﻿Shaw. 
  

  

  Phil. 
  Mag. 
  Ser. 
  6, 
  Vol. 
  26, 
  PI. 
  V. 
  

  

  

  Fig. 
  2. 
  

  

  Fig. 
  3. 
  

  

  FlB 
  - 
  4 
  - 
  Fio. 
  5. 
  

  

  [Tbe 
  reflected 
  spot 
  for 
  light-waves 
  would 
  occur 
  i. 
  each 
  case 
  to 
  the 
  left 
  of 
  the 
  u,ai„ 
  i.upression.] 
  

  

  