﻿Van 
  Name 
  and 
  Hill 
  — 
  Alcohol 
  and 
  Cane 
  Sugar. 
  553 
  

  

  ness 
  of 
  the 
  diffusion 
  layer 
  the 
  average 
  distance 
  from 
  the 
  sur- 
  

   face 
  of 
  the 
  solid 
  at 
  which 
  the 
  stirring 
  effect 
  of 
  the 
  eddies 
  and 
  

   cross-currents 
  prevailing 
  in 
  the 
  main 
  body 
  of 
  liquid 
  becomes 
  

   negligible. 
  The 
  relation 
  of 
  this 
  magnitude 
  to 
  the 
  viscosity 
  of 
  

   the 
  liquid 
  is 
  the 
  question 
  to 
  be 
  considered. 
  

  

  Table 
  VI. 
  

  

  Viscosity 
  and 
  Density 
  of 
  Solutions 
  at 
  25°. 
  

  

  Viscosity 
  Specific 
  Gravity 
  

   Coefficient 
  Water 
  at 
  25° 
  = 
  1 
  

  

  No 
  alcohol 
  or 
  sugar 
  0*00838 
  1-0606 
  

  

  Alcohol 
  1/4 
  molar 
  0-00903 
  1-0624 
  

  

  " 
  1/2 
  " 
  0-00942 
  T0592 
  

  

  " 
  1 
  " 
  0-01024 
  1-0552 
  

  

  " 
  2 
  " 
  , 
  0-01210 
  1-0478 
  

  

  " 
  3 
  " 
  0*01410 
  1-0416 
  

  

  Cane 
  sugar 
  1/32 
  molar 
  00889 
  1-0675 
  

  

  '. 
  " 
  " 
  1/16 
  " 
  0-00911 
  1-0717 
  

  

  " 
  " 
  1/8 
  " 
  0-00967 
  1-0799 
  

  

  " 
  " 
  1/4 
  " 
  001090 
  1-0963 
  

  

  " 
  " 
  1/2 
  '< 
  0-01521 
  1-1368 
  

  

  " 
  " 
  1 
  " 
  .... 
  _. 
  0-03272 
  1-2103 
  

  

  The 
  strict 
  mathematical 
  treatment 
  of 
  problems 
  in 
  viscosity, 
  

   in 
  all 
  but 
  the 
  simplest 
  cases, 
  offers 
  serious 
  difficulties, 
  and 
  

   would 
  do 
  so 
  in 
  the 
  present 
  instance. 
  On 
  purely 
  logical 
  

   grounds, 
  however, 
  it 
  seems 
  almost 
  certain 
  that 
  an 
  increase 
  in 
  

   viscosity, 
  other 
  factors 
  remaining 
  unchanged, 
  would 
  hinder 
  

   the 
  propagation 
  of 
  the 
  eddies 
  above 
  referred 
  to, 
  and 
  would 
  

   thus 
  produce 
  an 
  increase 
  in 
  the 
  thickness 
  of 
  the 
  diffusion 
  layer. 
  

   In 
  reality, 
  a 
  change 
  in 
  the 
  viscosity 
  of 
  a 
  liquid 
  usually 
  involves 
  

   an 
  appreciable 
  change 
  in 
  its 
  density, 
  and 
  an 
  increase 
  in 
  den- 
  

   sity, 
  with 
  the 
  resulting 
  increase 
  in 
  the 
  momentum 
  of 
  the 
  mov- 
  

   ing 
  liquid, 
  should 
  tend 
  to 
  make 
  the 
  eddies 
  more 
  persistent, 
  

   thus 
  acting, 
  so 
  far 
  as 
  its 
  effect 
  was 
  appreciable, 
  in 
  a 
  direction 
  

   opposite 
  to 
  that 
  of 
  an 
  increase 
  in 
  viscosity. 
  As 
  a 
  rule, 
  how- 
  

   ever, 
  the 
  change 
  in 
  density 
  would 
  be 
  small 
  compared 
  with 
  the 
  

   change 
  in 
  viscosity, 
  and 
  probably 
  of 
  minor 
  importance. 
  

  

  Alcohol 
  in 
  our 
  experiments 
  raised 
  the 
  viscosity 
  and 
  lowered 
  

   the 
  density 
  of 
  the 
  0*5 
  molar 
  potassium 
  iodide 
  solution 
  

   employed. 
  Cane 
  sugar 
  raised 
  the 
  viscosity 
  by 
  a 
  large 
  and 
  the 
  

   density 
  by 
  a 
  relatively 
  small 
  amount, 
  an 
  increase 
  of 
  280 
  per 
  

   cent 
  in 
  the 
  former 
  corresponding 
  to 
  an 
  increase 
  of 
  14 
  per 
  cent 
  

   in 
  the 
  latter. 
  Both 
  are 
  clearly 
  cases 
  where 
  an 
  increase 
  rather 
  

   than 
  a 
  decrease 
  in 
  the 
  thickness 
  of 
  the 
  diffusion 
  layer 
  would 
  be 
  

   expected. 
  Such 
  an 
  effect 
  would 
  be 
  in 
  the 
  right 
  direction 
  to 
  

   explain 
  the 
  fact 
  that 
  the 
  depression, 
  of 
  the 
  reaction 
  velocity 
  is 
  

  

  