﻿due 
  to 
  the 
  y 
  Rays 
  of 
  Radium 
  C. 
  

  

  229 
  

  

  absorbed, 
  so 
  that 
  the 
  results 
  given 
  are 
  quite 
  reliable 
  for 
  

   secondary 
  rays 
  of 
  the 
  y 
  type. 
  

  

  The 
  electroscope 
  here, 
  as 
  in 
  most 
  cases, 
  is 
  affected 
  not 
  

   merely 
  by 
  the 
  secondary 
  y 
  rays 
  which 
  traverse 
  it, 
  but 
  also 
  by 
  

   all 
  the 
  secondary 
  rays 
  caused 
  by 
  them 
  from 
  the 
  sides 
  of 
  the 
  

   electroscope 
  and 
  from 
  the 
  inner 
  side 
  of 
  the 
  screens. 
  There 
  

   seems 
  noway 
  of 
  evading 
  this 
  complexity; 
  and 
  if 
  all 
  the 
  con- 
  

   ditions 
  are 
  identical, 
  except 
  the 
  radiating 
  plates 
  employed^ 
  

   the 
  results 
  obtained 
  do 
  indicate 
  the 
  nature 
  and 
  magnitude 
  of 
  

   the 
  secondary 
  rays 
  of 
  the 
  y 
  type 
  passing 
  from 
  the 
  radiator 
  

   and 
  entering 
  the 
  electroscope. 
  

  

  The 
  measurements 
  obtained 
  are 
  given 
  in 
  the 
  following 
  four 
  

   tables 
  and 
  the 
  corresponding 
  four 
  diagrams. 
  The 
  radium 
  

   bromide 
  was 
  in 
  the 
  same 
  position, 
  as 
  nearly 
  as 
  possible, 
  for 
  

   all 
  four 
  series. 
  The 
  rays 
  under 
  investigation 
  are 
  all 
  ' 
  ; 
  incident/'' 
  

  

  not 
  

  

  Table 
  IV. 
  (See 
  fig. 
  1.) 
  

  

  Radium 
  in 
  lead 
  1 
  cm. 
  thick. 
  

  

  Aluminium 
  screens. 
  Secondary 
  radiators 
  stated. 
  

  

  j 
  Thickness 
  of 
  

   screens 
  in 
  turns. 
  

  

  Lead. 
  5 
  cms. 
  

  

  .12-2 
  

  

  041 
  4-26 
  

  

  0-82 
  j 
  1-74 
  

  

  175 
  j 
  -57 
  

  

  3-40 
  -22 
  

  

  7-10 
  46 
  

  

  Iron, 
  5 
  cms. 
  Brick. 
  6 
  cms. 
  

  

  8-4 
  

  

  3-81 
  

  

  2-5G 
  

  

  1-92 
  

  

  1-78 
  

  

  1-64 
  

  

  5-9 
  

  

  2-25 
  

  

  177 
  

  

  1-45 
  

  

  1-43 
  

  

  1-22 
  

  

  Fiff. 
  1. 
  

  

  

  

  

  i 
  

   i 
  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  it 
  mg 
  Ra 
  Br 
  z 
  in 
  Lead 
  

   icm 
  

  

  

  1 
  

  

  

  

  

  Aluminium 
  Screens 
  

  

  

  vv 
  

  

  

  

  

  Iron 
  

  

  

  

  

  

  ^. 
  

  

  

  

  Brick. 
  

   Lead 
  

  

  

  

  -o 
  

  

  