II. On the electric properties of insulating or non-conducting bodies

The object of the author in the first part of this memoir is to ascertain by experiment what condition is assumed by insulating or non-conducting bodies in the presence of an electrified body, and in what degree such condition is developed in insulating bodies of different kinds. In a memoir published nearly ten years ago (Ann. de Chim. et de Phys., xxvii. p. 134), he had shown that a cylinder of gum-lac, sulphur, stearic acid, or the like, suspended by a filament of silk, and brought near to a body charged with electricity, begins to oscillate in the same way as a cylinder of metal. The non-conducting cylinder, whilst under the influence of induction, behaves any body charged with opposite electricities, and returns to its natural state when the induction ceases. These experiments have now been very carefully repeated with cylinders formed of various insulating substances, made as nearly as possible of the same length and perfectly diselectrized. The air was rendered perfectly dry, and the inducing ball was charged with electricity to a constant degree, measured by the torsion-balance.