﻿ritli 
  the 
  Radium 
  Emanation. 
  

  

  307 
  

  

  ordinary 
  pressure 
  have 
  a 
  cluster 
  of 
  molecules 
  attached 
  which 
  

   move 
  with 
  them. 
  Since 
  the 
  emanation 
  itself 
  and 
  the 
  gases 
  

   associated 
  with 
  it 
  are 
  intensely 
  ionized, 
  it 
  is 
  possible 
  that 
  the 
  

   effective 
  volume 
  may 
  be 
  decreased 
  due 
  to 
  the 
  production 
  of 
  a 
  

   large 
  number 
  of 
  these 
  aggregates. 
  On 
  this 
  view, 
  the 
  decrease 
  

   of 
  volume 
  observed 
  during 
  the 
  first 
  two 
  hours 
  may 
  be 
  partly 
  

   due 
  to 
  the 
  increase 
  of 
  the 
  number 
  of 
  these 
  aggregates 
  conse- 
  

   quent 
  upon 
  the 
  increase 
  of 
  the 
  radiation 
  from 
  radium 
  C. 
  

  

  Experimental 
  Results. 
  

  

  We 
  shall 
  now 
  give 
  some 
  typical 
  examples 
  out 
  of 
  a 
  number 
  

   illustrating 
  the 
  initial 
  changes 
  in 
  volume. 
  The 
  capillary 
  

   tube 
  used 
  in 
  all 
  the 
  experiments 
  was 
  of 
  Jena 
  borosilicate 
  

   glass 
  of 
  very 
  uniform 
  bore, 
  0'58 
  mm. 
  in 
  diameter. 
  The 
  

   capillary 
  correction 
  was 
  equal 
  to 
  14 
  mm. 
  of 
  mercury. 
  The 
  

   tube 
  was 
  slowly 
  coloured 
  brown 
  by 
  the 
  emanation. 
  By 
  

   heating 
  the 
  tube 
  to 
  the 
  temperature 
  of 
  thermo-luminescence, 
  

   the 
  glass 
  again 
  became 
  quite 
  clear. 
  The 
  capillary 
  was 
  heated 
  

   at 
  the 
  beginning 
  of 
  each 
  experiment 
  to 
  drive 
  off 
  residual 
  

   gases. 
  The 
  gases 
  in 
  the 
  capillary 
  in 
  all 
  cases 
  obeyed 
  Boyle's 
  

   law 
  over 
  the 
  range 
  examined 
  within 
  the 
  limit 
  of 
  experimental 
  

   error. 
  

  

  Experiment 
  I. 
  — 
  This 
  illustrates 
  the 
  increase 
  of 
  volume 
  

   observed 
  for 
  very 
  impure 
  radium 
  emanation. 
  The 
  amount 
  

   of 
  emanation 
  in 
  the 
  capillary, 
  determined 
  by 
  direct 
  measure- 
  

   ment, 
  corresponded 
  to 
  67 
  mgrs. 
  of 
  pure 
  radium. 
  

  

  Time 
  after 
  introduction 
  

  

  Volume 
  of 
  gas 
  in 
  capillary 
  

  

  of 
  the 
  emanation 
  into 
  

  

  at 
  standard 
  pressure 
  and 
  

  

  capillary. 
  

  

  room 
  temperature. 
  

  

  2 
  minutes 
  

  

  0'154 
  c.mm. 
  

  

  6 
  „ 
  

  

  •169 
  „ 
  

  

  17 
  „ 
  

  

  •201 
  „ 
  

  

  28 
  „ 
  

  

  •235 
  „ 
  

  

  41 
  

  

  •260 
  ., 
  

  

  50 
  „ 
  

  

  •270 
  „ 
  

  

  64 
  „ 
  

  

  •280 
  ., 
  

  

  71 
  „ 
  

  

  •291 
  „ 
  

  

  81 
  „ 
  

  

  •297 
  „ 
  

  

  3-9 
  hours 
  

  

  •346 
  „ 
  

  

  21 
  

  

  •355 
  „ 
  

  

  At 
  the 
  end 
  of 
  24 
  hours 
  the 
  spectrum 
  of 
  the 
  gas 
  was 
  

   examined 
  in 
  the 
  capillary. 
  The 
  carbon 
  dioxide 
  spectrum 
  

  

  