﻿176 
  On 
  Ionization, 
  Ionic 
  Velocities, 
  and 
  Atomic 
  Sizes. 
  

  

  Among 
  the 
  metals 
  though 
  ^B^N^/v 
  varies 
  from 
  200 
  to 
  

   400, 
  the 
  approach 
  to 
  constancy 
  appears 
  remarkable 
  when 
  

   it 
  is 
  noticed 
  that 
  N 
  2 
  varies 
  from 
  1*53 
  to 
  8*4, 
  and 
  B 
  1 
  3 
  from 
  

   1*26 
  to 
  3*8. 
  In 
  the 
  six 
  fatty 
  acid 
  radicals 
  from 
  formic 
  to 
  

   caproic 
  the 
  approach 
  to 
  constancy 
  is 
  satisfactory. 
  In 
  the 
  

   halogen 
  atoms 
  ,\ 
  B 
  1/3 
  N 
  2 
  /v 
  fails 
  to 
  approach 
  constancy 
  in 
  a 
  

   striking 
  manner, 
  ranging 
  from 
  130 
  to 
  680. 
  It 
  is 
  probable 
  that 
  

   the 
  discrepancy 
  here 
  is 
  due 
  to 
  the 
  assumption 
  that 
  in 
  these 
  

   atoms 
  K 
  = 
  N 
  2 
  . 
  If 
  we 
  remember 
  that 
  the 
  halogens 
  are 
  heptads 
  

   as 
  well 
  as 
  monads, 
  and 
  that 
  therefore 
  each 
  halogen 
  atom 
  con- 
  

   tains 
  three 
  pairs 
  of 
  % 
  and 
  \} 
  as 
  neutrons, 
  or 
  as 
  doublets, 
  giving 
  

   each 
  the 
  possibility 
  of 
  acting 
  as 
  a 
  tri-stion, 
  we 
  can 
  see 
  that 
  the 
  

   assumption 
  K 
  = 
  N 
  2 
  is 
  unsafe. 
  The 
  exceptional 
  behaviour 
  of 
  

   H 
  and 
  OH 
  in 
  having 
  such 
  large 
  values 
  as 
  980 
  and 
  765 
  for 
  

   i\B 
  1/3 
  N 
  2 
  /v 
  is 
  probably 
  due 
  to 
  the 
  fact 
  that 
  these 
  are 
  the 
  ions 
  

   of 
  water 
  itself. 
  It 
  is 
  possible 
  therefore 
  that 
  these 
  two 
  ions 
  

   have 
  their 
  real 
  ionic 
  velocities 
  largely 
  increased 
  by 
  a 
  sort 
  of 
  

   Grotthus-chain 
  action, 
  whereby 
  an 
  H 
  or 
  an 
  OH, 
  instead 
  of 
  

   passing 
  through 
  the 
  space 
  of 
  a 
  water 
  molecule 
  which 
  is 
  

   in 
  front 
  of 
  it, 
  simply 
  combines 
  with 
  part 
  of 
  the 
  molecule 
  

   and 
  liberates 
  the 
  other 
  part 
  at 
  the 
  other 
  side, 
  so 
  that 
  the 
  same 
  

   effect 
  is 
  produced 
  as 
  if 
  the 
  ion 
  had 
  traversed 
  the 
  space 
  of 
  the 
  

   molecule 
  with 
  a 
  higher 
  velocity 
  than 
  the 
  true 
  ionic 
  velocity. 
  

  

  To 
  proceed 
  with 
  our 
  equation 
  (16) 
  to 
  the 
  calculation 
  of 
  a 
  x 
  

   absolutely, 
  let 
  us 
  fix 
  our 
  attention 
  on 
  the 
  ion 
  of 
  Li. 
  We 
  

   must 
  first 
  convert 
  {K 
  its 
  ionic 
  velocity 
  per 
  gramme 
  equivalent 
  

   G 
  into 
  the 
  velocity 
  of 
  an 
  atom 
  by 
  dividing 
  by 
  oG/4:7rpiai 
  3 
  ? 
  

   which 
  is 
  the 
  number 
  of 
  atoms 
  in 
  a 
  gramme 
  equivalent. 
  

   Again, 
  to 
  express 
  iX 
  in 
  O.G.S. 
  units 
  we 
  must 
  multiply 
  i\ 
  Q 
  

   cm." 
  -1 
  ohm 
  -1 
  by 
  10 
  -9 
  to 
  pass 
  to 
  the 
  electromagnetic 
  unit 
  of 
  

   resistance, 
  and 
  by 
  9 
  x 
  10 
  20 
  to 
  get 
  the 
  appropriate 
  C.G.S. 
  

   expression. 
  Again, 
  the 
  electrochemical 
  equivalent 
  of 
  hydrogen 
  

   is 
  "0001035 
  in 
  E.M. 
  units, 
  and 
  therefore 
  for 
  Li 
  

  

  M 
  1 
  A?=-000725/3xl0 
  10 
  

  

  in 
  electrostatic 
  units. 
  As 
  G//0i 
  = 
  B 
  given 
  along 
  with 
  i\ 
  and 
  

   N 
  in 
  Table 
  III., 
  we 
  have 
  for 
  Li 
  with 
  K 
  =80,v=l,^= 
  -01059, 
  

   and 
  pi 
  = 
  3*5. 
  

  

  & 
  a 
  3 
  x 
  35-5 
  x 
  9 
  x 
  10* 
  1 
  - 
  (lira 
  a 
  3 
  V 
  2 
  9xl0 
  2Q 
  x80 
  

  

  ( 
  l^o! 
  XO-50X9X10 
  -(4 
  Wl 
  ) 
  . 
  0007252x67rx 
  . 
  0105 
  9 
  x2 
  . 
  9gaj 
  

  

  ... 
  a 
  1 
  2 
  = 
  3-8xl0" 
  18 
  , 
  

  

  oi 
  =2xl0" 
  9 
  , 
  

  

  !t-V 
  = 
  7-5x10- 
  27 
  . 
  

  

  