﻿Recalculation 
  of 
  the 
  Vapour 
  Pressure 
  of 
  Mercury. 
  789 
  

  

  e 
  is 
  the 
  thermoelectric 
  force 
  of 
  the 
  element 
  copper-platinum 
  

   for 
  a 
  difference 
  of 
  temperature 
  of 
  1 
  degree. 
  

  

  e 
  = 
  0-72 
  . 
  10- 
  5 
  . 
  10 
  8 
  absolute 
  units. 
  

   e 
  2 
  = 
  0-52. 
  10 
  6 
  , 
  

  

  , 
  273. 
  0-52. 
  10 
  6 
  1KO 
  1ft 
  , 
  kl 
  . 
  

  

  &) 
  = 
  p— 
  ^ 
  — 
  r^ 
  — 
  — 
  - 
  r 
  = 
  lD'2 
  . 
  10 
  1 
  absolute 
  unit, 
  

  

  o/ 
  = 
  1-52 
  . 
  10~ 
  9 
  ohm. 
  

  

  The 
  mean 
  electric 
  conductivity 
  of 
  the 
  alloy 
  is 
  found 
  to 
  be* 
  

   3*09 
  . 
  10 
  4 
  ; 
  the 
  specific 
  electric 
  resistance 
  would 
  be 
  

  

  a) 
  = 
  0-323 
  . 
  10- 
  4 
  . 
  

  

  Considering 
  the 
  alloy 
  as 
  a 
  single 
  mixture 
  we 
  should 
  find 
  

  

  i(10-8 
  + 
  1'6) 
  . 
  10" 
  6 
  =0-062 
  . 
  10- 
  4 
  

  

  The 
  false 
  resistance 
  is 
  in 
  these 
  cases 
  far 
  too 
  small 
  to 
  

   explain 
  the 
  difference 
  between 
  the 
  observed 
  and 
  the 
  calculated 
  

   value 
  of 
  the 
  resistance 
  of 
  the 
  alloys. 
  This 
  result 
  may 
  partly 
  

   explain 
  why 
  Dr. 
  R. 
  S. 
  Willows 
  f 
  could 
  detect 
  no 
  difference 
  

   between 
  the 
  apparent 
  resistances 
  of 
  alloys 
  with 
  direct 
  current 
  

   and 
  with 
  alternating 
  current. 
  

  

  An 
  alloy 
  of 
  equal 
  volumes 
  of 
  copper 
  and 
  iron 
  has 
  a 
  false 
  

   resistance 
  amounting 
  to 
  1*5 
  per 
  cent, 
  of 
  that 
  of 
  copper. 
  

  

  Cambridge, 
  April 
  6th, 
  1908. 
  

  

  LXVI. 
  A 
  Recalculation 
  of 
  the 
  Vapour 
  Pressure 
  of 
  Mercury. 
  

   By 
  T. 
  H. 
  Labt, 
  B. 
  A., 
  Exhibition 
  of 
  1851 
  Research 
  Scholar, 
  

   Joule 
  Student 
  of 
  the 
  Royal 
  Society, 
  Emmanuel 
  College, 
  

   Cambridge* 
  . 
  

  

  THE 
  vapour-pressure 
  of 
  mercury 
  is 
  intrinsically 
  important: 
  

   it 
  has 
  been 
  determined 
  for 
  a 
  wider 
  range 
  of 
  temperatures 
  

   than 
  that 
  of 
  any 
  other 
  substance 
  ; 
  and 
  Professor 
  Nernst 
  hopes 
  

   to 
  be 
  able 
  to 
  find 
  the 
  integration 
  constant 
  of 
  the 
  equation 
  of 
  the 
  

   reaction 
  isochore 
  " 
  by 
  continuing 
  the 
  vapour-pressure 
  curves 
  

   as 
  far 
  as 
  possible 
  in 
  the 
  direction 
  of 
  very 
  small 
  pressures, 
  for 
  

   example 
  to 
  *001 
  mm." 
  § 
  Yet 
  the 
  greatest 
  — 
  and 
  it 
  should 
  be 
  

   added, 
  unnecessary 
  — 
  disagreement 
  is 
  to 
  be 
  found 
  in 
  the 
  

   current 
  values 
  of 
  this 
  vapour-pressure, 
  nor 
  is 
  there 
  any 
  table 
  

  

  * 
  Landolt-Bdrnstein 
  Physikalish-chemische 
  Tabellen, 
  3 
  Auflage, 
  p. 
  721a. 
  

   t 
  E. 
  S. 
  Willows, 
  'Proceedings 
  of 
  the 
  Physical 
  Society 
  of 
  London/ 
  

   vol. 
  xx. 
  p. 
  427 
  (1907). 
  

  

  % 
  Communicated 
  by 
  the 
  Author. 
  

  

  § 
  Nernst, 
  ' 
  Thermodynamics 
  and 
  Chemistry/ 
  New 
  York, 
  1907, 
  p, 
  60. 
  

  

  