﻿1000 
  Recombination 
  of 
  Jons 
  made 
  by 
  a 
  Rays. 
  

  

  Now 
  it 
  is 
  known 
  that 
  the 
  effect 
  of 
  water-vapour 
  on 
  the 
  

   ions 
  of 
  a 
  gas 
  is 
  to 
  decrease 
  their 
  mobility, 
  and 
  hence 
  these 
  

   observations 
  suggest 
  that 
  an 
  explanation 
  of 
  the 
  phenomenon 
  

   of 
  " 
  initial 
  recombination 
  " 
  may 
  possibly 
  be 
  found 
  in 
  the 
  

   presence 
  of 
  a 
  small 
  proportion 
  of 
  ions 
  of 
  very 
  small 
  mobility 
  

   in 
  the 
  gases 
  which 
  display 
  it 
  to 
  a 
  marked 
  degree. 
  It 
  is 
  easy 
  

   to 
  see 
  that 
  the 
  presence 
  of 
  such 
  ions 
  will 
  tend 
  to 
  increase 
  

   recombination 
  and 
  so 
  make 
  saturation 
  more 
  difficult. 
  For 
  it 
  

   a 
  column 
  of 
  positive 
  ions 
  is 
  flowing 
  through 
  a 
  similar 
  column 
  

   of 
  negative 
  ions, 
  recombination 
  ceases 
  when 
  the 
  columns 
  get 
  

   clear 
  of 
  each 
  other. 
  If 
  the 
  ions 
  are 
  all 
  of 
  the 
  same 
  mobility 
  

   this 
  happens 
  somewhere 
  near 
  the 
  central 
  plane 
  of 
  the 
  

   chamber. 
  Bat 
  if 
  there 
  is 
  present 
  an 
  ion 
  of 
  one-tenth 
  the 
  

   mobility 
  of 
  the 
  ordinary 
  ion, 
  it 
  will 
  take 
  ten 
  times 
  as 
  long 
  to 
  

   cross 
  the 
  chamber, 
  and 
  hence 
  will 
  be 
  in 
  danger 
  of 
  recom- 
  

   bination 
  for 
  almost 
  twice 
  as 
  long 
  a 
  time. 
  During 
  half 
  of 
  

   this 
  time 
  recombination 
  is 
  very 
  likely 
  to 
  occur, 
  since 
  the 
  ion 
  

   will 
  be 
  the 
  only 
  one 
  of 
  its 
  sign 
  in 
  a 
  dense 
  column 
  of 
  opposite 
  

   sign. 
  And 
  again, 
  such 
  an 
  ion, 
  being 
  larger 
  than 
  the 
  

   ordinary 
  ion, 
  would 
  make 
  more 
  collisions. 
  

  

  According 
  to 
  this 
  hypothesis 
  the 
  extent 
  to 
  which 
  a 
  gas 
  

   shows 
  " 
  initial 
  recombination 
  " 
  should 
  increase 
  with 
  the 
  

   extent 
  to 
  which 
  it 
  forms 
  heavy 
  ions 
  of 
  low 
  mobility. 
  Now, 
  

   since 
  the 
  formation 
  of 
  such 
  ions 
  is 
  likely 
  to 
  be 
  due 
  to 
  

   attractions 
  between 
  the 
  molecules, 
  it 
  is 
  likely 
  to 
  be 
  more 
  

   frequent 
  the 
  nearer 
  the 
  gas 
  is 
  to 
  its 
  boiling-point. 
  If, 
  then, 
  

   observations 
  are 
  made 
  all 
  under 
  similar 
  conditions 
  as 
  regards 
  

   apparatus, 
  temperature, 
  and 
  pressure, 
  a 
  gas 
  which 
  has 
  the 
  

   higher 
  boiling-point 
  should 
  always 
  show 
  more 
  " 
  initial 
  

   recombination." 
  In 
  the 
  following 
  table 
  several 
  gases 
  are 
  

   tabulated 
  in 
  the 
  order 
  of 
  the 
  degree 
  in 
  which 
  they 
  show 
  

   ' 
  initial 
  recombination 
  " 
  ; 
  hydrogen 
  shows 
  the 
  phenomenon 
  

   least, 
  sulphur 
  dioxide 
  most. 
  In 
  the 
  second 
  column 
  the 
  

   boiling-points 
  are 
  given 
  ; 
  it 
  will 
  be 
  observed 
  that, 
  in 
  accord- 
  

   ance 
  with 
  the 
  hypothesis, 
  they 
  increase 
  regularly 
  throughout 
  

   the 
  table. 
  In 
  the 
  third 
  column 
  the 
  solubilities 
  in 
  water 
  are 
  

   given, 
  for 
  it 
  was 
  thought 
  that 
  the 
  formation 
  of 
  heavy 
  ions 
  

   might 
  conceivably 
  be 
  dependent 
  on 
  this 
  property 
  to 
  some 
  

   extent. 
  It 
  will 
  be 
  observed 
  that 
  in 
  the 
  only 
  case 
  (ammonia) 
  

   in 
  which 
  the 
  order 
  of 
  solubility 
  is 
  different 
  from 
  that 
  of 
  

   boiling-point, 
  " 
  initial 
  recombination 
  " 
  appears 
  to 
  be 
  deter- 
  

   mined 
  rather 
  by 
  the 
  latter 
  than 
  by 
  the 
  former. 
  The 
  obser- 
  

   vations 
  refer 
  to 
  dry 
  gases 
  ; 
  solubility 
  might 
  be 
  of 
  greater 
  

   importance 
  if 
  the 
  gases 
  were 
  moist. 
  

  

  