Paris, C. Gerschel, ca. 1900. Original photo (14.0 x 10.0 cm), mounted on original publisher's cardboard (16.3 x 10.3 cm).

Portrait of the influential French chemist Pierre Eugène Marcellin Berthelot (1827-1907). He was "...noted for the Thomsen-Berthelot principle of thermochemistry. He synthesized many organic compounds from inorganic substances, providing a large amount of counterevidence to the theory of Jöns Jakob Berzelius that organic compounds required organisms in their synthesis. He is considered as one of the greatest chemists of all time." (Wikipedia). The photographer, Charle Gerschel, specialized in portraits, but surprisingly little is known about him. He was born in 1871, but the year of his death is variously recorded as 1930 and 1948. A fine portrait on cardboard, with Gerschel's advertisements printed on the rear. Very rare.