﻿Magnetization 
  on 
  the 
  Resistance 
  of 
  Graphite. 
  lt>7 
  

  

  the 
  specimens, 
  it 
  is 
  unfortunately 
  impossible 
  to 
  give 
  their 
  

   absolute 
  specific 
  resistance 
  with 
  any 
  exactitude. 
  

  

  Fig. 
  1. 
  

  

  Isothermals 
  (18°) 
  G 
  I. 
  

   From 
  equation 
  (1) 
  we 
  have, 
  taking 
  logarithms 
  

   log 
  R 
  = 
  log 
  A 
  + 
  m 
  log 
  £, 
  

  

  which 
  can 
  be 
  represented 
  by 
  a 
  straight 
  line 
  if 
  A 
  and 
  (m) 
  are 
  

   really 
  constants, 
  the 
  coordinates 
  being 
  log 
  (R' 
  — 
  R)/R 
  and 
  

   log 
  .6- 
  

  

  The 
  values 
  of 
  log 
  (R' 
  — 
  R)/R 
  and 
  log 
  «£), 
  corresponding 
  to 
  

   the 
  points 
  on 
  the 
  curves 
  shown 
  in 
  fig. 
  1, 
  when 
  plotted 
  were 
  

   found 
  to 
  lie 
  very 
  nearly 
  on 
  straight 
  lines 
  practically 
  parallel 
  

   to 
  one 
  another, 
  indicating 
  that 
  m 
  is 
  the 
  same 
  constant 
  for 
  

   each 
  of 
  these 
  specimens 
  G 
  I. 
  4, 
  10, 
  11, 
  12, 
  15. 
  In 
  the 
  case 
  of 
  

   G 
  I. 
  15 
  — 
  the 
  one 
  which 
  gave 
  an 
  increase 
  in 
  resistance 
  of 
  the 
  

   greatest 
  order 
  — 
  equation 
  (1) 
  did 
  not 
  hold 
  so 
  well 
  as 
  for 
  

   the 
  other 
  specimens, 
  although 
  the 
  mean 
  value 
  of 
  m 
  was 
  the 
  

   same 
  for 
  this 
  as 
  for 
  the 
  others. 
  The 
  values 
  of 
  A 
  and 
  m 
  

   obtained 
  for 
  the 
  different 
  specimens 
  are 
  given 
  in 
  Table 
  I. 
  

  

  For 
  each 
  specimen 
  m 
  = 
  l*7-l 
  5 
  *. 
  

  

  * 
  Within 
  the 
  experimental 
  

   m= 
  s/z 
  as 
  1*732 
  or 
  m 
  = 
  7/4. 
  

  

  errors 
  the 
  exponent 
  may 
  also 
  be 
  

  

  