A text-book on chemistryFor the use of schools and colleges . > off let there be placed a sec-ondary conductor, b c, ofbrass, supported on a glassstand, and at each extremity,b and c, of the conductor, letthere be arranged a pair ofcork balls, suspended by linen c^> threads, as shown in the figure. As soon as the ball ais electrified by turning the machine, and without anyspark passing from it to the secondary conductor, theballs will begin to diverge, showing that the conditionof that conductor is disturbed by the neighborhood ofthe excited ball, a. It will farther be found, on presenti
A text-book on chemistryFor the use of schools and colleges . > off let there be placed a sec-ondary conductor, b c, ofbrass, supported on a glassstand, and at each extremity,b and c, of the conductor, letthere be arranged a pair ofcork balls, suspended by linen c^> threads, as shown in the figure. As soon as the ball ais electrified by turning the machine, and without anyspark passing from it to the secondary conductor, theballs will begin to diverge, showing that the conditionof that conductor is disturbed by the neighborhood ofthe excited ball, a. It will farther be found, on presenting an excited pieceof sealing-wax to the pairs of cork balls, that one set isattracted and the other repelled. They are therefore inopposite electrical states. The disturbing ball is vitre-ously electrified, and that end of the secondary conduct-or nearest it is resinous, the farther end being vitreous. How may electrical excitement be produced ? What is meant byelectrical induction ? Describe Fig. 92. What occurs to the ballson the secondary conductor ? F2. 130 ELECTRICAL INDUCTION. Fig. 93. + 1 fii. uifil If the disturbing ball a be now removed, the electricdisturbance ceases and the corks no longer diverge. The phenomena of electrical induction are not depend-ent on the shape of bodies. Let there be two flat cir-cular plates, a 5, Fig, 93, supported onglass stands, and set a few inches apart,looking face to face. Let one of them, a,be electrified positively by contact withthe prime conductor, as indicated by thesign +. It immediately induces a changein the opposite plate, the nearest face ofwhich becomes negative, —, and the moredistant positive. It is evident that this disturbance isa consequence of the law that like electricities repel,and unlike ones attract. In the plate b both speciesof electricity exist; and a, being made positive, eventhough at a distance, exerts its attractive and repulsiveagencies on the electric fluid of 5, the negative electrici-ty of which it a
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