﻿Analysis 
  of 
  ft 
  Rays 
  from 
  Radium 
  B 
  and 
  Radium 
  C. 
  727 
  

  

  These 
  groups 
  are 
  strongly 
  marked 
  in 
  the 
  photographs 
  ob- 
  

   tained 
  with 
  wires 
  coated 
  with 
  radium 
  B 
  -f 
  C, 
  and 
  fainter 
  

   groups 
  in 
  very 
  nearly 
  the 
  same 
  positions 
  were 
  obtained 
  on 
  

   the 
  radium 
  C 
  plates. 
  To 
  test 
  this 
  point 
  further, 
  photographs 
  

   were 
  taken 
  with 
  very 
  short 
  exposures 
  of 
  wires 
  which 
  had 
  

   themselves 
  only 
  been 
  exposed 
  to 
  the 
  emanation 
  for 
  a 
  short 
  

   time, 
  and 
  thus 
  had 
  a 
  much 
  larger 
  proportion 
  of 
  radium 
  B 
  to 
  

   radium 
  C 
  than 
  usual. 
  The 
  groups 
  appeared 
  of 
  the 
  same 
  

   intensity, 
  relative 
  to 
  the 
  main 
  radium 
  B 
  lines, 
  as 
  in 
  the 
  other 
  

   radium 
  B 
  + 
  C 
  photographs, 
  showing 
  that 
  they 
  were 
  un- 
  

   doubtedly 
  due 
  to 
  radium 
  B. 
  

  

  Radium 
  C 
  Groups. 
  

  

  A 
  diagrammatic 
  representation 
  of 
  some 
  of 
  the 
  stronger 
  

   lines 
  from 
  radium 
  C 
  is 
  shown 
  in 
  fig. 
  2 
  (PI. 
  XII.). 
  It 
  is 
  seen 
  

   that 
  radium 
  C 
  gives 
  a 
  spectrum 
  in 
  which 
  the 
  difference 
  of 
  

   intensity 
  between 
  the 
  lines 
  is 
  relatively 
  not 
  so 
  marked 
  as 
  

   in 
  the 
  case 
  of 
  radium 
  B. 
  The 
  group 
  of 
  highest 
  velocity 
  

   observed 
  in 
  radium 
  C, 
  which 
  showed 
  up 
  clearly 
  on 
  the 
  

   photographs, 
  gave 
  the 
  value 
  of 
  Hp 
  = 
  8530. 
  Five 
  other 
  faint 
  

   lines 
  of 
  higher 
  velocity 
  are 
  recorded, 
  and 
  a 
  number 
  of 
  others 
  

   of 
  still 
  higher 
  velocity 
  could 
  be 
  faintly 
  seen. 
  Although 
  we 
  

   made 
  a 
  number 
  of 
  experiments 
  in 
  strong 
  magnetic 
  fields, 
  no 
  

   ■evidence 
  of 
  any 
  strong 
  line 
  of 
  higher 
  velocity 
  was 
  observed, 
  

   although 
  lines 
  up 
  to 
  H^ 
  = 
  20,000 
  would 
  have 
  been 
  observed 
  

   on 
  the 
  photographic 
  plates. 
  

  

  In 
  most 
  of 
  the 
  experiments 
  with 
  ft 
  rays, 
  an 
  ordinary 
  pro- 
  

   cess 
  plate 
  was 
  employed. 
  We 
  found 
  it, 
  however, 
  advan- 
  

   tageous 
  for 
  the 
  higher 
  fields 
  to 
  employ 
  X-ray 
  plates. 
  These 
  

   were 
  photographically 
  much 
  more 
  sensitive, 
  and 
  the 
  fainter 
  

   lines 
  in 
  the 
  strong 
  fields 
  were 
  more 
  clearly 
  seen. 
  We 
  have 
  

   included 
  a 
  fairly 
  complete 
  list 
  of 
  the 
  lines 
  from 
  H/9 
  = 
  9965 
  

   to 
  Hp 
  = 
  I8I0. 
  For 
  still 
  lower 
  values 
  of 
  H/?, 
  the 
  plates 
  ob- 
  

   tained 
  with 
  radium 
  as 
  a 
  source 
  were 
  crowded 
  with 
  fine 
  lines, 
  

   and 
  only 
  a 
  few 
  of 
  the 
  stronger 
  are 
  included 
  in 
  the 
  table 
  and 
  

   in 
  fig. 
  2 
  (PL 
  XII.). 
  For 
  example, 
  only 
  five 
  lines 
  have 
  been 
  

   included 
  between 
  Hp 
  = 
  I8I0 
  and 
  H|O 
  = 
  3260, 
  although 
  more 
  

   than 
  twenty 
  were 
  measured 
  up. 
  In 
  a 
  similar 
  way, 
  only 
  a 
  

   few 
  of 
  the 
  more 
  marked 
  lines 
  are 
  recorded 
  in 
  the 
  lower 
  fields. 
  

  

  A 
  complete 
  analysis 
  of 
  the 
  weaker 
  lines 
  would 
  take 
  a 
  large 
  

   amount 
  of 
  work, 
  but 
  it 
  was 
  not 
  felt 
  desirable 
  at 
  this 
  stage 
  to 
  

   include 
  them. 
  It 
  should 
  be 
  mentioned 
  that 
  the 
  radium 
  C 
  

   lines 
  extend 
  right 
  down 
  to 
  the 
  low 
  velocity 
  regions, 
  for 
  

   which 
  radium 
  B 
  shows 
  several 
  strong 
  lines. 
  It 
  is 
  of 
  interest 
  

   to 
  note 
  that 
  radium 
  (J 
  showed 
  complex 
  groups 
  in 
  about 
  the 
  

   same 
  region 
  as 
  for 
  radium 
  B. 
  We 
  have 
  alreadv 
  mentioned 
  

  

  3 
  2 
  

  

  