﻿934 
  Adsorption 
  of 
  Hydrogen 
  hy 
  Carhon. 
  

  

  urged 
  against 
  the 
  experiments 
  with 
  hydrogen, 
  nor 
  against 
  the 
  

   methods 
  employed 
  in 
  the 
  present 
  pnper. 
  

  

  No 
  mention 
  has 
  been 
  made 
  in 
  the 
  preceding 
  pages 
  of 
  the 
  

   large 
  evohition 
  of 
  heat 
  which 
  accompanies 
  sorption. 
  It 
  will 
  

   certainly 
  influence 
  some 
  of 
  the 
  methods 
  employed, 
  as 
  sorption 
  

   is 
  very 
  sensitive 
  to 
  temperature 
  changes. 
  Fortunately, 
  

   however, 
  the 
  experimental 
  results 
  cannot 
  be 
  ascribed 
  to 
  such 
  

   effects. 
  Most 
  probably 
  the 
  effects 
  of 
  these 
  heat 
  changes 
  

   would 
  be 
  in 
  the 
  very 
  opposite 
  direction 
  to 
  those 
  observed 
  in 
  

   each 
  case 
  ; 
  this 
  is 
  practically 
  certain 
  in 
  Table 
  VIII. 
  where 
  

   the 
  manipulation 
  was 
  very 
  rapid. 
  However, 
  Table 
  II. 
  may 
  

   be 
  discussed 
  ; 
  immediately 
  after 
  the 
  final 
  removal 
  of 
  gas 
  the 
  

   carbon 
  must 
  be 
  either 
  warmer 
  or 
  colder 
  than 
  the 
  liquid-air 
  

   bath. 
  In 
  the 
  first 
  case 
  the 
  above 
  sentence 
  holds 
  good, 
  the 
  

   temperature 
  influence 
  would 
  be 
  opposed 
  to 
  the 
  observed 
  

   pressure 
  changes. 
  The 
  second 
  case 
  is 
  obscure 
  unless 
  it 
  is 
  

   clearly 
  kept 
  in 
  mind 
  that 
  throughout 
  the 
  whole 
  period 
  from 
  

   *' 
  14 
  minutes 
  " 
  to 
  a 
  couple 
  of 
  hours 
  later 
  the 
  carbon 
  is 
  not 
  

   saturated 
  with 
  hydrogen 
  even 
  at 
  the 
  higher 
  final 
  temperature 
  ; 
  

   hence 
  if 
  sorption 
  be 
  simple 
  and 
  not 
  dual 
  in 
  its 
  nature 
  the 
  

   observed 
  intermediate 
  rise 
  of 
  pressure 
  is 
  a 
  priori 
  impossible. 
  

   A 
  division 
  of 
  the 
  total 
  surface 
  condensation 
  into 
  more 
  

   accessible 
  and 
  less 
  accessible 
  regions 
  does 
  not 
  sufiice 
  to 
  meet 
  

   this 
  difficulty, 
  for 
  it 
  ultimately 
  leads 
  to 
  the 
  untenable 
  

   alternative 
  explanation 
  of 
  my 
  experimental 
  results 
  — 
  that 
  a 
  

   considerable 
  fraction 
  of 
  the 
  surface 
  of 
  coconut 
  carbon, 
  at 
  the 
  

   very 
  lowest 
  estimate 
  one-seventh, 
  is 
  so 
  inaccessible 
  that 
  a 
  

   dozen 
  hours 
  are 
  necessary 
  for 
  hydrogen 
  to 
  come 
  fully 
  into 
  

   contact 
  with 
  it. 
  Similar 
  reasoning 
  holds 
  for 
  Table 
  YIII. 
  

  

  Finally 
  there 
  remains 
  but 
  one 
  objection 
  to 
  be 
  discussed. 
  

   The 
  apparent 
  after 
  diffusion 
  effect 
  cannot 
  be 
  caused 
  by 
  slow 
  

   chemical 
  action 
  ; 
  for 
  it 
  always 
  ceased 
  after 
  some 
  hoars, 
  and 
  

   further 
  no 
  difference 
  could 
  be 
  detected 
  in 
  the 
  amount 
  of 
  

   hydrogen 
  before 
  and 
  after 
  the 
  experiment. 
  

  

  Summary. 
  

  

  1. 
  It 
  is 
  considered 
  that 
  the 
  ^^ 
  adsorption 
  " 
  of 
  hydrogen 
  

   by 
  carbon 
  has 
  been 
  definitely 
  proven 
  to 
  consist 
  of 
  a 
  surface 
  

   condensation 
  and 
  a 
  diffusion 
  (solid 
  solution) 
  into 
  the 
  

   interior 
  of 
  the 
  carbon. 
  

  

  2. 
  The 
  surface 
  condensation 
  is 
  nearly 
  instantaneous 
  at 
  the 
  

   temperature 
  of 
  liquid 
  air, 
  requiring 
  only 
  a 
  few 
  minutes 
  io 
  

   maximo 
  ; 
  whereas 
  the 
  diffusion 
  requires 
  about 
  twelve 
  hours. 
  

  

  .3. 
  Various 
  experimental 
  methods 
  have 
  been 
  elaborated 
  for 
  

   the 
  isolation 
  and 
  study 
  of 
  these 
  phenomena. 
  

  

  