﻿On 
  the 
  Kinetic 
  Theorij 
  of 
  Matter. 
  695 
  

  

  the 
  negative 
  electrons 
  show 
  a 
  very 
  definite 
  spreading 
  out 
  in 
  

   excess 
  o£ 
  what 
  is 
  required 
  by 
  the 
  theory. 
  This 
  was 
  indeed 
  

   shown 
  by 
  the 
  older 
  experiments 
  ; 
  but 
  one 
  could 
  not 
  be 
  so 
  

   certain 
  o£ 
  it, 
  owing 
  to 
  the 
  limitations 
  o£ 
  the 
  apparatus 
  then 
  

   used. 
  The 
  matter 
  is 
  being 
  investigated 
  further 
  on 
  the 
  view 
  

   that 
  it 
  is 
  due 
  to 
  reflexion 
  of 
  the 
  electrons 
  from 
  the 
  plates, 
  and 
  

   it 
  would 
  be 
  uuprofitable 
  to 
  discuss 
  it 
  further 
  until 
  more 
  expe- 
  

   riments 
  have 
  been 
  made. 
  The 
  experiments 
  in 
  this 
  direction 
  

   have 
  not 
  been 
  confined 
  to 
  platinum, 
  but 
  have 
  included 
  an 
  

   infusible 
  alloy 
  called 
  nichrome 
  as 
  well. 
  

  

  Conclusions. 
  

  

  The 
  chief 
  point 
  of 
  this 
  paper 
  is 
  to 
  be 
  found 
  in 
  fig. 
  3, 
  which 
  

   exhibits 
  a 
  very 
  close 
  agreement 
  between 
  the 
  distribution 
  of 
  

   the 
  electrons 
  from 
  a 
  hot 
  platinum 
  strip, 
  in 
  the 
  absence 
  of 
  an 
  

   external 
  electric 
  field, 
  as 
  found 
  experimentally, 
  and 
  that 
  which 
  

   was 
  predicted 
  in 
  the 
  former 
  paper 
  on 
  the 
  hypothesis 
  that 
  the 
  

   electrons 
  emitted 
  from 
  the 
  strip 
  left 
  it 
  with 
  a 
  distribution 
  of 
  

   velocity 
  equivalent 
  to 
  that 
  required 
  by 
  Maxwell's 
  law. 
  

  

  In 
  conclusion 
  I 
  wish 
  to 
  thank 
  my 
  assistant 
  Mr. 
  Cornelius 
  Bol 
  

   for 
  his 
  assistance 
  in 
  carrying 
  out 
  these 
  experiments 
  and 
  for 
  

   drawing 
  the 
  diagrams 
  of 
  the 
  apparatus 
  used. 
  

  

  r 
  r 
  j 
  

  

  LXXI. 
  Notes 
  on 
  the 
  Kinetic 
  Theory 
  of 
  Matter. 
  By 
  0. 
  W. 
  

   Richardson, 
  M.A., 
  D.Sc, 
  Professor 
  of 
  Physics, 
  Princeton 
  

   University 
  *. 
  

  

  I^HE 
  present 
  communication 
  is 
  a 
  brief 
  discussion 
  of 
  the 
  

   expression 
  for 
  the 
  probability 
  Y{ii)du 
  that 
  a 
  molecule 
  

   leaving 
  any 
  surface 
  in 
  a 
  gas 
  should 
  have 
  a 
  velocity 
  component 
  

   perpendicular 
  to 
  that 
  surf 
  ace 
  which 
  lies 
  between 
  z^ 
  and 
  u 
  + 
  du. 
  

   The 
  value 
  of 
  this 
  probability 
  is 
  

  

  Y{u)du 
  = 
  2hnue-^"'''~du 
  (1) 
  

  

  where 
  m 
  is 
  the 
  mass 
  of 
  the 
  molecules 
  and 
  ~ 
  their 
  menn 
  

  

  translational 
  kinetic 
  energy. 
  This 
  result 
  was 
  stated 
  in 
  a 
  paper 
  

   by 
  Richardson 
  and 
  Brown 
  f 
  on 
  the 
  Kinetic 
  Energy 
  of 
  the 
  

   Negative 
  Electrons 
  emitted 
  by 
  Hot 
  Bodies. 
  It 
  wks 
  given 
  

   there 
  without 
  deduction 
  as 
  the 
  writers 
  were 
  under 
  the 
  

   impression 
  that 
  it 
  was 
  a 
  familiar 
  result. 
  A 
  number 
  of 
  

   persons, 
  however, 
  who 
  have 
  taken 
  an 
  interest 
  in 
  the 
  paper 
  

  

  * 
  Communicated 
  by 
  the 
  Author. 
  

   t 
  Phil. 
  Mag. 
  [6] 
  xvi. 
  p. 
  067 
  (1908). 
  

  

  