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introduced between the tvvo surfaces of the phial, that the ex-cess condensed on the inside, may pass to the opposite surface,and restore the equilibrium. This is called the discharging.

This is the substance of the theory of charging and discharg-ing of electrics.^. Those who are desirous of feeing a more par-ticular explanation, may consult Dr. Franklin’s Letters, Priestley’sHistory of Electricity, and Beccaria’s Treatise, who has wrotemany quarto pages to explain and establish his propositions.

Several ingenious experiments have likewise been invented tosupport this doctrine of charging and discharging of glass, whichare equally wonderful, curious, and entertaining, and so plau-sible that they appear to carry demonstration with them.

In order to give this theory a fair trial, I shall first transcribesome of the most curious,-and, as I think, convincing experi-ments in favour of the hypothesis; and, after making some ob-jections to the conclusions drawn from them, I intend to con-trast them with experiments which appear to confute the wholesystem. _ .

c - ; E XPERIMENT I.

- Take two bottles, equally charged through their hooks, onein each hand ; bring their hooks near to each other; no sparknor shock will follow, because each hook is disposed to give fire ;and neither to receive it.

If a person takes one jar by the wire, and the other by thecoating, and brings the wire of the one to the coating of theother, there will be immediately an explosion, and a shock, andhe will be sensible of it by the charge passing through him.

3 Franklin’s letters, p. 22. Becket’s essay, p. 42.

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