In Paris, Oersted spent about fifteen months, during which time he was in habitual relations with many of the savants who were just then reflecting great lustre on French science. To mention but a few: there was Cuvier, the leading naturalist of his age; Abbé Haüy, crystallographer of world-wide reputation; Biot, the brilliant expounder of physics; Charles, the discoverer of the law which bears his name; Berthollet, the associate of Monge the mathematician, and Lavoisier, the chemist. On his return to the Danish capital in 1804, Oersted delivered courses of lectures on electricity and magnetism, light and heat, before numerous and cultured audiences; and such was the success which he achieved that he was appointed, at the age of twenty-nine, to the chair of physics in the University of Copenhagen. For nearly forty-five years he was destined to occupy this academical position, so that his connection with that seat of learning rounded out the full period of half a century. While sedulously occupied with the duties of his chair and the pursuit of his favorite scientific subjects, Oersted was not unmindful of his civic and altruistic obligations. He frequently gave popular scientific lectures, which were open to women as well as to men. He helped in the organization of a bureau through which lectures would be given in various parts of the country, and thus became a pioneer in what we call to-day the university extension movement. When democratic ideas began to be discussed in Denmark after the French Revolution of 1830, Oersted was one of those who took part in the onward movement for the betterment of the people. In 1835, he coöperated in the foundation of the Society for the Freedom of the Press; and when Christian VIII. ascended the throne, he addressed the new monarch in a speech of liberal tendency, hailing him because of the interest which he took in the advancement of science and in the uplift of the masses.