﻿Forces 
  produced 
  hy 
  Flowing 
  Solutions, 
  593 
  

  

  The 
  tube 
  Avas 
  rinsed 
  out 
  with 
  chromic 
  acid 
  mixture, 
  the 
  end 
  

   h 
  joined 
  to 
  the 
  flask, 
  and 
  water 
  forced 
  through 
  at 
  different 
  

   pressures. 
  

  

  Three 
  difficulties 
  prevent 
  an 
  exact 
  agreement 
  between 
  the 
  

   results 
  obtained 
  and 
  the 
  theory. 
  The 
  first 
  arises 
  from 
  the 
  

   fact 
  that 
  the 
  introduction 
  of 
  the 
  electrodes 
  disturbs 
  the 
  flow 
  

   of 
  liquid, 
  both 
  through 
  the 
  electrodes 
  themselves, 
  and 
  from 
  

   the 
  unavoidable 
  distortion 
  of 
  the 
  glass 
  capillary 
  at 
  the 
  point 
  

   of 
  insertion. 
  Whether 
  we 
  neglect 
  this 
  disturbing 
  influence, 
  

   consider 
  the 
  space 
  round 
  the 
  electrodes 
  as 
  a 
  normal 
  capillary, 
  

   and 
  measure 
  the 
  actual 
  distance 
  from 
  electrode 
  to 
  electrode, 
  

   or 
  whether 
  we 
  neglect 
  the 
  distorted 
  spaces 
  themselves, 
  

   assuming 
  that 
  there 
  is 
  no 
  effect 
  within 
  them, 
  and 
  measure 
  

   the 
  distances 
  between 
  the 
  beginning 
  and 
  end 
  of 
  the 
  undis- 
  

   torted 
  capillary 
  system, 
  we 
  shall 
  always 
  make 
  a 
  certain 
  error. 
  

   It 
  was 
  thought 
  that 
  the 
  error 
  might 
  be 
  less 
  if 
  the 
  second 
  

   assumption 
  were 
  followed. 
  

  

  The 
  second 
  difficulty 
  arises 
  from 
  the 
  fact 
  that, 
  according 
  

   to 
  the 
  results 
  found 
  formerly 
  by 
  Dorn 
  and 
  Clark, 
  the 
  effects 
  

   obtained 
  are 
  dependent 
  on 
  time. 
  Clark 
  found 
  that 
  when 
  a 
  

   tube 
  was 
  rinsed 
  with 
  concentrated 
  sulphuric 
  acid 
  and 
  then 
  

   distilled 
  water, 
  and 
  then 
  water 
  forced 
  through 
  it 
  continuously 
  

   for 
  many 
  hours^ 
  a 
  decrease 
  in 
  the 
  electromotive 
  force 
  was 
  

   obtained 
  invariably, 
  which 
  amounted 
  in 
  some 
  cases 
  to 
  as 
  

   much 
  as 
  25 
  per 
  cent. 
  On 
  recleaning 
  the 
  tube 
  the 
  original 
  

   value 
  was 
  regained. 
  Dorn's 
  results 
  were 
  not 
  so 
  regular. 
  

   He 
  obtained 
  both 
  decreases 
  and 
  increases 
  of 
  voltage 
  with 
  

   lapse 
  of 
  time 
  ; 
  these 
  were 
  connected 
  apparently 
  with 
  the 
  

   method 
  used 
  to 
  cleanse 
  the 
  tube. 
  

  

  The 
  last 
  point 
  of 
  uncertainty 
  comes 
  into 
  the 
  results 
  from 
  

   the 
  calculation 
  of 
  the 
  actual 
  pressures 
  existing 
  between 
  the 
  

   electrodes. 
  We 
  know 
  the 
  total 
  pressure 
  applied. 
  This 
  is 
  

   not 
  entirely 
  used 
  up 
  in 
  the 
  tube. 
  With 
  pressures 
  of 
  half 
  an 
  

   atmosphere 
  or 
  more 
  the 
  liquid 
  does 
  not 
  escape 
  in 
  drops 
  from 
  

   the 
  tube, 
  but 
  forms 
  a 
  ray 
  possessing 
  kinetic 
  energy 
  corre- 
  

   sponding 
  to 
  a 
  certain 
  pressure, 
  so 
  that 
  the 
  drop 
  of 
  pressure 
  

   in 
  the 
  tube 
  is 
  less 
  than 
  the 
  difference 
  of 
  applied 
  pressure 
  to 
  

   atmospheric 
  pressure. 
  Moreover, 
  every 
  exit 
  from 
  and 
  

   entrance 
  into 
  an 
  electrode 
  space 
  causes 
  the 
  formation 
  of 
  

   eddies, 
  and 
  in 
  any 
  case 
  a 
  slight 
  drop 
  of 
  pressure 
  exists 
  even 
  

   in 
  the 
  non-capillary 
  portions 
  of 
  the 
  tube. 
  Being 
  unable 
  to 
  

   state 
  the 
  amount 
  of 
  these 
  losses, 
  we 
  calculated 
  on 
  the 
  as- 
  

   sumption 
  that 
  the 
  applied 
  pressure 
  was 
  entirely 
  used 
  up 
  in 
  

   the 
  five 
  capillary 
  stretches, 
  the 
  dimensions 
  of 
  which 
  have 
  

   been 
  given 
  *. 
  The 
  amount 
  of 
  pressure 
  used 
  up 
  in 
  each 
  portion 
  

   * 
  The 
  combined 
  length 
  of 
  the 
  three 
  electrode 
  spaces 
  was 
  12 
  mm. 
  

  

  