c ]

CHAPTER III.

5 the theory of insulating bodies examined, and some of the supposed

properties •which electricians have ascribed to glass, proved by ex-periments, not to exist.

r r 1HE essence of the Franklinian theory consists in this:

JL any substance, in order to its being capable of receivinga charge, must be insulating, impenetrable, sufficiently am-ple, and sufficiently thin.

i. It must be insulating j that is, of such a nature as not toallow the electric effluvia to move from one place to another,either along its surface, or through its pores.

I much doubt, whether either art or nature has yet producedan electric with the properties here described. A few experi-ments may probably place this subject in a dearer light.

Experiments to prove the eledlric fluid passes along the surface

os insulating bodies.

Experiment I.

Upon a stool with glass legs, lay a pane of glass, large enough

to cover it; and upon this pane, place four wine glasses, one ateach corner. Put a metal wire, fixed in a ' foot to support it.

* Pere Beccaria’s treatise, &c. p. 70.