﻿and 
  Active 
  Deposit 
  from 
  Thorium 
  and 
  Actinium. 
  299 
  

  

  paper 
  are 
  only 
  relative, 
  no 
  light 
  has 
  been 
  thrown 
  on 
  the 
  

   question 
  as 
  to 
  the 
  actual 
  number 
  of 
  a 
  particles 
  thrown 
  out 
  by 
  

   an 
  atom 
  of 
  any 
  one 
  of 
  the 
  substances. 
  The 
  writer 
  hopes 
  to 
  

   continue 
  the 
  present 
  investigation 
  and 
  extend 
  it 
  to 
  other 
  

   members 
  of 
  the 
  radioactive 
  family. 
  It 
  is 
  possible 
  that 
  light 
  

   may, 
  in 
  this 
  way, 
  be 
  thrown 
  on 
  the 
  question 
  of 
  the 
  actual 
  

   number 
  of 
  a 
  particles 
  thrown 
  off 
  by 
  atoms 
  of 
  the 
  different 
  

   active 
  substances. 
  

  

  Former 
  Results 
  ivith 
  Radium. 
  

  

  The 
  results 
  in 
  the 
  case 
  of 
  radium 
  are 
  added 
  here 
  for 
  the 
  

   sake 
  of 
  comparison. 
  They 
  were 
  obtained 
  from 
  curves 
  of 
  the 
  

   rise 
  and 
  decay 
  of 
  the 
  active 
  deposit 
  from 
  radium. 
  These 
  

   curves 
  were 
  obtained 
  by 
  the 
  writer 
  in 
  1905, 
  while 
  investi- 
  

   gating 
  the 
  transformation 
  periods 
  of 
  the 
  different 
  products 
  

   of 
  which 
  the 
  active 
  deposit 
  from 
  radium 
  is 
  composed. 
  

   Table 
  IV. 
  is 
  similar 
  to 
  Table 
  III., 
  but 
  gives 
  only 
  a 
  single 
  

   set 
  of 
  results. 
  These 
  results 
  indicate, 
  as 
  was 
  said 
  at 
  the 
  

   beginning 
  of 
  the 
  paper, 
  that 
  the 
  same 
  number 
  of 
  a 
  particles 
  

   are 
  thrown 
  off 
  by 
  the 
  disintegration 
  of 
  an 
  atom 
  of 
  either 
  

   radium 
  emanation, 
  radium 
  A, 
  or 
  radium 
  C. 
  

  

  Table 
  IV. 
  

  

  II. 
  

  

  Products. 
  Max. 
  range 
  

  

  in 
  air. 
  

  

  III. 
  

  

  Mean 
  free 
  

   path 
  in 
  

  

  Ea. 
  Emanation... 
  4 
  - 
  3 
  

  

  Eadiuni 
  A 
  4'8 
  

  

  71 
  

  

  Radium 
  C 
  

  

  Radium 
  A 
  + 
  C 
  .... 
  4-8+7*1 
  

  

  2-60 
  

  

  3-28 
  

   2 
  

  

  3-76 
  

  

  2 
  

  

  3-28 
  3-76 
  

   2 
  + 
  2 
  

  

  IV. 
  

  

  Ratio 
  of 
  paths. 
  

  

  Emanation. 
  

   Active 
  deposit. 
  

  

  •63 
  

  

  1-35 
  

  

  Cal. 
  ratio 
  of 
  

   ionization 
  

   Emanation. 
  

   Active 
  deposit. 
  

  

  ■62 
  

  

  117 
  

  

  VI. 
  

  

  Measured 
  

  

  ratio 
  of 
  

  

  ionizations. 
  

  

  ■63 
  

  

  ■51 
  

  

  114 
  

  

  The 
  vessel 
  used 
  had 
  a 
  diameter 
  of 
  4*8 
  cms. 
  and 
  a 
  length 
  

   of 
  20 
  cms. 
  The 
  active 
  deposit 
  was 
  on 
  the 
  central 
  electrode, 
  

   and 
  in 
  making 
  the 
  calculations 
  the 
  actual 
  length 
  of 
  the 
  

   vessel 
  was 
  taken 
  into 
  account. 
  

   Macdonald 
  Physics 
  Building, 
  

   McGill 
  University, 
  Montreal, 
  

   April 
  27th, 
  1908. 
  

  

  X2 
  

  

  