﻿882 
  Prof. 
  McLennan 
  and 
  Mr. 
  Keys 
  on 
  the 
  Electrical 
  

  

  set 
  of 
  measurements 
  the 
  capacity 
  of 
  the 
  electrode 
  and 
  the 
  

   system 
  connected 
  with 
  it 
  was 
  about 
  200 
  e.s.n., 
  and 
  the 
  

   distance 
  between 
  the 
  electrodes 
  A 
  and 
  B 
  was 
  about 
  5 
  mm. 
  

  

  Table 
  II. 
  

  

  Conductivity 
  imparted 
  to 
  Liquid 
  Air 
  by 
  Alpha 
  

   Rays 
  from 
  Polonium. 
  

  

  Potential 
  difference 
  applied 
  

  

  Deflexion 
  of 
  electrometer 
  

  

  to 
  electrode 
  EA. 
  

  

  (volts 
  per 
  min.). 
  

  

  1450 
  volts 
  (positive) 
  

  

  37-3 
  X 
  10" 
  2 
  

  

  1144 
  

  

  336 
  „ 
  

  

  912 
  

  

  28-5 
  

  

  570 
  

  

  26-5 
  „ 
  

  

  329 
  

  

  24-3 
  „ 
  

  

  81 
  

  

  16-6 
  „ 
  

  

  40-5 
  

  

  11*6 
  „ 
  

  

  From 
  the 
  form 
  of 
  the 
  curve 
  it 
  will 
  be 
  seen 
  that 
  even 
  with 
  

   the 
  highest 
  voltages 
  used 
  saturation 
  was 
  not 
  obtained. 
  There 
  

   is, 
  however, 
  a 
  distinct 
  bend 
  shown 
  in 
  the 
  curve 
  in 
  the 
  region 
  

   corresponding 
  to 
  about 
  150 
  volts. 
  

  

  It 
  is 
  difficult 
  to 
  give 
  a 
  complete 
  explanation 
  of 
  this 
  bend, 
  

   but 
  in 
  all 
  probability 
  the 
  phenonemon 
  has 
  to 
  do 
  either 
  with 
  a 
  

   volume 
  ionization 
  produced 
  in 
  the 
  liquid 
  air 
  by 
  some 
  unknown 
  

   radiation 
  of 
  a 
  penetrating 
  type 
  from 
  the 
  polonium, 
  or 
  by 
  

   beta 
  rays 
  due 
  to 
  some 
  active 
  impurity 
  in 
  the 
  polonium. 
  

   Possibly, 
  too, 
  it 
  may 
  have 
  been 
  due 
  in 
  part 
  at 
  least 
  to 
  a 
  

   diffusion 
  of 
  ions 
  into 
  the 
  body 
  of 
  the 
  liquid 
  air 
  from 
  the 
  thin 
  

   layer 
  of 
  ionization 
  produced 
  by 
  the 
  alpha 
  rays 
  close 
  to 
  the 
  

   plate 
  B. 
  It 
  is 
  clear 
  that 
  moderate 
  fields 
  would 
  in 
  all 
  

   probability 
  suffice 
  to 
  remove 
  all 
  such 
  ions 
  from 
  the 
  field 
  and 
  

   so 
  account 
  for 
  the 
  bend. 
  The 
  gradual 
  rise 
  in 
  the 
  curve 
  

   obtained 
  with 
  fields 
  about 
  200 
  volts 
  was 
  no 
  doubt 
  due 
  to 
  the 
  

   increasing 
  influence 
  exerted 
  by 
  the 
  field 
  in 
  overcoming 
  re- 
  

   combination 
  in 
  the 
  ionized 
  layer 
  of 
  liquid. 
  

  

  (b) 
  In 
  a 
  second 
  set 
  of 
  measurements 
  the 
  apparatus 
  shown 
  

   in 
  fig. 
  3 
  was 
  used. 
  This 
  consisted 
  of 
  a 
  plate 
  GH 
  separated 
  

   from 
  a 
  second 
  plate 
  EF 
  by 
  two 
  small 
  blocks 
  of 
  clean 
  ebonite. 
  

   The 
  plate 
  EF 
  was 
  provided 
  with 
  an 
  opening 
  shown 
  in 
  the 
  

   figure 
  somewhat 
  over 
  1 
  sq. 
  cm. 
  in 
  area. 
  A 
  third 
  plate 
  CABD 
  

   was 
  attached 
  to 
  EF 
  by 
  ebonite 
  supports 
  and 
  was 
  bent 
  so 
  

   that 
  the 
  portion 
  AB 
  occupied 
  nearly 
  all 
  the 
  space 
  provided 
  

   by 
  the 
  opening 
  in 
  FE. 
  

  

  