﻿the 
  Thermoelectro 
  motive 
  Force 
  of 
  Nickel 
  and 
  Iron. 
  193 
  

  

  No 
  change 
  whatever 
  in 
  the 
  temperature 
  at 
  which 
  the 
  change 
  

   of 
  slope 
  for 
  iron 
  occurred 
  was 
  produced 
  by 
  this, 
  although 
  

   the 
  two 
  curves 
  were 
  not 
  absolutely 
  coincident. 
  

  

  The 
  change 
  of 
  resistance 
  for 
  copper 
  was 
  determined 
  

   between 
  750° 
  and 
  1000°. 
  The 
  copper 
  wire 
  (No. 
  28 
  b.w.g.) 
  

   was 
  wound 
  on 
  a 
  mica 
  frame 
  and 
  was 
  heated 
  in 
  hydrogen. 
  

   It 
  is 
  known 
  that 
  up 
  to 
  500° 
  or 
  600° 
  the 
  resistance 
  of 
  copper 
  

   changes 
  like 
  platinum. 
  The 
  present 
  experiments 
  show 
  that 
  

   above 
  that 
  temperature 
  a 
  point 
  of 
  inflexion 
  occurs, 
  and 
  the 
  

   resistance-curve 
  becomes 
  convex 
  towards 
  the 
  temperature 
  

   axis. 
  

  

  Above 
  800° 
  the 
  curve 
  is 
  nearly 
  linear, 
  with 
  another 
  less 
  

   clearly 
  defined 
  change 
  of 
  slope 
  just 
  below 
  1000°. 
  

  

  Numerical 
  Results. 
  

  

  E.M.F. 
  in 
  microvolts. 
  

  

  Temperature 
  

   (Air- 
  Therm.). 
  

  

  Note. 
  

  

  Copper-Nickel. 
  

  

  -2907 
  

  

  2233 
  

  

  10335 
  

  

  4321 
  

  

  -191*2 
  

  

  99-8 
  

  

  445-5 
  

  

  1825 
  

  

  Liquid 
  air. 
  

   Steam. 
  

  

  Sulphur 
  vapour. 
  

   Aniline 
  vapour. 
  

  

  Copper-Iron 
  . 
  

   -2195 
  

   1334 
  

  

  870 
  

  

  684 
  

  

  98 
  

  

  -191-2 
  

   182-5 
  

  

  99-9 
  

   445*5 
  

  

  11-2 
  

  

  Liquid 
  air. 
  

   Aniline. 
  

   Steam. 
  

   Sulphur 
  vapour. 
  

  

  Iron-Nickel. 
  

  

  -5111 
  

  

  11807 
  

  

  3130 
  

  

  6160 
  

  

  -191-2 
  

   500 
  

   100 
  

   200 
  

  

  Liquid 
  air. 
  

  

  Phil. 
  Map. 
  S. 
  6. 
  Vol. 
  3. 
  No. 
  14. 
  Feb. 
  1902. 
  

  

  O 
  

  

  