﻿Higli-Frequency 
  Spectra 
  of 
  the 
  Elements. 
  

  

  1025 
  

  

  the 
  internal 
  structure 
  o£ 
  the 
  atom, 
  and 
  strongly 
  support 
  the 
  

   views 
  of 
  Rutherford* 
  and 
  of 
  Bohrj. 
  

  

  Kaye 
  % 
  has 
  shown 
  that 
  an 
  element 
  excited 
  by 
  a 
  stream 
  of 
  

   sufficiently 
  fast 
  cathode 
  rays 
  emits 
  its 
  characteristic 
  X 
  radia- 
  

   tion. 
  He 
  used 
  as 
  targets 
  a 
  number 
  of 
  substances 
  mounted 
  

   on 
  a 
  truck 
  inside 
  an 
  exhausted 
  tube. 
  A 
  magnetic 
  device 
  

   enabled 
  each 
  target 
  to 
  be 
  brought 
  in 
  turn 
  into 
  the 
  line 
  of 
  

   fire. 
  This 
  apparatus 
  was 
  modified 
  to 
  suit 
  the 
  present 
  work. 
  

   The 
  cathode 
  stream 
  was 
  concentrated 
  on 
  to 
  a 
  small 
  area 
  of 
  

   the 
  target, 
  and 
  a 
  platinum 
  plate 
  furnished 
  with 
  a 
  fine 
  vertical 
  

   slit 
  placed 
  immediately 
  in 
  front 
  of 
  the 
  part 
  bombarded. 
  The 
  

   tube 
  was 
  exhausted 
  by 
  a 
  Gaede 
  mercury 
  pump, 
  charcoal 
  in 
  

   liquid 
  air 
  being 
  also 
  sometimes 
  used 
  to 
  remove 
  water 
  vapour. 
  

   The 
  X 
  rays, 
  after 
  passing 
  through 
  the 
  slit 
  marked 
  S 
  in 
  fig. 
  1, 
  

  

  Fig. 
  I. 
  

  

  / 
  

  

  emerged 
  through 
  an 
  aluminium 
  window 
  *02 
  mm. 
  thick. 
  The 
  

   rest 
  of 
  the 
  radiation 
  was 
  shut 
  off 
  by 
  a 
  lead 
  box 
  which 
  sur- 
  

   rounded 
  the 
  tube. 
  The 
  rays 
  fell 
  on 
  the 
  cleavage 
  face, 
  C, 
  of 
  

   a 
  crystal 
  of 
  potassium 
  ferrocyanide 
  which 
  was 
  mounted 
  on 
  

   the 
  prism-table 
  of 
  a 
  spectrometer. 
  The 
  surface 
  of 
  the 
  crystal 
  

   was 
  vertical 
  and 
  contained 
  the 
  geometrical 
  axis 
  of 
  the 
  

   spectrometer. 
  

  

  * 
  Phil. 
  Mag. 
  xxi. 
  p. 
  669 
  (1911). 
  

  

  t 
  Phil. 
  Mag. 
  xxvi. 
  pp. 
  1, 
  476, 
  & 
  857 
  (1913). 
  

  

  % 
  Phil. 
  Trans. 
  Roy. 
  Soc, 
  A. 
  ccix. 
  p. 
  123 
  (1909). 
  

  

  