Lectures on electricity / by James Ferguson, F.R.S.

  • James Ferguson
Date:
1825
Catalogue details

Licence: Public Domain Mark

Credit: Lectures on electricity / by James Ferguson, F.R.S. Source: Wellcome Collection.

    32/112 (page 26)
    AN INTRODUCTION ductor, the feather will ily to the ball, and adhere to it as long as you keep working the machine.15 As fast as the feather receives the electric fire from the prime conductor, the fire runs off from the feather by the thread to the table, or to the hand that holds the thread. So that, although the feather is still receiving new fire, it parts with it as fast; and therefore there is no increase of its natural quantity : if there were, the feather would then be repelled from the prime conductor. —See Sec. I. § 4, 5, 6, and 7. i EXPERIMENT II. Electric Attraction. 43. Make a ring of wire, at least a foot larger in diameter than the glass globe of the machine, and tie pieces of fine linen threads to it, each about five inches Jong, and about two inches from each other. Then, having taken away the conductor G H, hold the ring in a horizontal position round the globe, and turn the globe by the winch. As soon as the globe begins to tuin i ound, all the threads will be attracted towards it, and point, toward its center, standing horizontally in- ward, and resembling the radii or spokes of a wheel. The person who holds the ring (Sect. I. § 3) carries off the electric fire from the threads and ring as fast as they receive it from the globe: and so they remain attracted by the globe as long as it is kept in motion, and brings fire from the cushion to the threads. ISote 15. The feather and prime conductor attract each other (we suppose) in proportion to their weights or quantities of matter : but the conductor, being heavy, cannot be sensibly moved by the attraction of the light feather.—Author. In answer to this observation, it may be stated, that in electricity, it is surface, and not mass, on which the attractive power depends.