﻿174 
  

  

  Dr. 
  J. 
  Kunz 
  on 
  Cathode 
  and 
  

  

  stage 
  of 
  pressure 
  (fig. 
  15) 
  we 
  observe 
  five 
  bright 
  well-defined 
  

   blue 
  beams 
  starting 
  from 
  the 
  holes 
  of 
  the 
  cathode 
  and 
  nearly 
  

   reaching 
  the 
  surface 
  of 
  the 
  glass 
  bulb. 
  These 
  rays 
  reach 
  a 
  

   maximum 
  of 
  luminosity 
  and 
  then 
  get 
  fainter 
  with 
  increasing 
  

  

  Fiff. 
  13. 
  

  

  Fig. 
  14. 
  

  

  vacuum 
  ; 
  while 
  the 
  phosphorescent 
  spot 
  on 
  the 
  glass 
  wall, 
  

   due 
  to 
  these 
  blue 
  beams, 
  becomes 
  surrounded 
  by 
  a 
  dark 
  ring 
  

   which 
  itself 
  gets 
  limited 
  outwards 
  by 
  a 
  now 
  bright 
  ring. 
  At 
  

   the 
  lowest 
  pressure 
  obtained, 
  the 
  central 
  circular 
  spot 
  is 
  

   found 
  to 
  be 
  surrounded 
  by 
  a 
  ring 
  of 
  faint 
  luminosity. 
  This 
  

   is 
  followed 
  by 
  a 
  dark 
  ring, 
  then 
  a 
  bright 
  ring, 
  continued 
  by 
  

   a 
  general 
  faint 
  phosphorescence 
  of 
  the 
  bulb 
  due 
  to 
  cathode 
  

   rays 
  starting 
  from 
  the 
  surface 
  of 
  the 
  cathode. 
  

  

  At 
  low 
  pressure 
  the 
  phenomena 
  observed 
  coincide 
  with 
  

   those 
  made 
  with 
  a 
  cylindrical 
  fcnbe. 
  The 
  live 
  holes 
  of 
  

   the 
  Bpherical 
  cathode 
  give 
  rise 
  to 
  the 
  same 
  kind 
  of 
  rays. 
  

   The 
  bluecolonr 
  in 
  bhe 
  air, 
  the 
  yellow 
  phosphorescence 
  on 
  

   the 
  glass 
  w;>ll. 
  and 
  the 
  amount 
  of 
  magnetic 
  deflexion 
  are 
  the 
  

   same 
  for 
  all 
  the 
  live 
  beams. 
  It 
  i- 
  especially 
  worth 
  noting 
  

  

  