﻿THE 
  

  

  AMERICANJOURNALOFSCIENCE 
  

  

  [FO 
  URTH 
  SERIES.] 
  

  

  Art. 
  XXXII. 
  — 
  The 
  Distribution 
  of 
  the 
  Active 
  Deposit 
  of 
  

   Radium 
  in 
  an 
  Electric 
  Field 
  (II) 
  ; 
  by 
  E. 
  M. 
  Wellisch, 
  

   Assistant 
  Professor 
  of 
  Physics 
  at 
  Yale 
  University. 
  

  

  Introductory. 
  

  

  1. 
  The 
  experiments 
  described 
  in 
  the 
  present 
  paper 
  are 
  a 
  

   continuation 
  of 
  the 
  investigation 
  made 
  by 
  Wellisch 
  and 
  Bron- 
  

   son* 
  on 
  the 
  distribution 
  of 
  the 
  active 
  deposit 
  of 
  radium 
  in 
  an 
  

   electric 
  field. 
  In 
  that 
  investigation 
  radium 
  emanation 
  mixed 
  

   with 
  air 
  was 
  introduced 
  into 
  a 
  cylindrical 
  condenser 
  and 
  the 
  

   relative 
  amounts 
  of 
  active 
  deposit 
  which 
  settled 
  on 
  the 
  central 
  

   electrode 
  and 
  on 
  the 
  case 
  were 
  determined 
  after 
  equilibrium 
  

   had 
  been 
  established 
  for 
  different 
  positive 
  potentials 
  applied 
  to 
  

   the 
  outer 
  electrode. 
  

  

  It 
  was 
  shown 
  that 
  the 
  part 
  of 
  the 
  active 
  deposit 
  which 
  settled 
  

   on 
  the 
  case 
  (anode) 
  was 
  due 
  to 
  the 
  diffusion 
  of 
  uncharged 
  car- 
  

   riers 
  ; 
  no 
  evidence 
  was 
  found 
  of 
  the 
  presence 
  of 
  negative 
  car- 
  

   riers 
  in 
  any 
  appreciable 
  amount. 
  It 
  was 
  found 
  also 
  that, 
  when 
  

   the 
  applied 
  potential 
  was 
  not 
  too 
  small, 
  the 
  distribution 
  of 
  the 
  

   active 
  deposit 
  was 
  independent 
  of 
  the 
  quantity 
  of 
  emanation 
  

   employed, 
  and 
  that 
  the 
  fraction 
  of 
  the 
  total 
  amount 
  which 
  

   settled 
  on 
  the 
  cathode 
  in 
  general 
  increased 
  with 
  increasing 
  

   potentials, 
  although 
  under 
  the 
  most 
  favorable 
  conditions 
  there 
  

   was 
  still 
  about 
  10 
  per 
  cent 
  which 
  was 
  deposited 
  on 
  the 
  case. 
  

   The 
  passage 
  of 
  Rontgen 
  rays 
  through 
  the 
  gas 
  during 
  the 
  expo- 
  

   sure 
  was 
  found 
  to 
  be 
  without 
  effect 
  on 
  the 
  distribution 
  except 
  

   when 
  the 
  applied 
  potential 
  was 
  small, 
  in 
  which 
  case 
  the 
  extra 
  

   ionization 
  produced 
  by 
  the 
  rays 
  caused 
  increased 
  recombination 
  

   with 
  the 
  charged 
  active 
  deposit 
  particles 
  and 
  in 
  this 
  manner 
  

   the 
  cathode 
  deposit 
  was 
  diminished. 
  Finally 
  it 
  was 
  found 
  that 
  

   for 
  potentials 
  which 
  were 
  not 
  too 
  small 
  the 
  ratio 
  of 
  the 
  equi- 
  

  

  * 
  Wellisch 
  and 
  Bronson, 
  Phil. 
  Mag., 
  ser. 
  6, 
  xxiii, 
  p. 
  714, 
  1912. 
  

   Am. 
  Jour. 
  Sci. 
  — 
  Fourth 
  Series, 
  Vol. 
  XXXVI, 
  No. 
  214. 
  — 
  October, 
  1913. 
  

   21 
  

  

  