﻿258 
  Prof. 
  More 
  and 
  Mr. 
  Mauchly: 
  Action 
  of 
  a 
  Magnetic 
  

  

  of 
  remaining 
  constant, 
  this 
  glow 
  rapidly 
  increases 
  with 
  

   flashes 
  of 
  white 
  heat 
  from 
  the 
  deposit 
  ; 
  if 
  this 
  occurs 
  the 
  

   strip 
  soon 
  burns 
  out. 
  For 
  this 
  reason 
  both 
  the 
  high 
  tension 
  

   and 
  the 
  heating 
  circuits 
  must 
  be 
  arranged 
  so 
  that 
  they 
  can 
  

   be 
  instantly 
  broken. 
  

  

  When 
  the 
  glow 
  discharge 
  is 
  seen 
  to 
  be 
  regular 
  the 
  

   magnetic 
  field 
  should 
  be 
  applied. 
  It 
  is 
  a 
  carious 
  fact 
  that 
  

   a 
  fresh 
  strip 
  and 
  a 
  fresh 
  charge 
  of 
  gas 
  behave 
  quite 
  differ- 
  

   ently 
  from 
  those 
  which 
  have 
  been 
  used 
  for 
  some 
  time. 
  At 
  

   times 
  it 
  takes 
  days, 
  and 
  always 
  hours, 
  of 
  constant 
  mnnipu- 
  

   latiou 
  before 
  a 
  good 
  and 
  constant 
  discharge 
  can 
  be 
  obtained 
  

   in 
  fresh 
  gas 
  ; 
  but 
  after 
  the 
  gas 
  has 
  been 
  once 
  broken 
  in, 
  the 
  

   rays 
  can 
  be 
  started 
  at 
  any 
  time. 
  And 
  it 
  is 
  with 
  fresh 
  gas 
  

   that 
  flashing 
  is 
  so 
  apt 
  to 
  occur. 
  This 
  is 
  somewhat 
  similar 
  

   to 
  the 
  results 
  found 
  by 
  Paalzow 
  and 
  Neesen 
  *, 
  that 
  a 
  mag- 
  

   netic 
  field 
  sometimes 
  helped 
  and 
  sometimes 
  hindered 
  the 
  

   discharge, 
  and 
  to 
  the 
  observation 
  of 
  Skinner 
  f, 
  who 
  notes 
  

   the 
  difficulty 
  at 
  times 
  of 
  getting 
  a 
  discharge 
  through 
  a 
  gas. 
  

  

  The 
  phenomena 
  connected 
  with 
  magnetic 
  rays 
  can 
  be 
  best 
  

   shown 
  by 
  describing 
  the 
  appearance 
  of 
  certain 
  typical 
  forms. 
  

   In 
  fig. 
  1 
  is 
  shown 
  the 
  appearance 
  of 
  the 
  discharge 
  when 
  

   there 
  is 
  no 
  magnetic 
  field 
  acting, 
  and 
  when 
  neither 
  the 
  

   gauze 
  sheath 
  covering 
  the 
  tube 
  nor 
  the 
  cathode 
  is 
  earthed. 
  

   The 
  branch 
  tubes 
  are 
  omitted 
  in 
  these 
  diagrams, 
  except 
  

   fig. 
  1, 
  and 
  the 
  cathode 
  is 
  indicated 
  at 
  C. 
  The 
  luminous 
  

   column 
  is 
  about 
  40 
  cm. 
  long 
  ; 
  it 
  sometimes 
  ends 
  in 
  a 
  more 
  

   or 
  less 
  sharp 
  point 
  and 
  sometimes 
  with 
  a 
  detached 
  knob, 
  as 
  

   shown 
  in 
  the 
  figure. 
  Extending 
  beneath 
  the 
  cathode 
  is 
  a 
  

   curved 
  tongue 
  of 
  pinkish-white 
  glow. 
  There 
  are 
  the 
  usual 
  

   phenomena 
  of 
  the 
  Crookes's 
  tube 
  present 
  to 
  the 
  right 
  of 
  the 
  

   cathode, 
  which 
  need 
  not 
  be 
  shown 
  ; 
  while 
  to 
  the 
  left 
  is 
  a 
  

   dark 
  space 
  similar 
  to 
  the 
  Crookes\s 
  dark 
  space 
  ; 
  and 
  beyond 
  

   it 
  for 
  several 
  centimetres 
  there 
  is 
  a 
  bluish 
  glow, 
  which 
  

   gradually 
  changes 
  into 
  the 
  more 
  pinkish 
  column, 
  BF. 
  

  

  /Bd 
  

  

  No 
  magnetic 
  field 
  screen 
  earthed, 
  cofhode 
  not 
  earthed. 
  

  

  If 
  we 
  now 
  leave 
  the 
  conditions 
  as 
  before, 
  except 
  to 
  earth 
  

   the 
  screen 
  (fig. 
  3), 
  the 
  luminous 
  glow, 
  BF, 
  nearly 
  doubles 
  

   in 
  length 
  and 
  gives 
  out 
  a 
  high 
  musical 
  note. 
  The 
  glow 
  

  

  * 
  Wied. 
  Ann. 
  vol. 
  lxiii. 
  p. 
  209 
  (1897). 
  

   f 
  Phil. 
  Mag. 
  vol. 
  1. 
  p. 
  563 
  (1900). 
  

  

  