﻿328 
  Pro£. 
  Rutherford 
  and 
  Mr. 
  Richardson 
  : 
  Analysis 
  

  

  conditions 
  are 
  given 
  in 
  the 
  following 
  table 
  as 
  an 
  illustration 
  

   of 
  the 
  accuracy 
  of 
  the 
  individual 
  measurements. 
  

  

  Thickness 
  

  

  

  

  

  

  

  of 
  

  

  A. 
  

  

  B. 
  

  

  0. 
  

  

  D. 
  

  

  E. 
  

  

  Aluminium. 
  

  

  

  

  

  

  

  mm.... 
  

  

  100 
  

  

  100 
  

  

  100 
  

  

  100 
  

  

  100 
  

  

  •065 
  

  

  74-0 
  

  

  74-7 
  

  

  75-2 
  

  

  77-3 
  

  

  77-5 
  

  

  •130 
  

  

  57-4 
  

  

  57'9 
  

  

  58-6 
  

  

  58-7 
  

  

  60-5 
  

  

  •195 
  

  

  

  45-2 
  

  

  45-7 
  

  

  45-4 
  

  

  46-4 
  

  

  •260 
  

  

  35-4 
  

  

  36-8 
  

  

  36-9 
  

  

  37-3 
  

  

  36-5 
  

  

  •390 
  

  

  24-5 
  

  

  25-2 
  

  

  21-8 
  

  

  25-5 
  

  

  24-3 
  

  

  •56 
  

  

  16-1 
  

  

  15-9 
  

  

  16-3 
  

  

  15-4 
  

  

  15-8 
  

  

  •82 
  

  

  

  10-8 
  

  

  10-8 
  

  

  10-5 
  

  

  10-0 
  

  

  1-12 
  

  

  8-3 
  

  

  8-4 
  

  

  8-3 
  

  

  7-5 
  

  

  7-5 
  

  

  1-97 
  

  

  6-2 
  

  

  

  

  5-7 
  

  

  5'1 
  

  

  5-6 
  

  

  394 
  

  

  43 
  

  

  4-7 
  

  

  

  42 
  

  

  4-2 
  

  

  A. 
  Rather 
  a 
  large 
  amount 
  of 
  material, 
  consisting 
  chiefly 
  of 
  aluminium. 
  

   Maximum 
  activity 
  was 
  3 
  divs. 
  per 
  niin. 
  /u=45. 
  

  

  B. 
  Thin 
  preparation. 
  Maximum 
  activity 
  7 
  divs. 
  per 
  min. 
  ju=45. 
  

  

  0. 
  Same 
  preparation 
  as 
  B. 
  Measurements 
  taken 
  a 
  fortnight 
  later. 
  

   ju 
  = 
  46. 
  

  

  D. 
  Thin 
  preparation, 
  containing 
  only 
  a 
  small 
  amount 
  of 
  aluminium 
  and 
  

   lead. 
  Preparation 
  was 
  placed 
  on 
  a 
  filter-paper 
  and 
  mounted 
  on 
  

   cardboard. 
  Maximum 
  activity 
  20 
  divs. 
  per 
  min. 
  /z 
  = 
  44. 
  

  

  E. 
  Same 
  preparation 
  as 
  D, 
  only 
  in 
  this 
  case 
  the 
  filter-paper 
  was 
  simply 
  

   suspended 
  between 
  the 
  poles 
  of 
  magnet. 
  (" 
  = 
  44. 
  

  

  Fig. 
  2. 
  

  

  140 
  

  

  -i 
  80 
  

   k 
  

  

  v 
  GO 
  

  

  l-8\ 
  

  

  ^ 
  \ 
  

  

  1-6 
  \ 
  | 
  

  

  •5 
  ?75 
  \-0 
  1-25 
  

  

  Thickniss 
  in 
  mms 
  of 
  Aluminium, 
  

  

  y 
  RA 
  YS 
  FROM 
  RADIUM 
  0. 
  

  

  One 
  of 
  the 
  several 
  curves 
  obtained 
  is 
  shown 
  in 
  fig. 
  2. 
  It 
  

   is 
  seen 
  that 
  the 
  greater 
  part 
  of 
  the 
  7- 
  radiation 
  is 
  absorbed 
  

  

  