- Michael Ben-Chaim
Gray, Stephen (bap. 1666, d. 1736), experimental philosopher, was baptized on 26 December 1666 at All Saints' Church, Canterbury, the fifth of the seven children of Matthias Gray (or Graye), a dyer, and Anne Tilman. He came from a family of rapidly rising artisans who lived in Canterbury for several generations. His great-grandfather bought the freedom of the city to trade as a blacksmith in 1599 and his grandfather was a blacksmith too, but his father established a family dyeing business. Gray entered the business and was granted the freedom of the city to trade as a dyer in 1692. Definitive information concerning his formal education is lacking, but it is likely that he received a useful primary education, probably at St Mary of the Poor Priests, one of the two schools in Canterbury that provided basic education for sons of local tradesmen.
During the 1690s Gray began to show a growing interest in natural curiosities. The acquisition of amateur knowledge of nature was considered a definite step into polite society, and was closely associated with social and economic ascent, giving a 'man of polite imagination … a kind of Property in every thing he sees' (The Spectator, 21 June 1712, 411). Through his brother Matthias, a grocer who became the mayor of Canterbury in 1692 and who was an amateur naturalist himself, Gray established links with two major centres of learning, the Royal Society of London and the Royal Greenwich Observatory. His connection with Henry Hunt, a minor official at the Royal Society from near Canterbury, earned him his first copies of the society's official journal, the Philosophical Transactions. His early experimental work was inspired by the articles he read in the journal. He studied insects in long-standing water, and systematically investigated small organisms in a variety of fluids readily available to him, such as 'wine, Brandie, vinegar, beer, spittle, urine, etc.' (A letter from Stephen Gray, PTRS, 19, 1696, 284). During the course of these studies he developed a special interest in designing observational equipment, such as a water microscope, which used a water droplet inserted in a tiny hole in a brass plate, and a method for improving the barometer so as to make the mercury level more accurately determinable. Moreover, like many other naturalists of his time, he developed an interest in palaeobiology. He carefully recorded his observations and studies in letters to Hans Sloane, the secretary of the Royal Society. Several of these records were published in the Philosophical Transactions.
From 1696 Gray was in regular contact with the astronomer royal, John Flamsteed. His astronomical reports primarily dealt with solar and lunar eclipses, the revolutions of Jupiter's satellites, and sunspots. He also devised a new technique for drawing a meridian line using the pole star, and explained how his observational arrangement could be used to confirm 'the truth of the Earth's motion' (A letter from Stephen Gray, PTRS, 22, 1701, 818). His reports suggest that he used several telescopes of different sizes, and it is possible that he constructed his own instruments, with lenses he ground himself.
Gray's letters to Flamsteed show a modest, loyal man, devoted to patient research. He worked determinedly, despite his poor health caused by years of hard labour as an artisan. Unlike wealthier naturalists he lacked the money to purchase books and instruments, which were made available to him by Flamsteed. Yet it was typical of the patronage system within which Gray pursued his scientific interests that his services to Flamsteed were not confined to astronomical observations. He was rewarded with an unusual commission in 1705: to investigate a ghost story, which excited Canterbury as well as London, relating the apparition of a dead woman, Mrs Veal. Gray responded to Flamsteed's request with a meticulous and sober account of the affair (which was also the topic of a successful short story written by Defoe).
However, it was through his electrical studies that Gray gained fame, by inaugurating a new approach to the phenomenon of electricity and interweaving philosophical learning with public entertainment. Writing to Hans Sloane in 1708, he reported his admiration of the 'Luciferous Experiments and Noble Discoveries' (Chipman, An unpublished letter of Stephen Gray, 34) in electrical phenomena that the curator of experiments at the Royal Society, Francis Hauksbee the elder, had published in the Philosophical Transactions over the previous three years. Emulating Hauksbee, Gray forwarded his own electrical experiments to Sloane. At the time of this letter Gray was staying at Trinity College, Cambridge, to assist the new Lucasian professor, Roger Cotes, in his attempts to establish an observatory there. He subsequently returned to Canterbury. In 1716 he moved to London and became an assistant to J. T. Desaguliers, Hauksbee's successor at the Royal Society.
