﻿422 
  Hydrogen 
  in 
  the 
  Atmosphere. 
  

  

  amount 
  (*00075) 
  corresponding 
  to 
  the 
  1 
  c. 
  c. 
  of 
  added 
  hydro- 
  

   gen. 
  We 
  may 
  say 
  then 
  that 
  the 
  copper 
  oxide 
  was 
  competent 
  

   to 
  account 
  for 
  a 
  small 
  addition 
  of 
  hydrogen 
  to 
  air. 
  

  

  Following 
  a 
  suggestion 
  from 
  the 
  spectroscopic 
  experi- 
  

   ments, 
  I 
  have 
  examined 
  the 
  effect 
  of 
  treatment 
  with 
  chlorine. 
  

   To 
  10 
  litres 
  of 
  air 
  10 
  c. 
  c. 
  (in 
  one 
  case 
  5 
  c. 
  c.) 
  of 
  hydrogen 
  

   were 
  added, 
  followed 
  by 
  excess 
  of 
  chlorine 
  and 
  exposure 
  to 
  

   sunshine. 
  The 
  excess 
  of 
  chlorine 
  having 
  been 
  removed 
  by 
  

   alkali, 
  the 
  air 
  was 
  desiccated 
  and 
  passed 
  through 
  the 
  furnace 
  

   as 
  usual. 
  The 
  resulting 
  gains 
  of 
  weight 
  in 
  the 
  phosphoric 
  

   tube 
  were 
  : 
  

  

  Dec. 
  31, 
  1901. 
  

  

  + 
  •00011 
  

  

  Jan. 
  2, 
  1902. 
  

  

  + 
  •00050 
  

  

  o, 
  „ 
  

  

  + 
  •00044 
  

  

  » 
  8, 
  » 
  

  

  + 
  •00030 
  

  

  Mean 
  + 
  -00034 
  

  

  According 
  to 
  these 
  figures, 
  the 
  treatment 
  with 
  chlorine 
  

   •after 
  hydrogen 
  left 
  the 
  gains 
  somewhat 
  larger 
  than 
  in 
  the 
  

   case 
  of 
  pure 
  air 
  ; 
  but 
  the 
  sunshine, 
  especially 
  on 
  Jan. 
  2, 
  was 
  

   feeble, 
  and 
  the 
  difference 
  of 
  *13 
  mg. 
  may 
  be 
  the 
  consequence 
  

   of 
  incomplete 
  insolation. 
  In 
  any 
  case 
  the 
  added 
  hydrogen 
  

   was 
  very 
  nearly 
  removed 
  by 
  the 
  chlorine. 
  

  

  In 
  two 
  experiments 
  10 
  litres 
  of 
  pure 
  air 
  were 
  subjected 
  to 
  

   the 
  chlorine 
  treatment, 
  and 
  after 
  removal 
  of 
  excess 
  were 
  

   mixed 
  with 
  1 
  c. 
  c. 
  of 
  hydrogen. 
  The 
  gains 
  of 
  weight 
  recorded 
  

   In 
  the 
  phosphoric 
  tubes 
  were 
  

  

  Jan. 
  1, 
  1902 
  i 
  + 
  -00082 
  

   „ 
  7, 
  „ 
  I 
  +-00069 
  

  

  Mean 
  + 
  -00075 
  

  

  The 
  difference 
  between 
  this 
  and 
  "00093 
  would 
  suggest 
  that 
  

   perhaps 
  some 
  original 
  hydrogen 
  had 
  been 
  removed 
  by 
  chlorine, 
  

   but 
  the 
  amount 
  is 
  very 
  small. 
  

  

  I 
  shall 
  best 
  fulfil 
  my 
  intention 
  if 
  I 
  refrain 
  from 
  attempting 
  

   to 
  sum 
  up 
  the 
  whole 
  of 
  the 
  evidence. 
  So 
  far 
  as 
  my 
  own 
  

   work 
  is 
  concerned, 
  the 
  natural 
  inference 
  from 
  it 
  would 
  be 
  

   that 
  the 
  free 
  hydrogen 
  in 
  country 
  air 
  does 
  not 
  exceed 
  ^-^ 
  of 
  

   the 
  volume. 
  If 
  I 
  may 
  make 
  a 
  suggestion, 
  it 
  would 
  be 
  in 
  

   favour 
  of 
  working 
  with 
  some 
  such 
  quantity 
  as 
  10 
  litres, 
  

   collected 
  in 
  glass 
  bottles, 
  and 
  of 
  comparisons 
  between 
  fresh 
  

   air 
  and 
  air 
  already 
  passed 
  once 
  or 
  twice 
  through 
  the 
  furnace- 
  

   tube. 
  

   f% 
  February 
  1902. 
  

  

  