Columbus performed his vast undertaking in an age of great deeds and great men, when Ficino taught the philosophy of Plato, when Florence was thrilled by the luring words and martyrdom of Savonarola, when Michael Angelo wrought his everlasting marvels of art. While Columbus, in his frail craft, was making his way to "worlds unknown, and isles beyond the deep," on the shores of the Baltic a young novitiate, amid the rigors of a monastic life, was tracing the course of the planets, and solving the problem in which Virgil delighted[47]--problems which had baffled Chaldean and Persian, Egyptian and Saracen. Columbus explained the earth, Copernicus explained the heavens. Neither of the great discoverers lived to see the result of his labors, for the Prussian astronomer died on the day that his work was published. But the centuries that have come and gone have only increased the fame of Columbus and Copernicus, and proven the greatness of their genius. COLUMBUS AND THE FOURTH CENTENARY OF HIS DISCOVERY. Commander CLEMENTS ROBERT MARKHAM, R. N., C. B., F. R. S., a noted explorer and talented English author. Midshipman in H. M. S. Assistance in the Franklin Search Expedition, 1850-51. Born July 20, 1830, at Stillingfleet, near York. From a paper read before the Royal Geographical Society of England, June 20, 1892. In the present year the fourth centenary of the discovery of America by Columbus will be celebrated with great enthusiasm in Spain, in Italy, and in America. That discovery was, without any doubt, the most momentous event since the fall of the Roman Empire in its effect on the world's history. In its bearings on our science, the light thrown across the sea of darkness by the great Genoese was nothing less than the creation of modern geography. It seems fitting, therefore, that this society should take some share in the commemoration, and that we should devote one evening in this session to a consideration of some leading points in the life of the foremost of all geographers. * * *