﻿Adsorption 
  of 
  Hydrogen 
  hy 
  Carbon. 
  

  

  919 
  

  

  liquid 
  air 
  employed 
  to 
  surround 
  the 
  carbon 
  bulb 
  was 
  not 
  

   constant. 
  The 
  rise 
  in 
  temperature 
  is 
  very 
  slow, 
  as 
  Travers 
  

   has 
  already 
  mentioned 
  * 
  ; 
  but 
  after 
  about 
  a 
  dozen 
  hours 
  it 
  

   begins 
  to 
  compensate 
  for 
  the 
  fall 
  in 
  pressure 
  due 
  to 
  the 
  slow 
  

   completion 
  of 
  the 
  absorption 
  of 
  the 
  gas. 
  Thus 
  in 
  all 
  cases 
  

   the 
  pressure 
  begins 
  to 
  rise 
  after 
  ten 
  or 
  twelve 
  hours, 
  due 
  to 
  

   the 
  evolution 
  of 
  gas 
  from 
  the 
  carbon 
  with 
  rising 
  temperature. 
  

   The 
  two 
  experiments 
  quoted 
  below 
  give 
  an 
  idea 
  of 
  the 
  rate 
  

   of 
  sorption 
  of 
  hydrogen. 
  In 
  both 
  cases 
  the 
  gas 
  was 
  placed 
  

   in 
  the 
  apparatus 
  at 
  room 
  temperature, 
  and 
  the 
  carbon 
  bulb 
  

   then 
  immersed 
  in 
  liquid 
  air. 
  

  

  Table 
  I. 
  

  

  These 
  experiments 
  demonstrate 
  the 
  extreme 
  rapidity 
  Avith 
  

   which 
  the 
  main 
  amount 
  of 
  the 
  gas 
  is 
  taken 
  up 
  (chiefly 
  surface 
  

   condensation), 
  and 
  further 
  that 
  the 
  absorption 
  of 
  gas 
  extends 
  

   over 
  at 
  least 
  a 
  dozen 
  hours, 
  a 
  fact 
  which 
  cannot 
  be 
  attributed 
  

   to 
  temperature 
  changes. 
  It 
  will 
  be 
  noted 
  that 
  the 
  carbon 
  

   had 
  been 
  previously 
  in 
  contact 
  with 
  the 
  gas 
  at 
  room 
  tempera- 
  

   ture 
  at 
  a 
  hundred-fold 
  pressure, 
  and 
  that 
  this 
  did 
  not 
  prevent 
  

   the 
  slow 
  diffusion 
  effect 
  (see 
  p. 
  930). 
  

  

  Supersaturated 
  Surface, 
  Empty 
  Interior. 
  

  

  These 
  experiments 
  are 
  considered 
  to 
  be 
  the 
  most 
  important 
  

   described 
  in 
  the 
  present 
  paper, 
  and 
  they 
  were 
  repeated 
  a 
  

   dozen 
  times 
  with 
  entirely 
  consistent 
  results. 
  The 
  procedure 
  

   was 
  as 
  follows 
  : 
  — 
  Carbon 
  freed 
  from 
  gas 
  by 
  exposure 
  to 
  a 
  

   vacuum 
  was 
  cooled 
  in 
  liquid 
  air 
  for 
  at 
  least 
  an 
  hour. 
  A 
  

   measured 
  amount 
  of 
  hydrogen 
  was 
  then 
  admitted, 
  and 
  after 
  

   a 
  few 
  minutes 
  a 
  measured 
  portion 
  removed. 
  The 
  apparatus 
  

  

  cit. 
  p. 
  14. 
  

  

  3Q2 
  

  

  