ELECTRICAL APPARATUS. 



277 



Cylinder for Dancing Pith Balls. (Fig. 303.) 

 This electrical apparatus consists of a glass cylinder 

 having metallic ends, one end supported on a small 

 stand, the other having a knob, or hook, to connect 

 with the prime conductor of an electrical machine ; 

 on exciting the machine, the pith balls placed 

 within the cylinder will dance up and down, carry- 

 ing the electricity from the upper to the lower 

 plate. 



Price, $1.50. 



Fig. 3!>3. 



Diverging Threads. (Fig. 304.) Tie 

 twenty fine linen threads together at eacli 

 end, so that there may be about 8 inches 

 distance from knot to knot ; hang this by 

 a wire loop, fastened to one of the knots, 

 to the conductor of the machine. Upon 

 charging the conductor, the threads will 

 recede from each other, forming a curious 

 balloon-shaped body. 



Expanding Threads. Instead of tying 

 the threads at both ends, let the lower end 

 be loose, and upon turning the machine 

 they will form a brush. Price, 25 cts. 



The Head of Hair. Fi s . 305. 



(Figs. 305 and 306.) 

 These are usually carved 

 figures of wood, having 

 long hair on their head. 

 They are supported by a 

 wire from the prime con- 

 ductor. When electri- 

 fied, the hair stands on 

 end in the most grotesque 

 manner. Each fibre is 

 in a state of repulsion to 

 its neighbor, but present 

 the point of a penknife, 

 and they will all fall 

 down. Price 75 cts. and $1.00. 



24 



Fig. 304. 



Fig. 303. 



