﻿630 
  Prof. 
  E. 
  M. 
  Wellisch 
  on 
  the 
  Distribution 
  of 
  the 
  

  

  the 
  abscissae 
  (denoted 
  by 
  I 
  160 
  ) 
  serve 
  as 
  a 
  measure 
  of 
  the 
  

   saturation 
  current. 
  

  

  The 
  continuous 
  curves 
  in 
  fig. 
  2 
  have 
  as 
  ordinates 
  Iy/Iieo? 
  

   i. 
  e. 
  the 
  value 
  of 
  the 
  current 
  obtained 
  with 
  V" 
  volts 
  applied 
  

   to 
  the 
  case 
  expressed 
  as 
  a 
  fraction 
  of 
  the 
  current 
  obtained 
  

   when 
  160 
  volts 
  were 
  applied. 
  

  

  The 
  broken 
  curves 
  refer 
  to 
  the 
  active 
  deposit 
  and 
  have 
  as 
  

   ordinates 
  Av/A 
  160 
  , 
  L 
  e. 
  the 
  cathode 
  deposit 
  obtained 
  with 
  

   V 
  volts 
  applied 
  to 
  the 
  case 
  expressed 
  as 
  a 
  fraction 
  of 
  the 
  

   cathode 
  deposit 
  obtained 
  when 
  a 
  positive 
  potential 
  of 
  160 
  

   volts 
  was 
  applied. 
  As 
  mentioned 
  above, 
  the 
  cathode 
  deposit 
  

   obtained 
  for 
  a 
  potential 
  of 
  160 
  volts 
  was 
  only 
  83*9 
  per 
  cent, 
  

   of 
  the 
  total 
  amount, 
  and 
  the 
  maximum 
  amount 
  obtainable 
  

   on 
  the 
  cathode 
  for 
  very 
  large 
  potentials 
  was 
  89*2 
  per 
  cent, 
  

   of 
  the 
  total. 
  

  

  By 
  plotting 
  the 
  curves 
  in 
  this 
  manner 
  the 
  two 
  sets 
  become 
  

   comparable 
  ; 
  the 
  continuous 
  curves 
  afford 
  a 
  measure 
  of 
  the 
  

   fraction 
  of 
  the 
  total 
  number 
  of 
  positive 
  ions 
  which 
  reach 
  

   the 
  cathode 
  corresponding 
  to 
  any 
  potential 
  Y, 
  while 
  the 
  

   broken 
  curves 
  similarly 
  afford 
  a 
  measure 
  of 
  the 
  fraction 
  of 
  

   the 
  total 
  number 
  of 
  positively 
  charged 
  particles 
  which 
  settle 
  

   on 
  the 
  cathode. 
  

  

  A 
  very 
  large 
  number 
  of 
  experimental 
  results 
  were 
  used 
  in 
  

   order 
  to 
  plot 
  the 
  curves 
  ; 
  for 
  the 
  sake 
  of 
  simplification 
  the 
  

   individual 
  results 
  are 
  not 
  recorded 
  in 
  the 
  diagram. 
  

  

  The 
  curves 
  in 
  fig. 
  2 
  all 
  refer 
  to 
  the 
  values 
  obtained 
  when 
  

   the 
  air 
  with 
  which 
  the 
  emanation 
  was 
  mixed 
  was 
  thoroughly 
  

   dried, 
  as 
  described 
  in 
  Section 
  4. 
  The 
  effect 
  of 
  a 
  small 
  

   amount 
  of 
  water 
  vapour 
  was 
  especially 
  marked 
  when 
  the 
  

   applied 
  potential 
  was 
  small. 
  In 
  illustration 
  of 
  this 
  point 
  

   some 
  of 
  the 
  results 
  obtained 
  for 
  dried 
  and 
  undried 
  air 
  are 
  

   recorded 
  below 
  : 
  — 
  

  

  Air 
  at 
  1 
  atmosphere 
  : 
  ) 
  A 
  T 
  /T 
  T 
  

  

  V 
  = 
  8 
  volts 
  f 
  Av 
  V 
  Il6 
  ° 
  II60 
  

  

  dried 
  with 
  special 
  caution 
  ..... 
  . 
  38*4 
  -61 
  3-21 
  

  

  containing 
  slight 
  traces 
  of 
  I 
  o-i 
  .o 
  .gi 
  o.oi 
  

  

  water 
  vapour 
  \ 
  " 
  ' 
  ' 
  

  

  It 
  is 
  worthy 
  of 
  notice 
  that 
  the 
  presence 
  of 
  small 
  quantities 
  

   of 
  water 
  vapour 
  does 
  not 
  appreciably 
  diminish 
  the 
  fraction 
  

   of 
  positive 
  ions 
  which 
  reach 
  the 
  cathode, 
  whereas 
  the 
  effect 
  

   on 
  the 
  number 
  of 
  positively 
  charged 
  deposit 
  particles 
  is 
  

   considerable. 
  It 
  has 
  for 
  some 
  lime 
  been 
  known 
  that 
  water 
  

   vapour 
  is 
  effective 
  in 
  causing 
  increased 
  recombination 
  of 
  

   ions, 
  but 
  the 
  above 
  results 
  serve 
  to 
  show 
  that 
  the 
  ions 
  are 
  

   not 
  nearly 
  so 
  sensitive 
  to 
  the 
  presence 
  of 
  vapour 
  as 
  the 
  

   active 
  deposit 
  particles. 
  

  

  