﻿550 
  Dr. 
  Meyer 
  Wildermau 
  on 
  Velocity 
  of 
  Molecular 
  

  

  every 
  letter 
  denotes 
  the 
  same 
  thing, 
  but 
  C 
  is 
  in 
  my 
  con- 
  

   ception 
  the 
  concentration 
  o£ 
  saturation 
  which 
  the 
  system 
  is 
  

   striving 
  to 
  reach, 
  owing 
  to 
  the 
  solution 
  in 
  contact 
  with 
  the 
  

   solid 
  being 
  unsaturated, 
  C/ 
  — 
  C 
  being 
  directly 
  proportional 
  to 
  

   the 
  force 
  driving 
  it 
  to 
  the 
  state 
  of 
  equilibrium, 
  while 
  Noyes 
  

   and 
  Whitney 
  assume 
  that 
  the 
  concentration 
  of 
  saturation 
  is 
  

   always 
  present 
  near 
  the 
  solid 
  salt, 
  while 
  the 
  concentration 
  of 
  

   the 
  rest 
  of 
  the 
  solution 
  is 
  entirely 
  another 
  one. 
  To 
  make, 
  

   however, 
  this 
  assumption 
  of 
  constant 
  saturation 
  at 
  a 
  surface 
  

   possible, 
  Bruner 
  and 
  Tolloczko 
  had 
  further 
  to 
  introduce 
  the 
  

   conception 
  of 
  infinite 
  speed 
  of 
  reaction 
  at 
  the 
  surface 
  of 
  the 
  

   solid, 
  while 
  following 
  them 
  Nernst 
  further 
  introduced 
  also 
  

   the 
  idea 
  of 
  " 
  infinitely 
  great 
  forces 
  acting 
  at 
  the 
  surface" 
  

   since 
  without 
  such 
  assumptions 
  the 
  above 
  explanation 
  cannot, 
  

   evidently, 
  be 
  upheld 
  ; 
  and 
  then 
  to 
  suit 
  the 
  idea 
  of 
  the 
  8 
  a 
  

   second 
  hypothesis 
  had 
  to 
  be 
  made, 
  by 
  Tolloczko 
  and 
  Bruner, 
  

   also 
  adopted 
  by 
  Nernst 
  and 
  Brunner, 
  that 
  the 
  solution 
  cannot 
  

   he 
  mixed 
  up 
  to 
  the 
  solid 
  itself 
  hut 
  the 
  mixing 
  stops 
  at 
  a 
  

   distance 
  from 
  the 
  solid. 
  Since 
  without 
  this 
  mysterious 
  

  

  property 
  we 
  get 
  from 
  y 
  = 
  K, 
  that 
  if 
  S 
  were 
  according 
  to 
  

  

  Noyes 
  and 
  Whitney 
  infinitely 
  small, 
  D, 
  or 
  the 
  diffusion 
  

   constants 
  as 
  calculated 
  from 
  this 
  equation, 
  would 
  only 
  prove 
  

   the 
  falsity 
  of 
  the 
  theory. 
  This 
  is 
  how 
  the 
  original 
  hypothesis 
  

   of 
  Noyes 
  and 
  Whitney, 
  which 
  seemed 
  to 
  be 
  very 
  simple, 
  

   grew 
  up 
  into 
  a 
  conglomerate 
  of 
  assumptions. 
  I 
  shall 
  now- 
  

   test, 
  step 
  by 
  step, 
  what 
  this 
  theory 
  and 
  all 
  its 
  assumptions 
  

   are 
  really 
  worth. 
  

  

  (a) 
  Let 
  us 
  now 
  first 
  see, 
  how 
  Noyes 
  and 
  Brunner 
  support 
  

   their 
  hypothesis, 
  following 
  in 
  all 
  essential 
  features 
  the 
  ideas 
  

   given 
  by 
  Bruner 
  and 
  Tolloczko. 
  About 
  the 
  first 
  Noyes 
  writes 
  : 
  

   "At 
  the 
  surface 
  of 
  contact 
  of 
  two 
  phases 
  (or 
  parts) 
  of 
  the 
  hetero- 
  

   geneous 
  system 
  equilibrium 
  is 
  extremely 
  quickly 
  established.'" 
  

   "This,'' 
  in 
  Nernst's 
  opinion, 
  "follows 
  already 
  a 
  priori 
  

   theoretically 
  as 
  a 
  necessity, 
  because 
  otherwise 
  noticeable 
  

   difference 
  of 
  the 
  chemical 
  potential 
  would 
  exist 
  at 
  the 
  

   separating 
  surface, 
  i. 
  e.^ 
  at 
  infinitely 
  near 
  points, 
  which 
  

   evidently 
  would 
  lead 
  to 
  infinitely 
  great 
  forces 
  and 
  velocities 
  of 
  

   reaction. 
  This, 
  however, 
  means 
  nothing 
  else 
  than 
  that 
  in 
  the 
  

   immediate 
  vicinity 
  of 
  the 
  two 
  surfaces 
  the 
  equilibrium 
  is 
  

   established 
  with 
  infinite 
  speed. 
  If 
  we 
  assume 
  what 
  is 
  more 
  

   nearly 
  true, 
  that 
  the 
  surface 
  of 
  separation 
  is 
  not 
  a 
  mathema- 
  

   tically 
  sharp 
  plane, 
  we 
  have 
  still 
  to 
  deal 
  with 
  dimensions 
  of 
  the 
  

   order 
  of 
  the 
  spheres 
  of 
  action 
  of 
  molecular 
  forces, 
  and 
  if 
  we 
  

   can 
  no 
  longer 
  speak 
  of 
  infinitely 
  great 
  velocities 
  of 
  reaction, 
  

   still 
  they 
  must 
  be 
  of 
  a 
  very 
  great 
  order, 
  which 
  practically 
  

  

  