﻿Van 
  Name 
  and 
  Hill 
  — 
  Alcohol 
  and 
  Cane 
  Sugar. 
  549 
  

  

  tends 
  to 
  weaken 
  confidence 
  in 
  the 
  mean 
  value 
  of 
  the 
  velocity 
  

   constant 
  as 
  a 
  proper 
  standard 
  for 
  comparing 
  different 
  experi- 
  

   ments. 
  We 
  have 
  therefore 
  preferred 
  to 
  use 
  values 
  determined 
  

   by 
  graphic 
  extrapolation. 
  The 
  corrected 
  velocity 
  constants 
  of 
  

   each 
  experiment 
  were 
  plotted 
  against 
  the 
  time 
  and 
  replaced 
  by 
  

   a 
  smooth 
  curve 
  in 
  the 
  form 
  of 
  a 
  line 
  of 
  very 
  slight 
  curvature, 
  

   convex 
  upward,* 
  which 
  was 
  then 
  extrapolated 
  back 
  to 
  time 
  

   zero. 
  The 
  value 
  of 
  the 
  constant 
  for 
  time 
  zero, 
  so 
  fixed, 
  has 
  

   been 
  taken 
  as 
  representative 
  of 
  the 
  experiment. 
  Although 
  

   this 
  method 
  fails 
  in 
  some 
  cases 
  to 
  give 
  sharp 
  results, 
  we 
  believe 
  

   that 
  in 
  general 
  the 
  extrapolated 
  values 
  represent 
  the 
  single 
  ex- 
  

   periments 
  more 
  accurately 
  than 
  the 
  averages 
  of 
  their 
  constants. 
  

  

  Table 
  IV. 
  

  

  Summary 
  of 
  Velocity 
  Constants. 
  

  

  K 
  observed 
  K 
  calculated 
  

  

  Average 
  Meau 
  of 
  by 
  

  

  Non-electrolyte 
  value 
  extrapolated 
  equation 
  of 
  

  

  values 
  Arrbenius 
  

  

  None 
  Ml 
  7-21 
  (7*21) 
  

  

  Alcohol, 
  1/4 
  molar 
  6'82 
  6'92 
  6*99 
  

  

  1/2 
  ." 
  ._ 
  6-53 
  6'67 
  6-77 
  

  

  " 
  1 
  " 
  5-99 
  6'12 
  6-34 
  

  

  " 
  2 
  " 
  5-16 
  5*24 
  5-53 
  

  

  " 
  3 
  " 
  4-35 
  4-41 
  4-78 
  

  

  Cane 
  Sugar, 
  1/32 
  m 
  6'80 
  6*87 
  707 
  

  

  " 
  1/16 
  " 
  0-61 
  6-69 
  6-94 
  

  

  " 
  " 
  1/8 
  " 
  .._ 
  6*25 
  6-30 
  6-67 
  

  

  " 
  " 
  1/4 
  " 
  5-52 
  5-56 
  6'15 
  

  

  " 
  " 
  l/'A 
  " 
  4-19 
  4-26 
  5-17 
  

  

  " 
  " 
  1 
  " 
  _. 
  2-28 
  ' 
  2-29 
  3-47 
  

  

  A 
  summary 
  of 
  the 
  measured 
  velocity 
  constants 
  is 
  given 
  in 
  

   Table 
  IV, 
  including 
  both 
  the 
  average 
  and 
  the 
  extrapolated 
  

   values. 
  For 
  reasons 
  given, 
  we 
  shall 
  base 
  all 
  further 
  calcula- 
  

   tions 
  upon 
  the 
  latter, 
  but 
  the 
  parallelism 
  between 
  the 
  two 
  sets 
  

   of 
  values 
  shows 
  that 
  this 
  choice 
  is 
  not 
  a 
  matter 
  of 
  much 
  impor- 
  

   tance, 
  as 
  the 
  general 
  nature 
  of 
  the 
  results 
  would 
  be 
  the 
  same 
  

   in 
  either 
  case. 
  

  

  In 
  the 
  last 
  column 
  of 
  Table 
  IV 
  are 
  constants 
  calculated 
  from 
  

   the 
  equation 
  of 
  Arrhenius, 
  using 
  the 
  values 
  a 
  = 
  0-124. 
  for 
  alco- 
  

   hol, 
  and 
  a 
  = 
  0*613 
  for 
  sugar. 
  These 
  two 
  values 
  were 
  obtained 
  

   by 
  averaging 
  (after 
  reducing 
  to 
  25°) 
  various 
  values 
  of 
  a 
  calcu- 
  

   lated 
  by 
  Arrhenius 
  f 
  both 
  from 
  his 
  own 
  diffusion 
  measure- 
  

  

  * 
  A 
  simple 
  calculation 
  sbows 
  tbat 
  tbe 
  constants 
  would 
  lie 
  on 
  a 
  curve 
  of 
  

   tbis 
  form 
  if 
  a 
  sligbt 
  oxidation 
  were 
  the 
  only 
  source 
  of 
  error. 
  

   f 
  Zeitschr. 
  pbys. 
  Chein., 
  x, 
  51, 
  1892. 
  

  

  