﻿372 
  Prof. 
  Richardson 
  and 
  Mr. 
  Brown 
  on 
  the 
  Kinetic 
  

  

  it 
  would 
  prove 
  impossible 
  to 
  disentangle 
  any 
  change 
  in 
  the- 
  

   coefficient 
  due 
  to 
  6 
  being 
  changed 
  from 
  changes 
  due 
  to 
  

   unknown 
  causes. 
  We 
  have 
  therefore 
  not 
  attempted 
  to 
  test 
  

   this 
  part 
  of 
  the 
  theory 
  by 
  experiments 
  on 
  platinum 
  itself. 
  

  

  The 
  negative 
  ionization 
  from 
  the 
  liquid 
  alloy 
  of 
  sodium 
  and 
  

   potassium 
  suggested 
  itself 
  as 
  a 
  more 
  likely 
  way 
  of 
  attacking 
  

   this 
  question. 
  With 
  this 
  substance 
  the 
  current 
  can 
  conve- 
  

   niently 
  be 
  measured 
  at 
  temperatures 
  as 
  low 
  as 
  500 
  p 
  absolute; 
  

   so 
  that 
  if 
  the 
  theory 
  were 
  obeyed 
  by 
  this 
  substance 
  the 
  value 
  

  

  ve 
  

  

  of 
  p-* 
  ought 
  to 
  be 
  about 
  three 
  times 
  as 
  great 
  as 
  in 
  the 
  expe- 
  

   riments 
  on 
  platinum. 
  In 
  making 
  experiments 
  with 
  this 
  

   substance 
  we 
  have 
  had 
  considerable 
  experimental 
  difficulties 
  

   to 
  contend 
  with, 
  and 
  so 
  far 
  have 
  only 
  been 
  able 
  to 
  obtain 
  

   results 
  of 
  a 
  qualitative 
  character. 
  So 
  far 
  as 
  our 
  expe- 
  

   riments 
  go, 
  they 
  indicate 
  that 
  the 
  nature 
  of 
  the 
  negative 
  

   ionization 
  from 
  the 
  substance 
  is 
  not 
  at 
  all 
  what 
  was 
  expected. 
  

   Instead 
  of 
  the 
  current 
  falling 
  off 
  more 
  rapidly 
  with 
  the 
  

   potential 
  than 
  with 
  hot 
  platinum, 
  it 
  falls 
  off 
  less 
  rapidly, 
  

   indicating 
  that 
  the 
  emitted 
  electrons 
  have 
  a 
  much 
  greater 
  

   quantity 
  of 
  kinetic 
  energy 
  than 
  those 
  emitted 
  from 
  platinum 
  

   at 
  a 
  much 
  higher 
  temperature. 
  The 
  experiments 
  that 
  we 
  

   have 
  been 
  able 
  to 
  make 
  with 
  the 
  alloy 
  so 
  far 
  are 
  not 
  sufficiently 
  

   accurate 
  to 
  decide 
  whether 
  the 
  formula 
  logi 
  — 
  logi 
  = 
  kV 
  is 
  

   obeyed 
  with 
  a 
  different 
  value 
  of 
  k 
  or 
  not. 
  We 
  hope 
  to 
  be 
  

   able 
  to 
  resume 
  this 
  part 
  of 
  the 
  investigation 
  in 
  the 
  autumn. 
  

  

  Discussion 
  of 
  Results. 
  

  

  In 
  presenting 
  the 
  results 
  of 
  this 
  investigation 
  the 
  method 
  

   has 
  been 
  adopted 
  of 
  making 
  certain 
  hypotheses 
  as 
  to 
  the 
  

   distribution 
  of 
  energy 
  among 
  the 
  emitted 
  electrons. 
  From 
  

   these 
  hypotheses 
  formulas 
  have 
  been 
  deduced 
  which 
  were 
  

   then 
  compared 
  with 
  the 
  experimental 
  observations. 
  This 
  

   method 
  is 
  justifiable 
  on 
  the 
  ground 
  that 
  these 
  theoretical 
  con- 
  

   siderations 
  first 
  suggested 
  the 
  investigation, 
  and 
  also 
  because 
  

   in 
  the 
  case 
  of 
  platinum 
  the 
  phenomena 
  are 
  in 
  accordance 
  

   with 
  the 
  theory. 
  We 
  have 
  seen, 
  however, 
  that 
  a 
  number 
  of 
  

   cases 
  have 
  arisen 
  where 
  the 
  law 
  of 
  distribution 
  of 
  energy 
  

   among 
  the 
  particles 
  does 
  not 
  coincide 
  with 
  Maxwell's 
  law, 
  

   so 
  that 
  to 
  analyse 
  these 
  cases 
  it 
  is 
  important 
  to 
  have 
  a 
  more 
  

   general 
  method 
  of 
  deducing 
  the 
  mode 
  of 
  distribution 
  of 
  the 
  

   energy 
  than 
  that 
  which 
  has 
  been 
  made 
  use 
  of. 
  This 
  may 
  

   always 
  be 
  done 
  in 
  the 
  following 
  way 
  : 
  — 
  First 
  of 
  all 
  construct 
  

   the 
  curve 
  giving 
  the 
  current-densities 
  as 
  ordinates 
  in 
  terms 
  

   of 
  the 
  opposing 
  potentials 
  as 
  abscissas. 
  Our 
  interpretation 
  

  

  