﻿324 
  E. 
  M. 
  Wellisch 
  — 
  Distribution 
  of 
  the 
  Active 
  Deposit 
  

  

  When 
  the 
  emanation 
  was 
  mixed 
  with 
  dry 
  hydrogen 
  the 
  max- 
  

   imum 
  value 
  obtained 
  for 
  the 
  percentage 
  cathode 
  activity 
  was 
  

   89*2, 
  the 
  same 
  as 
  that 
  obtained 
  with 
  air. 
  This 
  value 
  could 
  

   readily 
  be 
  obtained 
  with 
  a 
  potential 
  of 
  160 
  volts 
  and 
  with 
  

   hydrogen 
  at 
  a 
  pressure 
  of 
  1 
  atmosphere, 
  showing 
  that 
  there 
  is 
  

   very 
  little 
  columnar 
  recombination 
  in 
  this 
  gas. 
  Hydrogen 
  was 
  

   found 
  to 
  be 
  particularly 
  sensitive 
  to 
  the 
  presence 
  of 
  small 
  

   traces 
  of 
  water 
  vapor 
  ; 
  the 
  effect 
  of 
  the 
  water 
  vapor 
  was 
  to 
  in- 
  

   crease 
  the 
  potential 
  necessary 
  to 
  obtain 
  the 
  same 
  limiting 
  

   value. 
  

  

  Inasmuch 
  as 
  the 
  presence 
  of 
  minute 
  quantities 
  of 
  water 
  

   vapor 
  resulted 
  in 
  a 
  marked 
  diminution 
  of 
  the 
  amount 
  of 
  active 
  

   deposit 
  which 
  settled 
  on 
  the 
  cathode, 
  it 
  became 
  of 
  interest 
  to 
  

   ascertain 
  the 
  percentage 
  of 
  positively 
  charged 
  carriers 
  which 
  

   would 
  result 
  from 
  mixing 
  the 
  emanation 
  with 
  a 
  vapor. 
  For 
  this 
  

   purpose 
  ethyl 
  ether 
  was 
  chosen 
  ; 
  any 
  gas 
  which 
  remained 
  in 
  the 
  

   vessel 
  was 
  swept 
  out 
  by 
  a 
  stream 
  of 
  ether 
  which 
  had 
  previously 
  

   passed 
  through 
  P 
  9 
  B 
  . 
  The 
  following 
  results 
  were 
  obtained 
  : 
  

  

  Pressure 
  

  

  Potential 
  

  

  Percentage 
  Cathode 
  Activity 
  

  

  mm 
  

  

  Volts 
  

  

  

  82 
  

  

  160 
  

  

  6'4 
  

  

  85 
  

  

  1070 
  

  

  9-8 
  

  

  128 
  

  

  do 
  

  

  10*0 
  

  

  235 
  

  

  do 
  

  

  10-8 
  

  

  At 
  the 
  highest 
  pressure 
  there 
  was 
  a 
  large 
  current 
  passing 
  

   through 
  the 
  vapor 
  during 
  the 
  activation 
  due 
  mainly 
  to 
  the 
  fact 
  

   that 
  the 
  ether 
  being 
  near 
  the 
  point 
  of 
  condensation 
  was 
  partly 
  

   conducting 
  ; 
  this 
  conduction 
  current 
  may 
  have 
  been 
  respon- 
  

   sible 
  for 
  the 
  increased 
  amount 
  of 
  the 
  cathode 
  deposit 
  at 
  the 
  

   highest 
  pressure. 
  Apart 
  from 
  this 
  it 
  appears 
  that 
  for 
  ether 
  

   vapor 
  the 
  limiting 
  value 
  of 
  the 
  cathode 
  activity 
  is 
  approxi- 
  

   mately 
  10 
  per 
  cent. 
  

  

  Summary 
  and 
  discussion 
  of 
  results. 
  

  

  8. 
  When 
  the 
  emanation 
  is 
  mixed 
  with 
  any 
  gas 
  there 
  appears 
  

   to 
  be 
  a 
  definite 
  limit 
  to 
  the 
  fraction 
  of 
  the 
  active 
  deposit 
  which 
  

   settles 
  on 
  the 
  cathode. 
  This 
  limit 
  is 
  independent 
  of 
  the 
  pres- 
  

   sure 
  of 
  the 
  gas, 
  provided 
  it 
  is 
  high 
  enough 
  to 
  prevent 
  the 
  

   deposit 
  particles 
  from 
  recoiling 
  on 
  to 
  the 
  walls 
  of 
  the 
  vessel 
  ; 
  

   it 
  is 
  in 
  general 
  dependent 
  on 
  the 
  nature 
  of 
  the 
  gas. 
  This 
  lim- 
  

   iting 
  value 
  is 
  in 
  general 
  obtained 
  only 
  with 
  large 
  potentials 
  ; 
  

   with 
  smaller 
  potentials 
  the 
  fraction 
  of 
  the 
  cathode 
  deposit 
  is 
  

  

  