﻿of 
  Pressure 
  which 
  accompany 
  Point 
  Discharge. 
  

  

  33 
  

  

  Connexion 
  "between 
  the 
  Percentage 
  of 
  Oxygen 
  and 
  

   the 
  Contraction. 
  

  

  A 
  series 
  of 
  various 
  quantities 
  of 
  oxygen 
  in 
  hydrogen 
  

   ranging 
  from 
  0'0002 
  to 
  14 
  per 
  cent, 
  was 
  taken 
  and 
  the 
  fall 
  

   of 
  pressure, 
  p, 
  observed 
  in 
  each 
  due 
  to 
  the 
  passage 
  of 
  2*16 
  

   micro-amperes 
  for 
  2 
  minutes, 
  p 
  is 
  plotted 
  in 
  Curves 
  IV. 
  

   with 
  the 
  percentage 
  of 
  oxygen, 
  the 
  points 
  being 
  marked 
  

   by 
  dots. 
  The 
  distance 
  from 
  point 
  to 
  plate 
  was 
  2 
  cms. 
  

  

  It 
  will 
  be 
  seen 
  that 
  for 
  positive 
  discharge 
  through 
  nearly 
  

   pure 
  hydrogen 
  the 
  gas 
  contraction 
  amounts 
  to 
  about 
  

   10 
  molecules 
  per 
  ion 
  (N 
  = 
  10) 
  and 
  that 
  it 
  reaches 
  a 
  minimum 
  

   at 
  about 
  0*15 
  per 
  cent, 
  of 
  oxygen. 
  For 
  negative 
  discharge 
  

   its 
  value 
  is 
  about 
  25 
  molecules 
  per 
  ion 
  between 
  14 
  and 
  

   2 
  per 
  cent., 
  but 
  below 
  this 
  the 
  curve 
  rises 
  rapidly 
  to 
  a 
  high 
  

   peak 
  in 
  the 
  region 
  of 
  0*01 
  per 
  cent., 
  corresponding 
  to 
  about 
  

   75 
  molecules 
  per 
  ion. 
  (See 
  Curves 
  VIII. 
  for 
  magnified 
  

   drawing 
  of 
  peak.) 
  The 
  effect 
  of 
  the 
  current 
  on 
  the 
  oxygen 
  

   is 
  thus 
  far 
  from 
  obeying 
  the 
  laws 
  of 
  electrolysis 
  ; 
  and 
  this 
  is 
  

   consistent 
  with 
  observations 
  of 
  Warburg's 
  on 
  the 
  effects 
  of 
  

   point 
  discharge 
  through 
  oxygen 
  and 
  carbon 
  dioxide. 
  

  

  The 
  height 
  of 
  the 
  negative 
  peak 
  seems 
  to 
  depend 
  very 
  much 
  

   on 
  the 
  condition 
  of 
  the 
  discharging 
  point. 
  After 
  making 
  the 
  

   above 
  observations 
  we 
  used 
  the 
  same 
  platinum 
  wire 
  point 
  for 
  

   two 
  long 
  series 
  in 
  hydrogen 
  containing 
  nitrogen, 
  and 
  a 
  

  

  Dytie-Cm. 
  2 
  Curves 
  IV. 
  — 
  Oxygen 
  in 
  Hydrogen. 
  

  

  10' 
  

  

  \Z 
  I3%0xtj; 
  

  

  third 
  in 
  which 
  the 
  nitrogen 
  was 
  replaced 
  by 
  air 
  ; 
  and 
  on 
  

   returning 
  to 
  oxygen 
  directly 
  after 
  these 
  we 
  found 
  the 
  height 
  

   of 
  the 
  peak 
  was 
  about 
  halved, 
  while 
  at 
  the 
  highest 
  percentages 
  

   the 
  height 
  of 
  the 
  curve 
  had 
  somewhat 
  increased. 
  With 
  

   positive 
  discharge 
  on 
  the 
  other 
  hand 
  there 
  was 
  little 
  change. 
  

   This 
  second 
  series 
  of 
  oxygen 
  observations 
  is 
  given 
  in 
  

   Curves 
  IV. 
  (circles) 
  . 
  

  

  Phil. 
  Mag. 
  Ser. 
  6. 
  Vol. 
  16. 
  No. 
  91. 
  July 
  1908. 
  D 
  

  

  