﻿6M 
  Prof. 
  J. 
  J. 
  Thorns 
  

  

  on 
  on 
  

  

  of 
  the 
  cathode 
  are 
  curved 
  as 
  in 
  fig. 
  4. 
  A 
  corpuscle 
  starting 
  

   along 
  the 
  normal 
  from 
  P 
  would 
  on 
  account 
  of 
  its 
  inertia 
  not 
  

  

  Fiff. 
  4. 
  

  

  follow 
  the 
  line 
  of 
  force 
  PQ 
  but 
  some 
  path 
  PQ' 
  between 
  

   PC 
  and 
  PQ, 
  PC 
  being 
  the 
  normal 
  to 
  the 
  cathode. 
  If, 
  now, 
  

   the 
  corpuscle 
  produces 
  a 
  positive 
  ion 
  at 
  Q', 
  this 
  ion 
  as 
  it 
  

   moves 
  up 
  to 
  the 
  cathode 
  will 
  not 
  follow 
  the 
  path 
  Q'P 
  but 
  

   some 
  such 
  path 
  as 
  Q'P', 
  striking 
  the 
  cathode 
  at 
  P', 
  and 
  pro- 
  

   ducing 
  a 
  cathode 
  ray 
  at 
  P 
  x 
  . 
  Thus 
  the 
  positive 
  particle, 
  if 
  it 
  

   strikes 
  the 
  cathode 
  at 
  all, 
  will 
  not 
  give 
  rise 
  to 
  a 
  cathode 
  ray 
  

   to 
  replace 
  the 
  one 
  which 
  produced 
  it, 
  but 
  a 
  ray 
  starting 
  from 
  

   some 
  other 
  region. 
  If, 
  however, 
  the 
  line 
  of 
  force 
  starting 
  

   from 
  P 
  were 
  a 
  straight 
  line, 
  the 
  positive 
  particle 
  produced 
  

   by 
  the 
  ray 
  at 
  P 
  w 
  ould 
  strike 
  the 
  cathode 
  at 
  P. 
  When 
  the 
  

   discharge 
  is 
  in 
  a 
  steady 
  state 
  the 
  number 
  of 
  corpuscles 
  coming 
  

   from 
  any 
  region 
  must 
  be 
  proportional 
  to 
  the 
  number 
  of 
  

   positive 
  particles 
  falling 
  on 
  that 
  region. 
  Now 
  this 
  will 
  be 
  

   the 
  case 
  when 
  and 
  only 
  (except 
  perhaps 
  in 
  very 
  special 
  cases) 
  

   when 
  the 
  positive 
  rays 
  which 
  strike 
  the 
  region 
  are 
  those 
  

   produced 
  by 
  the 
  corpuscles 
  coming 
  from 
  it. 
  For 
  this 
  to 
  

   happen, 
  the 
  lines 
  of 
  force 
  from 
  that 
  region 
  must 
  be 
  straight 
  

   lines. 
  In 
  the 
  case 
  of 
  the 
  triangular 
  cathode 
  there 
  are 
  six 
  

   regions 
  where 
  the 
  lines 
  of 
  force 
  are 
  straight, 
  the 
  middle 
  

   points 
  of 
  the 
  sides 
  and 
  the 
  corners 
  ; 
  and 
  it 
  is 
  therefore 
  from 
  

   these 
  regions 
  that 
  we 
  should 
  expect 
  the 
  discharge 
  to 
  be 
  

   concentrated 
  ; 
  and 
  inasmuch 
  as 
  the 
  region 
  over 
  which 
  the 
  

   lines 
  are 
  approximately 
  straight 
  is 
  much 
  greater 
  at 
  the 
  middle 
  

   points 
  of 
  the 
  sides 
  than 
  at 
  the 
  corners, 
  we 
  should 
  expect 
  the 
  

   maximum 
  discharge 
  to 
  come 
  from 
  the 
  middle 
  point 
  of 
  

   the 
  sides. 
  

  

  