So wonderfully are these two states of Electricity, the _plus_ and _minus_, combined and balanced in this miraculous bottle! situated and related to each other in a manner that I can by no means comprehend! If it were possible that a bottle should in one part contain a quantity of air strongly comprest, and in another part a perfect vacuum, we know the equilibrium would be instantly restored _within_. But here we have a bottle containing at the same time a _plenum_ of electrical fire, and a _vacuum_ of the same fire; and yet the equilibrium cannot be restored between them but by a communication _without_! though the _plenum_ presses violently to expand, and the hungry vacuum seems to attract as violently in order to be filled. 5. The shock to the nerves (or convulsion rather) is occasion'd by the sudden passing of the fire through the body in its way from the top to the bottom of the bottle. The fire takes the shortest course, as Mr _Watson_ justly observes: But it does not appear, from experiment, that, in order for a person to be shocked, a communication with the floor is necessary; for he that holds the bottle with one hand, and touches the wire with the other, will be shock'd as much, though his shoes be dry, or even standing on wax, as otherwise. And on the touch of the wire (or of the gun-barrel, which is the same thing) the fire does not proceed from the touching finger to the wire, as is supposed, but from the wire to the finger, and passes through the body to the other hand, and so into the bottom of the bottle. EXPERIMENTS _confirming the above_. EXPERIMENT I. Place an electrised phial on wax; a small cork-ball suspended by a dry silk-thread held in your hand, and brought near to the wire, will first be attracted, and then repelled: when in this state of repellency, sink your hand, that the ball may be brought towards the bottom of the bottle; it will there be instantly and strongly attracted, 'till it has parted with its fire. If the bottle had an electrical atmosphere, as well as the wire, an electrified cork would be repelled from one as well as from the other. EXPERIMENT II. FIG. 1. From a bent wire (_a_) sticking in the table, let a small linen thread (_b_) hang down within half an inch of the electrised phial (_c_). Touch the wire of the phial repeatedly with your finger, and at every touch you will see the thread instantly attracted by the bottle. (This is best done by a vinegar cruet, or some such belly'd bottle). As soon as you draw any fire out from the upper part by touching the wire, the lower part of the bottle draws an equal quantity in by the thread. EXPERIMENT III.