Experiments and Observations on Electricity Made at Philadelphia in America · Benjamin Franklin
EXPERIMENT IV.
FIG. 3. Place an electricised phial on wax; take a wire (_g_) in form of a C, the ends at such a distance when bent, as that the upper may touch the wire of the bottle, when the lower touches the bottom: stick the outer part on a stick of sealing wax (_h_) which will serve as a handle. Then apply the lower end to the bottom of the bottle, and gradually bring the upper-end near the wire in the cork. The consequence is, spark follows spark till the equilibrium is restored. Touch the top first, and on approaching the bottom with the other end, you have a constant stream of fire, from the wire entering the bottle. Touch the top and bottom together, and the equilibrium will soon be restored, but silently and imperceptibly; the crooked wire forming the communication. FIG. 4. Let a ring of thin lead or paper surround a bottle (_i_), even at some distance from or above the bottom. From that ring let a wire proceed up, 'till it touch the wire of the cork (_k_). A bottle so fixt cannot by any means be electrised: the equilibrium is never destroyed: for while the communication between the upper and lower parts of the bottle is continued by the outside wire, the fire only circulates: what is driven out at bottom, is constantly supply'd from the top. Hence a bottle cannot be electrised that is foul or moist on the outside.
Place a man on a cake of wax, and present him the wire of the electrified phial to touch, you standing on the floor, and holding it in your hand. As often as he touches it, he will be electrified _plus_; and any one standing on the floor may draw a spark from him. The fire in this experiment passes out of the wire into him; and at the same time out of your hand into the bottom of the bottle. Give him the electrified phial to hold; and do you touch the wire; as often you touch it he will be electrified _minus_, and may draw a spark from any one standing on the floor. The fire now passes from the wire to you, and from him into the bottom of the bottle. Lay two books on two glasses, back towards back, two or three Inches distant. Set the electrified phial on one, and then touch the wire; that book will be electrified _minus_; the electrical fire being drawn out of it by the bottom of the bottle. Take off the bottle, and holding it in your hand, touch the other with the wire; that book will be electrised _plus_; the fire passing into it from the wire, and the bottle at the same time supply'd from your hand. A suspended small cork-ball will play between these books 'till the equilibrium is restored. When a body is electrised _plus_ it will repel an electrified feather or small cork-ball. When _minus_ (or when in the common state) it will attract them, but stronger when _minus_ than when in the common state, the difference being greater.
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