Passages for Priestley’s History of Electricity (II)
Draft: American Philosophical Society
[1766]

It ought to be so on Dr. F.’s Principles. If one Side be rubbed by the Finger; it acquires from the Finger some of the Electric Fluid. This being spread on the Glass as far as the Rubbing extended, repels an equal Quantity of that contain’d in the other Side of the Glass, and drives it out on that Side, where it stands as an Atmosphere, and so both sides are found plus. If the unrubb’d Side were in Contact with a Conductor communicating with the Earth, the Electric Fluid would be carried away, and then that Side would be left apparently in the natural State. If the electric Fluid found on the unrubb’d Side was really part of that which had been communicated by and from the Finger, and so had actually perm-[eated] the Glass, it might, when conducted away, be continually replac’d by fresh permeating Fluid communicated in the same Manner: But if the Effect is continually diminishing, while the suppos’d Cause repeated, continues the same, there seems reason to [doubt] the Relation between that Cause and the Effect. It appears difficult to conceive how Electric Fluid having pass’d thro’ a permeable Body, should make it more difficult for other Electric Fluid to follow, till at length none would pass thro’ at all.

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