﻿220 
  Wellisch 
  and 
  Woodrow 
  — 
  Columnar 
  Ionization. 
  

  

  In 
  order 
  to 
  determine 
  whether 
  the 
  scattering 
  of 
  the 
  alpha- 
  

   particles 
  produced 
  any 
  effect 
  on 
  the 
  relative 
  values 
  of 
  r 
  z 
  and 
  r 
  t 
  

   when 
  the 
  canals 
  were 
  employed, 
  readings 
  were 
  taken 
  of 
  the 
  

   current 
  with 
  the 
  polonium 
  at 
  different 
  distances 
  from 
  the 
  

   middle 
  of 
  the 
  ionization 
  vessel. 
  The 
  electric 
  field 
  was 
  1580 
  

   volts 
  per 
  centimeter 
  for 
  both 
  the 
  longitudinal 
  and 
  the 
  trans- 
  

   verse 
  fields. 
  The 
  results 
  are 
  shown 
  in 
  Table 
  III. 
  

  

  It 
  will 
  be 
  seen 
  now 
  that 
  in 
  every 
  case 
  the 
  value 
  of 
  r 
  t 
  is 
  

   greater 
  than 
  the 
  corresponding 
  value 
  of 
  r 
  z 
  . 
  The 
  curves 
  of 
  

   fig. 
  3 
  tend 
  to 
  the 
  same 
  maximum 
  value, 
  namely, 
  3*53. 
  

  

  Table 
  III. 
  

  

  Xz=1580 
  volts/cm.; 
  X*=630 
  volts/cni.; 
  r=i 
  76 
  oA*284 
  

  

  d. 
  

  

  ri. 
  

  

  r 
  t 
  . 
  

  

  d. 
  

  

  ri. 
  

  

  r 
  t 
  . 
  

  

  3*2 
  cm. 
  

   3-0 
  cm. 
  

  

  3-04 
  

   3-30 
  

  

  3*08 
  

   3-37 
  

  

  28 
  cm. 
  3*27 
  

   2-6 
  cm. 
  3-11 
  

  

  3-34 
  

   3-28 
  

  

  In 
  order 
  to 
  ascertain 
  the 
  reason 
  for 
  the 
  discrepancy 
  between 
  

   the 
  results 
  obtained 
  when 
  the 
  slit 
  and 
  the 
  canals 
  were 
  employed, 
  

   experiments 
  were 
  performed 
  in 
  which 
  only 
  small 
  portions 
  of 
  

   the 
  slit 
  previously 
  employed 
  were 
  effective. 
  The 
  oblique 
  rays 
  

   were 
  eliminated 
  by 
  placing 
  narrow 
  pieces 
  of 
  brass 
  over 
  the 
  

   ends 
  of 
  the 
  slit 
  so 
  as 
  to 
  leave 
  an 
  opening 
  in 
  the 
  center 
  l-7 
  min 
  

   in 
  length 
  and 
  0'5 
  mm 
  in 
  width. 
  The 
  corresponding 
  values 
  of 
  

   r 
  l 
  and 
  r 
  t 
  are 
  given 
  in 
  Table 
  IV 
  : 
  it 
  will 
  be 
  seen 
  that 
  the 
  ratios 
  

   for 
  the 
  longitudinal 
  and 
  transverse 
  fields 
  have 
  approximately 
  

   the 
  same 
  maximum 
  values. 
  The 
  results 
  thus 
  serve 
  to 
  confirm 
  

   those 
  obtained 
  when 
  the 
  canals 
  were 
  employed. 
  

  

  Table 
  IV. 
  

   d=2'68 
  cm.; 
  r=i 
  160 
  /ip. 
  

  

  

  Longitudinal 
  

  

  Field. 
  

  

  Transverse 
  Field. 
  

  

  p. 
  

  

  X. 
  

  

  iu 
  

  

  ri. 
  

  

  X. 
  

  

  it. 
  

  

  r 
  t 
  . 
  

  

  284 
  mm. 
  

  

  1580 
  

  

  0-560 
  

  

  3-42 
  

  

  630 
  

  

  0-391 
  

  

  3-40 
  

  

  400 
  

  

  1580 
  

  

  0'828 
  

  

  2*24 
  

  

  630 
  

  

  0-588 
  

  

  2-27 
  

  

  590 
  

  

  1580 
  

  

  1-370 
  

  

  1-40 
  

  

  630 
  

  

  0-962 
  

  

  1-38 
  

  

  760 
  

  

  1580 
  

  

  1-914 
  

  

  1-00 
  

  

  630 
  

  

  1-330 
  

  

  1-00 
  

  

  