﻿Hydrogen 
  in 
  the 
  Atmosphere. 
  41 
  7 
  

  

  hydrogen 
  had 
  been 
  added 
  were 
  certainly 
  and 
  easily 
  dis- 
  

   tinguished 
  by 
  the 
  visibility 
  of 
  the 
  C-line. 
  An 
  improvement 
  

   was 
  afterwards 
  effected 
  by 
  the 
  substitution 
  of 
  aluminium 
  

   points 
  for 
  platinum. 
  A 
  strong 
  preliminary 
  heating 
  reduced 
  

   the 
  C-line 
  with 
  a 
  stream 
  of 
  pure 
  dried 
  air 
  to 
  the 
  least 
  yet 
  

   seen, 
  only 
  just 
  continuously 
  visible, 
  and 
  contrasting 
  strongly 
  

   with 
  the 
  result 
  of 
  substituting 
  the 
  air 
  to 
  which 
  the 
  two 
  

   parts 
  in 
  10,000 
  of 
  hydrogen 
  had 
  been 
  added. 
  

  

  To 
  air 
  from 
  outside 
  one 
  thousandth 
  part 
  of 
  hydrogen 
  was 
  

   introduced 
  and 
  allowed 
  time 
  to 
  mix 
  thoroughly. 
  Excess 
  of 
  

   chlorine 
  was 
  then 
  added, 
  and 
  after 
  a 
  while 
  the 
  whole 
  was 
  

   exposed 
  to 
  strong 
  sunshine, 
  after 
  which 
  the 
  superfluous 
  

   chlorine 
  was 
  removed 
  by 
  alkali. 
  Tested 
  in 
  the 
  spectroscope, 
  

   this 
  sample 
  showed 
  only 
  about 
  the 
  same 
  signs 
  of 
  hydrogen 
  as 
  

   the 
  pure 
  air, 
  indicating 
  that 
  the 
  added 
  hydrogen 
  had 
  effec- 
  

   tively 
  been 
  removed 
  — 
  a 
  result 
  which 
  somewhat 
  surprised 
  me. 
  

  

  As 
  there 
  now 
  appeared 
  to 
  be 
  a 
  margin 
  for 
  further 
  dis- 
  

   crimination, 
  three 
  samples 
  were 
  prepared, 
  the 
  first 
  pare 
  air, 
  

   the 
  second 
  air 
  to 
  which 
  was 
  added 
  — 
  ^ 
  of 
  hydrogen, 
  and 
  the 
  

   third 
  air 
  with 
  addition 
  of 
  ^^ 
  of 
  hydrogen. 
  In 
  the 
  spectro- 
  

   scope 
  the 
  three 
  were 
  just 
  certainly 
  distinguishable, 
  showing 
  

   C 
  in 
  the 
  right 
  order. 
  The 
  chlorine-treated 
  mixture 
  showed 
  

   about 
  the 
  same 
  as 
  the 
  pure 
  air. 
  On 
  repetition 
  with 
  fresh 
  

   samples 
  these 
  results 
  were 
  confirmed. 
  

  

  In 
  my 
  former 
  note 
  J 
  mentioned 
  that 
  nitrous 
  oxide 
  and 
  

   oxygen 
  showed 
  the 
  C-line 
  as 
  much 
  as, 
  if 
  not 
  more 
  than, 
  air. 
  

   I 
  cannot 
  say 
  whether 
  this 
  result 
  is 
  inevitable, 
  but 
  the 
  gases 
  

   were 
  prepared 
  with 
  ordinary 
  care. 
  In 
  the 
  more 
  recent 
  repe- 
  

   tition 
  N 
  2 
  showed 
  the 
  C-line 
  about 
  the 
  same 
  as 
  the 
  air 
  to 
  

   which 
  -j-y^ 
  H 
  2 
  had 
  been 
  added. 
  Oxygen, 
  prepared 
  from 
  

   permanganate, 
  showed 
  C 
  much 
  more 
  than 
  does 
  pure 
  air 
  ; 
  

   and 
  there 
  was 
  not 
  much 
  change 
  when 
  oxygen 
  from 
  mixed 
  

   chlorates 
  of 
  potash 
  and 
  soda 
  was 
  substituted. 
  

  

  The 
  impurity 
  in 
  the 
  oxygen, 
  if 
  it 
  be 
  an 
  impurity 
  *, 
  does 
  

   not 
  appear 
  to 
  be 
  easily 
  removed. 
  The 
  visibility 
  of 
  C 
  was 
  not 
  

   perceptibly 
  diminished 
  by 
  passage 
  of 
  either 
  kind 
  of 
  oxygen 
  

   over 
  hot 
  copper 
  oxide. 
  On 
  the 
  other 
  hand 
  the 
  air 
  containing 
  

   jlj^ 
  of 
  added 
  hydrogen 
  was 
  reduced 
  by 
  the 
  same 
  treatment 
  

   to 
  equality 
  with 
  pure 
  air. 
  Possibly 
  the 
  impurity 
  is 
  a 
  hydro- 
  

   carbon 
  not 
  readily 
  burnt. 
  

  

  Neither 
  by 
  treatment 
  with 
  chlorine 
  could 
  oxygen 
  from 
  

   either 
  source 
  be 
  freed 
  from 
  the 
  property 
  of 
  exhibiting 
  the 
  

   C-line. 
  

  

  * 
  It 
  is 
  possible 
  that 
  traces 
  of 
  hydrogen, 
  derived 
  from 
  the 
  electrodes 
  or 
  

   from 
  the 
  glass, 
  show 
  more 
  in 
  oxygen 
  than 
  in 
  air. 
  

  

  