﻿Prof. 
  D. 
  N. 
  Mallik 
  on 
  Fcrmafs 
  Law. 
  155 
  

  

  BBt 
  j(U- 
  + 
  II*+H49-j«{l(g 
  -f 
  )++}■ 
  

  

  Hence 
  

  

  _(<L 
  r 
  '++)lJ<fcdScos/a 
  

  

  where 
  /* 
  = 
  angle 
  between 
  the 
  direction 
  of 
  motion 
  of 
  the 
  tube 
  

   and 
  the 
  normal 
  to 
  dS, 
  and 
  moreover 
  

  

  U 
  cos 
  fi= 
  lu 
  + 
  wit' 
  + 
  ww. 
  

   Hence 
  we 
  have 
  

  

  (fa 
  + 
  mv 
  + 
  mo)(|£ 
  + 
  + 
  V 
  S 
  ^ 
  

  

  -^)-D(I-f) 
  ++ 
  ]" 
  s 
  "*- 
  

  

  •'• 
  ^Vlf 
  + 
  rn 
  9 
  +nh)dS 
  

  

  ^{'(i-f)->- 
  

  

  We 
  get, 
  accordingly, 
  

  

  dt 
  J 
  Xb.c 
  By 
  B~/ 
  B?/ 
  w 
  0- 
  

  

  But 
  

  

  |t 
  + 
  |£ 
  + 
  |* 
  =p= 
  volume 
  density 
  of 
  electrification. 
  

  

  d* 
  By 
  B* 
  r 
  

  

  =j9, 
  where 
  p 
  is 
  the 
  total 
  current 
  in 
  the 
  

   direction 
  of 
  x. 
  

   This 
  agrees 
  with 
  Thomson's 
  results, 
  though 
  we 
  have 
  

   followed 
  a 
  different 
  mode 
  of 
  analysis. 
  

   Again, 
  since, 
  on 
  Maxwell's 
  theory, 
  

  

  4m 
  *="5i 
  Bi"'* 
  " 
  

  

  where 
  a, 
  /3, 
  7 
  are 
  the 
  components 
  of 
  magnetic 
  force, 
  

  

  a 
  = 
  47r(i7i 
  — 
  MNj), 
  &c, 
  

   showing 
  that 
  Faradav 
  tubes 
  in 
  motion 
  give 
  rise 
  to 
  a 
  mag- 
  

   netic 
  field. 
  

  

  