﻿296 
  Mr. 
  McClung 
  on 
  the 
  Bate 
  of 
  Recombination 
  of 
  

  

  From 
  these 
  curves 
  we 
  see, 
  what 
  we 
  should 
  naturally 
  expect* 
  

   that 
  the 
  rate 
  at 
  which 
  the 
  ions 
  recombine 
  is 
  much 
  greater 
  at 
  

   the 
  high 
  pressures 
  than 
  at 
  the 
  low 
  ones, 
  owing, 
  o£ 
  course, 
  to 
  

   the 
  fact 
  that 
  at 
  the 
  high 
  pressures 
  there 
  are 
  many 
  more 
  ions 
  

   produced 
  in 
  a 
  given 
  volume 
  of 
  the 
  gas, 
  and 
  therefore 
  the 
  

   chance 
  of 
  their 
  coming 
  in 
  contact 
  with 
  one 
  another 
  is 
  much 
  

   greater 
  than 
  at 
  low 
  pressures. 
  

  

  If 
  we 
  consider 
  the 
  theory 
  from 
  the 
  point 
  of 
  view 
  of 
  the 
  

   time 
  taken 
  for 
  the 
  maximum 
  number 
  of 
  ions 
  to 
  fall 
  to 
  half 
  

   their 
  value, 
  we 
  get 
  a 
  further 
  confirmation 
  of 
  it 
  from 
  experi- 
  

   ment. 
  By 
  determining 
  the 
  ratio 
  of 
  1ST 
  to 
  Q 
  at 
  each 
  pressure 
  

   and 
  substituting 
  these 
  values, 
  along 
  with 
  the 
  values 
  of 
  d 
  and 
  

   I 
  in 
  centimetres 
  in 
  equation 
  (8), 
  we 
  obtain 
  the 
  value 
  of 
  T 
  in 
  

   seconds 
  in 
  each 
  case. 
  Comparing 
  these 
  calculated 
  values 
  

   with 
  the 
  values 
  of 
  T 
  obtained 
  directly 
  from 
  the 
  curves, 
  we 
  

   find 
  the 
  agreement 
  fairly 
  close, 
  considering 
  the 
  fact 
  that 
  

   formula 
  (8) 
  is 
  only 
  an 
  approximate 
  formula, 
  and 
  also 
  that 
  a 
  

   slight 
  variation 
  in 
  the 
  intensity 
  of 
  the 
  rays 
  would 
  cause 
  a 
  

   corresponding 
  deviation 
  in 
  the 
  shape 
  o£ 
  the 
  curve, 
  and 
  there- 
  

   fore 
  a 
  slight 
  alteration 
  in 
  the 
  value 
  of 
  T 
  obtained 
  from 
  it. 
  

   A 
  comparison 
  of 
  these 
  values 
  of 
  T 
  is 
  given 
  for 
  several 
  

   different 
  pressures 
  in 
  Table 
  I. 
  

  

  Table 
  I. 
  

  

  1 
  

   Pressure. 
  

  

  Deflexion 
  

  

  for 
  N. 
  

  

  Deflexion 
  

   for 
  Q. 
  

  

  Value 
  of 
  | 
  

  

  2d 
  Calculated 
  

  

  "2d 
  — 
  I 
  ' 
  va 
  ^ 
  u8 
  °f 
  ^- 
  

  

  Value 
  of 
  T 
  

  

  obtained 
  

  

  from 
  curve. 
  

  

  3 
  atinos. 
  

   2 
  

  

  1 
  ,, 
  

  

  i 
  » 
  

  

  i 
  

  

  4 
  5J 
  

  

  236 
  

   196 
  

   181 
  

   154 
  

   136 
  

  

  143 
  

   112 
  

  

  51 
  

   41 
  

   26 
  

  

  1-66 
  -114 
  

   1-66 
  -122 
  

   1-66 
  -247 
  

   1-66 
  -259 
  

   1-66 
  -360 
  

  

  •137 
  

   •161 
  

   •203 
  

   •249 
  

  

  •368 
  

  

  The 
  agreement 
  between 
  theory 
  and 
  experiment 
  is 
  close 
  

   enough 
  to 
  show 
  that 
  the 
  theory 
  is 
  quite 
  valid 
  no 
  matter 
  from 
  

   which 
  point 
  of 
  view 
  it 
  may 
  be 
  considered. 
  

  

  We 
  see, 
  therefore, 
  that 
  the 
  relation 
  -r. 
  = 
  — 
  an 
  2 
  gives 
  actually 
  

  

  the 
  rate 
  at 
  which 
  the 
  ions 
  recombine 
  in 
  air, 
  not 
  only 
  at 
  atmo- 
  

   spheric 
  pressure, 
  but 
  also 
  for 
  air 
  at 
  pressures 
  other 
  than 
  

   atmospheric, 
  at 
  least 
  between 
  the 
  limits 
  already 
  indicated. 
  

  

  