﻿522 
  Prof. 
  Wellisch 
  and±Dv. 
  Woodrow 
  : 
  Experiments 
  

  

  It 
  might 
  be 
  expected 
  that 
  as 
  there 
  are 
  only 
  four 
  points 
  on 
  

   each 
  curve 
  it 
  would 
  be 
  very 
  difficult 
  to 
  produce 
  the 
  curves 
  

   as 
  stated 
  above, 
  especially 
  those 
  curves 
  corresponding 
  to 
  

   small 
  values 
  of 
  the 
  field 
  ; 
  however, 
  those 
  points 
  which 
  were 
  

   of 
  the 
  most 
  importance 
  for 
  our 
  subsequent 
  calculations 
  

   were 
  those 
  which 
  were 
  most 
  readily 
  obtained 
  by 
  this 
  

   method. 
  Moreover, 
  other 
  considerations 
  made 
  it 
  highly 
  

   probable 
  that 
  the 
  curves 
  corresponding 
  to 
  the 
  small 
  values 
  

   of 
  the 
  electric 
  field 
  intersected 
  the 
  axis 
  of 
  ordinates 
  at 
  points 
  

   close 
  to 
  one 
  another. 
  

  

  In 
  fig. 
  5 
  the 
  limiting 
  values 
  of 
  i\l 
  obtained 
  as 
  above 
  

   described 
  are 
  plotted 
  against 
  the 
  corresponding 
  values 
  of 
  

  

  Fisr. 
  5. 
  

  

  1.0 
  

   .9 
  

  

  .8 
  

  

  < 
  

  

  .7 
  

  

  .6 
  

  

  .5 
  

  

  Y 
  

  

  

  XT' 
  A 
  

  

  

  AIR 
  

  

  — 
  o 
  

  

  

  1 
  o 
  

  

  X" 
  

  

  

  

  

  

  

  

  

  f 
  

  

  

  

  

  fco. 
  

  

  

  

  

  b 
  

  

  

  [cy^c 
  

  

  

  

  

  

  E 
  

  

  

  

  

  

  

  

  

  

  / 
  

  

  

  

  

  

  

  

  

  f 
  

  

  

  

  

  

  

  

  

  .3 
  

   .2 
  

  

  r 
  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  X 
  

  

  200 
  40O 
  600 
  600 
  1000 
  1200 
  1400 
  1600 
  

  

  l/<?/fs 
  per 
  c/rv. 
  

  

  the 
  electric 
  field. 
  This 
  curve 
  refers 
  to 
  the 
  longitudinal 
  field 
  

   in 
  air 
  at 
  a 
  pressure 
  of 
  760 
  mm. 
  of 
  mercury, 
  and 
  may 
  be 
  con- 
  

   sidered 
  as 
  giving 
  the 
  fraction 
  of 
  the 
  total 
  ionization 
  produced 
  

   by 
  a 
  single 
  alpha 
  particle 
  which 
  is 
  carried 
  over 
  to 
  the 
  elec- 
  

   trodes 
  by 
  the 
  corresponding 
  electric 
  field. 
  The 
  curve 
  is 
  

   practically 
  identical 
  with 
  that 
  obtained 
  by 
  Moulin*; 
  it 
  

   intersects 
  the 
  axis 
  of 
  ordinates 
  at 
  a 
  point 
  represented 
  by 
  the 
  

   fraction 
  0*74. 
  The 
  ideal 
  curve 
  for 
  the 
  transverse 
  electric 
  

   field 
  could 
  not 
  be 
  obtained 
  with 
  the 
  same 
  degree 
  of 
  accuracy, 
  

   but 
  it 
  is 
  approximately 
  a 
  straight 
  line 
  parallel 
  to 
  the 
  X- 
  

   axis 
  and 
  with 
  1*0 
  as 
  ordinate 
  indicating 
  that 
  a 
  very 
  small 
  

   value 
  of 
  the 
  field 
  is 
  sufficient 
  to 
  prevent 
  recombination 
  of 
  

   the 
  ions. 
  

  

  * 
  Moulin, 
  16c. 
  cit. 
  p. 
  99. 
  

  

  