﻿Positive 
  Hays. 
  665 
  

  

  The 
  cathode 
  consists 
  of 
  two 
  parallel 
  triangles, 
  and 
  is 
  carried 
  

   by 
  a 
  stopper 
  working 
  in 
  a 
  ground-glass 
  tube. 
  By 
  turning 
  

   the 
  stopper 
  the 
  different 
  parts 
  of 
  the 
  triangular 
  cathode 
  

   could 
  be 
  brought 
  opposite 
  to 
  the 
  opening 
  in 
  the 
  tube 
  and 
  

   the 
  distribution 
  of 
  the 
  rays 
  round 
  the 
  triangle 
  studied. 
  I 
  

   found 
  that 
  this 
  distribution 
  depended 
  a 
  good 
  deal 
  upon 
  the 
  

   pressure 
  of 
  the 
  gas 
  in 
  the 
  discharge 
  -tube. 
  At 
  all 
  the 
  

   pressures 
  I 
  tried, 
  I 
  found 
  that 
  the 
  maximum 
  emission 
  of 
  

   ordinary 
  cathode 
  rays 
  was 
  along 
  the 
  line 
  starting 
  from 
  the 
  

   middle 
  points 
  of 
  the 
  sides 
  ; 
  at 
  the 
  higher 
  pressures, 
  this 
  was 
  

   the 
  only 
  direction 
  in 
  which 
  the 
  cathode 
  rays 
  could 
  be 
  de- 
  

   tected 
  ; 
  at 
  very 
  low 
  pressures, 
  however, 
  rays 
  could 
  be 
  detected 
  

   starting 
  from 
  the 
  corners 
  of 
  the 
  triangle 
  as 
  well 
  as 
  from 
  the 
  

   middle 
  points 
  of 
  the 
  sides, 
  few, 
  if 
  any, 
  however, 
  were 
  given 
  

   out 
  in 
  any 
  intermediate 
  position. 
  With 
  regard 
  to 
  the 
  positive 
  

   rays, 
  I 
  found 
  at 
  all 
  the 
  pressures 
  I 
  tried 
  that 
  these 
  streamed 
  

   off 
  from 
  both 
  the 
  corners 
  and 
  the 
  middle 
  points 
  of 
  the 
  sides, 
  

   there 
  were 
  but 
  few 
  in 
  any 
  intermediate 
  position 
  ; 
  the 
  most 
  

   abundant 
  stream 
  came, 
  as 
  was 
  the 
  case 
  for 
  cathode 
  rays, 
  from 
  

   the 
  middle 
  points 
  of 
  the 
  sides, 
  but 
  the 
  disproportion 
  between 
  

   the 
  streams 
  from 
  the 
  corners 
  and 
  from 
  the 
  sides 
  was 
  nothing- 
  

   like 
  so 
  great 
  for 
  the 
  positive 
  as 
  it 
  was 
  for 
  the 
  cathode 
  rays 
  ; 
  

   so 
  that 
  the 
  ratio 
  of 
  the 
  quantity 
  of 
  the 
  positive 
  rays 
  to 
  the 
  

   quantity 
  of 
  cathode 
  rays 
  was 
  greatest 
  at 
  the 
  corners 
  of 
  the 
  

   triangle. 
  

  

  I 
  also 
  measured 
  the 
  velocity 
  and 
  the 
  value 
  of 
  e/rn 
  for 
  the 
  

   positive 
  rays. 
  1 
  found 
  that 
  this 
  was 
  the 
  same 
  whether 
  the 
  

   rays 
  came 
  from 
  the 
  corners 
  or 
  from 
  the 
  sides, 
  and 
  the 
  same 
  

   as 
  that 
  of 
  one 
  type 
  of 
  Canalstrahlen 
  (the 
  type 
  for 
  which 
  

   e/m 
  = 
  10*), 
  which 
  went 
  down 
  the 
  tube 
  when 
  A 
  was 
  made 
  

   cathode. 
  In 
  the 
  case 
  of 
  the 
  positive 
  rays 
  coming 
  from 
  the 
  

   triangular 
  cathode, 
  often 
  only 
  a 
  small 
  fraction 
  were 
  at 
  all 
  

   affected 
  by 
  electric 
  and 
  magnetic 
  forces, 
  by 
  far 
  the 
  larger 
  

   portions 
  w 
  r 
  ere 
  quite 
  undeflected 
  by 
  these 
  forces 
  ; 
  so 
  that 
  the 
  

   phosphorescence 
  of 
  the 
  screen 
  when 
  the 
  magnetic 
  force 
  

   was 
  applied 
  to 
  the 
  tube 
  presented 
  the 
  appearance 
  of 
  a 
  

   bright 
  central 
  undeflected 
  patch 
  with 
  a 
  faintly 
  luminous 
  

   tail. 
  

  

  We 
  can, 
  I 
  think, 
  explain 
  this 
  distribution 
  of 
  the 
  rays 
  from 
  

   the 
  triangular 
  cathode 
  on 
  the 
  view 
  that 
  there 
  is 
  a 
  reciprocity 
  

   between 
  the 
  cathode 
  rays 
  and 
  the 
  positive 
  rays 
  of 
  the 
  follow- 
  

   ing 
  kind. 
  The 
  corpuscles 
  in 
  the 
  cathode 
  rays 
  are 
  due 
  to 
  the 
  

   impact 
  of 
  positive 
  ions 
  at 
  or 
  near 
  the 
  cathode, 
  while 
  the 
  

   positive 
  rays 
  are 
  due 
  to 
  the 
  impact 
  of 
  the 
  corpuscles 
  at 
  some 
  

   distance 
  from 
  the 
  cathode. 
  Let 
  us 
  consider 
  now 
  what 
  

   liappens 
  when 
  the 
  lines 
  of 
  electric 
  force 
  in 
  the 
  neighbourhood 
  

  

  