﻿1024 
  Mr. 
  H. 
  G. 
  J. 
  Moseley 
  on 
  the 
  

  

  effect 
  in 
  the 
  case 
  of 
  many 
  metals 
  and 
  alloys 
  are 
  subject 
  to 
  

   variations 
  as 
  great 
  as 
  an 
  octave 
  and 
  more. 
  This 
  difficulty 
  is 
  

   all 
  the 
  more 
  real 
  in 
  that 
  as 
  yet 
  we 
  are 
  not 
  in 
  a 
  position 
  to 
  

   determine 
  what 
  influences 
  on 
  and 
  in 
  the 
  extremely 
  thin 
  

   bounding 
  surface 
  of 
  the 
  metal 
  in 
  which 
  the 
  light 
  absorption 
  

   takes 
  place 
  are 
  the 
  determining 
  factors 
  in 
  this 
  displacement. 
  

  

  Berlin, 
  Physikalisches 
  Tnstitut 
  

   der 
  Universitat, 
  July 
  1913. 
  

  

  XCIII. 
  The 
  Hiah-Frequency 
  Spectra 
  of 
  the 
  Elements. 
  

   By 
  H. 
  G. 
  J. 
  Moseley, 
  M.A* 
  

  

  [Plate 
  XXIII.] 
  

  

  IN 
  the 
  absence 
  of 
  any 
  available 
  method 
  of 
  spectrum 
  

   analysis, 
  the 
  characteristic 
  types 
  of 
  X 
  radiation, 
  which 
  

   an 
  atom 
  emits 
  when 
  suitably 
  excited, 
  have 
  hitherto 
  been 
  

   described 
  in 
  terms 
  of 
  their 
  absorption 
  in 
  aluminium 
  f. 
  The 
  

   interference 
  phenomena 
  exhibited 
  by 
  X 
  rays 
  when 
  scattered 
  

   I 
  by 
  a 
  crystal 
  have 
  now, 
  however, 
  made 
  possible 
  the 
  accurate 
  

   determination 
  of 
  the 
  frequencies 
  of 
  the 
  various 
  types 
  of 
  

   radiation. 
  This 
  was 
  shown 
  by 
  W. 
  H. 
  and 
  W. 
  L. 
  Bragg 
  J, 
  

   who 
  by 
  this 
  method 
  analysed 
  the 
  line 
  spectrum 
  emitted 
  by 
  

   the 
  platinum 
  target 
  of 
  an 
  X-ray 
  tube. 
  C. 
  G. 
  Darwin 
  and 
  

   the 
  author 
  § 
  extended 
  this 
  analysis 
  and 
  also 
  examined 
  the 
  

   continuous 
  spectrum, 
  which 
  in 
  this 
  case 
  constitutes 
  the 
  greater 
  

   part 
  of 
  the 
  radiation. 
  Recently 
  Prof. 
  Bragg 
  || 
  has 
  also 
  

   determined 
  the 
  wave-lengths 
  of 
  the 
  strongest 
  lines 
  in 
  the 
  

   spectra 
  of 
  nickel, 
  tungsten, 
  and 
  rhodium. 
  The 
  electrical 
  

   methods 
  which 
  have 
  hitherto 
  been 
  employed 
  are, 
  however, 
  

   only 
  successful 
  where 
  a 
  constant 
  source 
  of 
  radiation 
  is 
  avail- 
  

   able. 
  The 
  present 
  paper 
  contains 
  a 
  description 
  of 
  a 
  method 
  

   of 
  photographing 
  these 
  spectra, 
  which 
  makes 
  the 
  analysis 
  of 
  

   the 
  X 
  rays 
  as 
  simple 
  as 
  any 
  other 
  branch 
  of 
  spectroscopy. 
  

   The 
  author 
  intends 
  first 
  to 
  make 
  a 
  general 
  survey 
  of 
  the 
  

   principal 
  types 
  of 
  high-frequency 
  radiation, 
  and 
  then 
  to 
  

   examine 
  the 
  spectra 
  of 
  a 
  few 
  elements 
  in 
  greater 
  detail 
  and 
  

   with 
  greater 
  accuracy. 
  The 
  results 
  already 
  obtained 
  show 
  

   that 
  such 
  data 
  have 
  an 
  important 
  bearing 
  on 
  the 
  question 
  of 
  

  

  * 
  Communicated 
  by 
  Prof. 
  E. 
  Rutherford, 
  F.R.S. 
  

   t 
  Cf. 
  Barkla, 
  Phil. 
  Mag. 
  xxii. 
  p. 
  396 
  (1911). 
  

   1 
  Proc. 
  Roy. 
  Soc. 
  A. 
  lxxxviii. 
  p. 
  428 
  (1913). 
  

   § 
  Phil. 
  Mag. 
  xxvi. 
  p. 
  210 
  (1913). 
  

   I! 
  Proc. 
  Roy. 
  Soc. 
  A. 
  lxxxix. 
  p. 
  246 
  (1913). 
  

  

  