﻿44 
  

  

  Determination 
  of 
  a 
  Constant 
  in 
  Capillarity, 
  

  

  M=:5-57xl0-i. 
  

  

  

  Tc. 
  

  

  pc. 
  

  

  •2604 
  

   •3489 
  

   •5576 
  

   •3045 
  

   •3654 
  

  

  on. 
  

  

  KIO^ 
  

  

  mUm^l^pc^'^ 
  

   Tc 
  

  

  20-4 
  

  

  22-2 
  

  

  36-4 
  

  

  19-2 
  

  

  21-7 
  

  

  Ether 
  

  

  466-6 
  

  

  487 
  

  

  556 
  

  

  561-5 
  

  

  633 
  

  

  74 
  

  

  60 
  

   153-8 
  

  

  78-05 
  

   112-5 
  

  

  20-5 
  

   21-2 
  

   38-1 
  

   19-5 
  

   21-2 
  

  

  Methyl 
  formate 
  

  

  Carbon 
  tetrachlori 
  de 
  ... 
  

   Benzene 
  

  

  Chloro-benzene 
  

  

  

  The 
  value 
  of 
  K 
  given 
  by 
  equation 
  (4) 
  will 
  not 
  apply 
  to 
  

   polymerized 
  liquids 
  because 
  the 
  value 
  o£ 
  A 
  is 
  then 
  not 
  a 
  

   constant, 
  but 
  varies 
  with 
  the 
  nature 
  of 
  the 
  liquid 
  and 
  its 
  

   temperature. 
  It 
  is 
  also 
  very 
  probable 
  that 
  the 
  relation 
  given 
  

   by 
  Whittaker 
  does 
  not 
  apply 
  to 
  such 
  liquids. 
  

  

  If 
  the 
  critical 
  density 
  and 
  temperature 
  of 
  a 
  liquid 
  is 
  known, 
  

   and 
  its 
  capillary 
  constants 
  for 
  temperatures 
  differing 
  by 
  a 
  

   small 
  interval, 
  the 
  internal 
  latent 
  heat 
  can 
  be 
  calculated 
  for 
  

   these 
  temperatures 
  by 
  the 
  equation 
  

  

  VT 
  "" 
  dn) 
  m^'pc'l^ 
  5-57 
  x 
  lO-^' 
  

  

  deduced 
  from 
  the 
  equations 
  (1), 
  (2), 
  and 
  (5). 
  An 
  inspection 
  

  

  of 
  Whittaker's 
  results 
  shows 
  that 
  K 
  or 
  -pp 
  is 
  very 
  constant 
  

  

  for 
  different 
  temperatures, 
  and 
  this 
  equation 
  would 
  therefore 
  

   give 
  fairly 
  accurate 
  results. 
  

  

  If 
  a 
  large 
  number 
  of 
  determinations 
  of 
  \ 
  for 
  different 
  

  

  temperatures 
  are 
  not 
  available, 
  the 
  values 
  of 
  X 
  and 
  -^ 
  in 
  the 
  

  

  above 
  equation 
  may 
  be 
  obtained 
  from 
  equation 
  (2), 
  the 
  

  

  constants 
  in 
  the 
  equation 
  having 
  first 
  been 
  determined 
  by 
  

  

  means 
  of 
  the 
  values 
  of 
  X 
  for 
  two 
  different 
  temperatures 
  . 
  This, 
  

  

  however, 
  will 
  not 
  give 
  very 
  accurate 
  values 
  for 
  L. 
  

  

  Equation 
  (5), 
  by 
  writing 
  it 
  in 
  the 
  form 
  

  

  E^ 
  __ 
  Mm'i^p.^ 
  ro 
  

  

  LT-- 
  T, 
  ' 
  

  

  maybe 
  used 
  to 
  find 
  either 
  of 
  the 
  critical 
  constants 
  it 
  contains 
  

   if 
  one 
  of 
  them 
  is 
  known. 
  The 
  right-hand 
  side 
  may 
  be 
  

   evaluated 
  for 
  any 
  convenient 
  temperature. 
  

   Cambridge, 
  March 
  20, 
  1909. 
  

  

  