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  XVTI. 
  On 
  the 
  Action 
  of 
  a 
  Magnetic 
  Field 
  upon 
  the 
  Electric 
  

   Discharge 
  through 
  Gases. 
  By 
  Louis 
  T. 
  More, 
  Professor 
  

   of 
  Physics, 
  and 
  S. 
  J. 
  Mauchly, 
  Hanna 
  Fellow 
  in 
  Physics, 
  

   Ihe 
  University 
  of 
  Cincinnati 
  *. 
  

  

  FT 
  ^HE 
  action 
  of 
  a 
  magnetic 
  field 
  on 
  the 
  electric 
  discharge 
  

   JL 
  through 
  gases 
  has 
  been 
  studied 
  almost 
  continuously 
  

   since 
  the 
  first 
  experiments 
  made 
  by 
  Plucker 
  in 
  1858. 
  An 
  

   excellent 
  resume 
  of 
  the 
  whole 
  subject 
  is 
  given 
  in 
  Sir 
  J. 
  J. 
  

   Thomson's 
  ' 
  Conduction 
  of 
  Electricity 
  through 
  Gases/ 
  The 
  

   theory 
  often 
  advanced 
  is 
  that 
  the 
  magnetic 
  field 
  causes 
  

   the 
  charged 
  particles 
  of 
  the 
  current, 
  and 
  especially 
  the 
  

   negatively 
  charged 
  electrons, 
  to 
  move 
  in 
  helical 
  paths 
  along 
  

   the 
  lines 
  of 
  magnetic 
  force. 
  This 
  action 
  must 
  certainly 
  

   occur, 
  and 
  it 
  explains 
  what 
  may 
  be 
  called 
  the 
  primary 
  effect 
  

   of 
  the 
  magnetic 
  field. 
  But 
  there 
  are 
  other 
  numerous 
  and 
  

   very 
  complicated 
  phenomena, 
  evidently 
  of 
  a 
  secondary 
  

   nature, 
  which 
  the 
  field 
  produces 
  and 
  which 
  apparently 
  have 
  

   not 
  been 
  included 
  in 
  the 
  theory. 
  Professor 
  Highi 
  has 
  made 
  

   an 
  elaborate 
  study 
  of 
  these 
  actions 
  of 
  the 
  magnetic 
  field, 
  

   during 
  which 
  he 
  has 
  greatly 
  extended 
  our 
  knowledge 
  of 
  the 
  

   subject 
  by 
  ingenious 
  experiments. 
  He 
  has 
  also 
  advanced 
  a 
  

   new 
  theory 
  to 
  account 
  for 
  both 
  the 
  primary 
  and 
  secondary 
  

   actions 
  of 
  the 
  field. 
  According 
  to 
  this 
  theory, 
  the 
  magnetic 
  

   field 
  causes 
  positive 
  ions 
  and 
  negative 
  electrons 
  to 
  unite 
  as 
  

   rather 
  loosely 
  bound 
  rotating 
  doublets, 
  which 
  are 
  then 
  driven 
  

   along 
  the 
  lines 
  of 
  magnetic 
  force. 
  The 
  secondary 
  effects, 
  he 
  

   explains 
  by 
  dissociation 
  of 
  the 
  doublets 
  as 
  they 
  move 
  out 
  of 
  

   the 
  field. 
  

  

  In 
  most 
  of 
  his 
  experiments, 
  Professor 
  Righi 
  disposes 
  the 
  

   magnetic 
  and 
  electric 
  fields 
  so 
  as 
  to 
  coincide 
  in 
  direction. 
  If 
  

   we 
  neglect 
  some 
  of 
  the 
  minor 
  details 
  of 
  his 
  work, 
  we 
  can 
  

   summarize 
  the 
  main 
  facts 
  brought 
  out 
  by 
  his 
  researches 
  

   (when 
  the 
  axis 
  of 
  the 
  magnetic 
  field 
  coincides 
  with 
  the 
  axis 
  

   of 
  the 
  vacuum 
  tube) 
  as 
  follows 
  : 
  — 
  

  

  In 
  the 
  region 
  of 
  the 
  negative 
  glow, 
  the 
  magnetic 
  field 
  

   produces 
  many 
  ion-electron 
  doublets 
  which 
  are 
  driven 
  away 
  

   from 
  the 
  cathode. 
  These 
  "magnetic 
  rays*' 
  appear 
  in 
  the 
  

   form 
  of 
  a 
  cone 
  of 
  blue 
  light 
  whose 
  axis 
  coincides 
  with 
  the 
  

   axis 
  of 
  the 
  tube 
  and 
  whose 
  apex 
  is 
  farthest 
  from 
  the 
  cathode. 
  

   He 
  finds 
  these 
  rays 
  to 
  be 
  electrically 
  neutral, 
  since 
  when 
  

   collected 
  in 
  a 
  Faraday 
  pail 
  they 
  give 
  to 
  it 
  no 
  charge. 
  Also, 
  

   if 
  an 
  auxiliary 
  or 
  test-magnet 
  be 
  held 
  near 
  the 
  tube, 
  the 
  rays 
  

   bend 
  directly 
  toward 
  or 
  away 
  from 
  its 
  pole, 
  according 
  to 
  its 
  

  

  * 
  Communicated 
  by 
  the 
  Authors. 
  

  

  