﻿Dtamagnetic 
  and 
  Weakly 
  Magnetic 
  Substances. 
  435 
  

  

  A. 
  Large 
  electromagnet. 
  

   a, 
  a'. 
  Pole-pieces 
  of 
  A. 
  

  

  S. 
  Experimental 
  slab 
  in 
  position. 
  

  

  B. 
  Balance. 
  

  

  The 
  pole-pieces 
  are 
  prismatic, 
  as 
  shown 
  in 
  figs. 
  2 
  and 
  3, 
  

  

  Ear. 
  2. 
  

  

  lie 
  

  

  