﻿Cathode 
  and 
  Canal 
  Rays 
  from 
  Hollow 
  Cathodes. 
  161 
  

  

  crystals. 
  Certain 
  crystals, 
  such 
  as 
  the 
  sulphates 
  of 
  neodymium 
  

   and 
  praseodymium, 
  possess 
  at 
  the 
  temperatures 
  of 
  liquid 
  or 
  

   solid 
  hydrogen 
  true 
  rays 
  o£ 
  absorption 
  of 
  a 
  fineness 
  as 
  great 
  

   as 
  the 
  rays 
  of 
  metallic 
  vapours. 
  The 
  rays 
  which 
  correspond 
  

   in 
  the 
  three 
  principal 
  spectra 
  are 
  very 
  sensibly 
  of 
  the 
  same 
  

   wave-length, 
  but 
  differ 
  in 
  breadth 
  and 
  intensity. 
  

  

  Let 
  us 
  denote 
  by 
  1, 
  2, 
  3 
  the 
  three 
  principal 
  directions 
  of 
  

   absorption 
  relative 
  to 
  one 
  of 
  these 
  rays. 
  We 
  shall 
  transmit 
  

   the 
  light 
  along 
  the 
  direction 
  of 
  the 
  magnetic 
  field. 
  We 
  can, 
  

   in 
  succession, 
  align 
  the 
  directions 
  1, 
  2, 
  3 
  parallel 
  to 
  the 
  

   light 
  and 
  to 
  the 
  field; 
  the 
  two 
  vibrations 
  simultaneously 
  

   observed 
  being 
  normal 
  to 
  this 
  direction 
  are 
  then 
  respectively 
  

   parallel 
  to 
  2 
  and 
  3, 
  1 
  and 
  3, 
  1 
  and 
  2. 
  When 
  the 
  rays 
  are 
  

   very 
  fine 
  and 
  occupy 
  exactly 
  the 
  same 
  position 
  in 
  both 
  

   spectra, 
  experiment 
  proves* 
  that 
  in 
  the 
  first 
  case 
  the 
  vibra- 
  

   tions 
  2 
  and 
  3 
  are 
  connected 
  together 
  by 
  the 
  fact 
  of 
  the 
  field 
  

   which 
  is 
  perpendicular 
  to 
  them 
  giving 
  magnetic 
  doublets 
  

   having 
  the 
  same 
  separation 
  ; 
  in 
  the 
  second 
  case 
  the 
  vibrations 
  

   1 
  and 
  3 
  also 
  give 
  rise 
  to 
  a 
  doublet, 
  but 
  this 
  doublet 
  is 
  different 
  

   from 
  the 
  first 
  ; 
  lastly, 
  in 
  the 
  third 
  case, 
  the 
  vibrations 
  1 
  and 
  2 
  

   give 
  rise 
  to 
  a 
  third 
  doublet 
  which 
  differs 
  from 
  both 
  the 
  others. 
  

  

  These 
  results 
  can 
  be 
  interpreted, 
  according 
  to 
  the 
  theory 
  

   of 
  a 
  quasi-elastic 
  force, 
  by 
  the 
  existence 
  of 
  three 
  principal 
  

   electromagnetic 
  magnitudes 
  for 
  the 
  absorbing 
  electrons 
  in 
  

   biaxial 
  crystals. 
  

  

  This 
  phenomenon 
  must 
  be 
  considered 
  as 
  the 
  generalization 
  

   of 
  phenomena 
  which, 
  in 
  isotropic 
  bodies 
  or 
  in 
  uniaxial 
  crystals, 
  

   are 
  connected 
  with 
  magnetic 
  rotatory 
  polarization 
  ; 
  for 
  it 
  

   proves 
  experimentally 
  in 
  the 
  more 
  complex 
  case 
  of 
  biaxial 
  

   crystals, 
  that 
  the 
  magnetic 
  field 
  produces 
  a 
  connexion 
  

   between 
  the 
  two 
  principal 
  vibrations 
  which 
  are 
  perpendicular 
  

   to 
  it. 
  

  

  April 
  23, 
  1908. 
  

  

  XI. 
  On 
  Cathode 
  and 
  Canal 
  Rays 
  from 
  Hollow 
  Cathodes. 
  

   By 
  Jakob 
  Kunz, 
  Dr. 
  phil., 
  Privatdozent 
  fur 
  Physik 
  am 
  

   eidg. 
  Polytechnikum, 
  Ziirich'f. 
  

  

  IN 
  his 
  paper, 
  " 
  Ueber 
  die 
  Canalstrahlengruppe," 
  Ver- 
  

   handlungen 
  der 
  deutschen 
  phy 
  si 
  kalis 
  chen 
  Gesellschaft 
  im 
  

   Jahre 
  1902, 
  p. 
  228, 
  E. 
  Goldstein 
  describes 
  canal-rays 
  starting 
  

   from 
  cathodes 
  made 
  of 
  two 
  separated 
  parallel 
  metal 
  plates 
  of 
  

   different 
  shape. 
  The 
  nature 
  of 
  these 
  rays 
  not 
  being 
  fully 
  

   determined, 
  the 
  following 
  experiments 
  were 
  made. 
  

  

  * 
  J. 
  Becquerel 
  and 
  Kanierlingh 
  Onnes, 
  loc. 
  cit. 
  

   f 
  Communicated 
  by 
  the 
  Author. 
  

  

  Phil. 
  Mag. 
  S. 
  6. 
  Vol. 
  16. 
  No. 
  91. 
  July 
  1908. 
  M 
  

  

  