VALLEY, EDMUND, was born October '29, 1656, at Ilaggeraton, near London, at a country-house belonging to his father, who was a soap-boller in Wine:theater-street, London. Ile was educated at St. Paul's School, under the care of Dr. Gale, and was placed at Queen's College, Oxford, in 1673, being then possessed of much erudition for his ago, and a strong turn for observation, as appears by his having discovered for himself before he left school the alteration in the varia tion of the magnetic inutile. At tho university, being well supplied with instruments by his father, ho began to apply himself to astronomy, and before lie readied the age of twenty he had given (in the 'Phil. Traus.') a memoir on the problem of Kepler, had invented a method of constructing the phases of a solar eclipse, and hal made many observations, particularly of Jupiter and Saturn, the results of which we shall presently see. Finding however that nothing could be dune in planetary astronomy without more correct tables of the stare, and relying upon Flamateud and lievelius for the amelioratiou of the northern catalogues, he determined, with his father's consent and assistance, to appropriate to hitneolf the task of feratiug a catalogue of the southeru hemisphere. Furnished with a recommeudation from Charles II. to the East India Company, he set sail for St. Helena in November 1676, and remained there two years. Ilia Catalogus Stet !arum Australium,' published in 1679, was the result of this Joyago, and contains, besides the positions of 350 stars, some other points of interest, particularly an observation of the transit of Mercury over the sun's disc, and a hint that such observations might be employed to determine the sun's parallax (afterwards so successfully carried into effect with the planet Venus). lie also notices the increased curvature of the moon's orbit when in quadratures, which was afterwards ex plained by Newton. In his voyage out he had observed the fact that the oscillations of a pendulum increase in duration as the instrument approaches the equator.
At his return from St. Helena the king granted him a mandamus to the University of Oxford for tho degree of Master of Arts, and he was elected a Fellow of the Royal Society. This body sent him to Danzig
in 1679 to judge of the observations of lievelius, who maintained the superior accuracy of instruments with simple eights, in opposition to Hook, who advocated the use of the telescope. Halley was a man of rapid movements : in November 1678 he returned from St. Helena ; in May 1679 he set out for Danzig, having in the interval published his catalogue, and procured his Oxford degree, and admission to the Royal Society. He returned from Danzig in July, and remained at home till the end of 1680, at which time be set out on a continental tour, accompanied by his schoolfellow Mr. Nelson, since well known as the author of a work on the Feasts and Fasts. In December, beiag on the road to Paris, he saw the celebrated comet of 1680 in its return I from perihelion, ',clog the first who perceived it since it was lost iu the preceding month. This body he observed with Cassini at Paris, and the observations thus made are remarkable as forming part of the foundation upon which Newton, in the ' Principle, verified his dedue Hon of a cumet's orbit from the theory of gravitation. He returned to England at tho end of 1031, and in 1682 married the daughter of Mr. Tooke, auditor of the Exchequer, with whom he lived fifty-fivo years. He resided at Islington till 1696, aud in 1683 published his theory of the Variation of the Magnet, followed by other papers iu subsequent years, containing ingenious speculations, now forgotten. His astro nomical occupations during this period consisted chiefly of lunar observations and comparisons. Ile was strongly of opinion that the moon would, when sufficiently known, furnish the means of finding the longitude, and at this period it seems that he had formed the idea of observing that body through a whole revolution of the nodes. His observations (1682.84) are published in Street's ' Astrociornit Carolina.' Ile was interrupted however by the state of his father's affairs, which had suffered by the great fire.