will be alfo repelled by the ball which commun. cates with the infide.

Place an infulated bottle fo that the ball may communicate with the conductor; let a wire alfo be connected with the coating, fo as to form a communication with the table. Now turn the machine, and, 1. On applying a cork ball, you will not find any figns of electricity in the coating, but you will find the ball (or infide) electrified with the vitreous power. 2. Remove the wire communicating with the table, and you will find the coating alfo electrified with the vitreous power; and this as often as you remove the wire, till the bottle is full charged. 3. When the bottle is full charged, remove it's communication both with the conductor and table, touch the coating, and the cork ball will remain fufpended by it, without any fign of being electrified; then touch the knob of the bottle with your hand, the cork ball will be Atrongly repelled from the coating, and be electrified with the refinous power. 4. Take another cork ball fufpended by filk, and touch the knob of the bottle therewith, and the cork ball will be electrified with the vitreous power and repelled. 5. Now touch the coating with your finger, and the cork ball will be repelled much further by the ball; but that which was repelled from the coating, now flies towards it, and remains at reft, till you touch the knob of the bottle with your finger; it will then be electrified as at first, and be violently repelled; the ball which was electrified by the knob of the bottle will now fly towards it. This change in the extent of the atmo fphere of the different powers, takes place almost inftantaneously as often as you touch the ball or coating.

Or you may connect the knob of the bottle with the conducte by a wire, and fufpend a cork ball to Z 4

touch

touch the conductor; then touch the coating, and the ball will be repelled from the conductor, while that next the coating is attracted; touch the knob of the bottle, and the ball will be repelled from the coating, and attracted by the conductor, and fo on, as often as you touch the knob or coating.

From hence it feems plainly to appear, 1. That the bottle is electrified with the vitreous power on the infide, and the refinous on the outfide. 2. That when the equilibrium of these powers is destroyed by leffening the quantity of one, the extreme part of the other expands itfelf into an extenfive atmosphere; but the atmosphere of the leffened power is condensed, as appears by the cork balls falling close to the conductor and coating. 3. It remains to be fhewn, how these powers came to be thus fituated on the infide and outfide of the bottle, or why they do not mix through the glass where they feem to have the greatest tendency to unite. Here it will be neceffary to confider the feparation of these powers between the globe and the cushion, for all the other phenomena are only a confequence of the feparation that takes place between thefe. Now the cylinder parts with it's refinous power to the cushion, in exchange for the vitreous; the conductor in like manner to the globe, and the infide of the bottle to the conductor; and fo the exchange would go on with the next conducting fubftance, but that the bottle gives fome obftruction to the paffage of the electrical powers; by which means the vitreous power, which paffes through the glafs to the conducting fubftance upon the outfide of the bottle, is carried off together with the vitreous power of the coating, along the wire which communicates with the table, in exchange for an equal quantity of the refinous power brought back by the wire to the coating of the bottle; till at length the refinous

power

power on the outfide is able to counterballance the vitreous power on the infide, and thus affords an opportunity for drawing off the refinous power on the infide of the bottle, to the conductor; fo that the bottle remains a partition between the two powers, and they cannot change place through the peculiarly conftructed pores of the glafs, while their furfaces are oppofed in fuch quantities.

For when the junction is made in the open air, or when their furfaces are oppofed in any quantity, it is not done without violence, occafioning a loud noife and a flash of fire, while bursting through to meet each other; for wherever the dif ferent powers unite in any quantity, they are much condenfed.

The violent convulfion felt through the body by completing a circle with the hands, is only occafioned by the different powers paffing in oppofition through the fame nerves. For if one perfon touches the coating, and another the top of the bottle, the bottle will be difcharged without giving either of them the fhock. Now it is very clear, that as much fire paffed through either of them, as if each had fingly discharged the bottle. But in this cafe the fire is diffufed through all parts of the body, and the fire brought in, is drawn from all parts of the body, and confequently the nerve cannot be fo much fhocked as in the former cafe, when all the fire paffes in oppofition through the fame nerves.

EXPERIMENTS ILLUSTRATING THE THEORY OF THE LEYDEN PHIAL.

Charge an infulated bottle, remove it from the conductor, and let a cork ball fufpended by filk hang against the outside of the bottle; touch the outfide or coating with your finger, the ball

will not be affected; but touch the knob of the bottle, and the ball immediately flies off, ftrongly electrified with the refinous power; and thus you may go on for a confiderable time, altering the ballance of the powers within and without fide the bottle, by alternately touching the top and the bottom of the bottle. The defenders of Franklin's fyftem will hardly fay, it is the return of the pofitive electricity which electrifies the ball negatively. The fact is, that when you touch the top, you take a spark of the vitreous power from the infide, and in exchange, give as much of the refinous power thereto; by this means, the force of the vitreous power within the bottle is leffened, which leaves the refinous power on the outfide in greater quantity, than the vitreous within fide, and confequently at liberty to exchange with any nonelectric in contact with it, and thus the ball becomes electrified with the refinous power.

Charge a bottle fully, and remove the wire from the table, and make the coating communicate with the conductor instead of the knob, and then turn the machine, and the refinous power with which the coating is electrified becomes covered with the vitreous power, and you may take as many fparks from it as you pleafe, without making any change in the charge of the bottle; for when you ftop turning, and remove the communication with the conductor, and touch the outfide of the coating with the finger, all figns of the vitreous power difappear; and when the circle is completed, the bottle is difcharged with as loud a report as it would have done before you applied the conductor to the coating; for the vitreous power within the bottle being undisturbed, kept an equal quantity of the retinous power firmly fixed to the outfide of the bottle.

But the cafe is different when you give the

vitreous

vitreous power from the infide an opportunity to efcape. Thus when the bottle is full charged as before, remove the wire that communicates with the table, and bring the coating in connection with the conductor; after a turn or two of the cylinder, take a spark from the ball of the bottle, and you will find that it will fly to a confiderable diftance, often double the distance you can draw a fpark from the conductor, because the vitreous power covering the refinous power on the coating, leffens the action on the vitreous power within the bottle, and therefore leaves that power greater freedom to fly off; but as you go on taking fparks, they gradually leffen, because after a fw, the vitreous power in the bottle is leffened, and the refinous power within increased by the quantity received in exchange on every fpark; and thus by a few fparks, the bottle is discharged; but if you go on to take more fparks, the bottle will be re-charged with the refinous power withinfide, instead of the vitreous, with which it was before charged.

Again, fuppofe fifty turns of the cylinder will charge your bottle, turn only twenty-five, and then remove the communication between the coating and table, and as you turn on, (whether you continue the communication from the conductor to the top of the bottle, or fhift it to the coating,) you will find the bottle electrified on both fides with the vitreous power; remove the bottle from the conductor, and then difcharge it with an infulated difcharger, and you will find the bottle ftill electrified, both within and without, with the vitreous power; but this electricity will difappear, by touching either the ball or coating with your finger.

To illufirate further the reciprocal exchange of the electric powers, here is an infulated bottle with a wire proceeding from the bottom, at right an

gles