﻿Hydrogen 
  in 
  the 
  Atmosphere. 
  4:19* 
  

  

  sulphuric 
  acid, 
  and 
  subsequently 
  by 
  phosphoric 
  anhydride, 
  

   Next 
  followed 
  the 
  hot 
  copper 
  oxide, 
  contained 
  in 
  a 
  hard 
  glass 
  

   tube 
  and 
  heated 
  by 
  an 
  ordinary 
  combustion-furnace. 
  Next 
  

   in 
  order 
  followed 
  the 
  U-tube 
  charged 
  with 
  phosphoric 
  anhy- 
  

   dride 
  whose 
  increase 
  of 
  weight 
  was 
  to 
  indicate 
  the 
  absorption 
  

   of 
  water, 
  formed 
  in 
  or 
  derived 
  from 
  the 
  furnace-tube. 
  The 
  

   U-tube 
  was 
  protected 
  upon 
  the 
  further 
  (down-stream) 
  side 
  by 
  

   other 
  phosphoric 
  tubes. 
  It 
  was 
  provided 
  with 
  glass 
  taps 
  and 
  

   was 
  connected 
  on 
  either 
  side 
  by 
  short 
  pieces 
  of 
  thick 
  rubber 
  

   of 
  which 
  but 
  little 
  was 
  exposed 
  to 
  the 
  passing 
  air. 
  The 
  

   counterpoise 
  in 
  the 
  balance 
  was 
  a 
  similar 
  closed 
  phosphoric 
  

   tube 
  of 
  very 
  nearly 
  the 
  same 
  volume, 
  and 
  allowance 
  was 
  made 
  

   for 
  the 
  pressure 
  and 
  temperature 
  of 
  the 
  air 
  included 
  in 
  the 
  

   working-tube 
  at 
  the 
  moment 
  when 
  the 
  taps 
  were 
  closed. 
  

  

  Two 
  parts 
  in 
  10,000 
  of 
  free 
  hydrogen, 
  i. 
  e. 
  2 
  c.c, 
  yield 
  on 
  

   combustion 
  the 
  same 
  volume 
  of 
  water-vapour, 
  and 
  of 
  this 
  the 
  

   weight 
  would 
  be 
  1*5 
  mg. 
  to 
  be 
  collected 
  in 
  the 
  phosphoric 
  

   tube. 
  Any 
  water, 
  due 
  to 
  hydrocarbons 
  originally 
  present 
  in 
  

   the 
  air 
  and 
  oxidized 
  in 
  the 
  furnace-tube, 
  would 
  be 
  additional 
  

   to 
  the 
  above 
  1*5 
  mg. 
  

  

  The 
  earlier 
  experiments, 
  executed 
  at 
  the 
  end 
  of 
  1900 
  and 
  

   beoinnino- 
  of 
  1901, 
  £ave 
  results 
  which 
  I 
  found 
  it 
  difficult 
  to 
  

   interpret. 
  The 
  gain 
  of 
  weight 
  from 
  the 
  passage 
  of 
  10 
  litres 
  

   of 
  fresh 
  air 
  was 
  about 
  *4 
  mg., 
  that 
  is, 
  far 
  too 
  little 
  ; 
  and, 
  

   what 
  was 
  even 
  more 
  surprising, 
  this 
  gain 
  was 
  not 
  diminished 
  

   when 
  the 
  air 
  after 
  passage 
  was 
  collected 
  and 
  used 
  over 
  and 
  

   over 
  again. 
  The 
  gain 
  appeared 
  to 
  have 
  nothing 
  to 
  do 
  with 
  

   hydrogen 
  originally 
  present 
  in 
  the 
  air, 
  being 
  maintained, 
  for 
  

   example, 
  when 
  a 
  single 
  litre 
  of 
  air 
  was 
  passed 
  round 
  and 
  

   round 
  eight 
  or 
  nine 
  times. 
  Neither 
  did 
  the 
  substitution 
  of 
  

   oxygen 
  for 
  air 
  make 
  any 
  important 
  difference. 
  Subsequently 
  

   it 
  was 
  found 
  that 
  the 
  gain 
  was 
  scarcely 
  diminished 
  when 
  the 
  

   furnace 
  remained 
  cold 
  during 
  the 
  passage 
  of 
  the 
  air. 
  

  

  Warned 
  by 
  M. 
  Gautier, 
  I 
  was 
  prepared 
  for 
  a 
  possible 
  gain 
  

   cf 
  weight 
  due 
  to 
  retention 
  of 
  oxygen 
  ; 
  but 
  this 
  gain 
  ought 
  to 
  

   be 
  additional, 
  and 
  should 
  not 
  mask 
  the 
  difference 
  between 
  

   air 
  containing 
  and 
  not 
  containing 
  free 
  hydrogen. 
  Faulty 
  

   manipulation 
  might 
  be 
  expected 
  to 
  entail 
  an 
  excessive 
  rather 
  

   than 
  a 
  defective 
  gain 
  ; 
  and 
  the 
  only 
  cause 
  to 
  which 
  I 
  could 
  

   attribute 
  the 
  non-appearance 
  of 
  the 
  hydrogen 
  was 
  a 
  failure 
  of 
  

   the 
  copper 
  oxide 
  to 
  do 
  its 
  work. 
  The 
  sample 
  which 
  I 
  had 
  

   employed 
  was 
  of 
  the 
  kind 
  sold 
  as 
  granulated. 
  M. 
  Gautier 
  

   himself 
  found 
  a 
  considerable 
  length 
  of 
  copper 
  oxide 
  necessary 
  

   to 
  complete 
  the 
  action. 
  The 
  question 
  is, 
  of 
  course, 
  not 
  one 
  

   of 
  length 
  merely, 
  but 
  rather 
  of 
  the 
  time 
  during 
  which 
  the 
  

   travelling 
  gas 
  remains 
  in 
  close 
  proximity 
  to 
  the 
  oxidizing 
  

  

  