﻿Virtual 
  Anode 
  in 
  the 
  Tubes 
  for 
  Magnetic 
  Rays. 
  853 
  

  

  formed. 
  Now 
  this 
  is 
  just 
  the 
  conclusion 
  to 
  which 
  one 
  comes 
  

   by 
  the 
  comparison 
  between 
  the 
  curves 
  relative 
  to 
  the 
  various 
  

   gases. 
  

  

  In 
  fact, 
  while 
  those 
  relative 
  to 
  the 
  gases 
  N, 
  0, 
  CO 
  

   (respective 
  molecular 
  weights 
  being 
  28, 
  32, 
  28) 
  are 
  very 
  

   near 
  each 
  other, 
  those 
  relative 
  to 
  C0 
  2 
  (molecular 
  weight 
  44) 
  

   stand 
  far 
  above 
  the 
  preceding 
  ones^ 
  while 
  those 
  relative 
  to 
  

   H 
  (molecular 
  weight 
  2) 
  are 
  to 
  be 
  found 
  very 
  much 
  below 
  all 
  

   the 
  others. 
  In 
  other 
  terms, 
  with 
  parity 
  of 
  the 
  magnetic 
  field 
  

   and 
  pressure 
  of 
  the 
  gas, 
  the 
  virtual 
  anode 
  is 
  formed 
  very 
  far 
  

   from 
  the 
  cathode 
  in 
  the 
  case 
  of 
  hydrogen, 
  much 
  less 
  far 
  from 
  

   the 
  cathode 
  in 
  the 
  case 
  of 
  nitrogen, 
  of 
  oxygen, 
  and 
  of 
  carbon 
  

   monoxide, 
  and 
  at 
  an 
  even 
  shorter 
  distance 
  from 
  the 
  cathode 
  

   in 
  the 
  case 
  of 
  carbonic 
  anhydride 
  (?). 
  At 
  the 
  same 
  time 
  the 
  

   total 
  length 
  of 
  the 
  luminous 
  phenomenon 
  (magnetic 
  rays 
  

   and 
  secondary 
  column) 
  varies 
  in 
  a 
  similar 
  way. 
  Nay, 
  with 
  

   ether 
  and 
  chloroform 
  vapour 
  (molecular 
  weights 
  74,119) 
  one 
  

   does 
  not 
  easily 
  succeed 
  in 
  noticing 
  the 
  phenomenon. 
  Traces 
  

   of 
  the 
  said 
  vapours 
  are 
  sufficient 
  in 
  the 
  case 
  of 
  certain 
  gases, 
  

   like 
  oxygen 
  and 
  hydrogen, 
  to 
  make 
  it 
  very 
  difficult 
  to 
  realize 
  

   the 
  experiment 
  of 
  the 
  virtual 
  anode. 
  As 
  a 
  general 
  rule, 
  the 
  

   limits 
  of 
  pressure 
  within 
  which 
  the 
  phenomena 
  in 
  question 
  

   are 
  fully 
  realized 
  vary 
  with 
  the 
  different 
  gases. 
  For 
  example, 
  

   in 
  the 
  case 
  of 
  the 
  tube 
  more 
  than 
  once 
  used 
  by 
  me, 
  the 
  

   pressure 
  may 
  vary 
  between 
  1 
  mm. 
  and 
  0*30 
  mm. 
  when 
  

   containing 
  hydrogen, 
  while 
  when 
  it 
  contains 
  carbonic 
  

   anhydride 
  it 
  is 
  necessary 
  for 
  the 
  pressure 
  not 
  to 
  exceed 
  much 
  

   0'36 
  mm., 
  and 
  one 
  may 
  reach 
  0*01 
  mm. 
  without 
  the 
  effects 
  

   being 
  much 
  altered. 
  Among 
  the 
  different 
  gases 
  I 
  have 
  also 
  

   noticed 
  other 
  differences 
  of 
  a 
  smaller 
  value. 
  For 
  instance, 
  

   the 
  curves 
  I 
  have 
  obtained 
  with 
  oxygen 
  are 
  more 
  inclined 
  

   upwards 
  than 
  those 
  relative 
  to 
  carbon 
  monoxide, 
  so 
  that 
  

   it 
  happens 
  that 
  the 
  curve 
  of 
  one 
  of 
  the 
  gases 
  lies 
  partly 
  

   above 
  and 
  partly 
  below 
  that 
  of 
  the 
  other 
  gas 
  with 
  equal 
  

   pressure. 
  

  

  1 
  have 
  obtained 
  results 
  of 
  some 
  interest 
  by 
  using 
  gaseous 
  

   mixtures. 
  Apart 
  from 
  the 
  case 
  of 
  vapours, 
  even 
  of 
  water 
  

   steam, 
  which 
  seem 
  to 
  attenuate 
  the 
  phenomena, 
  by 
  the 
  

   mixture 
  of 
  two 
  gases 
  in 
  different 
  proportions 
  the 
  following- 
  

   curious 
  phenomenon 
  is 
  generally 
  observed. 
  By 
  causing 
  the 
  

   intensity 
  of 
  the 
  magnetic 
  field 
  to 
  gradually 
  increase, 
  starting 
  

   from 
  0, 
  a 
  beam 
  of 
  magnetic 
  rays 
  is 
  first 
  suddenly 
  formed 
  at 
  

   a 
  certain 
  intensity 
  of 
  the 
  field, 
  which 
  beam 
  is 
  prolonged 
  into 
  

   a 
  short 
  secondary 
  column. 
  The 
  total 
  length 
  of 
  the 
  luminosity 
  

   then 
  attains 
  a 
  maximum, 
  and 
  subsequently 
  diminishes 
  to 
  a 
  

   minimum 
  and 
  then 
  increases 
  again. 
  Sometimes 
  I 
  have 
  

  

  