﻿544: 
  Van 
  Name 
  and 
  Rill 
  — 
  Alcohol 
  and 
  Cane 
  Sugar. 
  

  

  factor. 
  The 
  present 
  article 
  gives 
  the 
  results 
  of 
  a 
  study 
  of 
  the 
  

   effects 
  of 
  ethyl 
  alcohol 
  and 
  of 
  cane 
  sugar 
  at 
  different 
  concen- 
  

   trations 
  upon 
  the 
  velocity 
  of 
  the 
  reaction 
  between 
  iodine 
  and 
  

   cadmium. 
  Not 
  only 
  is 
  this 
  reaction 
  especially 
  suitable 
  for 
  the 
  

   purpose 
  on 
  account 
  of 
  the 
  accuracy 
  of 
  the 
  iodine 
  titration, 
  but 
  

   it 
  possesses 
  the 
  great 
  advantage 
  over 
  those 
  used 
  by 
  the 
  investi- 
  

   gators 
  just 
  mentioned 
  that 
  no 
  gas 
  is 
  evolved. 
  

  

  The 
  last 
  point 
  is 
  of 
  special 
  importance. 
  Since 
  an 
  evolution 
  

   of 
  gas 
  must 
  rupture 
  the 
  diffusion 
  layer 
  and 
  stir 
  it 
  to 
  some 
  

   extent 
  with 
  the 
  escape 
  of 
  each 
  gas-bubble, 
  the 
  velocity 
  of 
  such 
  

   a 
  reaction 
  is 
  by 
  no 
  means 
  as 
  strictly 
  dependent 
  upon 
  the 
  rate 
  

   of 
  diffusion 
  as 
  when 
  no 
  gas 
  is 
  given 
  off. 
  The 
  number 
  and 
  dis- 
  

   tribution 
  of 
  the' 
  points 
  of 
  bubble 
  formation, 
  for 
  example, 
  are 
  

   important 
  factors 
  over 
  which 
  the 
  experimenter 
  has 
  little 
  or 
  no 
  

   control. 
  Reactions 
  in 
  which 
  gases 
  are 
  evolved 
  are, 
  therefore, 
  

   poorly 
  adapted 
  for 
  quantitative 
  tests 
  of 
  the 
  diffusion 
  theory, 
  a 
  

   fact 
  which 
  has 
  not 
  thus 
  far 
  received 
  the 
  attention 
  which 
  it 
  

   deserves. 
  

  

  The 
  apparatus 
  and 
  procedure 
  were 
  practically 
  identical 
  with 
  

   those 
  employed 
  by 
  Yan 
  Name 
  and 
  Bosworth. 
  In 
  brief, 
  it 
  con- 
  

   sisted 
  in 
  subjecting 
  to 
  the 
  action 
  of 
  the 
  violently 
  stirred 
  iodine 
  

   solution 
  circular 
  disks 
  of 
  cadmium, 
  38'3 
  mm 
  in 
  diameter 
  and 
  

   0.5mm 
  thick, 
  which 
  were 
  held 
  in 
  an 
  accurately 
  fixed 
  position 
  

   relative 
  to 
  the 
  stirrer 
  and 
  to 
  the 
  wall 
  of 
  the 
  containing 
  beaker. 
  

   The 
  velocity 
  constants 
  were 
  calculated 
  from 
  the 
  equation 
  

  

  K 
  = 
  2*3 
  — 
  log 
  —, 
  in 
  which 
  v 
  is 
  the 
  volume 
  of 
  the 
  solu- 
  

  

  tion, 
  and 
  c, 
  and 
  c 
  2 
  the 
  concentrations 
  of 
  iodine 
  (determined 
  by 
  

   titration) 
  at 
  the 
  beginning 
  and 
  end 
  of 
  the 
  time 
  interval 
  £ 
  2 
  — 
  £,, 
  

   (usually 
  ten 
  minutes 
  in 
  length). 
  All 
  solutions 
  were 
  0*5 
  molar 
  

   with 
  respect 
  to 
  potassium 
  iodide, 
  and 
  either 
  O'Ol 
  or 
  0M)0l 
  

   molar 
  with 
  respect 
  to 
  sulphuric 
  acid, 
  the 
  lower 
  acidity 
  being 
  

   used 
  when 
  cane 
  sugar 
  was 
  present. 
  The 
  temperature 
  was 
  

   25° 
  ± 
  (Vl°, 
  and 
  the 
  rate 
  of 
  stirring 
  200 
  revolutions 
  per 
  minute. 
  

   Except 
  where 
  otherwise 
  stated, 
  all 
  details 
  of 
  the 
  manipulation 
  

   were 
  the 
  same 
  as 
  given 
  in 
  the 
  article 
  just 
  cited. 
  The 
  method 
  

   there 
  described 
  for 
  determining 
  and 
  applying 
  corrections 
  for 
  

   the 
  slight 
  variations 
  in 
  the 
  rate 
  of 
  stirring 
  has 
  been 
  systemati- 
  

   cally 
  employed 
  in 
  the 
  present 
  work, 
  although 
  it 
  was 
  again 
  found 
  

   that 
  in 
  most 
  cases 
  the 
  corrections 
  had 
  a 
  negligible 
  effect 
  upon 
  

   the 
  final 
  result. 
  Since 
  the 
  very 
  full 
  data 
  given 
  for 
  some 
  of 
  

   the 
  experiments 
  in 
  the 
  former 
  paper 
  will 
  serve 
  to 
  illustrate 
  all 
  

   essential 
  points 
  in 
  the 
  calculations, 
  we 
  shall 
  in 
  general 
  give 
  

   in 
  this 
  paper 
  only 
  the 
  final 
  corrected 
  series 
  of 
  velocity 
  con- 
  

   stants 
  obtained 
  in 
  each 
  experiment. 
  

  

  in 
  the 
  experiments 
  in 
  which 
  ethyl 
  alcohol 
  was 
  present, 
  evap- 
  

   oration 
  from 
  the 
  solution 
  was 
  often 
  much 
  increased, 
  making 
  

  

  1 
  

  

  