﻿354 
  Mr. 
  W. 
  Sutherland 
  on 
  

  

  in 
  a 
  cm.3 
  at 
  0° 
  C. 
  and 
  1 
  atmo. 
  ^mv^ 
  = 
  3joV288/273 
  with 
  

  

  p 
  = 
  1,014,000, 
  V 
  = 
  1, 
  N 
  = 
  4 
  X 
  10^^ 
  

  

  2{4>(a, 
  + 
  a-^-¥'f(a^ 
  + 
  a,)}/onv' 
  = 
  C7288 
  = 
  2-41, 
  

  

  .-. 
  ^(ai 
  + 
  a3)4-'f(ai4-«3) 
  = 
  916 
  X 
  lO-^^. 
  

  

  If 
  E' 
  were 
  due 
  to 
  two 
  opposite 
  electrons 
  o£ 
  charge 
  e 
  at 
  

   distance 
  x 
  apart, 
  we 
  should 
  have 
  

  

  <^(«i 
  + 
  as) 
  + 
  i/r(ai 
  + 
  a^) 
  = 
  e^x/ia?, 
  

  

  whence 
  x 
  = 
  0*0352 
  x 
  lO'^. 
  

  

  I 
  hope 
  to 
  show 
  in 
  a 
  future 
  communication 
  that 
  the 
  

   fundamental 
  mode 
  of 
  motion 
  determining 
  the 
  structure 
  of 
  

   all 
  spectra 
  is 
  that 
  of 
  two 
  opposite 
  electrons 
  vibrating 
  within 
  

   each 
  atom 
  about 
  positions 
  at 
  a 
  mean 
  distance 
  apart 
  of 
  the 
  

   order 
  0'05 
  x 
  lO"^. 
  It 
  seems 
  very 
  probable 
  then 
  that 
  this 
  

   electric 
  moment 
  E', 
  which 
  we 
  have 
  been 
  investigating 
  here, 
  

   is 
  the 
  moment 
  of 
  this 
  pair 
  of 
  electrons 
  M-hich 
  at 
  the 
  same 
  

   fixed 
  distance 
  apart 
  in 
  all 
  atoms 
  determine 
  all 
  radiation 
  and 
  

   the 
  structure 
  of 
  all 
  spectra. 
  The 
  further 
  investigation 
  of 
  C 
  

   must 
  be 
  a 
  matter 
  of 
  special 
  experiment^ 
  just 
  as 
  in 
  the 
  case 
  of 
  

   C 
  in 
  the 
  viscosity 
  of 
  gases. 
  

  

  The 
  coefficients 
  of 
  diffusion 
  D 
  of 
  ions 
  in 
  gases 
  are 
  propor- 
  

   tional 
  to 
  their 
  mobilities, 
  being 
  a 
  measure 
  of 
  their 
  mobilities 
  

   Tinder 
  the 
  driving 
  force 
  of 
  a 
  certain 
  space-rate 
  of 
  chaiige 
  of 
  

   partial 
  pressure, 
  instead 
  of 
  the 
  electric 
  force 
  of 
  a 
  volt/cm. 
  

   Their 
  values 
  have 
  been 
  investigated 
  chiefly 
  by 
  Town 
  send, 
  

   and 
  have 
  been 
  found 
  to 
  be 
  some 
  such 
  fraction 
  as 
  a 
  fifth 
  or 
  a 
  

   tenth 
  of 
  those 
  for 
  comparable 
  uncharged 
  molecules. 
  This 
  

   difference 
  has 
  been 
  generally 
  ascribed 
  to 
  the 
  formation 
  of 
  

   molecular 
  clusters 
  round 
  each 
  ion. 
  From 
  the 
  foregoing 
  it 
  is 
  

   plain 
  that 
  the 
  difference 
  is 
  due 
  to 
  the 
  operation 
  of 
  the 
  

   electrically 
  induced 
  viscosity 
  6 
  on 
  the 
  ions. 
  In 
  making 
  a 
  

   useful 
  comparison 
  of 
  the 
  two 
  types 
  of 
  diflfusion 
  coefficient 
  we 
  

   must 
  remember 
  that 
  we 
  are 
  assuming 
  the 
  ion 
  in 
  a 
  pure 
  gas 
  

   to 
  be 
  of 
  half 
  the 
  mass 
  and 
  half 
  the 
  volume 
  of 
  the 
  molecule. 
  

   Townsend 
  has 
  determined 
  D 
  for 
  the 
  positive 
  ions 
  in 
  CO2 
  as 
  

   0-023, 
  and 
  for 
  the 
  negative 
  0-026, 
  mean 
  0-0245. 
  For 
  

   comparison 
  with 
  this 
  we 
  must 
  cboose 
  the 
  value 
  of 
  the 
  

   diffusion 
  coefficient 
  for 
  a 
  gas 
  which 
  has 
  about 
  half 
  the 
  

   molecular 
  mass 
  44 
  of 
  CO2 
  and 
  half 
  its 
  molecular 
  volume. 
  

   The 
  nearest 
  we 
  can 
  get 
  to 
  this 
  is 
  to 
  take 
  the 
  case 
  of 
  CO 
  

   whose 
  molecular 
  mass 
  is 
  28 
  diffusing 
  into 
  CO2 
  with 
  a 
  

   coefficient 
  0-131, 
  or 
  that 
  of 
  O2 
  with 
  coefficient 
  0*136. 
  In 
  

   these 
  cases 
  the 
  molecular 
  volume 
  of 
  CO 
  and 
  O2 
  is 
  nearly 
  

  

  