﻿408 
  

  

  Dr. 
  T. 
  S. 
  Tay 
  

  

  lor 
  on 
  

  

  the 
  Range 
  and 
  

  

  the 
  ionization 
  over 
  a 
  short 
  distance. 
  This 
  was 
  done 
  by 
  ad- 
  

   vancing 
  the 
  source 
  towards 
  the 
  ionization 
  chamber 
  in 
  steps 
  

   o£ 
  3 
  millimetres 
  each 
  and 
  observing 
  the 
  rate 
  of 
  leak 
  of 
  

   the 
  electroscope 
  for 
  each 
  position. 
  Then 
  the 
  difference 
  

   between 
  the 
  readings 
  obtained 
  for 
  two 
  successive 
  positions 
  

   gave 
  the 
  difference 
  between 
  the 
  ionization 
  produced 
  in 
  the 
  

   3 
  millimetres 
  of 
  the 
  path 
  of 
  the 
  rays 
  that 
  had 
  been 
  

   moved 
  beyond 
  the 
  limits 
  of 
  the 
  ionization 
  chamber 
  and 
  that 
  

   produced 
  in 
  the 
  3 
  millimetres 
  of 
  the 
  path 
  just 
  added 
  to 
  

   the 
  limits 
  of 
  the 
  chamber. 
  Thus, 
  the 
  difference 
  between 
  

   the 
  readings 
  obtained 
  for 
  the 
  source 
  at 
  10 
  cm. 
  and 
  10*3 
  cm. 
  

   respectively 
  from 
  the 
  ionization 
  chamber 
  gave 
  the 
  difference 
  

   between 
  the 
  ionization 
  produced 
  in 
  the 
  3 
  millimetres 
  of 
  

   the 
  path, 
  10 
  to 
  10*3 
  cm., 
  and 
  that 
  produced 
  in 
  the 
  

   3 
  millimetres 
  12*4 
  to 
  12*7 
  cm. 
  The 
  part 
  of 
  the 
  path 
  of 
  the 
  

   lays 
  10*3 
  to 
  12'4 
  cm. 
  was 
  common 
  to 
  both 
  positions. 
  The 
  

   method 
  of 
  deriving 
  the 
  ionization 
  curve 
  may 
  be 
  illustrated 
  

   further 
  by 
  the 
  data 
  recorded 
  in 
  Table 
  II., 
  which 
  is 
  a 
  partial 
  

   si;t 
  of 
  readings 
  for 
  hydrogen. 
  The 
  values 
  in 
  the 
  columns 
  

   under 
  " 
  Eange 
  " 
  are 
  the 
  distances 
  of 
  the 
  source 
  from 
  the 
  

   gauze 
  forming 
  the 
  top 
  of 
  the 
  ionization 
  vessel. 
  The 
  values 
  

   under 
  " 
  Ionization 
  " 
  represent 
  the 
  relative 
  rates 
  of 
  leak 
  

   of 
  the 
  electroscope 
  due 
  to 
  the 
  ionization 
  in 
  the 
  vessel 
  for 
  

   the 
  corresponding 
  disiances 
  of 
  the 
  source 
  from 
  it, 
  the 
  natural 
  

   leak 
  of 
  the 
  electroscope 
  and 
  the 
  apparatus 
  being 
  subtracted. 
  

   The 
  values 
  under 
  "Ionization 
  per 
  3 
  millimetres" 
  are 
  the 
  

   values 
  of 
  the 
  ionization 
  for 
  a 
  shallow 
  ionization 
  vessel, 
  

   3 
  millimetres 
  deep, 
  as 
  derived 
  from 
  the 
  values 
  in 
  the 
  previous 
  

   column 
  by 
  the 
  method 
  cited 
  above. 
  

  

  Table 
  II. 
  

  

  

  Total 
  

  

  Ionization 
  

  

  

  

  Ionization 
  

  

  Eange. 
  

  

  Ionization 
  

  

  per 
  3 
  mm. 
  

  

  Eange. 
  

  

  Ionization. 
  

  

  per 
  3 
  nun. 
  

  

  

  in 
  chamber. 
  

  

  of 
  path. 
  

  

  

  

  of 
  path. 
  

  

  176 
  

  

  

  

  

  

  

  

  

  173 
  

  

  16 
  

  

  1-6 
  

  

  149 
  

  

  879 
  

  

  110 
  

  

  17-0 
  

  

  59 
  

  

  43 
  

  

  M-6 
  

  

  94-1 
  

  

  10-5 
  

  

  16-7 
  

  

  14-0 
  

  

  8-1 
  

  

  14-3 
  

  

  95-7 
  

  

  9-7 
  

  

  164 
  

  

  26-2 
  

  

  122 
  

  

  140 
  

  

  92-7 
  

  

  9-2 
  

  

  16-1 
  

  

  401 
  

  

  139 
  

  

  | 
  137 
  

  

  87-6 
  

  

  8-8 
  

  

  15-8 
  

  

  54-0 
  

  

  13-9 
  

  

  ! 
  134 
  

  

  82-0 
  

  

  8-3 
  

  

  155 
  

  

  66 
  6 
  

  

  126 
  

  

  ! 
  131 
  

  

  77-2 
  

  

  7-8 
  

  

  152 
  

  

  78-5 
  

  

  11-9 
  

  

  12-8 
  

  

  730 
  

  

  77 
  

  

  By 
  plotting 
  the 
  values, 
  derived 
  in 
  the 
  above 
  manner, 
  for 
  

   the 
  ionization 
  per 
  3 
  millimetres 
  of 
  the 
  path 
  against 
  the 
  

   corresponding 
  range, 
  the 
  ionization 
  curve 
  was 
  obtained. 
  

  

  