Profession: chemist

Dumas did important work in organic chemistry, and on molecular and atomic weights. De Candolle, the warmly supportive de la Rive and Saussure were senior members of Geneva’s scientific community, the first two also teaching him. Humboldt encouraged him to move to Paris, where he taught Thénard’s course before succeeding him. Wöhler brought him a pound of platinum, Thomson worked under him, and Kekulé attended his lectures and befriended him. Liebig, not wholly a rival, also visited, and wrote an article with him. A famously inspiring teacher, Dumas persuaded his student Pasteur (a lifelong friend) to give up art for chemistry.

Gregory, an influential teacher, first isolated morphine in a usable form (though it took twenty years for its great advantages as a painkiller to be appreciated). Having graduated in medicine in Edinburgh, Gregory studied under Liebig on his famous chemistry course in Giessen; Liebig became a good friend, Gregory doing much to make his pioneering work on organic chemistry available in Britain. Gregory assisted Turner in London for a year; Liebig and he later collaborated on an extensively updated edition of Turner’s ‘Elements of Chemistry.’ Crum Brown was one of Gregory’s Edinburgh students.

Stromeyer pioneered the hands-on, laboratory-based approach to chemistry teaching developed in Germany, as well as being a significant analytical chemist in his own right, discovering the element cadmium. He studied with Gmelin’s father in Göttingen before becoming a postgraduate pupil of Vauquelin in Paris. Bunsen and Mitscherlich were the most important of his students. Gmelin and Turner studied with him too; Turner felt himself indebted to Stromeyer, was proud in later years to call himself a friend, and dedicated a book to him.

Chevreul did fundamental work in organic chemistry, wrote influentially about colour, was a pioneer gerontologist, and aged 100 took part in the first-ever photo-interview (with Nadar). He studied under, assisted and succeeded Vauquelin, and also knew Fourcroy, Lamarck, Jussieu, Geoffroy and Cuvier from the Natural History Museum. Gay-Lussac and he patented a better way of making candles. He gave Seurat (who had written to him) a scientific basis for his ideas about colour, and had Faraday, Ampère and Liebig as friends. Wöhler wrote excitedly to Berzelius, another friend and admirer, about meeting him in Paris.

Paulze was Lavoisier’s wife and importantly, his collaborator; later she (briefly and stormily) married Rumford. Lavoisier’s co-worker Laplace was fond of her, but Guyton was cold-shouldered for not having supported him. She studied with David and painted her close friend Franklin. Her visitors included Monge, Berthollet, Fourcroy, Lagrange, Arago, Biot, Delambre, Humboldt, Edgeworth, Priestley, Watt and Young. She converted Saussure, a correspondent, to the ‘new’ chemistry. Cuvier thanked her warmly for the two volumes of Lavoisier’s research that she produced after his death. Banks sent her a gift of passion-fruit.

Jussieu, Condillac, Lacaille, Nollet and Guettard all taught him as a young man. Together with Berthollet, Fourcroy and Guyton de Morveau he established a consistent sytem of nomenclature in chemistry, which still underpins the science. He married Paulze when she was 13; she went on assist and collaborate with him. Working together with Laplace he demonstrated (with guinea pigs) that respiration was a form of combustion. His rival Priestley corresponded with him, he installed lightning-conductors on a church roof with Franklin, and with Haüy determined the exact weight of the kilogram.

Klaproth, described as “incorruptibly accurate”, was a pioneer of analytic chemistry, discovering or co-discovering several metallic elements. Berzelius, the truly great chemist of the age, was a correspondent, and closely involved in the discovery or identification of some of the same elements. Van Marum also corresponded with Klaproth, while Humboldt made a point of introducing his friend Gay-Lussac to him. Bode was a professional colleague; Klaproth’s naming of uranium, after Uranus, helped seal the planet’s agreed name. Werner was both student and friend, while the orientalist Julius Klaproth was his son.