﻿On 
  Ionization 
  in 
  various 
  Gases. 
  

  

  879- 
  

   The 
  

  

  pressures 
  in 
  a 
  chamber 
  of 
  moderately 
  small 
  dimensions 
  

   chamber 
  was 
  made 
  o£ 
  a 
  piece 
  o£ 
  brass 
  tube 
  7*5 
  cms. 
  in 
  

   diameter 
  and 
  13 
  cms. 
  long, 
  closed 
  at 
  the 
  lower 
  end 
  by 
  a 
  flat 
  

   circular 
  plate 
  of 
  brass. 
  The 
  upper 
  end 
  was 
  partly 
  closed 
  by 
  a 
  

   similar 
  brass 
  plate, 
  in 
  which 
  was 
  cut 
  a 
  concentric 
  circular 
  

   hole 
  4 
  cms. 
  in 
  diameter. 
  Both 
  plates 
  were 
  soldered 
  to 
  the 
  

   tube 
  with 
  silver, 
  and 
  the 
  upper 
  surface 
  of 
  the 
  upper 
  plate 
  was 
  

   " 
  tinned'"' 
  with 
  ordinary 
  soft 
  solder. 
  The 
  hole 
  in 
  the 
  upper 
  

   plate 
  permitted 
  the 
  entrance 
  of 
  the 
  electrode, 
  and 
  was 
  closed 
  

  

  Ficr. 
  1. 
  

   7b 
  £L£cr/?OM£r£/? 
  

  

  To 
  £/}RTH 
  

  

  To 
  G/3S 
  /1PPAf?/iTUS 
  

  

  To 
  BflTTERY 
  

  

  by 
  another 
  smaller 
  brass 
  plate 
  6 
  cms. 
  in 
  diameter 
  with 
  a 
  

   bevelled 
  and 
  " 
  tinned 
  ''' 
  edge. 
  This 
  plate 
  was 
  also 
  pierced 
  

   with 
  a 
  concentric 
  hole 
  into 
  which 
  was 
  hard-soldered 
  a 
  short 
  

   length 
  of 
  iron 
  gas-pipe. 
  The 
  upper 
  end 
  of 
  the 
  iron 
  pipe 
  was 
  

   coned 
  out 
  and 
  ground 
  to 
  fit 
  a 
  glass 
  tube, 
  furnished 
  with 
  a 
  

   side 
  tube 
  through 
  which 
  to 
  introduce 
  the 
  gas 
  under 
  experi- 
  

   ment 
  into 
  the 
  chamber. 
  The 
  upper 
  end 
  of 
  the 
  glass 
  tube 
  was 
  

   drawn 
  down 
  and 
  coned 
  out 
  so 
  as 
  to 
  form 
  a 
  small 
  cup, 
  and 
  into 
  

   this 
  cup 
  was 
  ground 
  the 
  bulged 
  middle 
  of 
  a 
  length 
  of 
  thin 
  

  

  