ELECTRIC EXPERIMENTS. 



FIG. 166. 



diverge. Explain. Extend toward it your clenched fist ; the leaves 

 seek the fist. Explain. Instead of your fist, hold a needle toward 

 the tassel ; it will be blown away. Explain. Hold the needle 

 upright under the tassel. The strips will collapse. Explain. 



(8.) If the prime conductor 

 be provided with a point, 

 the flame of a candle held 

 near will be blown away as 

 shown in Fig. 166. If the 

 candle be placed upon the 

 prime conductor and a 

 pointed conductor be held 

 in the hand near the candle, 

 the flame will be still blown 

 away. Explain. 



(9.) Stand upon the insu- 

 lating stool and place your 

 left hand upon the prime 

 conductor of the electric ma- 

 chine. Hold in your right hand a sewing-needle with the tip of the 

 forefinger covering the end of the needle. Bring the right hand 

 cautiously near the gold-leaf electroscope. Notice the divergence 

 of the leaves. Now uncover the point of the needle and bring it 

 near the electroscope. Notice the marked and immediate increase 

 in the divergence of the leaves. Explain. 



(10.) Place an "electric whirl" (which consists of a set 

 of horizontal wire arms radiating from a pivot-supported 

 centre, the pointed ends being all bent in the same direc- 

 tion) upon the prime conductor. Work the machine and 

 the arms will revolve. (See Fig. 167.) Explain. 



(11.) The " electric orrery," represented in Fig. 168, is a 

 pretty modification of the "electric whirl." The short FIG. 167. 

 balanced bar is provided with a pointed conductor to pro- 

 duce rotary motion upon its supporting 

 pivot, which is one end of the long balanced 

 bar. This longer bar is also provided with 

 a pointed conductor and supported in turn 

 upon a pivot, which may be attached to the 

 prime conductor. When the machine is 

 worked, the long bar revolves upon its fixed 

 pivot ; the short bar revolves upon its 

 FIG. 168, moving pivot. 



