﻿600 
  

  

  Mr. 
  J. 
  Satterly 
  on 
  the 
  Amount 
  of 
  

  

  From 
  the 
  numbers 
  in 
  the 
  last 
  table 
  the 
  following 
  results 
  

   were 
  calculated. 
  The 
  time 
  factors 
  of 
  the 
  radium 
  solution 
  were 
  

   obtained 
  from 
  the 
  curves 
  of 
  fig. 
  3. 
  

  

  Table 
  V. 
  

  

  Date. 
  

  

  Weather 
  and 
  

  

  Amount 
  of 
  Eadium 
  required 
  per 
  cub. 
  

  

  

  Barometer. 
  

  

  metre 
  of 
  Air 
  to 
  keep 
  up 
  the 
  quantity 
  

  

  

  

  of 
  Emanation 
  to 
  the 
  observed 
  amount. 
  

  

  Jan. 
  27 
  

  

  Dry 
  ; 
  757, 
  falling. 
  

  

  150xl0- 
  12 
  grm. 
  

  

  „ 
  31 
  

  

  ,, 
  75S, 
  falling. 
  

  

  85xl0" 
  12 
  „ 
  

  

  Feb. 
  4 
  

  

  ., 
  771, 
  rising. 
  

  

  50xl0- 
  ]2 
  ,, 
  

  

  6 
  

  

  780, 
  steady. 
  

  

  8oxl0- 
  12 
  „ 
  

  

  „ 
  14 
  

  

  769, 
  falling. 
  

  

  160XI0- 
  12 
  ,. 
  

  

  „ 
  27 
  

  

  Wet 
  ; 
  753, 
  falling. 
  

  

  35X10 
  -12 
  ,, 
  

  

  Mar. 
  6 
  

  

  Damp; 
  743, 
  steady. 
  

  

  75xl0-; 
  2 
  „ 
  

  

  „ 
  11 
  

  

  Fine 
  ; 
  760, 
  rising. 
  

  

  67xl0~ 
  1J 
  „ 
  

  

  Mean... 
  88xl0 
  -12 
  grm. 
  

  

  Some 
  more 
  measurements 
  made 
  in 
  April 
  and 
  May 
  agreed 
  

   very 
  nearly 
  with 
  these. 
  The 
  mean 
  of 
  the 
  three 
  results 
  given 
  

   by 
  Eve 
  in 
  his 
  paper 
  (the 
  mistake 
  in 
  his 
  calculations 
  makes 
  

   all 
  his 
  results 
  too 
  large 
  ; 
  I 
  have 
  corrected 
  them 
  according 
  to 
  

   the 
  rules 
  stated 
  above) 
  is 
  26 
  x 
  10~ 
  12 
  gm. 
  so 
  that 
  it 
  would 
  

   seem 
  that 
  there 
  was 
  much 
  more 
  emanation 
  in 
  the 
  air 
  of 
  

   Cambridge 
  than 
  in 
  the 
  air 
  of 
  Montreal. 
  Now 
  Professor 
  

   Thomson 
  * 
  found 
  that 
  Cambridge 
  tap-water 
  contained 
  a 
  large 
  

   quantity 
  of 
  radium 
  emanation, 
  and 
  therefore 
  it 
  is 
  not 
  

   surprising 
  that 
  the 
  air 
  of 
  Cambridge 
  should 
  contain 
  more 
  than 
  

   the 
  normal 
  amount 
  of 
  emanation. 
  

  

  Although 
  the 
  correlation 
  is 
  not 
  very 
  definite 
  the 
  results 
  

   above 
  seem 
  to 
  indicate 
  that 
  with 
  a 
  falling 
  barometer 
  the 
  

   amount 
  of 
  emanation 
  in 
  the 
  atmosphere 
  increases, 
  unless 
  this 
  

   fall 
  is 
  accompanied 
  by 
  wet 
  weather. 
  A 
  rising 
  barometer 
  

   seems 
  to 
  give 
  about 
  the 
  same 
  amount 
  o£ 
  emanation 
  as 
  a 
  steady 
  

   barometer 
  at 
  high 
  or 
  low. 
  

  

  In 
  this 
  connexion 
  it 
  is 
  interesting 
  to 
  note 
  that 
  Campbell 
  and 
  

   Wood 
  f 
  found 
  that 
  weather 
  conditions 
  were 
  entirely 
  without 
  

   effect 
  on 
  the 
  spontaneous 
  ionizations 
  of 
  air 
  in 
  closed 
  vessels. 
  

  

  Nearly 
  all 
  the 
  runs 
  given 
  in 
  the 
  table 
  above 
  are 
  short 
  runs 
  

   (1J 
  hrs. 
  to 
  4\Jr 
  hrs.) 
  taken 
  in 
  the 
  afternoon. 
  Later 
  on, 
  I 
  made 
  

   some 
  long 
  runs, 
  during 
  the 
  night 
  and 
  day. 
  For 
  the 
  night 
  

   runs 
  the 
  air-current 
  was 
  started 
  at 
  about 
  6 
  or 
  8 
  o'clock 
  in 
  

   the 
  evening, 
  and. 
  left 
  on 
  till 
  about 
  7 
  or 
  9 
  or 
  12 
  o'clock 
  in 
  the 
  

  

  • 
  Phil. 
  Mag. 
  Sept. 
  1902. 
  

   t 
  Phil. 
  M*g. 
  Feb. 
  1907. 
  

  

  