﻿552 
  Dr. 
  Meyer 
  Wilderman 
  on 
  Velocity 
  of 
  Molecular 
  

  

  their 
  own 
  experiments 
  on 
  p. 
  ^2, 
  giving 
  the 
  variation 
  o£ 
  the 
  

   constant 
  A 
  with 
  temperature 
  — 
  the 
  only 
  experiments 
  which 
  

   ought 
  to 
  have 
  brought 
  some 
  support 
  to 
  their 
  assumptions 
  — 
  

   tend 
  to 
  support 
  t?ieir 
  views, 
  but 
  on 
  the 
  contrary 
  disprove 
  

   the 
  same. 
  The 
  equations 
  (3) 
  and 
  (4) 
  of 
  Nernst 
  and 
  Brunner 
  

   are 
  not 
  deduced 
  according 
  to 
  proved 
  conceptions, 
  but 
  are 
  

   nothing 
  else 
  than 
  a 
  graphical 
  adaptation 
  to 
  the 
  above 
  men- 
  

   tioned 
  conceptions, 
  which 
  became 
  unavoidable, 
  to 
  make 
  

   them 
  artificially 
  fit 
  into 
  a 
  known 
  equation. 
  But 
  as 
  Nernst 
  

   and 
  Brunner 
  admit, 
  that 
  it 
  is 
  impossible 
  to 
  assume 
  that 
  there 
  

   should 
  be 
  on 
  the 
  one 
  hand 
  a 
  layer 
  of 
  complete 
  rest, 
  where 
  

   the 
  equalization 
  takes 
  place 
  only 
  by 
  diffusion, 
  and 
  on 
  the 
  

   other 
  hand 
  a 
  layer 
  outside 
  the 
  same, 
  where 
  equalization 
  takes 
  

   place 
  only 
  by 
  convection 
  caused 
  by 
  the 
  stirring, 
  — 
  it 
  follows 
  

   from 
  this 
  that 
  even 
  if 
  Bruner 
  and 
  Tolloczko's, 
  Nernst 
  and 
  

   Brunner's 
  assumption 
  of 
  two 
  layers 
  be 
  made, 
  a 
  gradual 
  

   transformation 
  of 
  the 
  second 
  layer 
  into 
  the 
  first 
  under 
  a 
  

   gradual 
  diminution 
  of 
  convection 
  must 
  take 
  place 
  ; 
  the 
  straight 
  

   line 
  AB 
  is 
  therefore 
  arbitrary, 
  and 
  must 
  be 
  replaced 
  by 
  a 
  

   curve, 
  of 
  an 
  unknown 
  equation, 
  in 
  all 
  probability 
  by 
  a 
  

   logarithmic 
  curve, 
  and 
  the 
  value 
  D 
  is 
  not 
  CB, 
  but 
  a 
  value 
  which 
  

   may 
  be 
  considerably 
  greater 
  ; 
  and 
  the 
  whole 
  deduction 
  of 
  

   equation 
  4, 
  that 
  is 
  of 
  my 
  equation, 
  from 
  the 
  diffusion 
  con- 
  

   ceptions 
  is 
  arbitrary 
  : 
  the 
  strict 
  existence 
  of 
  my 
  equation 
  is, 
  

   in 
  my 
  opinion, 
  for 
  this 
  reason, 
  if 
  anything, 
  a 
  proof 
  that 
  their 
  

   conceptions 
  are 
  wrong, 
  not 
  that 
  they 
  are 
  right. 
  Moreover, 
  

   for 
  all 
  we 
  know, 
  there 
  is 
  no 
  reason 
  whatever 
  to 
  assume, 
  that 
  

   even 
  if 
  a 
  saturated 
  solution 
  be 
  formed 
  at 
  the 
  surface 
  of 
  the 
  

   solid, 
  this 
  should 
  not 
  form 
  only 
  an 
  infinitely 
  thin 
  film, 
  as 
  

   originally 
  assumed 
  byNoyes 
  and 
  Whitney, 
  that 
  this 
  film 
  should 
  

   not 
  be 
  of 
  the 
  size 
  of 
  the 
  sphere 
  of 
  a 
  molecule, 
  that 
  is 
  of 
  the 
  

   dimensions 
  10~^^ 
  mm. 
  instead 
  of 
  Nernst's 
  0*02 
  mm., 
  and 
  

   that 
  the 
  liquid 
  from 
  outside 
  this 
  film 
  should 
  not 
  enter 
  it, 
  

   2. 
  e. 
  should 
  not 
  reach 
  the 
  very 
  surface 
  of 
  the 
  solid 
  itself 
  

   diluting 
  the 
  same. 
  Indeed, 
  in 
  case 
  of 
  solidification 
  of 
  water 
  

   in 
  a 
  U-tube. 
  i. 
  e. 
  even 
  ivitliout 
  stirring, 
  the 
  water 
  reaches 
  the 
  

   ice 
  or 
  the 
  ice 
  the 
  water 
  to 
  a 
  proximity 
  of 
  about 
  10~^^ 
  mm. 
  — 
  

   why 
  should 
  this 
  not 
  be 
  the 
  case 
  with 
  the 
  liquid 
  in 
  contact 
  

   with 
  the 
  solid 
  especially 
  when 
  it 
  is 
  stirred 
  ? 
  The 
  very 
  value 
  

   calculated 
  by 
  Nernst 
  and 
  Brunner, 
  by 
  the 
  use 
  of 
  diffusion 
  

   constants, 
  for 
  ^^ 
  8 
  '^ 
  as 
  being 
  equal 
  to 
  '02 
  mm., 
  which 
  seems 
  

   to 
  them 
  " 
  as 
  very 
  probable/'' 
  seems 
  to 
  me 
  on 
  the 
  contrary 
  

   very 
  improbable, 
  in 
  view 
  of 
  the 
  results 
  obtained 
  for 
  solidi- 
  

   fication 
  of 
  water. 
  With 
  these 
  much 
  more 
  natural 
  assumptions 
  

   for 
  8j 
  &c., 
  their 
  deduction 
  of 
  equation 
  (4) 
  would 
  again 
  

   cease 
  to 
  hold 
  good, 
  and 
  the 
  actual 
  values 
  of 
  the 
  diffusion 
  

  

  