In their attempts to systematize the experimental production of electrical effects, Hauksbee and Desaguliers had reaffirmed the traditional assumption associating electrical effects with the material properties of the amber-like bodies known as electrics. However, Gray's early reports challenged this basic assumption. He noted that attraction and repulsion were not systematically related to the electric, since very light objects in its vicinity attracted and repelled one another as well. In an article dated 1720, Gray introduced a new concept by which he attributed electrical effects to the 'communication' of the electrical ‘vertue’, rather than to the electric itself (PTRS, 31, 1720, 140–48). This concept of electrical conductivity provided the crucial means for a breakthrough in electrical research: it created the opportunity to recognize, investigate, and reproduce new phenomena that were no longer confined to the behaviour of electrics.
Gray was admitted to the Charterhouse as a pensioner in 1720. Towards the end of the 1720s his innovative work began to be publicly appreciated, as he embarked upon a new experimental project, which consisted in the development of techniques for the ‘communication’ of electricity. The new trials were held in his residence at the Charterhouse and at the estates of John Godfrey, an amateur astronomer, and Granvil Wheler, a fellow of the Royal Society. His experimental reports show his determination to transmit electricity as far as possible, using a variety of materials as 'lines of communication'. From 1731 until his death in 1736, his audience included members of the Royal Society, who rewarded him with a fellowship in 1733 and the first Copley medal for scientific achievement, as well as companies of ladies and gentlemen who witnessed his performances at the Charterhouse. He held his audience by exciting sparks from water, turning Charterhouse schoolboys into electrical conductors, and condensing the electric vertue in various materials over a period of weeks. The communicated electrical vertue rapidly conquered the market of polite culture. The new effects were soon exhibited as 'philosophical fireworks' which, along with other conjuring tricks, popularized experimental natural philosophy.
In the poetic imagery of his assistant at the Charterhouse, Anna Williams, who was a daughter of one of the pensioners, Gray's experimental virtuosity was the emblematic key 'to break the sleep of elemental fire: To rouse the pow'rs that actuate Nature's frame' (Williams, 42). In the eyes of William Stukeley, a contemporary fellow of the Royal Society, the spectacular identification of the new principle of communication singled Gray out as 'the father, at least first propagator, of electricity' (Family Memoirs, 378). For experimental philosophers in Britain and on the continent, Gray's work comprised the conceptual basis for the distinction between conductors and non-conductors and the recognition that all material bodies fall into these categories, and it paved the path for the invention of the Leyden jar.
Gray's last contribution to science was an electrical simulation of pendulum motion to explain planetary motion—an endeavour to link his astronomical experience with his achievements as an electrician. Shortly before his death, as he was lying ill at the Charterhouse, he communicated an outline of the new project to the secretary of the Royal Society in person. Gray died the next day, 17 February 1736.
- D. H. Clark and L. Murdin, ‘The enigma of Stephen Gray, astronomer and scientist, 1666–1736’, Vistas in Astronomy, 23 (1979), 351–404
- M. Ben-Chaim, ‘Social mobility and scientific change: Stephen Gray's contribution to electrical research’, British Journal for the History of Science, 23 (1990), 3–24
- R. A. Chipman, ‘An unpublished letter of Stephen Gray on electrical experiments, 1707–1708’, Isis, 45 (1954), 33–40
- J. L. Heilbron, Electricity in the 17th and 18th centuries: a study of early modern physics (1979)
- S. Schaffer, ‘Natural philosophy and public spectacle in the eighteenth century’, History of Science, 21 (1983), 1–43
- S. Schaffer, ‘Self evidence’, Critical Inquiry, 18 (1992), 327–62
- R. A. Chipman, ‘The manuscript letters of Stephen Gray, FRS, 1666/7–1736’, Isis, 49 (1958), 414–33
- I. B. Cohen, ‘Neglected sources for the life of Stephen Gray’, Isis, 45 (1954), 41–50
- J. T. Desaguliers, A course of experimental philosophy, 2 vols. (1734–44)
- F. Hauksbee, Physico-mechanical experiments on various subjects, 2nd edn (1719)
- J. Priestley, The history and present state of electricity, 3rd edn, 1 (1775)
- A. Williams, ‘On the death of Stephen Gray’, Miscellanies in prose and verse (1766), 42
- parish register (baptism), 26/12/1666, Canterbury, All Saints' Church
- ‘A letter from Granvile Wheler esq., to Dr Mortimer … containing some remarks on the late Stephen Gray FRS his electrical circular experiment’, PTRS, 41 (1739–41), 118–25
- NMM, Greenwich, Royal Observatory
- BL, Sloane MSS
- RS, letters to Royal Society
Wealth at Death
received Charterhouse pension