﻿Adsorption 
  of 
  Hydrogen 
  hy 
  Carbon. 
  927 
  

  

  The 
  effects 
  of 
  this 
  considerable 
  disturbance 
  had 
  vanished 
  

   in 
  less 
  than 
  14 
  minutes, 
  which 
  observation 
  affords 
  a 
  maximum 
  

   value 
  for 
  the 
  time 
  required 
  for 
  surface 
  equilibrium 
  and 
  for 
  

   thermal 
  effects. 
  Indeed 
  even 
  this 
  must 
  be 
  mainly 
  attributed 
  

   to 
  the 
  diffusion 
  simultaneously 
  involved. 
  Part 
  of 
  the 
  diffu- 
  

   sion 
  is 
  further 
  due 
  to 
  the 
  fact 
  that 
  rather 
  more 
  gas 
  wa.s 
  taken 
  

   out 
  than 
  was 
  added. 
  

  

  Surface 
  Action 
  at 
  Higher 
  Pressure. 
  

  

  Since 
  the 
  amount 
  of 
  solid 
  solution 
  is 
  proportional 
  to 
  the 
  

   square 
  root 
  of 
  the 
  pressure 
  (see 
  later), 
  whereas 
  the 
  amount 
  

   of 
  adsorption 
  varies 
  only 
  with 
  the 
  cube 
  root 
  of 
  the 
  pressure, 
  

   diffusion 
  must 
  be 
  much 
  more 
  prominent 
  at 
  higher 
  pressure. 
  

   For 
  this 
  reason 
  the 
  isolation 
  of 
  the 
  time 
  required 
  for 
  surface 
  

   action 
  is 
  much 
  more 
  difficult. 
  No 
  attempt 
  was 
  made 
  in 
  the 
  

   following 
  experiment 
  to 
  minimise 
  this 
  disturbing 
  diffusion 
  

   factor. 
  The 
  procedure 
  was 
  as 
  before, 
  except 
  that 
  the 
  

   hydrogen 
  was 
  removed 
  by 
  quickly 
  opening 
  the 
  connexion 
  

   to 
  the 
  Toepler 
  pump 
  and 
  then 
  the 
  same 
  amount 
  of 
  gas 
  was 
  

   replaced 
  a 
  few 
  minutes 
  later. 
  

  

  Table 
  XI. 
  

  

  Eemarks. 
  

  

  Time. 
  

  

  Pressure. 
  

  

  Difference. 
  

  

  1 
  Removed 
  gas 
  

  

  ! 
  Put 
  gas 
  in 
  again 
  

  

  minute. 
  

   

  

  3 
  minutes. 
  

   3 
  

  

  4 
  

  

  6 
  

   11 
  

   24 
  

   70 
  

  

  4 
  hours. 
  

  

  161-3 
  mm. 
  

  

  120 
  mm. 
  

  

  175-3 
  mm. 
  

   165-7 
  „ 
  

   163-6 
  „ 
  

   162-5 
  „ 
  

   160-9 
  „ 
  

   160-6 
  „ 
  

  

  - 
  9-6 
  n»m. 
  

   -11-7 
  „ 
  

   -12-8 
  „ 
  

   -14-4 
  „ 
  

   -14-7 
  „ 
  

  

  i 
  

   i 
  

  

  Solubility 
  at 
  Higher 
  Pressure. 
  

  

  As 
  would 
  be 
  expected 
  from 
  the 
  relatively 
  great 
  import- 
  

   ance 
  of 
  diffusion 
  at 
  higher 
  pressure 
  no 
  alternation 
  was 
  

   here 
  observed 
  in 
  the 
  sign 
  of 
  the 
  pressure 
  changes 
  when 
  

   carrying 
  out 
  experiments 
  of 
  the 
  type 
  of 
  those 
  in 
  Table 
  YII. 
  

  

  