Volume 1

A manual of electricity, magnetism, and meteorology / [D. Lardner].

  • Dionysius Lardner
Date:
1841-1844
Catalogue details

Licence: Public Domain Mark

Credit: A manual of electricity, magnetism, and meteorology / [D. Lardner]. Source: Wellcome Collection.

    27/464 page 7
    (8.) About the year 1730 commenced that splen- did series of discoveries which has proceeded with accelerated speed to the present day, and now forms the body of electrical science. Mr. SrepHen Grey, a pensioner of the Charter House, impelled by a passionate enthusiasm, engaged in a course of ex- perimental researches, in which were developed some general principles, which produced important effects on subsequent investigations. (9.) The most considerable discovery of Mr.Grey was, that all material substances might be reduced, in reference to electrical phenomena, to two classes, electrics and non-electrics; the former, including all bodies then supposed to be capable of electric ex- citation by friction; and the other, those which were incapable of it. He also discovered that non- electrics were capable of acquiring the electric state by contact with excited electrics. As the experi- ments which led to these conclusions were of the highest interest, we shall here state them. (10.) Desiring to make some experiments with an excited glass tube, he procured one about three feet and a half long, and an inch and a quarter in dia- meter. To keep the interior free from dust, he stopped it at the ends with corks. When this tube was excited, he happened to present one of the corks to a feather, and was surprised to observe that the feather was first attracted, and then re- pelled by the cork, in the way it was wont to be by the glass tube itself. He concluded from this, that the electric virtue conferred on the tube by friction passed spontaneously to the cork. B 4
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