42 



APPLICATION OF 



18 inches to 2 feet; if it be a cylinder, Fig. 2, the diameter 

 may be from 8 to 14 inches. 



Fig. 2. 



The auxiliary apparatus is very simple ; 

 the most essential instruments are, 



First, a Leyden Jar, fitted up with a 

 Lane's Electrometer, Fig. 3, by which 

 shocks of any required force may be given. 



Secondly, a pair of Directors, Fig. 4. 

 Occasionally one of the brass balls may be 

 unscrewed, and a wooden point substituted 

 for it. When shocks are applied by the 

 aid of these directors, they are placed at 

 the opposite extremities of the part through 

 which the charge is to pass; and being 

 respectively connected by conducting wires 

 or chains, the one with the outside of the 

 jar, and the other with the receiving ball 



Fig. 4. 



U 



