Exp. 3. If the ball or feather used in the preceding experiment is suspended by a silk thread instead of the metallic wire, it will at first be attracted by the conduc tor, and then immediately repelled, and will not return to it again till it has imparted its electricity to some con ducting body.
Exil. 4. Take a number of threads, from 10 to 1 8, and about a foot long, and, having tied them together at both ends, suspend them by the upper knot to the conductor of the machine. As soon as the threads arc electrified, the lower knot will rise, and they will swell out in the middle, and assume a spherical form. This experiment was first made by Mr Wheeler.
Exp. 5. Suspend a metallic plate, or a wooden plate covered with tinfoil, either from the conductor of the ma chine, or from a separate stand connected by a chain with the conductor ; and at the distance of three or four inches below it place a similar plate on a stand connect ed with the ground. Put some pieces of gold leaf or thin paper between these plates, and when the conduc tor is electrified, they will be attracted and repelled al ternately by the two plates, and will continue their motion as long as the electricity remains in the conduc tor.
This experiment is rendered doubly interesting, by using small painted figures cut out of paper. These figures will dance upon the lower plate as if they were really animated, and will exhibit a number of attitudes of the most singular kind.
This experiment is excellently represented in Plate CCXL111. Fig. 2. where every part of the apparatus is so distinctly seen as to require no description.
.Exp. 6. Place two small bells on separate glass pil lars, three-fourths of an inch distant, so that the bells arc insulated. Suspend by a silk thread a clapper, or small brass ball, so as to hang in the middle between the bells. One of the bells being made to communicate by a con ducting substance with the conductor of the machine, and the other with the ground, the small ball of brass will oscillate between the two bells, striking them alter nately, and producing an electrical chime.
This experiment is still more interesting, if we hang three bells upon a horizontal rod of brass communicat ing with the prime conductor. The two outermost bells must be suspended by metallic wires or chains, and the middle one by a silk thread, so as not to com municate with the rod, but to have a communication with the ground or table, by means of a chain going from the inside of the hell. A clapper or brass ball is
suspended by silk strings upon the same horizontal rod, and between each of the two bells. As soon as the con ductor is electrified, the brass balls will be alternately attracted and repelled by the adjacent bells, and by stri king against them, they will produce a chime by no means disagreeable.
This experiment is distinctly represented in Fig. 3. Plate CCXLIII. A still more interesting variation of the experiment is represented in Fig. 4. where a b is a rod of solid glass, supported upon a wooden stand, and passing through a perforated ball, No. 5. The other end of the glass rod supports two metallic arms cross ing each other at right angles, having suspended at their extremities, by means of wires, four bells, 1, 2, 3, 4. From a point of each of these arms, equidistant from the extremity and the point of intersection, is suspended a brass ball by silk threads. Upon electrifying the con ductor, all the five bells will be set a ringing at the same tinge.
Exp. 7 Place upon the prime conductor a pointed wire, and by means of it electrify the inside of a very dry glass tumbler or jar. Place several pith balls on the table, and cover them by the glass thus electrified.
They will immediately begin to leap up and down against the sides of the vessel, and will thus be alter nately attracted by it and the table for a considerable time.
Exp. 8. Suspend from the prime conductor a cir cular ring of brass or any other metal, about a foot in diameter, so that the ring is in a horizontal position. Place below the ring a circular plate of metal of a larger diameter than the ring, upon a stand like that re presented in Fig. 2, so that it cm be placed at different distances from the ring. Take a very small hollow hall of glass, blown extremely thin, and about two inches in diameter, and having brought the surface of the metallic plate to a distance from the ring less than its diameter, place the ball within the ring, and upon the plate, and as soon as the ring is electrified it will attract the ball, which will be animated at the same time with a rotatory motion, and a circular motion of translation. If the ex periment be made in the dark, the ball will appear lu minous at all the points where it successively touches the ring.