﻿of 
  Radium 
  in 
  an 
  Electric 
  Field. 
  

  

  323 
  

  

  potential 
  when 
  the 
  air 
  in 
  the 
  ionization 
  vessel 
  contains 
  only 
  a 
  

   very 
  small 
  amount 
  of 
  emanation. 
  These 
  points 
  are 
  plotted 
  

   both 
  for 
  ionization 
  current 
  and 
  activity 
  as 
  separate 
  curves 
  in 
  

   fig. 
  3 
  ; 
  they 
  may 
  be 
  regarded 
  as 
  limiting 
  curves 
  which 
  corre- 
  

   spond 
  to 
  the 
  absence 
  of 
  volume 
  recombination 
  in 
  the 
  vessel 
  

   even 
  at 
  the 
  smallest 
  potentials 
  employed. 
  The 
  upward 
  slope 
  

   of 
  the 
  curves 
  is 
  due 
  entirely 
  to 
  the 
  fact 
  that 
  increasing 
  poten- 
  

   tials 
  prevent 
  more 
  and 
  more 
  the 
  recombination 
  of 
  the 
  positive 
  

   ions 
  or 
  particles 
  with 
  negative 
  ions 
  which 
  are 
  produced 
  inside 
  

   the 
  a-particle 
  column. 
  

  

  It 
  will 
  be 
  seen 
  from 
  the 
  curves 
  that 
  any 
  given 
  potential 
  

   brings 
  over 
  to 
  the 
  cathode 
  a 
  larger 
  fraction 
  of 
  ions 
  than 
  of 
  pos- 
  

  

  Fig. 
  3. 
  

  

  t.10 
  

  

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  i 
  

  

  

  

  

  

  

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  CURVE 
  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  M/K 
  I 
  

  

  

  

  

  

  

  

  

  

  

  

  

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  1 
  1 
  

  

  ill! 
  

  

  

  

  

  

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  i 
  ! 
  

  

  

  

  

  

  

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  : 
  

  

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  i 
  

  

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  1 
  

  

  OO 
  1 
  

  

  10 
  1 
  

  

  20 
  1 
  

  

  30 
  1 
  

  

  40 
  1 
  

  

  VOLT 
  

  

  50 
  1 
  

  

  S 
  

  

  SO 
  

  

  itively 
  charged 
  deposit 
  particles 
  ; 
  at 
  a 
  potential 
  of 
  about 
  40 
  

   volts 
  the 
  two 
  curves 
  practically 
  coincide. 
  The 
  difference 
  be- 
  

   tween 
  the 
  two 
  curves 
  can 
  be 
  explained 
  by 
  supposing 
  that 
  the 
  

   negative 
  ions 
  which 
  are 
  produced 
  in 
  the 
  column 
  recombine 
  

   with 
  the 
  positively 
  charged 
  active 
  particles 
  with 
  greater 
  facility 
  

   than 
  with 
  the 
  positive 
  ions. 
  

  

  Emanation 
  mixed 
  with 
  Carbon 
  Dioxide, 
  Hydrogen, 
  

   and 
  Ethyl 
  Ether. 
  

  

  7. 
  When 
  the 
  emanation 
  was 
  mixed 
  with 
  dry 
  C0 
  2 
  at 
  various 
  

   pressures 
  it 
  was 
  found 
  that 
  the 
  maximum 
  value 
  obtained 
  for 
  

   the 
  percentage 
  cathode 
  activity 
  was 
  80*7. 
  In 
  order 
  to 
  obtain 
  

   this 
  value 
  with 
  potentials 
  less 
  than 
  1000 
  volts 
  the 
  pressure 
  had 
  

   to 
  be 
  less 
  than 
  about 
  150 
  mm 
  . 
  

  

  