THE bicentenary of the birth of the French astronomer Jean-Sylvain Bailly, who was born in Paris on September 15, 1736, and perished on the scaffold at the age of fifty-seven years, recalls a career of great interest, for Bailly was not only a cultivated and distinguished man of science, but he was also one of the enthusiastic philanthropists who at the coming of the French Revolution adopted with ardour the popular cause and endeavoured to secure for the people sound constitutional reforms. The son of a keeper of the King's pictures, it was intended that he should follow in his father's footsteps as a painter, but literature proved more attractive than art, and science more alluring than either. It was his acquaintance with Lacaille that led him to astronomy, and one of his earliest labours was the reduction of Lacaille's observations on zodiacal stars. He also became known for his researches on Jupiter's satellites, but his greatest work was his “Histoire de l'Astronomie”, a work full of animated description, luminous narrative and interesting detail. The correspondent of Voltaire and Buffon, the contemporary of D'Alembert and Diderot, Bailly's versatility was recognized by the unusual honour of his being elected a member of the Academy of Sciences, the French Academy and the Academie des Inscriptions et Belles Lettres.