﻿Active 
  Deposit 
  of 
  Radium 
  in 
  an 
  Electric 
  Field. 
  631 
  

  

  Referring 
  again 
  to 
  the 
  curves 
  of 
  fig. 
  2, 
  it 
  is 
  seen 
  that 
  in 
  

   general 
  the 
  " 
  activity 
  " 
  curve 
  for 
  any 
  given 
  voltage 
  lies 
  

   below 
  the 
  ionization 
  curve 
  for 
  the 
  corresponding 
  voltage. 
  

   This 
  is 
  almost 
  certainly 
  to 
  be 
  ascribed 
  to 
  the 
  increased 
  re- 
  

   combination 
  with 
  negative 
  ions 
  which 
  occurs 
  with 
  the 
  active 
  

   particles 
  as 
  compared 
  with 
  the 
  positive 
  ions, 
  even 
  when 
  the 
  

   air 
  with 
  which 
  the 
  emanation 
  is 
  mixed 
  is 
  thoroughly 
  dried. 
  

  

  Cathode 
  Deposit 
  for 
  very 
  Small 
  Quantities 
  of 
  

   Emanation 
  in 
  Dry 
  Air. 
  

  

  6. 
  If 
  the 
  curves 
  in 
  fig. 
  2 
  are 
  produced 
  so 
  as 
  to 
  intersect 
  

   the 
  axis 
  of 
  ordinates, 
  we 
  obtain 
  points 
  which 
  afford 
  a 
  measure 
  

   of 
  the 
  fraction 
  of 
  ions 
  and 
  of 
  positively 
  charged 
  deposit 
  

   particles 
  which 
  would 
  be 
  obtained 
  by 
  the 
  application 
  of 
  the 
  

   corresponding 
  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 
  

  

  Fie. 
  3. 
  

  

  LiO 
  

  

  i 
  1 
  III 
  

  

  

  

  

  

  

  ! 
  

  

  

  -it 
  ; 
  boNTiNu) 
  

  

  US 
  CUR 
  

  

  ft 
  

  

  

  

  

  

  

  

  

  

  

  1 
  

  

  

  

  

  

  

  .SO 
  

  

  .so 
  

  

  JO 
  

   .60 
  

   50 
  

  

  <M 
  

  

  JO 
  

   .20 
  

  

  to 
  

  

  ht 
  r-DioKtM 
  

  

  Am 
  | 
  

  

  CURVE 
  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  ■»' 
  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  / 
  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  / 
  

  

  ' 
  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  / 
  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  / 
  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  ) 
  150 
  

  

  VOLTS. 
  

  

  curves 
  which 
  correspond 
  to 
  the 
  absence 
  of 
  volume 
  recombi- 
  

   nation 
  in 
  the 
  vessel 
  even 
  at 
  the 
  smallest 
  potentials 
  employed. 
  

   The 
  upward 
  slope 
  of 
  the 
  curves 
  is 
  due 
  entirely 
  to 
  the 
  fact 
  

   that 
  increasing 
  potentials 
  prevent 
  more 
  and 
  more 
  the 
  recom- 
  

   bination 
  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 
  

  

  2 
  U2 
  

  

  