278 



BENJ. PIKE S, JR., DESCRIPTIVE CATALOGUE. 



Fig. 337. 



Radiating Feathers. (Fig. 

 307.) This is a metallic ring, 

 supported on a glass pillar, and 

 at six or eight equally distant 

 points around this ring tie a 

 thread, not silk, a few inches 

 long, the other end of which 

 bears a feather. Connect the 

 metal ring with the conductor 

 of the machine, by a wire or 

 chain, and the feathers being 

 electrified will repel each other 

 until they will stand at equal 

 distances like the spokes of a 

 wheel. Price, $1.50. 



Fig. 308. 



The Electrical 

 Swing (Fig. 308) is 

 another amusing in- 

 strument, and acts, 

 as will be immedi- 

 ately perceived, up- 

 on the principle of 

 attraction and re- 



Eulsion. The insu- 

 lted brass ball, A, 

 is connected with 

 the prime conductor, 

 while the opposite 

 ball, B, communi- 

 cates with the earth. 

 The light figure re- 

 presented as sitting 

 on a silken cord is 

 first drawn towards 

 A, where it receives 

 a charge which it 

 discharges on B, and thus is kept swinging between the two 

 balls. Price, $3.00. 



Electrical See- Saw. (Fig. 309, next page.) Consists of 

 a mahogany base about one foot long, supporting at its 

 centre a brass beam, after the manner of a scale beam, made 



