﻿Positive 
  Electricitij. 
  839 
  

  

  plate 
  d^ 
  and 
  the 
  positive 
  ions, 
  after 
  passing 
  through 
  the 
  

   hole, 
  travelled 
  through 
  the 
  strong 
  magnetic 
  field 
  produced 
  

   by 
  a 
  Du 
  Bois 
  magnet. 
  The 
  magnetic 
  deflexion 
  o£ 
  the 
  rays 
  

   was 
  measured 
  by 
  the 
  ratio 
  between 
  the 
  charges 
  received 
  by 
  

   the 
  disk 
  h 
  and 
  the 
  cylinder 
  a 
  : 
  these 
  were 
  connected 
  with 
  

   Wilson 
  tilted 
  electroscopes, 
  and 
  the 
  ratio 
  o£ 
  the 
  charges 
  

   measured 
  in 
  the 
  way 
  described 
  in 
  my 
  paper 
  on 
  the 
  Positive 
  

   Rays 
  (Phil 
  Mag. 
  Oct. 
  1908). 
  

  

  I£ 
  V 
  is 
  the 
  fall 
  o£ 
  potential 
  between 
  the 
  gauze 
  and 
  the 
  top 
  

   of 
  the 
  plate, 
  

  

  eY 
  = 
  ^mi:\ 
  

  

  -while 
  the 
  magnetic 
  deflexion 
  gave 
  the 
  value 
  of 
  mu/e. 
  

  

  Thus 
  from 
  these 
  results 
  mje 
  and 
  v 
  can 
  be 
  determined. 
  

  

  We 
  find 
  that 
  for 
  these 
  slowly 
  moving 
  positive 
  rays 
  the 
  

   velocity 
  depends 
  upon 
  the 
  strength 
  of 
  the 
  electric 
  field. 
  

  

  The 
  point 
  that 
  I 
  wish 
  to 
  dwell 
  upon 
  here 
  is, 
  that 
  in 
  some 
  

   -cases 
  the 
  method 
  seemed 
  to 
  give 
  values 
  of 
  ejin 
  for 
  the 
  positive 
  

   ions 
  much 
  greater 
  than 
  10^. 
  I 
  think 
  these 
  high 
  values 
  are 
  

   not 
  genuine, 
  but 
  I 
  will 
  first 
  describe 
  the 
  effects 
  which 
  seem 
  

   to 
  indicate 
  them. 
  We 
  may 
  get, 
  perhaps, 
  the 
  clearest 
  idea 
  of 
  

   these 
  by 
  describing 
  what 
  happens 
  when 
  the 
  arrangement 
  is 
  

   altered 
  so 
  as 
  to 
  send 
  negative 
  ions 
  and 
  not 
  positive 
  through 
  

   the 
  same 
  hole 
  in 
  the 
  top 
  plate. 
  

  

  In 
  this 
  case 
  the 
  corpuscles 
  and 
  negative 
  ions 
  pass 
  through 
  

   the 
  plate. 
  

  

  If 
  we 
  compare 
  the 
  charges 
  on 
  the 
  disk 
  and 
  the 
  cylinder 
  

   when 
  there 
  is 
  no 
  magnetic 
  field 
  on, 
  we 
  find 
  that 
  in 
  general 
  

   there 
  is 
  more 
  negative 
  charo-e 
  on 
  the 
  cvlinder 
  than 
  on 
  the 
  

   disk, 
  and 
  the 
  effect 
  of 
  a 
  small 
  magnetic 
  field, 
  say 
  200 
  units, 
  

   is 
  greatly 
  to 
  diminish 
  the 
  proportion 
  of 
  the 
  negative 
  charge 
  

   on 
  the 
  cylinder 
  to 
  that 
  on 
  the 
  disk 
  : 
  when 
  the 
  magnetic 
  

   force 
  is 
  greatly 
  increased 
  this 
  proportion 
  again 
  increases, 
  due 
  

   to 
  the 
  deflexion 
  by 
  the 
  magnet 
  of 
  the 
  heavy 
  negative 
  ions 
  

   from 
  the 
  disk 
  to 
  the 
  cylinder. 
  

  

  It 
  will 
  be 
  noticed 
  that 
  the 
  effect 
  of 
  putting 
  on 
  the 
  small 
  

   magnetic 
  field 
  is 
  to 
  diminish 
  the 
  scattering. 
  This 
  is 
  what 
  

   we 
  should 
  expect 
  if 
  these 
  were 
  negative 
  corpuscles 
  getting 
  

   through 
  the 
  hole 
  when 
  there 
  was 
  no 
  magnetic 
  field. 
  If 
  these 
  

   rays 
  were 
  rather 
  diffuse 
  they 
  would 
  reach 
  the 
  sides 
  of 
  the 
  

   cylinder. 
  

  

  Now 
  when 
  a 
  magnetic 
  field 
  of 
  say 
  100 
  units 
  is 
  put 
  on, 
  

   it 
  twists 
  up 
  the 
  path 
  of 
  the 
  particles 
  into 
  very 
  small 
  circles, 
  

   so 
  that 
  they 
  are 
  prevented 
  by 
  it 
  from 
  even 
  getting 
  as 
  far 
  as 
  

   either 
  of 
  the 
  Faraday 
  cylinders. 
  

  

  The 
  magnetic 
  field 
  is 
  not 
  sufficient 
  to 
  affect 
  appreciably 
  

  

  3 
  L 
  2 
  

  

  