﻿Conductivity 
  imparted 
  to 
  Liquid 
  Air 
  hy 
  Alpha 
  Rays. 
  887 
  

  

  Y. 
  Ionization 
  in 
  Air 
  at 
  Atmospheric 
  Pressure 
  

   by 
  Alpha 
  Bays. 
  

  

  In 
  another 
  set 
  of 
  measurements 
  the 
  polonium 
  -coated 
  plate 
  

   used 
  in 
  the 
  experiments 
  with 
  the 
  liquid 
  air 
  and 
  with 
  the 
  air 
  

   at 
  the 
  high 
  pressure 
  described 
  in 
  sections 
  III. 
  and 
  IV., 
  was 
  

   attached 
  to 
  the 
  end 
  of 
  an 
  electrode 
  provided 
  with 
  a 
  guard- 
  

   tube 
  and 
  inserted 
  at 
  the 
  centre 
  of 
  a 
  cylindrical 
  copper 
  

   ionization-chamber 
  about 
  10 
  cm. 
  in 
  diameter 
  and 
  about 
  

   12 
  cm. 
  in 
  length. 
  The 
  air 
  in 
  this 
  cylinder 
  was 
  kept 
  at 
  

   atmospheric 
  pressure, 
  and 
  as 
  the 
  range 
  of 
  the 
  alpha 
  rays 
  

   from 
  polonium 
  is 
  about 
  3'8 
  cm. 
  in 
  air 
  at 
  this 
  pressure 
  it 
  is 
  

   clear 
  that 
  the 
  dimensions 
  of 
  the 
  receiver 
  were 
  such 
  as 
  to 
  

   insure 
  the 
  complete 
  absorption 
  of 
  all 
  the 
  alpha 
  radiation 
  

   emitted 
  by 
  the 
  plate. 
  The 
  electrode 
  was 
  connected 
  as 
  before 
  

   to 
  the 
  quadrants 
  of 
  the 
  electrometer, 
  and 
  the 
  currents 
  were 
  

   measured 
  with 
  different 
  fields 
  applied 
  to 
  the 
  region 
  traversed 
  

   by 
  the 
  rays. 
  Here 
  again 
  it 
  was 
  found 
  necessary 
  to 
  attach 
  

   a 
  sulphur 
  condenser 
  of 
  high 
  capacity 
  to 
  the 
  quadrant 
  system 
  

   in 
  order 
  to 
  take 
  the 
  readings 
  conveniently. 
  The 
  total 
  

   capacity 
  of 
  the 
  measuring 
  system 
  used 
  in 
  this 
  case 
  was 
  

   8112 
  e.s.u. 
  

  

  A 
  set 
  of 
  readings 
  taken 
  with 
  this 
  arrangement 
  both 
  with 
  

   positive 
  and 
  negative 
  potentials 
  applied 
  to 
  the 
  cylindrical 
  

   receiver 
  is 
  given 
  in 
  Table 
  V., 
  and 
  the 
  curves 
  corresponding 
  

   to 
  these 
  are 
  shown 
  in 
  fig. 
  6 
  (PI. 
  X 
  VIII.). 
  

  

  Table 
  V. 
  

  

  Ionization 
  produced 
  in 
  air 
  at 
  Atmospheric 
  Pressure 
  by 
  

   the 
  Alpha 
  Rays 
  from 
  the 
  Polonium. 
  

  

  Potential 
  applied 
  

  

  Current 
  (rise 
  in 
  volts) 
  

  

  Current 
  (rise 
  in 
  volts) 
  

  

  to 
  receiver. 
  

  

  with 
  positive 
  field. 
  

  

  with 
  negative 
  field. 
  

  

  Volts. 
  

  

  Volts 
  per 
  min. 
  

  

  Volts 
  per 
  min. 
  

  

  730 
  

  

  3-71 
  

  

  423 
  

  

  538 
  

  

  371 
  

  

  4-18 
  

  

  445 
  

  

  366 
  

  

  4-23 
  

  

  3*2 
  

  

  376 
  

  

  4-18 
  

  

  213 
  

  

  382 
  

  

  398 
  

  

  130 
  

  

  3-00 
  

  

  355 
  

  

  79 
  

  

  271 
  

  

  3-00 
  

  

  385 
  

  

  1-96 
  

  

  1-85 
  

  

  205 
  

  

  •96 
  

  

  ■93 
  

  

  10 
  

  

  •35 
  

  

  •34 
  

  

  