He entered Trinity College, Cambridge, June 5, 1660, just as England was astir with restoration festivities, and he soon devoted himself to mathematical studies. Euclid he took in at a glance, and afterward proceeded to master Descartes's geometry. Isaac Barrow, then Lucasian Professor of Mathematics, became his friend and tutor; and the pupil repaid the master's kind attention by services rendered to him in connection with his optical lectures. In 1669, Newton succeeded Barrow in his professorship. He rose to eminence in the university, and in 1688 was chosen its representative in the Convention parliament. In 1695 he was appointed Warden of the Mint, and was promoted to the Mastership in 1699. After his appointment to a government office he left Cambridge to reside in London, and occupied for a time a house in Jermyn Street. From 1710 till two years before his death he lived close to Leicester Square. Next door to Orange Street Chapel there stands an old house which has seen a good many changes, and is identified as the abode of Sir Isaac, who had been knighted by Queen Anne in 1705. We visited it many years ago. The part of the house most intimately associated with his name is the little observatory perched on the roof. We were permitted to ascend into that spot, to see it desecrated by its present use, for there we found a shoemaker busy at his toil. A glass cupola probably crowned the observatory in Newton's time, and evidently there was a window in each of the four walls. So here he looked out on the London of nearly a century and a half ago, hardly less crowded and smoky about the neighborhood than now. Overhead, where Newton turned his eyes with most interest, we know it was just the same; the same beautiful stars shining out on a cold winter's night, the same planets sailing along the same blue ocean, the same moon throwing its light over the same old city. What observations, keen and searching, what calculations, intricate and profound, what speculations, far-reaching and sublime, must there have been, when one of the most gifted of mortals from that spot looked out upon the heavens, and in thought went forth on voyages of discovery into the distant regions of the universe! At the calm, still hour of midnight, Sirius watching over the city of sleepers, Jupiter carrying his brilliant lamp along his ancient pathway, every one of the luminaries in the place appointed by Him who calleth them all by their names--there stood the thoughtful man, with his reflecting telescope, occupied with thoughts which we common mortals in vain endeavor to conjecture.