110 ELEMENTS OF STATIC ELECTRICITY. 



windows, directly opposite the combs IT and L ; and, on 

 its rear surface, are cemented two paper inductors T 

 and X; T extending from H to L, and X from V to K ; 

 and each armed with a row of points, projecting into 

 each window. 



Machines of this kind are often constructed with 

 more than two plates ; sometimes with a large number. 

 The plates are also sometimes placed in a horizontal 

 position. Ebonite plates are also used ; but are objec- 

 tionable, for reasons already given. 



THE TOPLER MACHINE. The Topler machine has 

 the same general construction as the Holtz ; but, on 

 the front surface of the revolving plate, are cemented 

 a number of small metal discs, called carriers; usually 

 made of tin-foil with raised brass centers, which, as the 

 plate revolves, are brought into contact with four wire 

 brushes; two attached to the stationary plate, and two 

 to the uninsulated combs. In this way the machine is 

 made self-inciting, as already mentioned. 



The windows, and the rows of points projecting into 

 them, used in the Holtz stationary plate, are omitted 

 from the stationary plate of the Topler: and the paper 

 inductors are made longer, and have small tin-foil in- 

 ductors under them, connected, by tin-foil strips, with 

 each other and also with the two brushes attached to 

 this plate. 



Fig. 37 represents a Topler machine constructed by 

 the author, and patented April 10, 1883, and December 

 8, 1885. The principal points covered by the patents 

 are as follows : 



1. The outside coatings of the Leyden jars C and 

 D are of sheet brass, f nickel plated ; and are screwed 

 firmly to the base ; forming cups into which the jars 



