﻿624 
  Prof. 
  E. 
  M. 
  Wellisch 
  on 
  the 
  Distribution 
  of 
  the 
  

  

  equilibrium 
  ionization 
  currents 
  in 
  the 
  gas 
  for 
  two 
  different 
  

   potentials 
  was 
  equal 
  to 
  the 
  ratio 
  of 
  the 
  corresponding 
  cathode 
  

   activities. 
  

  

  The 
  main 
  object 
  of 
  the 
  present 
  series 
  of 
  experiments 
  was 
  

   to 
  extend 
  the 
  investigation 
  in 
  various 
  directions 
  ; 
  in 
  parti- 
  

   cular, 
  it 
  was 
  thought 
  desirable 
  to 
  ascertain 
  the 
  effect 
  on 
  the 
  

   distribution 
  of 
  employing 
  a 
  containing 
  vessel 
  of 
  different 
  

   dimensions 
  and 
  of 
  mixing 
  the 
  emanation 
  with 
  gases 
  other 
  

   than 
  air, 
  and, 
  in 
  addition, 
  to 
  make 
  a 
  detailed 
  investigation 
  

   of 
  the 
  distribution 
  when 
  small 
  potentials 
  were 
  employed. 
  

   The 
  main 
  experimental 
  results 
  of 
  the 
  previous 
  research 
  have 
  

   been 
  confirmed, 
  but 
  the 
  fresh 
  results 
  which 
  have 
  been 
  

   obtained 
  necessitate 
  a 
  modification 
  of 
  the 
  theory 
  which 
  was 
  

   suggested 
  in 
  explanation 
  of 
  the 
  phenomena. 
  

  

  Experimental 
  Procedure. 
  

  

  2. 
  The 
  method 
  employed 
  for 
  ascertaining 
  the 
  distribution 
  

   of 
  the 
  active 
  deposit 
  was 
  the 
  same 
  as 
  that 
  which 
  had 
  pre- 
  

   viously 
  been 
  employed. 
  The 
  radium 
  emanation 
  obtained 
  

   usually 
  from 
  a 
  quantity 
  of 
  carnotite, 
  or 
  in 
  some 
  cases 
  from 
  

   an 
  aqueous 
  solution 
  of 
  a 
  radium 
  salt, 
  was 
  passed 
  into 
  the 
  

   containing 
  vessel 
  and 
  remained 
  there 
  under 
  the 
  desired 
  con- 
  

   ditions 
  of 
  potential, 
  pressure, 
  &c, 
  until 
  radioactive 
  equi- 
  

   librium 
  was 
  established 
  ; 
  in 
  general 
  this 
  period 
  was 
  about 
  

   3 
  hours. 
  The 
  emanation 
  was 
  blown 
  out 
  by 
  means 
  of 
  a 
  strong 
  

   current 
  of 
  air 
  from 
  a 
  force-pump, 
  and 
  the 
  ebonite 
  plug 
  con- 
  

   taining 
  the 
  central 
  electrode 
  was 
  then 
  removed. 
  A 
  fresh 
  

   electrode 
  was 
  suspended 
  in 
  the 
  vessel, 
  and 
  the 
  ionization 
  

   current 
  due 
  to 
  the 
  " 
  case 
  " 
  activity 
  was 
  measured 
  at 
  10 
  and 
  

   15 
  minutes 
  after 
  the 
  emanation 
  had 
  been 
  removed 
  ; 
  the 
  

   activity 
  on 
  the 
  central 
  electrode 
  was 
  measured 
  by 
  suspending 
  

   it 
  in 
  a 
  vessel 
  of 
  construction 
  identical 
  with 
  that 
  which 
  

   contained 
  the 
  emanation, 
  and 
  observing 
  the 
  ionization 
  current 
  

   at 
  20 
  and 
  25 
  minutes 
  after 
  the 
  emanation 
  had 
  been 
  removed. 
  

   The 
  activity 
  when 
  in 
  equilibrium 
  with 
  the 
  emanation 
  was 
  

   then 
  calculated 
  in 
  the 
  usual 
  manner. 
  

  

  The 
  diagram 
  of 
  connexions 
  is 
  the 
  same 
  as 
  that 
  given 
  in 
  

   the 
  previous 
  paper, 
  and 
  is 
  reproduced 
  in 
  fig. 
  1 
  ; 
  in 
  the 
  

   present 
  investigation 
  R 
  and 
  R/ 
  were 
  wire 
  resistances 
  of 
  

   50,000 
  and 
  10,000 
  ohms 
  respectively. 
  The 
  Dolezalek 
  elec- 
  

   trometer 
  had 
  a 
  platinum 
  suspension, 
  and 
  with 
  120 
  volts 
  on 
  

   the 
  needle 
  the 
  sensitiveness 
  was 
  180 
  mm. 
  per 
  volt. 
  C 
  and 
  B 
  

   represent 
  capacities 
  which 
  could 
  be 
  added 
  to 
  the 
  system 
  by 
  

   means 
  of 
  the 
  key 
  K, 
  and 
  the 
  total 
  capacity 
  of 
  the 
  system 
  

   was 
  then 
  increased 
  21 
  times. 
  A 
  potentiometer 
  device, 
  not 
  

   shown 
  in 
  the 
  diagram, 
  was 
  employed 
  when 
  measurements 
  of 
  

  

  