The astronomer-mathematician Fatio, originator of a mechanistic theory of gravity, is now known primarily as an associate of others. At 18 he introduced himself to Cassini with an account of Saturn’s rings, subsequently studying under him in Paris. Going to the Netherlands to warn William of Orange of a plot against him, he worked with Huygens, then settling in London became Newton’s very close friend (exciting some latter-day speculation as to its nature, Newton seemingly suffering a breakdown when the relationship ended). He was friendly with Locke and corresponded widely, including with Leibniz, whom he charged with ‘stealing’ Newton’s invention of calculus.
He was a close friend of Swift, Pope and Gay, fellow-members of the ‘Scriblerus Club’ (which met in his house), and is thought to have directly inspired some of Swift and Pope’s work. He met Newton and Pepys in Oxford, where a private pupil of his was studying; later he found himself caught in a row between Newton and Flamsteed over Flamsteed’s star catalogue. Sloane was a correspondent, and Handel a friend — Arbuthnot officially managed his opera productions within the U.K. Swift and he were fond of perpetrating practical jokes, as well as making mischief with political pamphlets they published.
Stirling made small but significant advances to the work of both Newton, whose friendship he enjoyed during his decade in London, and Euler, who wrote congratulating him on the usefulness of his results. Maclaurin, a friend, respected his work and appears to have tried to help his career, though Stirling’s support of the Jacobites worked against him. De Moivre, working on similar problems, corresponded, as did Clairaut and Bradley. Arbuthnot proposed Stirling’s election to the Royal Society; however, distracted by mining business, Stirling himself took 2 years to reply to Euler, and failed to propose him in turn.
One of the most influential scientists and mathematicians ever, Newton was a key figure in the scientific revolution. Barrow taught him at Cambridge and recommended him as his own successor. Halley was one of his keenest supporters – his zealous enthusiasm encouraged Newton to publish his Principia Mathematica. Newton met Huygens in London, told his former friend Flamsteed to stick to observation (not theory), and tried to discredit Leibniz (corresponding via Oldenburg as intermediary). He corresponded with Boyle about alchemy, Pepys about gambling odds, and Hooke (whose criticisms hurt) about optics. Cheselden advised against operating when Newton was dying.
Leibniz was perhaps the last great universalist, contributing to disciplines from biology to probability and from theology to linguistics. He was one of the three great 17thC rationalist philosophers, the inventor (independently of Newton) of infinitesimal calculus, and advanced the design of calculating machines. Huygens was a mentor. Leibniz spent several days in deep discussion with Spinoza, met Boyle, Leeuwenhoek and Goldbach, and corresponded extensively with the Bernoullis, von Tschirnhaus, Arnauld, Bayle, Sloane and Oldenburg. Newton and he never met nor corresponded directly. Wallis wrote refusing him permission to teach cryptography to students in Hannover.
Notable for much more than his comet, the prodigy Halley started observing with Flamsteed even before the Royal Observatory was built. His catalogue of Southern stars made his name aged 22, though Flamsteed – never hurried, and later his professional enemy – criticised his hasty methods. Cassini, met in Paris, advised him on observing the transit of Mercury. Halley discussed the shape of an orbit with Wren and Hooke, but beaten by the maths, asked Newton for the answer. He knew Pepys and Arbuthnot well, met Leibniz en route to Vienna, and travelled to Danzig to resolve Hevelius and Hooke’s acrimonious dispute.
Buffon prepared natural history for its modernisation. Maupertuis acted as his mentor. D’Alembert called him “the great phrasemonger.” Daubenton collaborated with him for eight years before being unceremoniously ditched. Helvétius and Rousseau stayed with him, Hume and Jefferson were correspondents, Châtelet consulted him on Newton, and Lamarck took his teenage son around Europe. Smellie translated his Histoire Naturelle, Buffon trying to impress him with his important Scottish contacts. Buffon mocked Voltaire’s ideas about fossils, and got Winsløw and Lacépède posts in the royal gardens, realigned by him as a research centre.
A leading figure of the Scottish Enlightenment, Maclaurin’s work in geometry and algebra had him compared to the leading continental mathematicians of his time; he was also an inspiring teacher (and a professor aged only 19). Halley invited him to London, where he also met Newton (whose helpful friendship Maclaurin described as the greatest honour and happiness of his life). He corresponded extensively with Clairaut, and also with Campbell, Monro and Stirling – both Monro and Stirling were friends, though Stirling’s strong Jacobite leanings put them on opposite sides when Maclaurin led the defence of Edinburgh.
Although Celsius is best known for the temperature scale bearing his name, he was primarily an astronomer. Having visited the main centres of astronomy in Europe, meeting Cassini among others, he was instrumental in the expedition led by Maupertuis going to Swedish (now Finnish) Lapland rather than to Norway; Clairaut was a companion on this difficult journey to establish the Earth’s true shape, which led to Cassini’s obstinate defiance of their findings. Celsius gave short shrift to Swedenborg’s ideas about magnetic declination. Linnaeus, a correspondent, recommended the flipping of the temperature scale shortly after Celsius’ death.
Jennings and Empson, fellow-students, co-founded a literary magazine with Bronowski. An aspirant poet at the time, he helped Riding on a project in Mallorca, before falling out (Graves found him smug). He bumped into Beckett in Paris, editing an anthology and translating a surrealist magazine with him (putting Duchamp’s notes into English). He interviewed Durrell, and struck his colleague Attenborough as inspired. Huxley and Ayer were fellow radio ‘brains’. He discussed plans for an institute with Salk, becoming colleagues there with his great friend Szilard, Crick (who inherited an office and a model brain from him), and Monod.