﻿576 
  Mr. 
  F. 
  L. 
  Hitchcock 
  on 
  

  

  disintegrate 
  the 
  molecule 
  into 
  positive 
  and 
  negative 
  ions. 
  The 
  

   apparent 
  masses 
  of 
  the 
  ions 
  therefore 
  depend 
  on 
  the 
  ratio 
  of 
  

   the 
  electric 
  force 
  to 
  the 
  pressure. 
  

  

  10. 
  The 
  results 
  of 
  these 
  experiments 
  throw 
  some 
  light 
  on 
  

   the 
  constitution 
  of 
  molecules 
  of 
  gases. 
  We 
  are 
  led 
  to 
  con- 
  

   clude 
  that: 
  — 
  It 
  is 
  possible 
  to 
  detach 
  a 
  particle 
  from 
  the 
  

   molecule 
  of 
  a 
  gas 
  which 
  is 
  small, 
  as 
  regards 
  mass 
  and 
  linear 
  

   dimensions, 
  compared 
  with 
  the 
  molecule 
  of 
  hydrogen, 
  also 
  

   the 
  particles 
  produced 
  from 
  molecules 
  of 
  different 
  gases 
  are 
  

   identically 
  the 
  same. 
  

  

  The 
  mass 
  of 
  the 
  negative 
  ion 
  coming 
  from 
  a 
  zinc 
  plate 
  was 
  

   previously 
  shown 
  by, 
  Professor 
  Thomson* 
  to 
  be 
  small 
  com- 
  

   pared 
  with 
  the 
  molecule 
  of 
  hydrogen. 
  The 
  method 
  which 
  

   he 
  adopted 
  did 
  not 
  involve 
  any 
  of 
  the 
  principles 
  underlying 
  

   the 
  present 
  investigations. 
  

  

  A 
  considerable 
  number 
  of 
  phenomena 
  connected 
  with 
  the 
  

   electric 
  discharge 
  in 
  gases 
  may 
  be 
  explained 
  in 
  a 
  general 
  way 
  

   by 
  taking 
  into 
  consideration 
  the 
  physical 
  properties 
  of 
  these 
  

   negative 
  ions. 
  Thus 
  some 
  of 
  the 
  effects 
  of 
  variation 
  of 
  

   pressure, 
  electric 
  force, 
  and 
  distance 
  between 
  the 
  plates 
  can 
  

   be 
  accounted 
  for. 
  Also 
  the 
  high 
  conductivity 
  of 
  gases 
  under 
  

   rapidly 
  alternating 
  forces 
  may 
  be 
  due 
  to 
  the 
  fact 
  that 
  the 
  

   negative 
  ions 
  traverse 
  a 
  long 
  distance 
  before 
  they 
  are 
  dis- 
  

   charged 
  by 
  the 
  electrodes. 
  There 
  are, 
  however, 
  many 
  

   phenomena 
  for 
  which 
  these 
  physical 
  properties 
  supply 
  no 
  

   explanations 
  : 
  such 
  as 
  the 
  appearance, 
  at 
  the 
  electrodes, 
  of 
  

   the 
  constituents 
  of 
  compound 
  gases. 
  

  

  The 
  experiments 
  with 
  ultra-violet 
  light 
  show 
  that 
  in 
  car- 
  

   bonic 
  acid 
  the 
  conductivity 
  may 
  arise 
  from 
  the 
  genesis 
  of 
  

   small 
  negative 
  ions. 
  I 
  am 
  at 
  present 
  continuing 
  the 
  researches 
  

   with 
  other 
  gases 
  and 
  vapours, 
  so 
  as 
  to 
  obtain 
  some 
  additional 
  

   evidence 
  on 
  this 
  point, 
  as 
  it 
  is 
  to 
  be 
  expected 
  that 
  similar 
  

   phenomena 
  may 
  occur 
  with 
  other 
  compound 
  gases. 
  

  

  LXVII. 
  On 
  Vector 
  Differentials. 
  

   By 
  Frank 
  Lauren 
  Hitchcock 
  f. 
  

  

  1. 
  TN 
  studying 
  physical 
  quantities 
  we 
  are 
  led 
  to 
  make 
  a 
  

   _L 
  distinction 
  between 
  those 
  which 
  have 
  by 
  their 
  very 
  

   nature 
  a 
  direction 
  in 
  space, 
  and 
  those 
  which, 
  on 
  the 
  other 
  

   hand, 
  may 
  be 
  thought 
  of 
  as 
  mere 
  numbers. 
  Directed 
  quan- 
  

   tities 
  are 
  conveniently 
  called 
  vectors, 
  and 
  non- 
  directed 
  ones 
  

   scalar 
  s. 
  

  

  * 
  J. 
  J. 
  Thomson, 
  Phil. 
  Mag. 
  December 
  1900. 
  

   t 
  Communicated 
  by 
  the 
  Author. 
  

  

  