﻿Tlie 
  Motion 
  of 
  Electrons 
  in 
  Solids. 
  

   Experiment 
  commenced 
  March 
  19^/i, 
  1909. 
  

   Normal 
  leak 
  = 
  4:*3 
  divisions 
  per 
  hour. 
  

  

  209 
  

  

  Cold 
  specimen. 
  

  

  Hot 
  specimen 
  (1000° 
  C). 
  

  

  Date. 
  

  

  Corrected 
  leak. 
  

  

  Date. 
  

  

  Corrected 
  leak. 
  

  

  Interral. 
  

  

  Ratio 
  

   (cold/liot). 
  

  

  March 
  19th 
  ... 
  

  

  10-3 
  div3. 
  per 
  hr. 
  

  

  Mar. 
  19th 
  ... 
  

  

  6-ldivs.perhr. 
  

  

  

  1-69 
  

  

  ,. 
  26th 
  ... 
  

  

  58-6 
  ., 
  ,. 
  

  

  „ 
  26th... 
  

  

  26-2 
  ., 
  „ 
  

  

  7 
  days. 
  

  

  2-24 
  

  

  „ 
  29th 
  ... 
  

  

  73 
  5 
  „ 
  

  

  „ 
  29th... 
  

  

  34-2 
  „ 
  

  

  10 
  „ 
  

  

  215 
  

  

  April 
  lat 
  ... 
  

  

  84-7 
  „ 
  „ 
  

  

  April 
  Ist 
  ... 
  

  

  45-4 
  „ 
  

  

  13 
  „ 
  

  

  1-87 
  

  

  „ 
  15th 
  ... 
  

  

  140-0 
  „ 
  

  

  „ 
  15th 
  ... 
  

  

  62-3 
  „ 
  „ 
  

  

  27 
  .. 
  

  

  2-25 
  

  

  It 
  was 
  found 
  in 
  all 
  cases 
  that 
  the 
  change 
  in 
  the 
  ratio 
  cold/ 
  hot 
  

   was 
  not 
  sufficiently 
  decided 
  to 
  show 
  that 
  the 
  rate 
  of 
  produc- 
  

   tion 
  of 
  Uranium 
  X 
  at 
  1000° 
  C. 
  was 
  sensibly 
  different 
  from 
  

   that 
  at 
  ordinary 
  atmospheric 
  temperatures. 
  

  

  In 
  conclusion, 
  I 
  wish 
  to 
  thank 
  Professor 
  Strutt 
  for 
  

   suggesting 
  these 
  experiments 
  and 
  for 
  his 
  help 
  and 
  interest 
  

   throughout. 
  

  

  XXIV. 
  2 
  he 
  Motion 
  of 
  Electrons 
  in 
  Solids. 
  Part 
  II. 
  — 
  

   Radiation 
  of 
  all 
  Wave-lengths 
  in 
  a 
  perfectly 
  Rejiectino 
  

   Enclosure, 
  Satural 
  Radiation. 
  Dependence 
  of 
  Katural 
  

   Radiation 
  on 
  the 
  Laio 
  of 
  Force. 
  By 
  J. 
  H. 
  Jeans, 
  M.A., 
  

   F.R.S.* 
  

  

  A 
  general 
  Formula 
  for 
  the 
  Emission 
  of 
  Radiation 
  

   of 
  all 
  Wave-lengths. 
  

  

  25. 
  TX 
  the 
  lirst 
  part 
  of 
  this 
  paper 
  we 
  discussed 
  radiation 
  

   A 
  of 
  great 
  wave-length 
  only 
  : 
  our 
  first 
  task 
  in 
  

   discussing 
  radiation 
  of 
  all 
  wave-lengths 
  must 
  be 
  to 
  find 
  

   general 
  analytical 
  expressions 
  for 
  the 
  radiation 
  emitted 
  by 
  

   moving 
  electrons, 
  which 
  shall 
  be 
  valid 
  throughout 
  the 
  whole 
  

   spectrum. 
  

  

  Consider 
  an 
  element 
  of 
  volume 
  dv, 
  so 
  small 
  that 
  its 
  linear 
  

   dimensions 
  may 
  be 
  neglected 
  in 
  comparison 
  with 
  the 
  wave- 
  

   length 
  of 
  any 
  radiation 
  under 
  discussion. 
  We 
  regard 
  the 
  

   motion 
  of 
  an 
  electron 
  in 
  this 
  element 
  as 
  the 
  creation 
  of 
  a 
  

   series 
  of 
  imaginary 
  electric 
  doublets. 
  Let 
  M 
  (components 
  

  

  * 
  Communicated 
  by 
  the 
  Author. 
  

   Phil. 
  Mag. 
  S. 
  ti. 
  Vol. 
  18. 
  Xo. 
  103. 
  July 
  1909. 
  P 
  

  

  