﻿260 
  Prof. 
  More 
  and 
  Mr. 
  Mauchly: 
  Action 
  of 
  a 
  Maynetic 
  

  

  BG, 
  appears. 
  While 
  this 
  core 
  is 
  shown 
  detached 
  from 
  the 
  

   cathode, 
  it 
  is 
  really 
  attached 
  to 
  the 
  cathode 
  by 
  fine 
  pencils 
  

   of 
  cathode 
  rays 
  proceeding 
  from 
  the 
  deposit 
  on 
  the 
  cathode, 
  

   which 
  often 
  show 
  a 
  helical 
  path 
  under 
  the 
  action 
  of 
  the 
  field. 
  

   The 
  core 
  of 
  magnetic 
  rays, 
  BG, 
  bends 
  toward 
  or 
  away 
  from 
  

   a 
  test-magnet, 
  and 
  the 
  column, 
  BEF, 
  has 
  the 
  characteristic 
  

   action 
  of 
  an 
  induced 
  column 
  when 
  acted 
  on 
  by 
  the 
  test- 
  

   magnet 
  ; 
  that 
  is, 
  the 
  reversed 
  curvature 
  on 
  the 
  two 
  sides 
  of 
  

   the 
  place, 
  E, 
  which 
  Professor 
  Righi 
  has 
  called 
  the 
  virtual 
  

   anode, 
  No 
  one 
  can 
  see 
  the 
  phenomena 
  above 
  described 
  

   without 
  being 
  convinced 
  that 
  the 
  action 
  of 
  the 
  magnetic 
  

   field 
  is 
  simply 
  to 
  push 
  the 
  luminous 
  discharge 
  away 
  from 
  

   the 
  cathode. 
  In 
  further 
  confirmation 
  of 
  this 
  fact, 
  we 
  are 
  

   now 
  able, 
  by 
  adjusting 
  the 
  pressure, 
  the 
  potential, 
  and 
  the 
  

   temperature 
  of 
  the 
  cathode, 
  to 
  obtain 
  an 
  identical 
  distribution 
  

   of 
  the 
  glow 
  in 
  the 
  tube, 
  the 
  virtual 
  anode, 
  and 
  the 
  reversed 
  

   bending 
  of 
  the 
  induced 
  column 
  when 
  there 
  is 
  no 
  magnetic 
  

   field 
  acting. 
  That 
  is, 
  the 
  appearance 
  of 
  the 
  discharge 
  

   without 
  a 
  magnetic 
  field 
  (fig. 
  4) 
  may 
  be 
  made 
  the 
  same 
  as 
  

   the 
  appearance 
  with 
  a 
  magnetic 
  field 
  (fig. 
  5). 
  There 
  is, 
  of 
  

   course, 
  the 
  one 
  difference, 
  that 
  the 
  cone 
  of 
  magnetic 
  rays 
  is 
  

   replaced 
  by 
  a 
  cylindrical 
  beam 
  of 
  cathode 
  rays. 
  

  

  A 
  very 
  curious 
  and 
  significant 
  action 
  sometimes 
  takes 
  

   place 
  in 
  the 
  pinkish 
  band 
  e, 
  which 
  we 
  shall, 
  in 
  future, 
  call 
  

   the 
  positive 
  column. 
  If 
  the 
  field 
  is 
  made 
  rather 
  too 
  intense, 
  

   slight 
  variations 
  in 
  the 
  other 
  factors 
  cause 
  this 
  positive 
  

   column, 
  e, 
  to 
  move 
  towards 
  the 
  cathode, 
  instead 
  of 
  away 
  

   from 
  it 
  as 
  in 
  the 
  last 
  case. 
  When 
  this 
  happens, 
  the 
  band> 
  

   continues 
  to 
  approach 
  the 
  cathode 
  until 
  it 
  unites 
  with 
  the 
  

   negative 
  glow 
  c, 
  or 
  else 
  disappears. 
  Although 
  the 
  magnetic 
  

   rays 
  persist, 
  the 
  induced 
  column 
  now 
  shows 
  no 
  double 
  arid 
  

   reversed 
  curvature 
  with 
  a 
  test-magnet. 
  

  

  Before 
  considering 
  any 
  further 
  experiments, 
  we 
  should 
  

   first 
  discuss 
  the 
  effect 
  of 
  substituting 
  a 
  Wehnelt 
  cathode 
  for 
  

   the 
  high 
  potential 
  cold 
  cathode 
  which 
  is 
  used 
  by 
  other 
  

   investigators. 
  It 
  is 
  quite 
  evident 
  that 
  the 
  Wehnelt 
  cathode 
  

   produces 
  effects 
  which 
  in 
  themselves 
  approximate 
  to 
  the 
  

   action 
  of 
  the 
  magnetic 
  field. 
  We 
  have 
  an 
  abundance 
  of 
  

   slow 
  moving 
  cathode 
  rays 
  which 
  emanate 
  from 
  the 
  deposit 
  

   and 
  stream 
  away 
  from 
  the 
  cathode, 
  the 
  potential 
  drop 
  at 
  

   the 
  cathode 
  is 
  lowered 
  and 
  the 
  current 
  is 
  large. 
  

  

  The 
  effect 
  of 
  the 
  magnetic 
  field 
  in 
  lowering 
  the 
  potential 
  

   drop 
  at 
  the 
  cathode 
  is 
  well 
  known. 
  This 
  fact 
  was 
  discovered 
  

   by 
  Paalzow 
  and 
  Neesen 
  *. 
  Later, 
  Almy 
  t 
  found 
  that 
  a 
  

   * 
  Paalzow 
  and 
  Neesen, 
  I. 
  c. 
  

   f 
  Almy, 
  Proc. 
  Camb. 
  Phil. 
  Soc. 
  vol. 
  xi. 
  p. 
  183 
  (1901). 
  

  

  