﻿776 
  Dr. 
  J. 
  Kunz 
  on 
  the 
  Corpuscular 
  

  

  Now 
  Professor 
  J. 
  J. 
  Thomson 
  *, 
  by 
  a 
  comparison 
  o£ 
  the 
  

   numbers 
  of 
  free 
  corpuscles 
  and 
  the 
  mean 
  free 
  path 
  in 
  dif- 
  

   ferent 
  metals, 
  came 
  to 
  the 
  conclusion 
  that 
  the 
  mechanism 
  by 
  

   which, 
  according 
  to 
  this 
  first 
  corpuscular 
  theory, 
  the 
  electric 
  

   current 
  is 
  supposed 
  to 
  be 
  conveyed, 
  is 
  at 
  most 
  only 
  a 
  part 
  

   and 
  not 
  the 
  whole 
  of 
  the 
  process 
  of 
  metallic 
  conduction. 
  

  

  § 
  5. 
  The 
  Thomson 
  l\fect. 
  

  

  If 
  the 
  number 
  of 
  corpuscles 
  in 
  unit 
  volume 
  of 
  a 
  metal 
  

   increases 
  with 
  increasing 
  temperature, 
  there 
  must 
  be 
  electric 
  

  

  Fia:. 
  3. 
  

  

  X 
  

  

  /GO 
  

  

  < 
  -h 
  

  

  A 
  - 
  

  

  B 
  

  

  +x 
  

  

  oix 
  

  

  forces 
  X 
  along 
  the 
  bar, 
  which, 
  following 
  the 
  notation 
  of 
  § 
  2, 
  

   are 
  found 
  to 
  be 
  equal 
  to 
  

  

  v 
  4 
  arr 
  BlogN 
  

  

  i-T- 
  

  

  6 
  e 
  

  

  x 
  

  

  and 
  tend 
  to 
  move 
  the 
  corpuscles 
  from 
  left 
  to 
  right. 
  Hence 
  

   a 
  corpuscle 
  in 
  travelling 
  from 
  x 
  + 
  dx 
  to 
  x, 
  will 
  abstract 
  from 
  

   the 
  metal 
  an 
  amount 
  of 
  heat 
  whose 
  mechanical 
  equivalent 
  is 
  

   Xe 
  dx, 
  or 
  

  

  6 
  ox 
  6 
  dl 
  

  

  The 
  corpuscle 
  when 
  at 
  x-\-dx 
  has 
  an 
  amount 
  of 
  kinetic 
  energy 
  

   equal 
  to 
  «( 
  T 
  + 
  ^dx 
  V 
  while 
  at 
  x 
  its 
  kinetic 
  energy 
  is 
  

  

  equal 
  to 
  aT; 
  hence 
  between 
  x-\-dx 
  and 
  x 
  the 
  corpuscle 
  will 
  

  

  ?}T 
  

  

  lose 
  a 
  part 
  of 
  its 
  kinetic 
  energy 
  equal 
  to 
  a~-dx, 
  which 
  is 
  

  

  communicated 
  to 
  the 
  metal 
  in 
  the 
  form 
  of 
  heat. 
  The 
  trans- 
  

   ference 
  of 
  this 
  amount 
  of 
  heat 
  is 
  an 
  irreversible 
  process. 
  

   Thus 
  the 
  total 
  amount 
  of 
  heat 
  communicated 
  by 
  the 
  corpuscle 
  

   to 
  the 
  metal 
  is 
  : 
  

  

  T 
  . 
  4 
  T 
  31ogN 
  _ 
  . 
  

   a=— 
  dx 
  ~^al 
  — 
  =%— 
  al, 
  or 
  

   OX 
  6 
  oL 
  

  

  * 
  J, 
  J. 
  Thomson, 
  l 
  Corpuscular 
  Theory 
  of 
  Matter/ 
  p. 
  75 
  (1907). 
  

  

  