ARAGO, one of the founders of nineteenth-century science, was born near Perpignan, France, February 26th, 1786. His discoveries in magnetism and optics combined with his work as an astronomer to make him one of the most famous men of his day, and he increased his celebrity by his uncompromising republicanism. As a member of the French Chamber of Deputies in 1830, he was one of the leaders of the most advanced section of the Republican party. In 1848, after the fall of Louis Philippe, he became Minister of War and Marine, using his influence in the ministry to secure the abolition of slavery in the French colonies and of flogging in the army and navy. After the coup d’état he refused allegiance to Louis Napoleon, and offered his resignation from a scientific board of which he was a member. With a good taste he could show on occasion, Louis refused to accept it, and when Arago died, October 2d, 1853, decreed him a funeral with the highest possible honors. Besides his numerous scientific works, Arago wrote a volume of studies of the lives of scientific men, which has become a part of popular literature in English as well as in French.