Gray, Stephen (DNB00)
GRAY, STEPHEN (d. 1736), electrician, was a pensioner of the Charterhouse in London. Thomson, the historian of the Royal Society, observes that the absence of any further biographical details is remarkable; but Desaguliers intimates that Gray's ‘character was very particular, and by no means amiable.’ Priestley, in his ‘History of Electricity,’ avers that no student of electricity ever ‘had his heart more entirely in the work.’ His passionate fondness for new discoveries exposed him to many self-deceptions; but his researches led to very valuable results bearing upon the communication, the conduction, and the insulation of electricity. He was the first to divide all material substances into electrics and non-electrics, according as they were or were not subject to electric excitation by friction. He also discovered that non-electrics could be transformed into the electric state by contact with disturbed and active electrics. Gray's manifold experiments led to the division of substances into conductors and non-conductors. Du Fay recognised the value of Gray's discoveries, and was one of the earliest men of science to apply them. Gray was led from experiments made with a glass tube and a down-feather tied to the end of a small stick to try the effect of drawing the feather through his fingers. He found that the small downy fibres of the feather were attracted by his finger. The success of this experiment depended upon principles not then in Gray's mind; but he was encouraged to proceed, and found that many other substances were electric. He discovered that light was emitted in the dark by silk and linen, and in greater degree by a piece of white pressing paper. He thus gradually mastered the principle of the communication of electric power from native-electrics to other bodies. In 1729 Gray, after many fruitless attempts to make metals attractive by heating, rubbing, and hammering, recollected an earlier suspicion of his own, that as a tube communicated its light to various bodies when rubbed in the dark, it might possibly at the same time convey an electricity to them. He tried experiments with an ivory ball and a feather, and, by studying their attraction, ultimately discovered that electricity could be carried any distance perpendicularly by a thread or other communicator, and (in conjunction with Mr. Wheeler) that a silken line carried at right angles horizontally would continue to conduct the generated electricity to great lengths from the perpendicular course. Gray pursued his investigations alone and with Wheeler, and paved the way for Musschenbroeck's invention of the Leyden phial, the formation of electric batteries, &c. He was the author of several practical papers in the ‘Philosophical Transactions,’ having been elected a fellow of the Royal Society in 1732. He died on 25 Feb. 1736.
[Thomson's Hist. of Royal Soc.; Priestley's Hist. of Electricity; Phil. Trans.]