does 
  not 
  take 
  much 
  time, 
  for 
  in 
  

   one 
  experiment 
  quoted 
  later 
  (Table 
  XV.) 
  carbon 
  was 
  ex- 
  

   posed 
  to 
  gas 
  at 
  a 
  pressure 
  of 
  1200 
  mm. 
  at 
  room 
  temperature. 
  

   It 
  took 
  only 
  65 
  seconds 
  to 
  plunge 
  the 
  whole 
  of 
  the 
  carbon 
  

   bulb 
  into 
  liquid 
  air, 
  but 
  meanwhile 
  the 
  pressure 
  had 
  fallen 
  

   to 
  .35 
  mm. 
  

  

  But 
  while 
  the 
  initial 
  stages 
  o£ 
  the 
  surface 
  condensation 
  

   may 
  consequently 
  be 
  enormously 
  rapid, 
  it 
  does 
  not 
  follow 
  

   that 
  the 
  final 
  equilibrium 
  value 
  is 
  fully 
  attained 
  in 
  such 
  a 
  

   short 
  time. 
  The 
  following 
  experiment 
  was 
  carried 
  out 
  in 
  

   order 
  to 
  test 
  this 
  point. 
  The 
  carbon 
  bnlb 
  was 
  allowed 
  to 
  

   stand 
  for 
  a 
  daj^ 
  in 
  liquid 
  air 
  with 
  59 
  c.c. 
  (corr.) 
  hydrogen. 
  

   Then 
  a 
  measured 
  amount 
  of 
  gas 
  was 
  added 
  and 
  almost 
  im- 
  

   mediately 
  removed 
  again. 
  

  

  Table 
  X. 
  

  

  Remarks. 
  

  

  Time. 
  

  

  Pressure. 
  

  

  Difference. 
  

  

  Put 
  in 
  12-49 
  c.c. 
  (corr.) 
  

  

  minute. 
  

  

  _ 
  

  

  _ 
  

  

  

  I 
  

  

  35-H 
  mm. 
  

  

  — 
  

  

  

  2^ 
  minutes. 
  

  

  34-5 
  „ 
  

  

  — 
  

  

  Removed 
  13-14 
  c.c. 
  (corr.) 
  ... 
  

  

  3-5 
  „ 
  

  

  — 
  

  

  

  

  

  n 
  .. 
  

  

  20-26 
  mm. 
  

  

  — 
  

  

  

  9| 
  „ 
  

  

  20 
  35 
  „ 
  

  

  + 
  0-09 
  mm. 
  

  

  

  13 
  „ 
  

  

  20 
  40 
  „ 
  

  

  + 
  0-14 
  „ 
  

  

  

  19 
  

  

  20-47 
  „ 
  

  

  + 
  0-21 
  „ 
  

  

  

  47 
  

  

  20-47 
  „ 
  

  

  + 
  0-21 
  „ 
  

  

  

  88 
  

  

  20-49 
  „ 
  

  

  + 
  0-23 
  „ 
  

  

  