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 uation. In 1660 he took a second journey into France; and the year following he visited England, where he communicated the art of polishing glasses for telescopes, and was admitted a member of the Royal Society. The air-pump, then recently invented, he materially improved; and about the same time he also discovered the laws of the collision of elastic bodies, as did afterwards Wallis and Wren, who disputed with him the honor of the discovery. After a stay of some months in England, Hüygens returned to France, where, in 1633, his merit became so conspicuous, that Colbert resolved to bestow on him such a pension as might induce him to establish himself at Paris. This resolution was not carried into effect until 1665, when letters in the king's name were written to the Hague, where the philosopher then resided, inviting him to repair to Paris, and offering him a considerable pension, with other advantages. Hüygens accepted the proposal; and from 1666 to 1681, settled at Paris, where he was admitted a member of the Royal Academy.

During this period he was chiefly engaged in mathematical pursuits: he wrote and published several works, which were favorably received; and he invented and improved some useful instruments and machines. By continued application, his health began to be impaired, and he at length found it necessary to return to his native country—a step somewhat accelerated by the revocation of the Edict of Nantes, which rendered him liable to molestations, although assured of the fullest privilege to follow his own religious opinions. He accordingly left the French metropolis in 1681; passed the remainder of his days in his own country, and in the pursuit of his favorite subjects; and died at the Hague on the 8th of June 1683, in the sixty-seventh year of his age. 'This illustrious man,' continues our authority, 'gave his whole time to science; he loved a quiet studious life, and found sufficient enjoyment in pursuing curious and useful researches. He was modest, amiable, cheerful, and in all respects as estimable in private life as he was eminent in science. It is not a little singular that the discovery of the real nature, or at least of the true figure, of the luminous ring which encompasses the planet Saturn, should have been made by the same individual who invented the pendulum clock and the micrometer.' His inventions, however, were more of a mathematical and mechanical than of an astronomical character; and we safely predict, that had Hüygens lived in the present day, he would have risen to superlative fame as a mechanician and engineer.

HALLEY.

Dr. Edmund Halley, a name well known in the annals of astronomy, was the only son of a soap-boiler in London, and was born in 1656. He received the rudiments of his education at St. Paul's School in his native city; and in his seventeenth year, became a commoner in Queen's College, Oxford. At first he applied himself to the study of the languages and sciences, but at length gave himself wholly up to that of astronomy; and before he had attained his nineteenth year, published a method of finding the aphelia and eccentricity of planets, which supplied a defect in the Keplerian theory of planetary notions. By some observations on a spot on the sun's disk in the summer of 1676, he established the certainty of the motion of that body round its own axis; and in the same year fixed the