ELECTRICAL APPARATUS. 



275 



insulator, and although all the rest of the apparatus remain 

 as before, yet the figures will not dance. The reason is this, 

 the upper plate being charged by its connexion with the 

 machine, the figures are attracted by it, they becoming charg- 

 ed are repelled by the upper, and attracted by the lower 

 plate. When they touch this their charge is removed by 

 that contact, and conveyed to the earth, while the figures 

 jump again for a fresh supply, and thus they move alter- 

 nately from the one to the other plate. When the lower 

 plate, however, is insulated, the extra portion brought to it 

 cannot escape, and it becomes charged in the same manner 

 as the upper one, therefore the figures have no tendency to 

 move between them. 



If in cutting out the figure the head is heavier than the 

 feet, it will dance head downwards ; damping the feet in 

 the mouth will usually remedy the defect, but this, at the 

 same time, gives them a tendency to adhere to the upper 

 plate, while wetting the head makes them dance on the 

 lower plate. Female figures usually dance more regularly 

 because of the weight of the lower part of the dress. In 

 all the figures the head should be somewhat pointed, either 

 by the adjunct of a steeple-crowned hat, or something similar 

 put upon it. Price, in copper, $1.25 and $1.50. 



Electrical Plates for Dancing 

 Images, with adjusting Rod. A 

 more elegant arrangement for 

 dancing images (Fig. 301) con- 

 sists of a polished mahogany base, 

 about 8 inches long and 10 inches 

 wide, on which is fastened a me- 

 tallic plate, about 8 inches in 

 diameter, having a hook connect- 

 ed with the plate from the under 

 side of the base. A glass pillar, 

 attached to a brass base at the 

 bottom, and having at the top a 

 cap, supporting a curved wire, 

 terminating in a ball having a 

 hole, through which a rod slides 

 vertically, one end of which has 

 a knob, and the other a metallic plate, with well rounded 

 edges, and supported directly over the plate in the base. 



