attention to problems of vegetable chemistry, discovering the methods by which free nitrogen can be fixed under the influence of electrical discharge and the part played by the microbes of the soil in the fixation of nitrogen. For these researches a laboratory was built for him at Meudon. At the same time Berthelot published a series of important works on the history of chemistry and of alchemy, showing wide scholarship and archeological research. He also published a series of works on the philosophy of science, of ethics and of education.
Berthelot was active in public af-