﻿Rate 
  of 
  Recombination 
  of 
  Ions 
  in 
  Gases. 
  283 
  

  

  centimetre 
  of 
  the 
  substance. 
  This, 
  for 
  a 
  crystal 
  of 
  the 
  cubic 
  

   class, 
  is, 
  in 
  Voigt's 
  mathematical 
  theory, 
  the 
  analogue 
  to 
  the 
  

   electric 
  effect 
  discovered 
  in 
  quartz 
  by 
  the 
  brothers 
  Curie, 
  and 
  

   measured 
  by 
  aid 
  of 
  thin 
  metal 
  foils 
  attached 
  to 
  the 
  two 
  faces 
  

   of 
  the 
  plate 
  and 
  metallically 
  connected 
  to 
  the 
  two 
  principal 
  

   electrodes 
  of 
  an 
  electrometer. 
  

  

  XXX. 
  Hie 
  Rate 
  of 
  Recombination 
  of 
  Ions 
  in 
  Gases 
  under 
  

  

  Different 
  Pressures. 
  By 
  R. 
  K. 
  McClung, 
  M. 
  A., 
  formerly 
  

  

  Demonstrator 
  of 
  Physics, 
  Mc 
  Gill 
  University, 
  Montreal; 
  1851 
  

  

  . 
  Exhibition 
  Scholar, 
  McG'ill 
  University, 
  Trinity 
  College, 
  

  

  Cambridge 
  *. 
  

  

  ANY 
  gas 
  which 
  has 
  been 
  exposed 
  to 
  Rontgen 
  rays, 
  retains 
  

   the 
  ionization 
  thus 
  produced 
  for 
  a 
  short 
  time 
  after 
  

   the 
  source 
  of 
  radiation 
  has 
  been 
  removed. 
  The 
  negative 
  

   and 
  positive 
  ions 
  take 
  an 
  appreciable 
  time 
  to 
  recombine 
  with 
  

   one 
  another; 
  and 
  it 
  is 
  necessary 
  in 
  some 
  cases 
  to 
  take 
  into 
  

   consideration 
  the 
  rate 
  at 
  which 
  these 
  ions 
  disappear 
  by 
  

   recombination. 
  This 
  question 
  of 
  the 
  rate 
  of 
  recombination 
  of 
  

   ions 
  has 
  been 
  investigated 
  by 
  Prof. 
  Rutherford 
  (Phil. 
  Mag. 
  

   Nov. 
  1897) 
  for 
  air 
  and 
  some 
  other 
  gases 
  at 
  atmospheric 
  

   pressure. 
  In 
  that 
  paper 
  he 
  points 
  out 
  that 
  if, 
  when 
  the 
  rate 
  

   of 
  production 
  becomes 
  equal 
  to 
  the 
  rate 
  of 
  recombination, 
  the 
  

   rays 
  be 
  then 
  stopped, 
  the 
  rate 
  at 
  which 
  the 
  conducting 
  

   particles 
  decay 
  is 
  given 
  by 
  the 
  equation 
  

   dn 
  

  

  dt=- 
  an 
  >- 
  _ 
  a) 
  

  

  where 
  n 
  is 
  the 
  number 
  of 
  ions 
  per 
  c.c. 
  in 
  the 
  gas 
  at 
  any 
  time 
  

   t 
  after 
  the 
  rays 
  have 
  ceased, 
  and 
  a 
  is 
  a 
  constant 
  for 
  any 
  given 
  

   gas 
  at 
  ordinary 
  atmospheric 
  pressure. 
  If 
  N 
  be 
  the 
  maximum 
  

   number 
  of 
  ions 
  per 
  c.c. 
  when 
  a 
  steady 
  state 
  has 
  been 
  reached 
  

   before 
  the 
  cessation 
  of 
  the 
  rays, 
  then 
  the 
  above 
  equation 
  

   becomes 
  by 
  integration 
  

  

  --4=«* 
  ( 
  2 
  ) 
  

  

  Object 
  of 
  Investigation. 
  

  

  At 
  the 
  suggestion 
  of 
  Professor 
  Rutherford, 
  the 
  present 
  

   research 
  was 
  undertaken 
  in 
  order 
  to 
  ascertain 
  the 
  conditions 
  

   which 
  exist 
  in 
  regard 
  to 
  the 
  recombination 
  of 
  the 
  ions 
  in 
  

   gases 
  under 
  pressures 
  other 
  than 
  atmospheric 
  pressure, 
  and 
  to 
  

   find 
  the 
  relation 
  between 
  the 
  rates 
  of 
  recombination 
  at 
  dif- 
  

   ferent 
  pressures. 
  The 
  objects 
  of 
  the 
  present 
  investigation 
  

   have 
  been 
  therefore 
  : 
  — 
  

  

  (1) 
  To 
  determine 
  whether 
  the 
  law 
  of 
  recombination, 
  as 
  set 
  

   * 
  Communicated 
  by 
  Prof. 
  E. 
  Rutherford. 
  

  

  