﻿constituting 
  Full 
  Radiation 
  or 
  White 
  Light. 
  793 
  

  

  component 
  sine 
  curves, 
  without 
  thereby 
  altering 
  the 
  dis- 
  

   tribution 
  o£ 
  energy 
  in 
  any 
  manner. 
  That 
  is, 
  we 
  may 
  

   expect 
  

  

  /Ol') 
  = 
  - 
  \ 
  F(a)^COS 
  { 
  ccx-cl>(cc) 
  }dcc. 
  . 
  . 
  (15) 
  

  

  to 
  be 
  a 
  more 
  general 
  solution 
  o£ 
  (2) 
  than 
  (10) 
  or 
  (11). 
  

   This 
  in 
  fact 
  is 
  so, 
  as 
  may 
  be 
  verified 
  by 
  splitting 
  up 
  (2) 
  

   into 
  the 
  two 
  equations 
  

  

  and 
  

  

  F(a) 
  cos 
  (/)(«) 
  = 
  1 
  /(aa) 
  cos 
  x/judfi 
  

  

  ,'»oo 
  

  

  F{a)^ 
  sin 
  (f)(cc) 
  = 
  j 
  fifju) 
  sina/Ac;?^, 
  

  

  and 
  trying 
  to 
  find 
  a 
  solution 
  o£ 
  these 
  — 
  in 
  the 
  same 
  manner 
  

   in 
  which 
  (3) 
  and 
  (4) 
  were 
  solved 
  — 
  ^w^hich 
  at 
  the 
  same 
  time 
  

   satisfies 
  both 
  of 
  them. 
  Equation 
  (15) 
  will 
  be 
  the 
  result. 
  

  

  It 
  is 
  no 
  longer^ 
  of 
  course, 
  believed 
  that 
  white 
  light 
  consists 
  

   of 
  a 
  succession 
  of 
  pulses 
  all 
  of 
  exactly 
  the 
  same 
  form. 
  It 
  

   consists 
  rather 
  of 
  a 
  succession 
  of 
  pulses 
  capable 
  of 
  being 
  

   represented 
  by 
  an 
  equation 
  with 
  one 
  or 
  more 
  arbitrary 
  

   parameters, 
  the 
  number 
  of 
  pulses 
  emitted 
  per 
  second 
  which 
  

   have 
  their 
  parameters 
  lying 
  within 
  definite 
  limits 
  being 
  

   given 
  by 
  some 
  law 
  analogous 
  to 
  the 
  Maxwellian 
  distribution 
  

   law. 
  But 
  the 
  form 
  we 
  have 
  obtained 
  may 
  probably 
  be 
  

   looked 
  upon 
  as 
  some 
  mean 
  or 
  average 
  form 
  of 
  the 
  pulses, 
  

   and 
  may 
  perhaps 
  be 
  of 
  some 
  value 
  in 
  determining, 
  to 
  a 
  

   first 
  approximation 
  at 
  least, 
  by 
  what 
  intermolecular 
  forces 
  

   the 
  free 
  electrons 
  in 
  a 
  substance 
  must 
  be 
  acted 
  upon 
  in 
  

   order 
  to 
  give 
  the 
  observed 
  distribution 
  of 
  energy 
  in 
  the 
  

   spectrum. 
  Although, 
  as 
  we 
  have 
  seen, 
  the 
  problem 
  does 
  

   not 
  admit 
  of 
  a 
  definite 
  solution, 
  yet 
  it 
  is 
  not 
  impossible 
  

   that 
  physically 
  all 
  the 
  pulses 
  in 
  white 
  light 
  may 
  be 
  (say) 
  

   even 
  ones. 
  For 
  instance, 
  if 
  an 
  electron 
  moves 
  in 
  a 
  straight 
  

   line 
  against 
  an 
  opposing 
  force 
  w^hich 
  is 
  a 
  function 
  of 
  the 
  

   distance, 
  and 
  which 
  is 
  insensible 
  at 
  the 
  beginning 
  of 
  the 
  

   motion 
  but 
  becomes 
  sufficiently 
  powerful 
  to 
  bring 
  it 
  to 
  rest 
  

   and 
  reverse 
  its 
  motion, 
  the 
  pulse 
  produced 
  will 
  obviously 
  

   be 
  an 
  even 
  one, 
  under 
  which 
  conditions 
  the 
  form 
  of 
  the 
  pulse 
  

   for 
  a 
  given 
  distribution 
  of 
  energy 
  is 
  unique. 
  

  

  Phil. 
  Mag, 
  S. 
  6. 
  Vol. 
  18. 
  No. 
  107. 
  ^Yor. 
  1909. 
  3 
  G 
  

  

  