﻿16 
  

  

  Dr. 
  W. 
  M. 
  Hicks 
  on 
  the 
  Michelson-Morley 
  

  

  Then 
  

  

  i. 
  e. 
  

  

  or 
  

  

  Again, 
  

  

  or 
  

  

  BAA' 
  = 
  

  

  = 
  B'A'A, 
  

  

  (b 
  — 
  cc 
  - 
  

  

  =*'+«, 
  

  

  « 
  + 
  

  

  -*-. 
  

  

  BAA' 
  = 
  <£- 
  

  

  .«_ 
  2 
  . 
  

  

  sin 
  BAA' 
  

  

  A'B 
  V 
  

  

  sin 
  a. 
  

  

  " 
  A'L 
  _ 
  o 
  

  

  sin 
  — 
  ^- 
  z 
  - 
  

  

  

  V 
  

  

  whence 
  

  

  V 
  — 
  v 
  

   tan 
  ^4>'= 
  T? 
  -tan 
  ^ 
  </> 
  ? 
  

  

  (i) 
  

  

  which 
  gives 
  the 
  law 
  of 
  reflexion. 
  In 
  this 
  it 
  is 
  to 
  be 
  remem- 
  

   bered 
  that 
  v 
  is 
  to 
  be 
  regarded 
  as 
  positive 
  when 
  the 
  plane 
  

   moves 
  towards 
  the 
  incident 
  light. 
  

  

  It 
  can 
  easily 
  be 
  shown 
  from 
  the 
  above 
  that 
  if 
  J) 
  v 
  denotes 
  

   v{V 
  2 
  + 
  ^+2Vvcos0}, 
  

  

  £ 
  Ye 
  2 
  + 
  ve 
  2 
  

  

  e 
  1ST 
  "' 
  

  

  a 
  formula 
  which 
  later 
  will 
  be 
  found 
  very 
  useful. 
  

  

  Change 
  in 
  Wave-length, 
  — 
  In 
  fig. 
  4 
  let 
  A 
  4 
  ... 
  represent 
  a 
  

   train 
  of 
  wave-crests 
  incident 
  on 
  the 
  mirror 
  at 
  any 
  moment. 
  

  

  Rff. 
  4. 
  

  

  B 
  1 
  . 
  . 
  . 
  the 
  corresponding 
  reflected 
  wave 
  -crests. 
  The 
  figure 
  

   shows 
  at 
  once 
  that, 
  V, 
  X 
  denoting 
  the 
  wave-lengths 
  of 
  the 
  

  

  