HORROX (Jeremiah)

, an eminent English astronomer, was born at Toxteth in Lancashire, about the year 1619. From a grammar school in the country, he was sent to Cambridge, where he spent some time in academical studies. About 1633 he began to apply himself to the study of astronomy: but living at that time with his father at Toxteth, in very moderate circumstances, and being destitute of books and other assistances for such studies, he could not make any considerable progress in it. About the year 1636, he formed an acquaintance with Mr. William Crabtree, of Broughton near Manchester, who was engaged in the same studies, with whom a mutual correspondence was carried on till his death; sometimes communicating their improvements to Mr. Samuel Foster, professor of geometry at Gresham College in London. Having now obtained a companion in his studies, Mr. Horrox assumed new vigour, procured other instruments and books, and was pursuing his studies and observations with great assiduity, when he was suddenly cut off by death, the 3d of January 1640, in the 22d year of his age.

What we have of his writings is sufficient to shew how great a loss the world had by his death. He had just finished his Venus in Sole visa, 1639, a little before, as appears by some of the letters to his friend Mr. Crabtree, by which also it appears that he made his observations on that phenomenon at Hool near Liverpool. This tract, of Venus seen in the Sun, was published at Dantzick in 1668, by Hevelius, together with his own Mercurius in Sole visus May 3, 1661. His other posthumous works, or rather his imperfect papers, were published by Dr. Wallis, in 1673, 4to, with some account of his life; in which we find he first asserts and promotes the Keplerian astronomy against the hypothesis of Lansberg; which he proves to be inconsistent with itself, and neither agreeing with observations nor theory. He likewise reasons very justly concerning the celestial bodies and their motions, vindicates Tycho Brah from some objections made to his hypothesis, and gives a new theory of the moon: to which are added the Lunar Numbers of Mr. Flamsteed. There are also extracts from several letters between him and Mr. Crabtree, upon various astronomical subjects; with a catalogue of astronomical observations.

There are two things particularly which will perpetuate the memory of this very extraordinary young man. The one is, that he was the first that ever predicted or saw the planet Venus in the sun; for we do not find that any persons, besides himself and Mr. Crabtree, ever beheld such a phenomenon. Though he was not apprised of the great use that was to be made of it, in discovering the parallax and distance of the sun and planets, yet he made from it many useful observations, corrections, and improvements in the theory of the motions of Venus.—Secondly, his New Theory of Lunar Motions, which Newton himself made the ground work of all his astronomy, relative to the moon, who always spoke of our author as a genius of the first rank.

HORSE-Shoe, in Fortisication, is a work sometimes of a round, sometimes of an oval sigure, inclosed with a parapet, raised in the ditch of a marshy place, or in low grounds; sometimes also to cover a gate; or to serve as a lodgment for soldiers, to prevent surprises, or relieve an over-tedious defence.