﻿220 
  Mr. 
  P. 
  J. 
  Kirkby 
  on 
  the 
  Electrical 
  Conductivities 
  

   Therefore, 
  to 
  determine 
  R, 
  one 
  has 
  

  

  V 
  

  

  x 
  = 
  

  

  Rlog 
  

  

  = 
  30xp. 
  

  

  (3) 
  

  

  In 
  the 
  case 
  of 
  column 
  A 
  we 
  may 
  take 
  C 
  = 
  47. 
  The 
  negative 
  

   current 
  corresponding 
  to 
  the 
  voltage 
  333 
  is 
  180. 
  

   Therefore 
  by 
  equation 
  (1) 
  

  

  C__180 
  , 
  ,^a 
  2 
  

  

  C. 
  " 
  47 
  ~ 
  X 
  { 
  *~ 
  y) 
  P-a 
  2 
  

  

  47 
  

   b_ 
  

  

  a 
  

  

  w 
  

  

  From 
  (3) 
  since 
  log- 
  =5*3, 
  V 
  = 
  333, 
  p 
  = 
  6*8, 
  we 
  get 
  

   333 
  

  

  R 
  = 
  

  

  and 
  therefore, 
  

  

  30x(v8x5*3 
  

   b 
  2 
  -a 
  2 
  43 
  

  

  = 
  *31 
  cm. 
  

  

  = 
  0216, 
  

  

  for 
  a='0103 
  cm., 
  6 
  = 
  2 
  # 
  08 
  cm. 
  Therefore 
  (4) 
  gives 
  

  

  ( 
  i-(.z—y)x-0216 
  = 
  3 
  : 
  83. 
  

  

  Now 
  a?>y>l, 
  so 
  that 
  x 
  lies 
  between 
  383 
  and 
  3 
  - 
  89. 
  

   Therefore 
  by 
  equation 
  (2) 
  the 
  positive 
  current 
  cannot 
  exceed 
  

  

  47{l-f 
  2-89 
  x 
  -0216} 
  or 
  50. 
  

  

  If 
  we 
  take 
  z 
  to 
  be 
  equal 
  to 
  half 
  the 
  lower 
  limit 
  just 
  found, 
  

   which 
  is 
  more 
  or 
  less 
  justified 
  by 
  the 
  illustration 
  given 
  above, 
  

   we 
  should 
  get 
  for 
  the 
  positive 
  current 
  48. 
  This 
  agrees 
  very 
  

   well 
  with 
  the 
  observed 
  value 
  50. 
  

  

  We 
  may 
  apply 
  the 
  same 
  theory 
  to 
  the 
  columns 
  B, 
  C, 
  D 
  

   for 
  the 
  voltage 
  370. 
  Simple 
  calculations 
  give 
  : 
  — 
  

  

  

  

  

  

  | 
  

  

  Values 
  

  

  of 
  + 
  

  

  

  C 
  - 
  

  

  R. 
  

  

  Ir 
  - 
  a- 
  ' 
  

  

  Limits 
  of 
  

  

  X. 
  

  

  

  

  

  

  

  

  

  

  

  calculated. 
  

   23-5 
  

  

  observed. 
  

   23-8 
  

  

  E 
  ...... 
  

  

  18 
  

  

  •66 
  

  

  •1 
  

  

  ' 
  11-4, 
  12-6 
  

  

  1 
  - 
  

  

  C 
  

  

  16 
  

  

  1-083 
  

  

  •272 
  

  

  11-6, 
  15-5 
  

  

  36-8 
  

  

  303 
  

  

  D 
  

  

  3-8 
  

  

  1-32 
  

  

  •405 
  

  

  ! 
  21 
  % 
  35 
  

  

  18-6 
  

  

  8-0. 
  

  

  It 
  will 
  thus 
  be 
  seen 
  that 
  these 
  calculations, 
  rough 
  as 
  they 
  

   are, 
  are 
  capable 
  of 
  giving 
  accurate 
  agreement 
  with 
  observed 
  

  

  