﻿Ionic 
  Velocities, 
  and 
  Atomic 
  Sizes, 
  165 
  

  

  for 
  equilibrium 
  

  

  cm(l— 
  i)—c 
  l 
  m 
  2 
  i 
  2 
  

  

  :•:=■■ 
  r^=V- 
  -*»■ 
  ■• 
  • 
  • 
  • 
  •(') 
  

  

  1— 
  z 
  c 
  m 
  • 
  ■>-- 
  

  

  This 
  is 
  the 
  simple 
  mass-action 
  formula 
  which 
  Ostwald 
  found 
  

   to 
  be 
  true 
  for 
  over 
  200 
  weak 
  organic 
  acids 
  dissolved 
  in 
  water, 
  

   and 
  to 
  fail 
  completely 
  for 
  ordinary 
  binary 
  electrolytes. 
  Jt 
  is 
  

   to 
  be 
  noticed 
  that 
  the 
  solvent 
  is 
  supposed 
  to 
  exert 
  no 
  effect 
  

   except 
  in 
  so 
  far 
  as 
  it 
  influences 
  the 
  values 
  of 
  c 
  and 
  d 
  . 
  These 
  

   being 
  determined, 
  the 
  processes 
  of 
  dissociation 
  and 
  combina- 
  

   tion 
  are 
  supposed 
  to 
  go 
  on 
  as 
  if 
  the 
  solute 
  were 
  in 
  a 
  vacuum. 
  

   Recently 
  in 
  volume 
  xvii. 
  of 
  Zeit. 
  f. 
  pltys. 
  Chem. 
  Rudolphi 
  

   has 
  given 
  an 
  empirical 
  formula 
  for 
  the 
  ionization 
  of 
  an 
  ordinary 
  

   binary 
  electrolyte, 
  namely, 
  

  

  P/(l-i)=kvK 
  , 
  .. 
  (2) 
  

  

  which 
  in 
  vol. 
  xviii. 
  van't 
  Hoff 
  has 
  proposed 
  to 
  replace 
  by 
  

  

  *7(i->') 
  2 
  =fc', 
  (3) 
  

  

  as 
  perhaps 
  a 
  better 
  and 
  more 
  easily 
  interpreted 
  form. 
  In 
  

   vol. 
  xix. 
  Storch 
  uses 
  ip/(l—i) 
  = 
  kcP~ 
  l 
  , 
  where 
  p 
  like 
  k 
  is 
  a 
  

   parameter 
  varying 
  from 
  one 
  electrolyte 
  to 
  another. 
  Kohl- 
  

   rausch 
  (Beibl. 
  Ann. 
  d. 
  Ph. 
  xxv. 
  p. 
  35) 
  finds 
  

  

  l-l/iP=Jto-£ 
  (4) 
  

  

  to 
  be 
  an 
  accurate 
  empirical 
  formula 
  for 
  dilute 
  solutions 
  from 
  

   m 
  = 
  'l 
  to 
  m 
  = 
  -0001 
  (v=10 
  to 
  ?; 
  = 
  10 
  4 
  ). 
  

  

  All 
  these 
  formula? 
  are 
  empirical 
  and 
  applicable 
  only 
  to 
  

   dilute 
  solutions. 
  In 
  them 
  i 
  is 
  taken 
  to 
  be 
  given 
  by 
  the 
  ratio 
  

   of 
  the 
  specific 
  molecular 
  conductivity 
  of 
  the 
  solution 
  at 
  

   strength 
  m 
  to 
  that 
  at 
  infinitely 
  small 
  strength, 
  that 
  is 
  at 
  

   infinite 
  dilution. 
  Now, 
  no 
  stipulation 
  is 
  made 
  here 
  about 
  

   the 
  viscosity 
  of 
  solutions, 
  because 
  the 
  formula? 
  apply 
  only 
  to 
  

   dilutions 
  where 
  the 
  difference 
  of 
  the 
  viscosity 
  of 
  the 
  solution 
  

   from 
  that 
  of 
  pure 
  water 
  can 
  be 
  merged 
  in 
  the 
  experimental 
  

   errors 
  in 
  the 
  measurement 
  of 
  molecular 
  conductivity. 
  But 
  

   to 
  satisfactorily 
  investigate 
  dissociation 
  in 
  solutions 
  we 
  must 
  

   be 
  free 
  to 
  push 
  the 
  investigation 
  to 
  far 
  higher 
  strengths 
  than 
  

   hitherto, 
  in 
  fact 
  right 
  up 
  to 
  saturation, 
  and 
  therefore 
  we 
  must 
  

   take 
  account 
  of 
  the 
  effect 
  of 
  viscosity 
  on 
  conductivity. 
  It 
  

   has 
  been 
  argued 
  that 
  because 
  an 
  electrolyte 
  dissolved 
  in 
  a 
  

   stiff 
  jelly 
  has 
  nearly 
  the 
  same 
  conductivity 
  as 
  a 
  pure 
  aqueous 
  

   solution 
  of! 
  the 
  same 
  strength, 
  viscosity 
  can 
  be 
  of 
  little 
  

   importance; 
  but 
  it 
  is 
  obvious 
  that 
  the 
  correct 
  inference 
  is 
  

   that 
  in 
  the 
  jelly 
  the 
  water 
  is 
  so 
  immersed 
  in 
  the 
  gelatine 
  

  

  