David Brewster

1781 (Jedburgh, Scotland) – 1868 (Melrose)

Among his closest friends were Talbot (they corresponded in detail about Talbot’s photographic inventions), Roget (who was delighted by Brewster’s kaleidoscope), and Scott. On continental visits, he met Berthollet, Poisson, Arago, Biot, Laplace, Gay-Lussac, Pictet and de la Rive, while Gauss wrote his last-ever letter to him. Ordinarily mild, he found himself completely at odds with Whewell, Wheatstone and Fresnel. He taught Adamson the calotype process and introduced him to Hill, joined Babbage and Herschel in founding the British Association, and fell in love with his pupil, the cousin of his good friend-to-be, Somerville.

Thomas Paine

1737 (Thetford, England) – 1809 (New York)

Paine was a member of the radical dissident group around Johnson, also including Godwin, Wollstonecraft, Blake, Price, Priestley and Franklin (who encouraged his first visit to America). Priestley’s and Paine’s fortunes were intertwined, both being burned in effigy in England and ending as eminent yet half-forgotten refugees in America, former members of Jefferson’s intellectual circle. Paine left Godwin and others to see his ‘Rights of Man’ published while on Blake’s advice he fled to France. Condorcet was among his French ‘philosophe’ friends. Paine met Fulton in Paris, and gave a model of his iron bridge design to Peale.

Erasmus Darwin

1731 (Elston, England) – 1802 (Breadsall)

The Lunar Society’s lynchpin, Boulton, Small, Edgeworth, Josiah Wedgwood, Priestley, Watt, Keir and Withering were friends and associates — Boulton, Wedgwood, Watt, Edgeworth and Small (whose deathbed Darwin was beside) particularly close. He borrowed botanical books from Banks, advised Beddoes to set up in Bristol, translated his correspondent Linnaeus’s work, and contrived a ‘casual’ meeting with Rousseau in Dovedale. Coleridge was enthralled by his learning if not his versifying, while Franklin (lifelong friend and mentor) grumbled about his pond’s smell. Fuseli, another good friend, illustrated his ‘Botanic Garden.’

James Watt

1736 (Greenock, Scotland) – 1819 (Handsworth, England)

Watt did far more than mechanically improve the steam engine – he invented the concept of feedback, for example. In Scotland, Black got Watt employed as instrument-maker (the start of a long close friendship), Hutton became a close friend while Smith (perhaps unappreciative) also met him. Among Lunar Society colleagues in England, Priestley hugely admired him, Small advised him, the steam-enthusiast Darwin became a particularly close friend, while the entrepreneur Boulton entered a highly successful 25-year partnership with him. He developed equipment for Beddoes, sold engines to Fulton, contributed to Brewster’s encyclopaedia, and corresponded with Thomas Wedgwood (about photography), Berthollet and Coulomb.

Benjamin Thompson, Count Rumford

Benjamin Thompson;Count Rumford;Reichsgraf von Rumford

1753 (Woburn, Mass.) – 1814 (Auteuil, France)

Rumford was devious, pompous, a philanthropist, philanderer and spy, whose dictatorial manner left him friendless. With Banks and Cavendish, he founded the Royal Institution, personally selecting Davy and Young as scientific lecturers (before leaving the R.I. abruptly, possibly embezzling its funds). He caused John Trumbull’s arrest, took Watt’s designs, crossed the English Channel with the horrified Gibbon, and worked with Volta while lying low in Italy. Lagrange, Laplace, Berthollet and Delambre became his companions in Napoleon’s Paris, where he contracted a disastrous marriage with Paulze. He bequeathed Davy his gold watch.

Charles Babbage

1791 (London) – 1871 (London)

Babbage and John Herschel became friends as students, and stayed close colleagues for life. With Peacock and Whewell they started a society at Cambridge to counter the poor maths teaching there. Babbage discussed geothermal ideas with Lyell, map-making with Humboldt (who invited Gauss to meet Babbage over breakfast), wrote to Davy about a calculating engine, and influenced both Darwin and Mill. Among his huge circle of friends and correspondents were Dickens, Stowe, Ruskin and Mendelssohn; Cameron, Martineau and Somerville; Nasmyth, Brunel, Boole and de Morgan; and scientists from Ampère to Le Verrier.

George Eastman

1854 (Waterville, New York) – 1932 (Rochester, New York)

Edison was an early customer of Eastman’s — their inventions were mutually complementary — and cooperated with him over a long period. Baekeland sold his photographic-paper invention to him for thirty times what he’d thought reasonable. Pathé had met Eastman early in the century, and made contact again in the 1920’s to merge their firms. Barnard briefly worked with Eastman (who was adept at employing the right people); Frances Benjamin Johnston had her first camera sent to her by Eastman, a family friend, and acted as his business agent in Washington, but it is unclear what kind of contact they enjoyed.

George Eastman knew…

Henry David Thoreau

1817 (Concord, Mass.) – 1862 (Concord)

Thoreau, not as reclusive as reputed, was friends (often close) with many authors of mid-19th-century classics. He worked for his neighbour and mentor Emerson as tutor, handyman and gardener. Hawthorne was a fireside companion, described his ugliness as honest and agreeable, and took him to dine with Longfellow. Whitman gave him a personal copy of ‘Leaves of Grass’. Thoreau told Louisa May Alcott how frogs were more confiding in the spring (she said that his beard would deflect amorous advances). He built a fancy summerhouse for her father, and sent Agassiz specimens from Walden Pond at age 12.

Henry David Thoreau knew…

Alois Senefelder

1771 (Prague) – 1834 (Munich)

Weber’s father knew Senefelder from the Bavarian Court Theatre. Father and son learned lithography from him — the 14-year-old Weber actually being apprenticed to him so he could one day publish his own music, and becoming very proficient at the technique, before his father had a falling-out with Senefelder.

Alois Senefelder knew…

Claude Niépce

1763 (?Chalon-sur-Saône, France) – 1828 (Kew, England)

Nicéphore Niépce was his younger brother, now much better known from his connection with Daguerre and photography. But the two brothers worked together on a hydraulic engine with fewer moving parts than others, the world’s first internal combustion engine, as well as pioneering photographic processes. Claude’s death in 1828 — he had gone to England to try to expoit their internal combustion engine — has probably contributed to his marginalisation. Carnot in his official position examined the Niépce’s hydraulic engine and was impressed by it, but told them the emperor had decided upon someone else’s plan.

Claude Niépce knew…