RECENTLY, about four hundred French scientists and one hundred ladies filled the large hall of the PROFESSOR RAMSEY LECTURING IN THE HALL OF THE FRENCH SOCIETE D'ENCOURAGEMENT,PARIS. building belonging to Le Societe d'Encouragement—a French equivalent to the British Society of Arts —Paris, when Prof. Ramsey delivered a lecture on argon, the newly discovered element in the atmosphere. Prof. Ramsey spoke fluently in excellent French. The general properties of argon having been previously explained to the Academy by M. Berthelot, and described by almost every French paper, the speaker confined himself to narrating the' circumstances of the discovery and the peculiarities of argon. In the more abstruse parts of his lecture Prof. Ramsey was assisted by a magic lantern. The concluding portion of the lecture was devoted to a discussion of the hypothetical presence of“ helium” in company with argon, in a rare mineral from Norway. A hand spectroscope had been placed for the purpose on each side of the chair, exhibiting- separately the rays of argon and the rays of helium. At the conclusion of the address, the whole of the audience broke into a loud round of applause, while Prof. Ramsey handed over to M. Berthelot a glass tube full of argon and helium, in order that the great French scientist might make fresh and crucial investigations.