﻿920 
  

  

  Dr. 
  J. 
  W. 
  McBain 
  on 
  the 
  Mechanism 
  of 
  the 
  

  

  was 
  then 
  left 
  to 
  itself 
  and 
  pressure 
  readings 
  were 
  taken 
  at 
  

   suitable 
  intervals 
  extending 
  over 
  the 
  next 
  twenty-four 
  hours. 
  

   l^osv 
  after 
  carbon 
  has 
  been 
  exposed 
  for 
  a 
  few 
  minutes 
  to 
  

   gas 
  the 
  surface-condensation 
  comes 
  into 
  equilibrium 
  with 
  the 
  

   pressure 
  of 
  the 
  gas. 
  Immediately 
  following 
  the 
  reduction 
  of 
  

   the 
  pressure 
  by 
  removal 
  of 
  some 
  of 
  the 
  hydrogen 
  from 
  the 
  

   apparatus, 
  the 
  surface 
  was 
  in 
  a 
  state 
  of 
  supersaturation 
  and 
  

   quickly 
  threw 
  off 
  gas, 
  and 
  thus 
  the 
  pressure 
  actually 
  rose 
  for 
  

   a 
  few 
  minutes 
  in 
  spite 
  of 
  the 
  fact 
  that 
  the 
  interior 
  of 
  the 
  

   carbon 
  was 
  nearly 
  destitute 
  of 
  dissolved 
  hydrogen. 
  But 
  

   after 
  the 
  first 
  few 
  minutes 
  the 
  diffusion 
  into 
  the 
  interior 
  which 
  

   had 
  been 
  going 
  on 
  continuously, 
  once 
  more 
  resumed 
  the 
  upper 
  

   hand, 
  and 
  the 
  pressure 
  now 
  fell 
  for 
  hours. 
  Three 
  experiments 
  

   are 
  cited 
  in 
  illustration 
  of 
  this. 
  In 
  Table 
  II. 
  the 
  amount 
  o£ 
  

   liquid 
  air 
  was 
  insufficient 
  and 
  the 
  rise 
  in 
  temperature 
  was 
  

   rapid 
  and 
  continuous. 
  

  

  Table 
  II. 
  

  

  Kemarks. 
  

  

  Time. 
  

  

  Pressure. 
  

  

  Difference. 
  

  

  Put 
  in 
  77 
  '55 
  c.c. 
  (corr.) 
  H2... 
  

  

  0-1^ 
  minute. 
  

  

  49-0 
  mm. 
  

  

  _ 
  

  

  Took 
  out 
  39-28 
  c.c. 
  (corr.) 
  ... 
  

  

  4^-14 
  minutes. 
  

  

  — 
  

  

  — 
  

  

  

  16^ 
  „ 
  

  

  8-23 
  mm. 
  

  

  — 
  

  

  

  18^ 
  „ 
  

  

  8-35 
  „ 
  

  

  +0-12 
  mm. 
  

  

  

  20|- 
  „ 
  

  

  8-47 
  „ 
  

  

  +0-24 
  „ 
  1 
  

  

  

  25^ 
  „ 
  

  

  8-50 
  „ 
  

  

  +0-27 
  „ 
  ; 
  

  

  

  31 
  

  

  8-48 
  „ 
  

  

  +0-25 
  „ 
  1 
  

  

  

  42 
  

  

  8-46 
  ., 
  

  

  +0-2-, 
  „ 
  1 
  

  

  

  70 
  

  

  8-42 
  „ 
  

  

  +0-19 
  „ 
  1 
  

  

  

  138 
  

  

  8-41 
  „ 
  

  

  +0-18 
  „ 
  ! 
  

  

  

  19 
  hours. 
  

  

  1014 
  „ 
  

  

  + 
  1-91 
  „ 
  

  

  Table 
  III. 
  

  

  Eemarks. 
  

  

  Time. 
  

  

  Pressure. 
  

  

  Difference. 
  

  

  Put 
  in 
  71-20 
  c.c. 
  (corr.) 
  

  

  0-| 
  minute. 
  

  

  _ 
  

  

  _ 
  

  

  Took 
  out 
  25-13 
  c.c. 
  (corr.) 
  ... 
  

  

  3-1 
  li 
  minutes. 
  

  

  — 
  

  

  — 
  

  

  

  13 
  „ 
  

  

  8-70 
  mm. 
  

  

  

  

  

  141 
  „ 
  

  

  8-78 
  „ 
  

  

  +0-08 
  mm. 
  

  

  

  16 
  „ 
  

  

  8-80 
  „ 
  

  

  +0-10 
  „ 
  

  

  

  18 
  

  

  8-82 
  „ 
  

  

  +012 
  „ 
  

  

  

  20 
  „ 
  

  

  8-75 
  „ 
  

  

  +005 
  „ 
  

  

  

  27 
  „ 
  

  

  8-64 
  „ 
  

  

  -006 
  „ 
  

  

  

  42 
  

  

  8-56 
  „ 
  

  

  -014 
  „ 
  

  

  

  105 
  

  

  8-43 
  „ 
  

  

  -0-27 
  „ 
  

  

  

  285 
  

  

  8-38 
  „ 
  

  

  -0-32 
  „ 
  

  

  

  22 
  hours 
  

  

  9-72 
  „ 
  

  

  +1-02 
  „ 
  

  

  