It is supposed that the impelling power of the Globe, or the Knob of a positively charged bottle, drives the particles of the Electricity through the substance of the Ball, wire &c. (with which they are in contact,) with great velocity, and [moving?] in a straight Line; But the Electricity having enter’d the vacuum, the repulsion of its particles immediately takes place, and the tube is instantly fill’d with Light. The dense white Atmosphere upon the opposite Ball is imagin’d to proceed from this cause, for as every particle is supposed to be in a state of repellency with respect to its next neighbour, and as the Vacuum gives them a free liberty of expanding themselves, or standing at their greatest distance from each other: they will not enter the opposite ball in the tube in a point or small space as they do in the open Air, but (as before observed,) having free liberty to expand themselves, their natural property of repelling each other, causes them actually to do so, and thus the Wire and ball, becomes illumin’d with a very dense Atmosphere of the particles of Electricity, which they enter in all parts, at the same time, in order to their conveyance into those bodies, placed to receive them at the end of the Brass work.

By this simple and easy process, may an ocular demonstration be at all times given, of the truth and propriety of Dr. Franklins hypothesis of the Leiden Bottle &c. And if his Doctrines are but embraced, till his Opponents bring as good proofs of their being erroneous; I flatter myself that Learned, Candid and Ingenious Gentleman, will scarcely wish them to be retained longer.

Mr. Henly sends his most grateful acknowledgments of Dr. Franklins favour of this day, and assures him the injunctions in his Card shall be stric[tly complied?] with. Mr. H. earnestly hopes to hear o[f the health?] of his worthy Friend and the whole family.