﻿552 
  Van 
  Name 
  and 
  Rill 
  — 
  Alcohol 
  and 
  Cane 
  Sugar. 
  

  

  Table 
  V. 
  

  

  K 
  obs. 
  a 
  calo. 
  K 
  calc. 
  

   a 
  = 
  0'144 
  

  

  No 
  alcohol 
  ov 
  sugar 
  7*21 
  

  

  Alcohol 
  1/4 
  molar 
  ' 
  6'92 
  0-163 
  6 
  95 
  

  

  " 
  1/2 
  " 
  6-67 
  0-152 
  6-71 
  

  

  " 
  1 
  " 
  ._ 
  6*12 
  0-157 
  6-19 
  

  

  " 
  2 
  " 
  5-24 
  0-147 
  5-28 
  

  

  " 
  3 
  " 
  4-41 
  144 
  (4-41) 
  

  

  K 
  calc. 
  

   a 
  = 
  0-925 
  

  

  Cane 
  sugar 
  1/32 
  molar 
  6*87 
  153 
  7'00 
  

  

  " 
  " 
  1/16 
  " 
  -.. 
  6-69 
  1-18 
  6'80 
  

  

  " 
  " 
  1/8 
  " 
  6*30 
  1-04 
  6-40 
  

  

  " 
  " 
  1/4 
  " 
  5'56 
  0-975 
  5'64 
  

  

  " 
  1/2 
  " 
  .. 
  4-26 
  925 
  (4'26) 
  

  

  " 
  " 
  1 
  " 
  2-29 
  0-872 
  2*08 
  

  

  good 
  as 
  any. 
  This, 
  of 
  course, 
  only 
  confirms 
  what 
  was 
  clearly 
  

   indicated 
  by 
  the 
  nature 
  and 
  magnitude 
  of 
  the 
  variation 
  in 
  the 
  

   calculated 
  values 
  of 
  a. 
  

  

  In 
  short, 
  the 
  effect 
  of 
  cane 
  sugar 
  upon 
  the 
  rate 
  of 
  solution 
  

   of 
  cadmium 
  appears 
  to 
  be 
  larger, 
  and 
  to 
  increase 
  less 
  rapidly 
  

   with 
  the 
  concentration, 
  than 
  is 
  called 
  for 
  by 
  Arrhenius' 
  equa- 
  

   tion, 
  while 
  with 
  alcohol 
  the 
  deviations 
  from 
  the 
  equation 
  are 
  

   small 
  but 
  probably 
  of 
  the 
  same 
  nature. 
  

  

  These 
  deviations 
  can 
  easily 
  be 
  explained 
  if 
  we 
  admit 
  that 
  a 
  

   change 
  in 
  the 
  viscosity, 
  under 
  otherwise 
  constant 
  conditions, 
  

   may 
  alter 
  not 
  only 
  the 
  rate 
  of 
  diffusion 
  bat 
  also 
  the 
  thickness 
  of 
  

   the 
  diffusion 
  layer, 
  the 
  latter 
  effect 
  being, 
  of 
  course, 
  one 
  of 
  

   which 
  Arrhenius' 
  equation 
  takes 
  no 
  account. 
  As 
  Table 
  Yl 
  

   shows, 
  both 
  alcohol 
  and 
  sugar 
  raised 
  the 
  viscosity 
  of 
  the 
  

   potassium 
  iodide 
  solution 
  used. 
  

  

  In 
  considering 
  this 
  hypothesis 
  we 
  wish 
  to 
  oppose 
  the 
  view 
  

   sometimes 
  taken 
  that 
  the 
  diffusion 
  layer 
  consists 
  of 
  liquid 
  

   which, 
  relatively 
  to 
  the 
  dissolving 
  solid, 
  is 
  nearly 
  or 
  wholly 
  at 
  

   rest. 
  On 
  the 
  contrary, 
  it 
  is 
  probable 
  that 
  its 
  outer 
  portions 
  

   possess 
  a 
  very 
  considerable 
  motion 
  relative 
  to 
  the 
  solid, 
  

   but 
  only 
  in 
  a 
  plane 
  essentially 
  parallel 
  to 
  the 
  surface 
  of 
  

   the 
  latter, 
  and, 
  therefore, 
  normal 
  to 
  the 
  direction 
  of 
  the 
  

   concentration 
  slope, 
  so 
  that 
  the 
  rate 
  at 
  which 
  dissolved 
  

   material 
  is 
  transported 
  across 
  the 
  diffusion 
  layer 
  is 
  not 
  materi- 
  

   ally 
  affected 
  by 
  the 
  motion 
  of 
  the 
  liquid 
  layer 
  itself. 
  The 
  

   thickness 
  of 
  this 
  layer 
  is 
  not 
  necessarily 
  constant 
  at 
  a 
  given 
  

   point 
  on 
  the 
  surface 
  of 
  the 
  solid, 
  but 
  is 
  more 
  probably 
  subject 
  

   to 
  periodic 
  variations 
  dependent 
  upon 
  the 
  passage 
  of 
  the 
  blades 
  

   of 
  the 
  stirrer. 
  We 
  are, 
  therefore, 
  to 
  understand 
  as 
  the 
  thick- 
  

  

  