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CHAPTER XIII.

Miscellaneous experiments and observations, with remarks on severaleleCiric phœnomena which have not yet been satisfactorily accountedfor.

SECTION I.

8 there have been but few attempts (that I have seen) since_/3L Mr. Symmer’s experiments with his silk stockings, to as-, certain the strength of cohesion in electrified bodies, I have madeseveral trials to find out what force is necessary to separate dif-ferent electrified substances, both when insulated and otherwise,in order to fix on some general law. After many unsuccessfulendeavours, I can add but little more on this subject than i - e-peat my experiments ; which may probably serve as hints tosome more ingenious and indefatigable enquirer, whose patiencemay be better adapted to encounter the difficulties which shallarise in this pursuit than my own.

she description of the apparatus used in the following experiments.

Let a represent- a mahogany foot, with a glass tube bfixed in it, about eighteen or twenty inches long, and per-pendicularly to the horizon (fee plate II. fig. 6.) Upon thetop of the glass tube let there be fixed, either by a screw or asocket, the arm c, with a brass pully d at the end of it, to turnvery freely on its axis. To one end of the fine silk e, whichflips in the groove of the brass pulley, is fixed a glass vessel

A a with