﻿y-Rai/s 
  of 
  Uranium 
  and 
  Radium. 
  

  

  633 
  

  

  one 
  another 
  an 
  arbitrary 
  constant 
  has 
  been 
  added 
  to 
  the 
  

   logarithm 
  ol: 
  the 
  ionization 
  leak 
  in 
  some 
  cases. 
  The 
  numbers 
  

   on 
  the 
  curves 
  refer 
  to 
  the 
  numbers 
  in 
  the 
  first 
  column 
  o£ 
  the 
  

   table. 
  

  

  For 
  mercury 
  a 
  different 
  arrangement 
  had 
  necessarily 
  to 
  be 
  

   adopted. 
  A 
  circular 
  hole 
  11*5 
  cm. 
  in 
  diameter 
  was 
  cut 
  in 
  a 
  

   block 
  o£ 
  wood 
  4 
  cm. 
  thick, 
  and 
  to 
  the 
  bottom 
  was 
  fixed 
  a 
  

   circular 
  plate 
  o£ 
  glass 
  about 
  3 
  mm. 
  thick. 
  This 
  was 
  provided 
  

   with 
  levelling 
  screws, 
  and 
  placed 
  close 
  over 
  the 
  preparations. 
  

   It 
  was 
  levelled 
  and 
  sufficient 
  mercury 
  placed 
  in 
  it 
  completely 
  

   to 
  cover 
  the 
  surface, 
  and 
  then 
  weighed 
  amounts 
  of 
  mercury 
  

   were 
  added 
  or 
  withdrawn. 
  In 
  experiments 
  Nos. 
  1 
  and 
  2 
  the 
  

   base 
  of 
  the 
  electroscope 
  was 
  a 
  plate 
  of 
  lead 
  1*2 
  cm. 
  thick. 
  

   In 
  experiment 
  No. 
  3 
  it 
  was 
  two 
  sheets 
  of 
  tinfoil. 
  The 
  results 
  

   in 
  the 
  latter 
  case 
  lie 
  on 
  a 
  continuous 
  curve 
  convex 
  to 
  the 
  origin, 
  

   and 
  no 
  one 
  value 
  can 
  be 
  assigned 
  to 
  X. 
  

  

  Table 
  I. 
  — 
  Uranium 
  X. 
  7-Itays. 
  

   Brass 
  Electroscope, 
  absorbing 
  plates 
  forming 
  base. 
  

  

  ^0. 
  

  

  Distance. 
  

  

  Material. 
  

  

  Density. 
  

  

  Range 
  (cm.). 
  

  

  X(cm.)-i. 
  

  

  X/c^xlOO. 
  

  

  11 
  

  

  

  

  

  -33 
  to 
  2-55 
  

  

  -687 
  

  

  5-05 
  

  

  - 
  

  

  8-25 
  

  

  Mercury. 
  

  

  13-59 
  

  

  -33 
  to 
  2-60 
  

  

  -760 
  

  

  5-59 
  

  

  3j 
  

  

  

  

  

  Not 
  ex 
  

  

  ponential. 
  

  

  

  41 
  

   5; 
  

  

  j> 
  

  

  Lead. 
  

  

  11-40 
  

  

  1-26 
  to 
  5-00 
  

   1-9 
  to 
  5-00 
  

  

  -634 
  

   •620 
  

  

  5-56 
  

   5-44 
  

  

  ?} 
  

  

  » 
  

  

  Copper. 
  

  

  8-81 
  

  

  3-0 
  to 
  8-0 
  

   1-9 
  to 
  6-8 
  

  

  -413 
  

   •430 
  

  

  4^69 
  

  

  4-88 
  

  

  81 
  

   9/ 
  

  

  >. 
  

  

  Brass. 
  

  

  8-35 
  

  

  1-8 
  to 
  6-0 
  

   1-1 
  to 
  5-8 
  

  

  •410 
  

   •443 
  

  

  4-91 
  

   5^30 
  

  

  101 
  

   11; 
  

  

  M 
  

  

  Iron. 
  

  

  7-62 
  

  

  2-52 
  to 
  7-57 
  

  

  •335 
  

   -394 
  

  

  4-40 
  

   5-17 
  

  

  12 
  

  

  '» 
  

  

  Tin. 
  

  

  7-245 
  

  

  1-90 
  to 
  5-51 
  

  

  •351 
  

  

  4-84 
  

  

  13 
  

  

  >» 
  

  

  Zinc. 
  

  

  7-07 
  

  

  1-9 
  to 
  6-0 
  

  

  •373 
  

  

  5-27 
  

  

  15 
  

  

  14-63 
  

  

  Slate. 
  

  

  2-85 
  

  

  60 
  to 
  12-6 
  

  

  •158 
  

  

  5-54 
  

  

  14 
  

  

  ,, 
  

  

  Aluminium. 
  

  

  2-77 
  

  

  5-0 
  to 
  11-5 
  

  

  •148 
  

  

  5-34 
  

  

  16 
  

  

  " 
  

  

  Glass. 
  

  

  2-52 
  

  

  5-2 
  to 
  10-3 
  

  

  •165 
  

  

  6-54 
  

  

  Eelow 
  this 
  the 
  has 
  

  

  e 
  consist 
  

  

  ed 
  of 
  1-26 
  ci 
  

  

  n. 
  of 
  Lead 
  

  

  

  18 
  

  

  1 
  

  

  \ 
  MagnesiaBrick. 
  

  

  1-92 
  

  

  2-7 
  to 
  11-8 
  

  

  •1029 
  

  

  5-36 
  

  

  17 
  

  

  >> 
  

  

  Sulphur. 
  

  

  1-79 
  

  

  2-2 
  to 
  11-6 
  

  

  •1046 
  

  

  5-84 
  

  

  19 
  

  

  J, 
  

  

  ParaflBn 
  Wax. 
  

  

  0-862 
  

  

  3-8 
  to 
  11-4 
  

  

  •0576 
  

  

  6-68 
  

  

  20 
  

  

  ,, 
  Pine-Wood. 
  

  

  0-386 
  

  

  2-0 
  to 
  11-5 
  

  

  •0214 
  

  

  5-54 
  

  

  1 
  

  

  Mean 
  value 
  of 
  A/^=-0536. 
  

   Pliil 
  Mag, 
  S. 
  6. 
  Vol. 
  18. 
  No. 
  106. 
  Oct. 
  1909. 
  

  

  2U 
  

  

  