Paris, J. [L.] Boilly, 1820. Engraved broadsheet (36.3 x 27.3 cm).

A rarely-seen portrait of the French chemist Claude Louis Berthollet (1748-1822). He became vice president of the French Senate in 1804 and is known for his scientific contributions to theory of chemical equilibria via the mechanism of reverse chemical reactions, and for his contribution to modern chemical nomenclature. On a practical basis, Berthollet was the first to demonstrate the bleaching action of chlorine gas, and was first to develop a solution of sodium hypochlorite as a modern bleaching agent. Interestingly, he has a small mollusc named after him ( Rissoina bertholleti, from the Red Sea), which suggests that he was interested in zoology too. The artist, Julien-Léopold Boilly (1796-1874) was noted for his album of lithographs, Iconographie de l'Institut royal de France ou collection des portraits des Membres composant les quatre académies depuis 1814 jusqu'en 1825 (1820-1825). His portraits are much less stiff and formal than many by his contemporaries. Signed by the artist in the lower left margin of the portrait and dated 1820. The caption states the date of his birth and the years when Berthollet was elected as a member of the Académie, and the Institut. Uncut. With in the lower left corner a small, oval blindstamp, 'Galerie Vivienne Bénard'. Some light creasing and denting in the right margin; otherwise very good.