﻿Radium 
  Emanation 
  in 
  the 
  Atmosphere. 
  591 
  

  

  chloride, 
  a 
  charcoal 
  tube, 
  a 
  gauge, 
  and 
  to 
  the 
  pump. 
  When 
  

   the 
  pump 
  was 
  started 
  the 
  stream 
  of 
  air 
  began, 
  and 
  gradually 
  

   increased 
  up 
  to 
  a 
  steady 
  value 
  which 
  was 
  adjusted, 
  by 
  clipping 
  

   the 
  indiarubber 
  connecting 
  tubes, 
  to 
  about 
  half 
  a 
  litre 
  per 
  

   minute. 
  The 
  current 
  was 
  kept 
  passing 
  at 
  this 
  rate 
  for 
  a 
  given 
  

   period. 
  Meanwhile 
  the 
  testing 
  vessel 
  was 
  exhausted 
  and 
  

   tilled 
  with 
  dry 
  air 
  several 
  times 
  and 
  the 
  air 
  leak 
  taken 
  at 
  

   intervals. 
  The 
  insulation 
  leak 
  was 
  also 
  tested 
  and 
  the 
  sensi- 
  

   tiveness 
  of 
  the 
  electrometer 
  measured. 
  When 
  the 
  period 
  for 
  

   passing 
  the 
  air 
  had 
  elapsed 
  the 
  charcoal 
  tube 
  was 
  taken 
  and 
  

   laid 
  on 
  the 
  furnace. 
  One 
  end 
  was 
  connected 
  with 
  an 
  auxiliary 
  

   glass 
  tube 
  containing 
  coconut 
  charcoal 
  (whose 
  function 
  was 
  

   to 
  purify 
  the 
  air 
  drawn 
  from 
  outside 
  from 
  any 
  emanation 
  it 
  

   might 
  contain), 
  the 
  connecting 
  tube 
  between 
  them 
  being 
  at 
  

   first 
  tightly 
  clipped, 
  and 
  the 
  other 
  end 
  was 
  connected 
  to 
  an 
  

   aspirator, 
  say 
  aspirator 
  a. 
  The 
  two 
  taps 
  of 
  the 
  aspirator 
  were 
  

   opened 
  and 
  water 
  allowed 
  to 
  run 
  out. 
  The 
  stream 
  quickly 
  

   stopped 
  as 
  the 
  other 
  end 
  of 
  the 
  charcoal 
  tube 
  was 
  closed. 
  The 
  

   burners 
  were 
  then 
  lighted 
  and 
  the 
  tube 
  heated 
  to 
  a 
  red 
  heat. 
  

   When 
  the 
  temperature 
  had 
  sufficiently 
  risen, 
  the 
  clip 
  joining 
  

   the 
  two 
  charcoal 
  tubes 
  was 
  unscrewed 
  and 
  the 
  aspirator 
  then 
  

   drew 
  emanation-free 
  air 
  into 
  the 
  heated 
  charcoal 
  tube, 
  and 
  

   this 
  sweeping 
  out 
  the 
  emanation 
  in 
  the 
  heated 
  tube 
  was 
  

   collected 
  in 
  the 
  aspirator. 
  When 
  sufficient 
  gas 
  had 
  been 
  col- 
  

   lected 
  in 
  one 
  aspirator 
  the 
  taps 
  were 
  turned 
  and 
  the 
  aspirator 
  

   removed. 
  The 
  other 
  aspirator, 
  aspirator 
  b, 
  was 
  then 
  placed 
  

   in 
  position 
  and 
  filled 
  in 
  the 
  same 
  way. 
  Then 
  the 
  charcoal 
  

   tube 
  was 
  allowed 
  to 
  cool. 
  Nearly 
  all 
  the 
  emanation 
  w 
  r 
  as 
  

   collected 
  in 
  the 
  first 
  aspirator. 
  Sometimes 
  there 
  was 
  some 
  

   in 
  the 
  second, 
  often 
  there 
  was 
  none. 
  The 
  amounts 
  collected 
  

   w 
  r 
  ere 
  then 
  tested. 
  It 
  is 
  more 
  convenient 
  to 
  test 
  the 
  gas 
  

   collected 
  in 
  the 
  second 
  aspirator 
  first. 
  The 
  steady 
  value 
  of 
  

   the 
  air 
  leak 
  in 
  the 
  testing 
  vessel 
  having 
  been 
  found, 
  it 
  was 
  

   exhausted 
  by 
  the 
  pump 
  and 
  the 
  inlet-tube 
  then 
  clipped. 
  The 
  

   drying-tube 
  attached 
  to 
  it 
  w 
  T 
  as 
  then 
  exhausted 
  and 
  also 
  clipped. 
  

   This 
  tube 
  was 
  then 
  connected 
  to 
  the 
  upper 
  tap 
  of 
  the 
  aspi- 
  

   rator, 
  and 
  then 
  all 
  the 
  taps 
  being 
  opened 
  the 
  water 
  rose 
  in 
  the 
  

   aspirator, 
  driving 
  the 
  contained 
  air 
  and 
  emanation 
  into 
  the 
  

   testing 
  vessel. 
  The 
  pressure 
  in 
  the 
  testing 
  vessel 
  usually 
  just 
  

   got 
  up 
  to 
  atmospheric 
  pressure 
  when 
  all 
  the 
  gas 
  collected 
  had 
  

   been 
  passed 
  in. 
  

  

  The 
  leak 
  was 
  then 
  taken. 
  Mr. 
  Eve 
  states 
  that 
  he 
  rarely 
  took 
  

   initial 
  leaks, 
  they 
  being 
  small; 
  but 
  he 
  waited 
  for 
  three 
  hours 
  

   when 
  the 
  leak 
  had 
  increased 
  to 
  a 
  maximum. 
  This 
  increase 
  

   is 
  due 
  to 
  the 
  growth 
  of 
  the 
  radioactive 
  deposit 
  (Radium 
  A, 
  

   B, 
  and 
  C) 
  on 
  the 
  walls 
  of 
  the 
  vessel. 
  Sometimes 
  I 
  took 
  

  

  