﻿

  Emanation 
  in 
  the 
  Atmosphere 
  near 
  Eartlis 
  Surface. 
  625 
  

  

  A 
  standard 
  solution, 
  containing 
  10~ 
  9 
  grm. 
  of 
  radium, 
  was 
  

   then 
  placed 
  in 
  a 
  flask, 
  the 
  accumulated, 
  emanation 
  was 
  re- 
  

   moved, 
  and 
  air 
  was 
  passed 
  through 
  the 
  solution 
  to 
  the 
  three 
  

   iron 
  tubes 
  containing 
  charcoal, 
  and 
  the 
  experiment 
  was 
  in 
  

   all 
  other 
  respects 
  repeated 
  as 
  before. 
  

  

  Then 
  R'=10- 
  9 
  grm. 
  

  

  Y=0-40, 
  Y' 
  = 
  l-45 
  D/m. 
  

  

  Y=8m 
  3 
  . 
  

  

  T 
  = 
  3-7 
  days 
  = 
  3-19xl0 
  5 
  sees. 
  

  

  X=2'16 
  x 
  lO" 
  6 
  and 
  AT 
  = 
  0'69. 
  

  

  and 
  hence 
  B=10 
  -..£W 
  0*9 
  =23 
  .g 
  x 
  10-*. 
  

  

  r45 
  b 
  

  

  This 
  replaces 
  the 
  value 
  35 
  X 
  10" 
  )2 
  given 
  in 
  the 
  previous 
  

   paper. 
  

  

  Case 
  2. 
  — 
  The 
  mean 
  of 
  seven 
  observations, 
  made 
  in 
  

   July 
  and 
  August 
  1907 
  gave 
  Y 
  = 
  0\L12, 
  ^' 
  = 
  0-98 
  D/w, 
  

   R'=l-57 
  xlO- 
  9 
  gm, 
  V=l*56 
  m 
  3 
  , 
  T=27 
  days 
  = 
  2-32 
  x 
  

   10 
  5 
  sees. 
  

  

  Hence 
  R=57'4x 
  10" 
  12 
  , 
  in 
  place 
  of 
  127 
  x 
  10~ 
  12 
  grm. 
  as 
  

   given 
  in 
  the 
  previous 
  paper. 
  

  

  Case 
  3. 
  — 
  A 
  typical 
  example 
  is 
  given 
  for 
  a 
  result 
  sub- 
  

   sequent 
  to 
  11th 
  Nov. 
  1907, 
  namely, 
  that 
  of 
  26th 
  Dec. 
  1907. 
  

  

  R' 
  = 
  l-57xl0- 
  9 
  grm. 
  

  

  Y 
  = 
  0*39, 
  Y' 
  = 
  2-70D/m. 
  

  

  V 
  = 
  l-35m 
  3 
  . 
  

  

  T 
  = 
  2-32xl0 
  5 
  secs. 
  

   \T 
  = 
  0-50. 
  

  

  Htmce 
  R 
  = 
  84*2 
  x 
  10~ 
  12 
  grm. 
  In 
  every 
  case 
  the 
  value 
  of 
  Y' 
  

   is 
  given 
  after 
  deducting 
  that 
  due 
  to 
  the 
  emanation 
  in 
  the 
  air 
  

   passing 
  to 
  the 
  charcoal. 
  

  

  It 
  is 
  unnecessary 
  to 
  give 
  further 
  examples 
  of 
  the 
  method 
  

   of 
  calculation. 
  

  

  The 
  experiments 
  were 
  continued 
  for 
  almost 
  a 
  year 
  in 
  order 
  

   to 
  ascertain 
  the 
  relation 
  existing 
  between 
  the 
  amount 
  of 
  

   emanation 
  in 
  the 
  air 
  and 
  the 
  meteorological 
  conditions 
  

   existing 
  during 
  the 
  time 
  of 
  the 
  experiment. 
  As 
  the 
  air 
  was 
  

   passed 
  through 
  the 
  charcoal 
  for 
  a 
  little 
  more 
  than 
  two 
  and 
  a 
  

   half 
  days, 
  it 
  is 
  clear 
  that 
  the 
  amount 
  of 
  emanation 
  measured 
  

   is 
  not 
  dependent 
  on 
  merely 
  local 
  conditions. 
  The 
  radium 
  

   emanation 
  decays 
  to 
  half 
  value 
  in 
  about 
  3' 
  8 
  days. 
  With 
  a 
  

   wind 
  velocity 
  of 
  20 
  miles 
  an 
  hour, 
  the 
  emanation 
  collected 
  

  

  Phil. 
  Mag. 
  S. 
  6. 
  Vol. 
  16. 
  No. 
  94. 
  Oct. 
  1908. 
  2 
  T 
  

  

  