﻿7 
  74 
  Dr. 
  J. 
  Kunz 
  on 
  the 
  Corpuscular 
  

  

  This 
  formula 
  is 
  symmetrical 
  with 
  regard 
  to 
  the 
  coefficients 
  

   of 
  the 
  metals 
  a 
  and 
  b. 
  The 
  two 
  metals 
  playing 
  the 
  same 
  

   part, 
  we 
  may 
  conclude 
  from 
  this 
  symmetry 
  that 
  the 
  numbers 
  

   of 
  free 
  corpuscles 
  in 
  the 
  two 
  metals 
  are 
  the 
  following 
  

   functions 
  of 
  the 
  temperature 
  : 
  

  

  N 
  i 
  = 
  C 
  £ 
  la- 
  [W+ 
  ^ 
  (T 
  - 
  273)] 
  - 
  

  

  The 
  last 
  step 
  is 
  of 
  course 
  not 
  conclusive. 
  For 
  suppose 
  

  

  nnd 
  N,,= 
  C 
  € 
  ^ 
  [04+WT 
  - 
  273)+ 
  ^> 
  

  

  we 
  should 
  find 
  again 
  

  

  jj 
  1 
  1 
  [««-^+(^-^)(T-273)] 
  ? 
  

  

  N„=C 
  1 
  + 
  C 
  1 
  f-£«T+ 
  

  

  The 
  number 
  of 
  free 
  corpuscles 
  will 
  vary 
  approximately 
  as 
  

   the 
  absolute 
  temperature. 
  /3 
  a 
  for 
  some 
  metals 
  and 
  for 
  certain 
  

   intervals 
  of 
  temperature 
  of 
  other 
  metals 
  being 
  negative, 
  we 
  

   see 
  that 
  in 
  these 
  cases 
  the 
  number 
  N 
  rt 
  will 
  decrease 
  with 
  

   increasing 
  temperature. 
  The 
  electric 
  conductivity 
  is 
  pro- 
  

  

  portional 
  to 
  7s- 
  ? 
  an 
  d 
  D 
  y 
  experiment 
  it 
  has 
  been 
  shown 
  to 
  

  

  be 
  proportional 
  to 
  T 
  _1 
  ; 
  thus, 
  N 
  being 
  approximately 
  pro- 
  

   portional 
  to 
  T, 
  and 
  v 
  proportional 
  to 
  T 
  1/2 
  ? 
  / 
  the 
  mean 
  free 
  

   path 
  of 
  the 
  corpuscles 
  must 
  vary 
  approximately 
  as 
  T~ 
  3/2 
  . 
  The 
  

   variation 
  of 
  the 
  number 
  of 
  free 
  corpuscles 
  with 
  the 
  tempe- 
  

   rature 
  involves 
  a 
  still 
  more 
  rapid 
  variation 
  of 
  the 
  mean 
  free 
  

   path. 
  Thus 
  the 
  effects 
  which 
  depend 
  on 
  the 
  free 
  path, 
  such 
  

   as 
  the 
  effect 
  of 
  magnetic 
  force 
  on 
  electrical 
  resistance 
  or 
  the 
  

   absorption 
  of 
  light 
  by 
  the 
  metal, 
  would 
  be 
  greatly 
  influenced 
  

   by 
  the 
  lowering 
  of 
  the 
  temperature. 
  

  

  § 
  4. 
  The 
  Peltier 
  Effect. 
  

  

  Returning 
  to 
  the 
  suppositions 
  of 
  § 
  1, 
  we 
  find 
  an 
  electric 
  

   force 
  acting 
  at 
  the 
  junction 
  of 
  two 
  metals, 
  produced 
  by 
  the 
  

   different 
  number 
  of 
  corpuscles 
  per 
  unit 
  volume 
  in 
  the 
  two 
  

  

  