﻿Forces 
  produced 
  by 
  Flowing 
  Solutions. 
  

  

  601 
  

  

  Solution. 
  

   KCl 
  

  

  Concentration. 
  

  

  A. 
  

  

  B. 
  

  

  C. 
  

  

  Temp. 
  

  

  E3. 
  

  

  E2. 
  

  

  N/2000 
  

  

  482 
  

   905 
  

  

  238 
  

   447 
  

  

  0-050 
  

  

  19° 
  

  

  +0-001 
  

  

  +0-360 
  

   0-684 
  

  

  ■ 
  1 
  

  

  Solution. 
  1 
  Eg. 
  

  

  E,. 
  

  

  llK. 
  

  

  -Eiooo'f- 
  

  

  (At 
  -0a. 
  

  

  KCl 
  +0016 
  +0-352+4% 
  

  

  i 
  0-ft7fi 
  + 
  2o„ 
  

  

  0-3065x105 
  

  

  4-82x10-5 
  

   4-93 
  

  

  4-73+4% 
  

   4-84-1- 
  5> 
  0/^ 
  

  

  

  

  

  

  

  

  

  

  

  

  Discussion 
  of 
  Results. 
  

  

  The 
  experiments 
  just 
  described 
  lead 
  to 
  the 
  conclusion 
  that 
  

   Helmholtz^s 
  and 
  Dorn's 
  value 
  o£ 
  five 
  volts 
  for 
  the 
  potential 
  

   difference 
  between 
  glass 
  and 
  water 
  is 
  correct, 
  and 
  that 
  when 
  

   the 
  liquid 
  is 
  made 
  acid 
  or 
  alkaline 
  the 
  change 
  is 
  of 
  the 
  order 
  

   of 
  half 
  a 
  volt 
  to 
  the 
  negative 
  side 
  in 
  the 
  first 
  and 
  to 
  the 
  

   positive 
  side 
  in 
  the 
  second 
  case, 
  the 
  sign 
  always 
  applying 
  

   to 
  the 
  liquid. 
  If 
  this 
  change 
  is 
  compared 
  with 
  the 
  theory- 
  

   quoted 
  in 
  the 
  beginning 
  of 
  this 
  paper, 
  and 
  if 
  the 
  smallness 
  of 
  

   the 
  acidity 
  and 
  alkalinity 
  is 
  borne 
  in 
  mind, 
  it 
  is 
  found 
  that 
  

   the 
  sign 
  of 
  the 
  change 
  is 
  the 
  expected 
  one, 
  but 
  that 
  the 
  mag- 
  

   nitude 
  is 
  three 
  times 
  larger 
  than 
  the 
  theory 
  predicts. 
  The 
  

   supposition 
  is 
  suggested 
  that 
  an 
  influence 
  comes 
  into 
  play 
  

   which 
  enlarges 
  all 
  the 
  values 
  three 
  times. 
  Such 
  a 
  decrease 
  

   would 
  bring 
  the 
  value 
  of 
  the 
  glass-water 
  potential, 
  as 
  well 
  as 
  

   that 
  of 
  the 
  acid-alkali 
  change 
  at 
  the 
  glass, 
  to 
  the 
  magnitudes 
  

   to 
  be 
  expected. 
  The 
  Helmholtz 
  theory 
  does 
  not 
  allow 
  for 
  

   such 
  a 
  factor. 
  We 
  are 
  therefore 
  led 
  to 
  look 
  for 
  some 
  inter- 
  

   fering 
  phenomenon. 
  

  

  Knoblauch 
  *, 
  Perrin 
  t, 
  and 
  Freundlich 
  and 
  Makelt 
  have 
  

   found 
  facts 
  which 
  seem 
  to 
  have 
  an 
  important 
  bearing 
  on 
  this 
  

   question. 
  Perrin 
  especially, 
  in 
  an 
  electro-osmotic 
  investi- 
  

   gation 
  with 
  powdered 
  materials, 
  as, 
  for 
  example, 
  chromic 
  

   chloride, 
  and 
  carborundum, 
  found 
  that 
  the 
  direction 
  of 
  the 
  

   osmosis 
  and 
  therefore 
  the 
  sign 
  of 
  the 
  charge 
  at 
  the 
  surface 
  of 
  

   the 
  powdered 
  insulating 
  material, 
  always 
  changed 
  at 
  the 
  

   neutral 
  point, 
  the 
  liquid 
  becoming 
  positive 
  if 
  alkali 
  and 
  

   negative 
  if 
  acid. 
  From 
  his 
  results 
  it 
  must 
  be 
  concluded 
  that 
  

   pure 
  water 
  does 
  not 
  show 
  any 
  potential 
  difference 
  against 
  the 
  

   most 
  different 
  insulators. 
  This 
  view 
  is 
  in 
  striking 
  contrast 
  

  

  * 
  Zeitschr. 
  f.phys. 
  Chem. 
  xxxix. 
  p. 
  225 
  (1902). 
  

  

  t 
  J. 
  de 
  chhn. 
  phys. 
  ii. 
  p. 
  601 
  (1904) 
  ; 
  iii. 
  p. 
  50 
  (1905). 
  

  

  Phil. 
  Mag. 
  S. 
  6. 
  Yol. 
  18. 
  No. 
  106. 
  Oct. 
  1909. 
  2 
  S 
  

  

  