﻿936 
  Prof. 
  Bragg 
  and 
  Mr. 
  Madsen 
  : 
  An 
  Experimental 
  

  

  a 
  few 
  of 
  the 
  atoms 
  swept 
  over 
  by 
  the 
  wave, 
  and 
  the 
  absence 
  

   of 
  relation 
  between 
  the 
  velocity 
  of 
  the 
  secondary 
  electron, 
  on 
  

   the 
  one 
  hand, 
  and, 
  on 
  the 
  other, 
  the 
  intensity 
  of 
  the 
  radiation 
  

   and 
  the 
  nature 
  of 
  the 
  atom. 
  Also, 
  it 
  makes 
  provision 
  for 
  a 
  

   concentration 
  of 
  momentum. 
  This 
  theory, 
  however, 
  postu- 
  

   late- 
  a 
  very 
  special 
  and 
  complicated 
  structure 
  lof 
  the 
  aether. 
  

   And. 
  in 
  the 
  second 
  place, 
  it 
  (iocs 
  not 
  even 
  then 
  offer 
  an 
  

   explanation 
  of 
  all 
  the 
  phenomena. 
  

  

  If 
  a 
  "bundle 
  of 
  energy 
  ; 
  * 
  provides 
  the 
  energy 
  with 
  which 
  

   tlie 
  secondary 
  cathode 
  particle 
  leaves 
  the 
  atom, 
  then 
  the 
  

   energy-content 
  of 
  the 
  bundle 
  must 
  be 
  greater 
  than 
  the 
  

   energy 
  of 
  the 
  particle. 
  II', 
  on 
  the 
  other 
  hand, 
  as 
  in 
  the 
  case 
  

   of 
  the 
  X-rays, 
  the 
  energy 
  of 
  the 
  bundle 
  is 
  derived 
  from 
  that 
  

  

  of 
  the 
  arrested 
  cathode 
  particle, 
  the 
  former 
  must 
  he 
  less 
  than 
  

   the 
  latter. 
  Now. 
  it 
  seems 
  <|uite 
  clear 
  that 
  the 
  energy 
  of 
  the 
  

   secondary 
  electron 
  is 
  at 
  leasl 
  nearly 
  a- 
  greal 
  as 
  thai 
  of 
  the 
  

   primary 
  cathode 
  particle. 
  For 
  in 
  the 
  case 
  of 
  the 
  X-rays 
  the 
  

  

  velocity 
  of 
  the 
  secondary 
  electron 
  is 
  nearly 
  in 
  1 
  ". 
  and 
  is 
  there- 
  

   loir 
  much 
  the 
  same 
  as 
  that 
  of 
  the 
  cathode 
  rays 
  in 
  the 
  bulk 
  

   And 
  we 
  have 
  shown 
  above, 
  in 
  the 
  analogous 
  case 
  of 
  7 
  rays, 
  

   that 
  the 
  velocity 
  of 
  the 
  secondary 
  (3 
  ray, 
  produced 
  by 
  the 
  

   7 
  ray, 
  i- 
  practically 
  the 
  same 
  as 
  that 
  of 
  the 
  primary 
  ft 
  ray, 
  

   which 
  issues 
  with 
  the 
  7 
  ray. 
  We 
  must, 
  therefore, 
  conclude 
  

   on 
  this 
  hypothesis 
  that 
  the 
  energies 
  of 
  the 
  primary 
  electron, 
  

   the 
  bundle, 
  and 
  the 
  secondary 
  electron 
  are 
  ail 
  equal. 
  The 
  

   whole 
  of 
  the 
  energy 
  of 
  the 
  cathode 
  particle 
  in 
  the 
  X-ray 
  

   tube 
  is 
  converted 
  into 
  one 
  energy 
  bundle. 
  This 
  darts 
  away 
  

   from 
  the 
  anticathode, 
  and 
  sooner 
  or 
  later 
  causes 
  the 
  ejection 
  

   of 
  an 
  electron 
  from 
  some 
  atom 
  which 
  it 
  traverses, 
  handing 
  

   over 
  to 
  the 
  electron 
  the 
  whole 
  of 
  its 
  own 
  store 
  of 
  energy. 
  

   Replace 
  the 
  bundle 
  of 
  energy 
  by 
  a 
  neutral 
  pair, 
  and 
  the 
  

   whole 
  affair 
  seems 
  simple 
  enough. 
  But 
  surely 
  the 
  compli- 
  

   cation- 
  of 
  the 
  aether 
  structure 
  increase 
  the 
  more 
  closely 
  we 
  

   examine 
  the 
  process 
  under 
  which 
  rapidly 
  moving 
  electrons 
  

   in 
  the 
  X-ray 
  tube 
  disappear, 
  and 
  similar 
  electrons, 
  moving 
  

   at 
  the 
  same 
  rate, 
  appear 
  elsewhere, 
  if 
  we 
  are 
  to 
  consider 
  that 
  

   the 
  only 
  links 
  between 
  them 
  are 
  little 
  bundles 
  of 
  energy 
  

   moving 
  with 
  the 
  speed 
  of 
  light. 
  

  

  It 
  might 
  be 
  said, 
  perhaps, 
  that 
  one 
  bundle 
  contains 
  the 
  

   energy 
  of 
  several 
  arrested 
  electrons; 
  but 
  in 
  that 
  case 
  we 
  

   should 
  have 
  bundles 
  of 
  all 
  sizes 
  and 
  secondary 
  electrons 
  of 
  

   all 
  speeds 
  ; 
  or 
  that 
  several 
  bundles 
  might 
  pile 
  up 
  their 
  

   energies 
  in 
  one 
  atom 
  until 
  there 
  was 
  enough 
  for 
  the 
  ejection 
  

   of 
  one 
  secondary 
  electron 
  ; 
  but 
  then 
  we 
  should 
  return 
  to 
  the 
  

   difficulty 
  of 
  explaining 
  why 
  the 
  speed 
  is 
  independent 
  of 
  the 
  

   nature 
  of 
  the 
  atom. 
  

  

  