﻿182 
  Dr. 
  J. 
  Kunz 
  on 
  Cathode 
  and 
  

  

  plates 
  cathode 
  rays 
  as 
  well 
  as 
  positive 
  rays. 
  The 
  blue 
  cathode 
  

   rays 
  reach 
  a 
  maximum 
  o£ 
  luminosity 
  before 
  the 
  red 
  positive 
  

   rays. 
  As 
  the 
  latter 
  pass 
  through 
  a 
  field 
  of 
  negative 
  electri- 
  

   fication, 
  they 
  will 
  be 
  neutral 
  to 
  a 
  large 
  extent 
  and 
  not 
  much 
  

   liable 
  to 
  magnetic 
  deflexion. 
  

  

  (2) 
  If 
  we 
  connect 
  the 
  two 
  triangular 
  plates 
  not 
  by 
  means 
  

   of 
  thin 
  pins 
  but 
  by 
  larger 
  masses 
  of 
  metal, 
  so 
  that 
  the 
  only 
  

   free 
  space 
  between 
  the 
  plates 
  is 
  in 
  the 
  form 
  of 
  three 
  rect- 
  

   angular 
  ducts 
  (see 
  fig. 
  22) 
  crossing 
  one 
  another, 
  we 
  should 
  

   expect 
  the 
  six 
  holes 
  to 
  behave 
  in 
  the 
  same 
  way 
  at 
  a 
  certain 
  

   comparatively 
  high 
  pressure, 
  that 
  is 
  to 
  say, 
  we 
  should 
  expect 
  

   them 
  to 
  emit 
  bright 
  blue 
  beams 
  corresponding 
  to 
  those 
  

   observed 
  in 
  the 
  case 
  of 
  perforated 
  cylindrical 
  and 
  spherical 
  

   cathodes. 
  As 
  the 
  air 
  gets 
  exhausted, 
  the 
  visible 
  cathode 
  rays 
  

   from 
  the 
  openings 
  of 
  the 
  middle 
  of 
  the 
  sides 
  will 
  still 
  be 
  

   bright, 
  whereas 
  the 
  rays 
  from 
  the 
  corners 
  become 
  nearly 
  

   invisible. 
  At 
  a 
  still 
  lower 
  pressure 
  the 
  difference 
  in 
  luminosity 
  

   becomes 
  smaller. 
  Invisible 
  cathode 
  rays 
  start 
  from 
  all 
  the 
  

   six 
  holes, 
  probably 
  accompanied 
  by 
  a 
  weak 
  stream 
  of 
  positive 
  

   ions 
  and 
  neutral 
  molecules. 
  The 
  difference 
  of 
  appearance 
  in 
  

   the 
  previous 
  stage 
  is 
  due 
  to 
  the 
  fact, 
  that 
  the 
  negative 
  glow 
  

   before 
  the 
  sides 
  of 
  the 
  triangle 
  is 
  very 
  much 
  stronger 
  than 
  

   before 
  the 
  corners, 
  a 
  phenomenon 
  observed 
  without 
  exception 
  

   in 
  every 
  case 
  of 
  cathodes 
  having 
  sharp 
  corners. 
  As 
  there 
  is 
  

   no 
  large 
  open 
  side 
  from 
  which 
  the 
  positive 
  particles 
  may 
  be 
  

   collected 
  into 
  a 
  sharp 
  beam, 
  we 
  cannot 
  expect 
  to 
  find 
  a 
  distinct 
  

   beam 
  of 
  canal-rays. 
  The 
  experiment 
  has 
  perfectly 
  justified 
  this 
  

   inference 
  from 
  the 
  theory. 
  The 
  state 
  of 
  things, 
  in 
  which 
  

   the 
  difference 
  between 
  the 
  beams 
  is 
  most 
  conspicuous, 
  is 
  

   represented 
  in 
  the 
  figure 
  22, 
  which 
  shows 
  also 
  that 
  the 
  

   negative 
  glow 
  in 
  front 
  of 
  the 
  sides 
  is 
  more 
  intense 
  than 
  before 
  

   the 
  corners 
  of 
  the 
  triangle. 
  

  

  (3) 
  If 
  the 
  cathode 
  is 
  made 
  of 
  two 
  parallel 
  square 
  plates 
  

   separated 
  3 
  mm. 
  from 
  one 
  another 
  and 
  connected 
  by 
  thin 
  

   pins, 
  we 
  should 
  expect 
  to 
  find 
  at 
  a 
  comparatively 
  high 
  pressure 
  

   four 
  blue 
  broad 
  bands 
  starting 
  perpendicularly 
  from 
  either 
  

   side 
  of 
  the 
  square. 
  These 
  rays 
  will 
  disappear 
  with 
  decreasing 
  

   pressure 
  and 
  will 
  he 
  replaced 
  by 
  wd 
  beams 
  accompanied 
  by 
  

   cathode 
  rays, 
  invisible 
  in 
  air 
  and 
  hydrogen, 
  but 
  producing 
  

   bright 
  spots 
  of 
  phosphorescence. 
  This 
  expectation 
  is 
  satisfied 
  

   by 
  an 
  experiment 
  made 
  first 
  by 
  E. 
  Goldstein, 
  who 
  also 
  found 
  

   that 
  the 
  canal-rays 
  passing 
  between 
  the 
  two 
  plates 
  mark 
  

   their 
  paths 
  by 
  a 
  system 
  <>F 
  curves 
  drawn 
  on 
  the 
  inner 
  surface 
  

   of 
  the 
  plates. 
  The 
  positive 
  red 
  rays 
  were 
  found 
  to 
  be 
  very 
  

   bright 
  and 
  sharp 
  in 
  hydrogen. 
  They 
  are 
  not 
  deflected 
  by 
  a 
  

  

  