﻿

  Analysis 
  of 
  ft 
  Rays 
  from 
  Radium 
  B 
  and 
  Radium 
  C. 
  729 
  

  

  or 
  2Ej, 
  but 
  all 
  the 
  lines 
  between 
  Nos. 
  9 
  and 
  29 
  are 
  approxi- 
  

   mately 
  expressed 
  by 
  the 
  simple 
  difference 
  E 
  l5 
  and 
  no 
  lines 
  

   are 
  missing. 
  As 
  the 
  value 
  of 
  the 
  energies 
  of 
  the 
  fainter 
  

   lines 
  could 
  not 
  be 
  determined 
  with 
  the 
  same 
  precision 
  as 
  the 
  

   stronger 
  lines, 
  the 
  agreement 
  is 
  probably 
  as 
  close 
  as 
  one 
  

   could 
  expect 
  considering 
  the 
  difficulty 
  of 
  the 
  measurements. 
  

   It 
  should, 
  however, 
  be 
  pointed 
  out 
  that 
  a 
  line 
  of 
  medium 
  

   intensity 
  was 
  observed 
  before 
  nearly 
  all 
  of 
  the 
  strong 
  lines 
  on. 
  

   the 
  high 
  velocity 
  side. 
  As 
  far 
  as 
  measurements 
  could 
  be 
  made, 
  

   this 
  " 
  outrider 
  " 
  appeared 
  to 
  be 
  somewhat 
  closer 
  to 
  the 
  strong- 
  

   line 
  than 
  would 
  be 
  expressed 
  by 
  a 
  difference 
  of 
  the 
  energy 
  E^ 
  

   It 
  is, 
  however, 
  difficult 
  to 
  decide 
  this 
  point 
  definitely 
  on 
  

   account 
  of 
  the 
  wide 
  difference 
  in 
  intensity 
  of 
  the 
  two 
  lines. 
  

  

  It 
  is 
  also 
  of 
  interest 
  to 
  note 
  that 
  the 
  energy 
  of 
  each 
  of 
  the 
  

   lines 
  is 
  nearly 
  an 
  integral 
  multiple 
  of 
  the 
  common 
  difference. 
  

   This 
  is 
  clearly 
  seen 
  in 
  Table 
  III., 
  where 
  the 
  value 
  of 
  the 
  

   whole 
  number 
  is 
  given 
  in 
  column 
  VI. 
  and 
  the 
  corresponding 
  

   calculated 
  value 
  of 
  the 
  energy 
  in 
  column 
  VII. 
  If 
  this 
  

   relation 
  should 
  hold, 
  it 
  would 
  indicate 
  that 
  the 
  groups 
  of 
  

   ft 
  rays 
  observed 
  are 
  not 
  directly 
  due 
  to 
  the 
  original 
  ft 
  par- 
  

   ticle 
  which 
  causes 
  the 
  disturbance, 
  but 
  rather 
  to 
  the 
  emission 
  

   of 
  energy 
  in 
  the 
  /3-ray 
  form 
  consequent 
  on 
  the 
  vibrations 
  of 
  

   certain 
  definite 
  systems 
  of 
  electrons 
  within 
  the 
  atom. 
  

  

  Below 
  line 
  No. 
  29, 
  where 
  only 
  a 
  few 
  of 
  the 
  stronger 
  lines 
  

   are 
  given, 
  it 
  was 
  found 
  that 
  this 
  simple 
  relation 
  no 
  longer 
  

   held, 
  for 
  the 
  differences 
  » 
  between 
  some 
  of 
  the 
  lines 
  were 
  

   much 
  smaller 
  than 
  E 
  x 
  . 
  It 
  is. 
  to 
  be 
  anticipated 
  that 
  the 
  theo- 
  

   retical 
  analysis 
  of 
  the 
  slow 
  velocity 
  electrons 
  for 
  radium 
  C 
  

   would 
  be 
  very 
  complex 
  and 
  present 
  great 
  difficulties. 
  This 
  

   follows 
  from 
  the 
  fact 
  that 
  the 
  electrons, 
  as 
  their 
  velocities 
  

   decrease, 
  become 
  more 
  effective 
  in 
  exciting 
  y 
  rays 
  in 
  the 
  

   outer 
  regions 
  of 
  the 
  atoms. 
  

  

  The 
  value 
  of 
  E 
  x 
  found 
  by 
  experiment 
  is 
  only, 
  about 
  one- 
  

   third 
  of 
  the 
  value 
  calculated 
  from 
  Widdington's 
  results 
  on 
  

   certain 
  assumptions*. 
  It 
  is 
  intended 
  to 
  continue 
  experi- 
  

   ments, 
  and 
  to 
  analyse 
  in 
  detail 
  the 
  groups 
  of 
  ft 
  rays 
  from 
  

   other 
  radioactive 
  substances. 
  It 
  is 
  hoped 
  that 
  when 
  more 
  

   data 
  are 
  available 
  it 
  will 
  be 
  possible 
  to 
  test 
  with 
  consi- 
  

   derable 
  certainty 
  the 
  adequacy 
  of 
  any 
  theory 
  in 
  explanation 
  

   of 
  the 
  origin 
  of 
  ft 
  and 
  7 
  rays. 
  

  

  We 
  are 
  indebted 
  to 
  Mr. 
  J. 
  M. 
  Nuttall 
  for 
  his 
  kind 
  assistance 
  

   in 
  some 
  of 
  the 
  measurements. 
  

  

  University 
  of 
  Manchester, 
  

   July 
  1913. 
  

  

  * 
  See 
  Rutherford, 
  "Origin 
  of 
  /3 
  and 
  y 
  rays," 
  Phil. 
  Mag. 
  Oct. 
  and 
  Dec. 
  

   1912. 
  

  

  