﻿Positive 
  Electricity, 
  823 
  

  

  illuminated 
  than 
  any 
  other 
  part 
  of 
  the 
  ribbon 
  ; 
  in 
  others 
  the 
  

   ilhimination 
  is 
  fairly 
  uniform 
  throughout. 
  

  

  Fis-. 
  2. 
  Fig. 
  3. 
  

  

  t 
  

  

  I 
  • 
  

  

  I 
  

  

  On 
  the 
  other 
  side 
  of 
  the 
  undeflected 
  position 
  there 
  is 
  a 
  

   luminous 
  tail, 
  formed, 
  as 
  the 
  direction 
  of 
  the 
  deflexions 
  

   shows, 
  of 
  negatively 
  electritied 
  particles. 
  The 
  brightness 
  of 
  

   this 
  in 
  comparison 
  with 
  the 
  positive 
  part 
  changes 
  very 
  con- 
  

   siderably 
  : 
  in 
  some 
  cases 
  it 
  is 
  too 
  faint 
  to 
  be 
  easily 
  perceived, 
  

   in 
  others 
  it 
  is 
  sometimes 
  almost 
  as 
  bright 
  as 
  the 
  positive 
  part 
  

   of 
  the 
  ribbon 
  ; 
  in 
  general, 
  however, 
  it 
  is 
  much 
  feebler 
  and 
  

   there 
  is 
  distinct 
  discontinuity 
  in 
  the 
  brightness 
  of 
  the 
  light 
  

   in 
  the 
  tail 
  and 
  in 
  the 
  other 
  portions. 
  

  

  If 
  j/ 
  is 
  the 
  vertical, 
  x 
  the 
  horizontal 
  deflexion 
  of 
  the 
  rays, 
  

  

  r 
  oc 
  yjx 
  

  

  ejin 
  oc 
  y^jx. 
  

  

  Thus 
  when 
  the 
  ribbon 
  is 
  straight, 
  the 
  values 
  of 
  y/x 
  and 
  there- 
  

   fore 
  the 
  velocity 
  of 
  the 
  particles 
  are 
  approximately 
  constant, 
  

   while 
  y^/x 
  ranges 
  from 
  zero 
  up 
  to 
  a 
  maximum 
  value 
  at 
  the 
  

   end 
  of 
  the 
  strip. 
  This 
  maximum 
  value, 
  in 
  all 
  the 
  cases 
  I 
  have 
  

   tried, 
  gives 
  a 
  value 
  of 
  e/m 
  equal 
  to 
  10^. 
  

  

  When 
  the 
  pressure 
  of 
  the 
  gas 
  is 
  reduced, 
  the 
  luminosity 
  of 
  

   the 
  band 
  concentrates 
  into 
  a 
  spot 
  or 
  spots 
  and 
  presents 
  the 
  

   appearance 
  shown 
  in 
  fig. 
  3. 
  There 
  is 
  a 
  bright 
  spot 
  at 
  the 
  

   end 
  and 
  a 
  faint 
  band 
  which 
  at 
  low 
  pressures 
  becomes 
  almost 
  

   invisible 
  connecting 
  this 
  spot 
  with 
  the 
  position 
  of 
  the 
  

   undeflected 
  spot 
  ; 
  at 
  this 
  place 
  there 
  is 
  not 
  infrequently 
  a 
  

   considerable 
  amount 
  of 
  luminosity 
  even 
  when 
  the 
  magnet 
  is 
  on. 
  

   Tills 
  luminosity 
  is 
  often 
  indistinct 
  and 
  sometimes 
  vanishes. 
  

   When 
  it 
  is 
  present 
  it 
  indicates 
  the 
  presence 
  of 
  a 
  considerable 
  

   number 
  of 
  rays 
  which 
  are 
  not 
  deflected 
  in 
  passing 
  through 
  

   the 
  magnetic 
  and 
  electric 
  fields, 
  and 
  which 
  are 
  therefore 
  not 
  

   charged 
  when 
  they 
  pass 
  through 
  these 
  fields. 
  Neglecting 
  for 
  

   a 
  moment 
  the 
  faint 
  luminosity 
  connecting 
  the 
  spots, 
  the 
  

   bundle 
  of 
  rays 
  in 
  this 
  case 
  consists 
  of 
  a 
  mixture 
  of 
  positively 
  

   electrified 
  particles 
  and 
  electrically 
  neutral 
  systems, 
  uncharged 
  

   rays 
  we 
  may 
  call 
  them 
  ; 
  these 
  uncharged 
  rays^ 
  however, 
  in 
  

   their 
  course 
  through 
  the 
  gas 
  may 
  gradually 
  get 
  broken 
  up 
  

  

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