Guettard, famously blunt, was a pioneer of geological field-work. He studied botany with Réaumur and Jussieu. Linnaeus corresponded, naming a genus after him; Haller and the amateur botanist Rousseau were also in contact. Lavoisier’s father was a friend of Guettard, who employed the young Lavoisier as an assistant (encouraging him to go on to study chemistry); they made several geological field-trips together, and were commissioned to produce the first (unfinished) geological map of France. Daubenton was a close colleague. Buffon approvingly quoted Guettard’s Polish researches, despite the animosity between them.
d’Aubuisson (or Aubuisson, as he is also referred to) was one of the first to point to the problem with his influential teacher Werner’s ideas about the origins of igneous rocks. The writer Novalis was a student at Freiberg at the same time as Aubuisson, and credited him with teaching him mathematics.
Buch was one of the influential Werner’s best-known students, who increasingly questioned Werner’s beliefs about rock-formation, in favour of the plutonist views that still hold today. He met both Humboldts while studying in Freiberg — Alexander (who became a lifelong friend) and he both lodged with Werner, and journeying back from studying Vesuvius with Gay-Lussac, visited Volta in northern Italy. Buch was impressed by Wöhler’s knowledge, helping him get his first job. Contemptuous of the young Agassiz’s glacial theories, Buch shouted at him; Charpentier and Élie de Beaumont joined the two on a fractious hike in the Jura, following Agassiz’s lecture.
Werner had a double influence: on geology and in particular the significance of stratification, and on German Romanticist writing and philosophy (in both cases through the students he taught). Klaproth was one of Werner’s own teachers. Among his many students were Humboldt, Mohs, Charpentier, del Rio, von Buch and d’Aubuisson de Voisins; both Humboldt and von Buch lived with Werner while studying in Freiberg. The writer Novalis and the philosopher and poet Steffens also studied geology with him (as did Robert Jameson, whose own lectures in geology bored the 16-year-old Darwin).
A polymath, Saussure was a founder of geology (a word he coined) and of alpinism. He collected plant specimens for Haller, his mentor and friend. Bonnet got him to train for his ascent of Mont Blanc by climbing the stairs 8 or 9 times daily. He helped fund the Montgolfiers, and took temperature-readings inside their balloon. Volta inspired him. He met Guyton de Morveau in Dijon, Buffon in Paris, Franklin in London, and dined with Banks the evening before Bank’s departure on Cook’s voyage. Humboldt visited, after one of his cyanometers, and Jefferson offered him a post in Virginia when he’d fallen on hard times.
Despite d’Orbigny’s obsolete ideas (including that there had been 28 creations of life, and 27 total extinctions), much of his detailed work has had continued relevance. Audubon was a childhood friend in France (d’Orbigny’s father gave him drawing lessons). Cuvier and Geoffroy taught him, and were responsible for the seven-year South American expedition he undertook (Cuvier died while he was away). Humboldt, met in Paris (and whose colleague Bonpland was a family friend of the d’Orbigny’s), correctly asserted that the funds for the expedition wouldn’t be enough. Darwin corresponded though never met him, and thought his work second only to Humboldt’s.
King authored a classic geological text, led classic geological surveys, and promoted the use of contour-lines to specify altitude. Ruskin and Doré were among his heroes (he’d founded a group at Yale inspired by Ruskin’s writings); he travelled to Europe in his retirement to meet them both. Dana taught him at Yale, and Agassiz at Harvard. Bierstadt, the painter of sublime Western landscapes, was among his artist friends, joining in on some of his wilderness trips, as also did the photographers Watkins (whom King greatly admired) and O’Sullivan. He seems to have got on well with all.
Buckland taught him. He visited Cuvier and Humboldt in Paris, wrote excitedly to Mantell about Lamarck’s ideas, and became a close colleague of Sedgwick and Whewell. He made volcanic observations with Murchison in France and Italy, corresponded with Agassiz, and asked Fitzroy to look out for erratic boulders (Fitzroy gave Darwin Lyell’s book to read, as influential on him as it was on others). Hooker, Huxley, Herschel and Darwin all became good friends (he also knew Browning), Whewell expressed concern about his evolutionary beliefs, while the brilliant but obtuse Owen made a point of antagonising him (as with many others).
Werner taught Charpentier, and was a colleague of his father’s. Venetz, a friend and colleague, often met with Charpentier to discuss ideas together; Venetz was at first more persuaded about some puzzling aspects of glacial action than his more sceptical friend. Charpentier hosted Lyell, and later Schimper for a 3-month stay that was crucial in his formalisation of a full theory of glaciation; Agassiz was already there, initially to study fossils not glaciers, while Venetz also visited. Agassiz dedicated his subsequent work on glaciation to Charpentier and Venetz, conveniently forgetting to mention his old friend Schimper’s contribution.
As a young geologist visiting Cumbria, he met Wordsworth, whom he befriended, Southey and Dalton. Murchison and he visited Germany, Tyrol, Wales and Scotland together, but collaboration on a paper led to a long bitter feud. Darwin learned his geology from him (Henslow introduced them); they stayed friends for life, despite Sedgwick’s strong antipathy to Darwin’s evolutionary theory. Owen, Lyell and de la Beche were professional colleagues and the eccentric Buckland his counterpart at Oxford. Whewell, Herschel and Airy were all close to him. Agassiz examined his fossil fish collection and became a firm friend.