﻿Wellisch 
  and 
  Woodrow 
  — 
  Columnar 
  Ionization. 
  219 
  

  

  It 
  will 
  be 
  seen 
  from 
  fig. 
  3 
  that 
  for 
  values 
  of 
  X 
  greater 
  than 
  

   400 
  volts 
  per 
  centimeter 
  r 
  x 
  is 
  greater 
  than 
  r 
  t 
  . 
  This 
  experimental 
  

   result 
  was 
  verified 
  in 
  several 
  subsequent 
  determinations 
  and 
  

   appeared 
  thus 
  to 
  support 
  the 
  view 
  that 
  there 
  is 
  extra 
  ionization 
  

   produced 
  when 
  the 
  electric 
  field 
  is 
  longitudinal. 
  

  

  The 
  slit 
  was 
  now 
  removed 
  and 
  in 
  its 
  place 
  was 
  inserted 
  a 
  

   'canal' 
  system 
  consisting 
  of 
  twenty-five 
  small 
  holes 
  drilled 
  in 
  a 
  

   small 
  brass 
  rod 
  6 
  mra 
  in 
  length 
  and 
  4 
  mm 
  in 
  diameter. 
  There 
  was 
  

   a 
  central 
  ' 
  canal 
  ' 
  l 
  mm 
  in 
  diameter 
  surrounded 
  by 
  twenty-four 
  

   smaller 
  'canals,' 
  each 
  - 
  4 
  mD1 
  in 
  diameter. 
  In 
  this 
  manner 
  the 
  

   electric 
  field 
  was 
  more 
  rigorously 
  longitudinal 
  or 
  transverse 
  to 
  

   the 
  alpha-particle 
  trajectories 
  than 
  when 
  the 
  slit 
  was 
  employed. 
  

   A 
  value 
  was 
  obtained 
  for 
  the 
  range 
  of 
  the 
  alpha-particle 
  iden- 
  

   tical 
  with 
  that 
  found 
  previously. 
  

  

  Fig. 
  3. 
  

  

  Ratio 
  

  

  A- 
  

  

  

  B 
  

  

  

  -o- 
  

  

  

  

  

  

  

  f 
  

  

  -"-"■"A 
  

  

  

  

  

  

  

  

  

  f 
  

  

  

  

  

  

  

  

  

  

  

  

  A=L0NGI 
  

   B 
  = 
  TRAM 
  

  

  TUD1NAL 
  

   5VERSE 
  

  

  HELD 
  

  

  

  

  

  

  

  

  

  

  

  

  

  

  ZOO 
  

  

  400 
  

  

  600 
  

  

  800 
  

  

  1000 
  

  

  1200 
  

  

  1^00 
  1600 
  

  

  Volts 
  per 
  cm. 
  

  

  The 
  values 
  obtained 
  for 
  r 
  x 
  and 
  r 
  t 
  are 
  given 
  in 
  Table 
  II, 
  and 
  

   the 
  corresponding 
  curves 
  are 
  shown 
  in 
  fig. 
  3. 
  

  

  Table 
  II. 
  

  

  d=2 
  , 
  6cm.; 
  r=i 
  76 
  o/i 
  2 
  6i. 
  

  

  

  Longitudinal 
  Field. 
  

  

  Transverse 
  Field. 
  

  

  p- 
  

  

  X. 
  

  

  iu 
  

  

  Tl. 
  

  

  X. 
  

  

  it. 
  

  

  n. 
  

  

  261 
  

  

  1580 
  

  

  0-385 
  

  

  

  630 
  

  

  0-435 
  

  

  

  400 
  

  

  1580 
  

  

  0-610 
  

  

  

  530 
  

  

  0-685 
  

  

  

  760 
  

  

  105 
  

  

  1-13 
  

  

  2-94 
  

  

  42 
  

  

  1-48 
  

  

  3-40 
  

  

  760 
  

  

  420 
  

  

  1-26 
  

  

  3-28 
  

  

  210 
  

  

  1-54 
  

  

  3-54 
  

  

  760 
  

  

  1050 
  

  

  1-32 
  

  

  3*43 
  

  

  420 
  

  

  1-53 
  

  

  3-52 
  

  

  760 
  

  

  1580 
  

  

  T34 
  

  

  3*48 
  

  

  630 
  

  

  1-53 
  

  

  3-52 
  

  

  Am. 
  Jour. 
  Sci.— 
  Fourth 
  Series, 
  Vol. 
  XXXVI, 
  No. 
  213. 
  — 
  September. 
  1913. 
  

   15 
  

  

  