﻿216 
  Mr. 
  P. 
  J. 
  Kirkby 
  on 
  tlie 
  Electrical 
  Conductivities 
  

  

  numbers 
  which 
  belong 
  to 
  different 
  pressures. 
  Nevertheless, 
  

   only 
  those 
  sets 
  of 
  observations 
  are 
  presented 
  during 
  which 
  

   the 
  bulb 
  remained 
  constant 
  within 
  the 
  limits 
  of 
  other 
  expe- 
  

   rimental 
  errors. 
  

  

  4. 
  It 
  thus 
  appears 
  that 
  there 
  is 
  a 
  remarkable 
  difference 
  in 
  

   the 
  behaviour 
  of 
  positive 
  and 
  negative 
  ions 
  when 
  moving 
  in 
  a 
  

   small 
  pressure 
  under 
  electric 
  force. 
  

  

  The 
  curves 
  here 
  given 
  (fig. 
  2) 
  serve 
  as 
  an 
  illustration 
  of 
  the 
  

  

  Fiar. 
  2. 
  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  / 
  

  

  1 
  

  

  / 
  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  / 
  

  

  / 
  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  / 
  

  

  / 
  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  // 
  

  

  / 
  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  .4 
  

  

  // 
  

  

  V 
  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  y 
  

  

  

  

  

  1 
  

  

  

  

  

  

  

  

  

  

  

  

  pf£ 
  

  

  s 
  

  

  ^ 
  

  

  V 
  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  y! 
  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  ffi 
  

  

  fS^ 
  

  

  t 
  .& 
  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  /"/l 
  

  

  •fssa 
  

  

  <rs 
  3- 
  

  

  rJ 
  f>0*l"' 
  

  

  

  20 
  40 
  60 
  80 
  100 
  120 
  140 
  160 
  180 
  200 
  220 
  240 
  260 
  280 
  300 
  320 
  340 
  360 
  38o 
  

  

  columns 
  B 
  and 
  Gr. 
  The 
  abscissa? 
  measure 
  the 
  potentials 
  of 
  

   the 
  aluminium 
  cylinder 
  whether 
  positive 
  or 
  negative. 
  The 
  

   ordinates 
  of 
  the 
  four 
  curves 
  are 
  simply 
  proportional 
  to 
  the 
  

   numbers 
  in 
  the 
  four 
  columns 
  respectively 
  of 
  B 
  and 
  G. 
  Each 
  

   pair 
  of 
  curves 
  exhibits 
  how, 
  as 
  the 
  intensity 
  of 
  the 
  field 
  

   between 
  the 
  cylinders 
  is 
  increased, 
  the 
  negative 
  current 
  

   rapidly 
  separates 
  itself 
  in 
  magnitude 
  from 
  the 
  corresponding 
  

   positive 
  current. 
  

  

  It 
  was 
  ito 
  give 
  prominence 
  to 
  this 
  curious 
  distinction 
  

   between 
  the 
  positive 
  and 
  negative 
  electrolytic 
  currents 
  in 
  a 
  

   gas 
  under 
  low 
  pressure, 
  that 
  coaxial 
  cylinders 
  were 
  used. 
  

   And 
  to 
  demonstrate 
  it 
  the 
  more 
  emphatically, 
  a 
  thin 
  wire 
  was 
  

   used 
  in 
  order 
  that 
  there 
  might 
  be 
  a 
  great 
  electric 
  intensity 
  in 
  

   the 
  field 
  of 
  force. 
  

  

  5. 
  Owing 
  to 
  the 
  constants 
  of 
  the 
  apparatus, 
  it 
  does 
  not 
  

   appear 
  possible 
  to 
  exhibit 
  any 
  exact 
  or 
  detailed 
  agreement 
  

   between 
  all 
  the 
  numbers 
  given 
  in 
  the 
  table 
  above 
  and 
  

   Professor 
  Townsend's 
  theory; 
  but 
  the 
  tests 
  which 
  have 
  sug- 
  

   gested 
  themselves 
  show, 
  as 
  far 
  as 
  they 
  go, 
  a 
  satisfactory 
  

   agreement. 
  

  

  Let 
  a, 
  I) 
  be 
  the 
  radii 
  of 
  the 
  internal 
  and 
  external 
  cylinders. 
  

   Let 
  N 
  be 
  the 
  number 
  of 
  ions 
  of 
  one 
  kind 
  generated 
  per 
  second 
  

  

  