﻿1875.] 
  

  

  Hydrogen 
  and 
  Acids 
  on 
  Iron 
  and 
  Steel. 
  

  

  173 
  

  

  the 
  wire 
  connected 
  with 
  the 
  zinc 
  pole 
  of 
  the 
  battery 
  was 
  found 
  to 
  bubble. 
  

   Twenty-two 
  hours' 
  longer 
  immersion, 
  the 
  battery 
  working 
  all 
  the 
  time, 
  

   caused 
  the 
  bubbles 
  to 
  be 
  more 
  abundant 
  ; 
  the 
  toughness 
  of 
  the 
  wire 
  

   was 
  also 
  diminished 
  and 
  its 
  surface 
  blackened. 
  The 
  wire 
  at 
  the 
  

   positive 
  pole 
  was, 
  however, 
  unchanged, 
  either 
  on 
  the 
  surface 
  or 
  in 
  

   toughness 
  "*. 
  

  

  From 
  this 
  we 
  see 
  that 
  not 
  only 
  is 
  acid 
  not 
  indispensable 
  for 
  the 
  pro- 
  

   duction 
  of, 
  at 
  all 
  events, 
  the 
  major 
  portion 
  of 
  these 
  changes 
  in 
  iron, 
  but 
  

   the 
  latter 
  can 
  be 
  equally 
  well 
  produced 
  in 
  an 
  alkaline 
  solution. 
  

  

  The 
  apparatus 
  remaining 
  unchanged, 
  the 
  soda 
  was 
  next 
  replaced 
  by 
  

   hydrochloric 
  acid, 
  1*20 
  sp. 
  gr. 
  On 
  then 
  immersing 
  the 
  iron-wire 
  elec- 
  

   trodes 
  for 
  only 
  2 
  or 
  3 
  seconds, 
  the 
  negative 
  electrode, 
  where 
  hydrogen 
  

   was 
  given 
  off, 
  was 
  found 
  to 
  froth 
  freely 
  when 
  the 
  fractured 
  extremity 
  was 
  

   wetted, 
  as 
  much, 
  in 
  fact, 
  as 
  after 
  15 
  minutes' 
  immersion 
  when 
  the 
  cur- 
  

   rent 
  was 
  broken. 
  Half 
  an 
  hour's 
  immersion 
  failed 
  to 
  produce 
  any 
  similar 
  

   change 
  on 
  the 
  positive 
  electrode 
  where 
  no 
  hydrogen 
  was 
  liberated. 
  The 
  

   absence 
  of 
  effect 
  on 
  the 
  positive 
  electrode 
  is 
  all 
  the 
  morejrernarkable, 
  as 
  a 
  

   piece 
  of 
  wire 
  of 
  exactly 
  the 
  same 
  quality, 
  and 
  immersed 
  an 
  equal 
  time 
  in 
  

   the 
  same 
  liquid, 
  but 
  unconnected 
  with 
  the 
  battery, 
  had 
  become 
  brittle 
  

   and 
  frothed 
  when 
  broken. 
  It 
  thus 
  appears 
  that 
  neither 
  oxygen 
  nor 
  chlo- 
  

   rine 
  are, 
  under 
  these 
  conditions, 
  occluded 
  by 
  iron, 
  or 
  if 
  occluded, 
  that 
  

   they 
  produce 
  no 
  sensible 
  change 
  in 
  its 
  physical 
  properties. 
  

  

  Nascent 
  hydrogen 
  having 
  been 
  shown 
  to 
  produce 
  these 
  effects, 
  a 
  trial 
  

   was 
  next 
  made 
  to 
  ascertain 
  if 
  any 
  similar 
  change 
  could 
  be 
  produced 
  in 
  iron 
  

   by 
  leaving 
  it 
  in 
  an 
  atmosphere 
  of 
  hydrogen 
  gas. 
  With 
  this 
  object 
  a 
  glass 
  

   tube 
  j" 
  in 
  diameter 
  was 
  filled 
  with 
  pieces 
  of 
  bright 
  iron 
  wire 
  T 
  y 
  in 
  dia- 
  

   meter, 
  and 
  a 
  current 
  of 
  hydrogen 
  passed 
  through 
  for 
  periods 
  of 
  1, 
  2, 
  and 
  

   8 
  hours 
  respectively, 
  but 
  without 
  any 
  perceptible 
  change 
  in 
  the 
  wire. 
  The 
  

   wires 
  were 
  then 
  placed 
  in 
  a 
  bottle 
  three 
  fourths 
  full 
  of 
  water, 
  and 
  hydrogen 
  

   made 
  to 
  bubble 
  violently 
  through 
  the 
  water 
  for 
  an 
  hour, 
  but 
  still 
  without 
  

   any 
  effect. 
  It 
  would 
  thus 
  appear 
  that 
  hydrogen 
  is 
  only 
  occluded 
  in 
  the 
  

   nascent 
  state 
  by 
  iron 
  in 
  the 
  cold. 
  Possibly, 
  however, 
  absorption 
  may 
  

   take 
  place 
  if 
  the 
  surfaces 
  are 
  chemically 
  clean. 
  The 
  late 
  Dr. 
  Graham, 
  in 
  

   his 
  valuable 
  papers 
  on 
  the 
  occlusion 
  of 
  hydrogen, 
  showed, 
  several 
  years 
  

   ago, 
  that 
  when 
  red-hot 
  iron, 
  palladium, 
  or 
  platinum 
  are 
  allowed 
  to 
  cool 
  in 
  

   an 
  atmosphere 
  of 
  hydrogen, 
  this 
  gas 
  is 
  occluded 
  by 
  them 
  in 
  large 
  quan- 
  

   - 
  tity 
  ; 
  and 
  in 
  the 
  'Proceedings 
  of 
  the 
  Eoyal 
  Society,' 
  1868, 
  xvi. 
  p. 
  422, 
  he 
  

   mentions 
  that 
  the 
  best 
  way 
  of 
  charging 
  any 
  of 
  these 
  metals 
  with 
  hydrogen 
  

   is 
  to 
  make 
  the 
  metal 
  act 
  as 
  the 
  negative 
  electrode 
  in 
  acidulated 
  water 
  for 
  

   a 
  battery 
  of 
  6 
  Bunsen's 
  cells 
  — 
  a 
  fact 
  unknown 
  to 
  the 
  writer 
  when 
  he 
  made 
  

   experiments. 
  

  

  Though 
  the 
  absorption 
  of 
  hydrogen 
  by 
  iron 
  is 
  no 
  doubt 
  the 
  cause 
  of 
  the 
  

   frothing 
  and 
  diminution 
  of 
  toughness 
  attendant 
  on 
  the 
  immersion 
  of 
  iron 
  

   in 
  hydrochloric 
  and 
  sulphuric 
  acids, 
  there 
  are 
  some 
  phenomena 
  which 
  

   * 
  Proc. 
  Lit. 
  and 
  Phil. 
  Soc. 
  Manch. 
  1874, 
  p. 
  130. 
  

  

  