In

a propensity to natural philosophy and astronomy. He studied mathematics under Peter Crugerus, in which he made a wonderful progress; and learned also to draw, to engrave, and to work both in wood and iron in such a manner as to be able to frame mechanical instruments. 1630 he set out upon his travels, on which he spent four years, visiting Holland, England, France, and Germany; and on his return was so taken up with civil affairs, that he was obliged to intermit his studies for some years, until his master, Crugerus, who foresaw his future fame, recalled him to the study of astronomy; and in 1639 Hevelius began to apply himself entirely to it, by building an observatory upon the top of his house, which he furnished with instruments for making the most accurate observations. He constructed excellent telescopes himself, and began his observations with the moon, whose various phases and spots he noted very accurately; "with a view," as he says, "of taking lunar eclipses with greater exactness, and removing those difficulties which frequently arise for want of being able to settle more precisely the quantity of an eclipse." When he had finished his course of observations, and prepared a great number of fine engravings, he published his work at Dantzick, 1647, under the title of "Selenographia, sive, Lunæ descriptio;" to which he added, by way of appendix, the phases of the other planets, as they are seen through the telescope, with observations upon them, upon the spots of the sun and Jupiter in particular; all engraved by himself upon copper, and distinctly placed before the eyes of the reader. At the entrance of this work there is a handsome mezzotinto of himself by Falek, as he then was, in his thirty-sixth year, with a just encomium, although in bad Latin verse.

After this, Hevelius continued to make his observations upon the heavens, and to publish, from time to time, whatever he thought might tend to the advancement of astronomy. In 1654 he published two epistles; one to the famous astronomer Ricciolus, "De motu Lunæ libratorio;" another to the no less famous Bulialdus, " De utriusque luminaris defectu." In 1656, a dissertation "De natura Saturni faciei, ejusque phasibus certa periodo redeuntibus." In 1661, "Mercurius in sole visus." In 1662, "Historiola de nova stella in collo Ceti." In 1665, "Prodromus Cometicus, or the history of a Comet, which appeared in 1664." In 1666, "The History of another Comet, which VOL. XVII. FF

appeared in 1665;" and, in 1668, "Cometographia, cometarum naturam, et omnium à mundo condito historiam exhibens." He sent copies of this work to several members of the royal society at London, and among the rest to Hooke; who in return sent Hevelius a description of the dioptric telescope, with an account of the manner of using it; and at the same time recommended it to him as greatly preferable to telescopes with plain sights. This gave rise to a dispute between them; the point of which was, "whether distances and altitudes could be taken with plain sights nearer than to a minute." Hooke asserted that they could not; but that, with an instrument of a span radius, by the help of a telescope, they might be determined to the exactness of a second. Hevelius, on the other hand, insisted, that, by the advantage of a good eye and long use, he was able with his instruments to come up even to that exactness; and appealing to experience and facts, sent by way of challenge eight distances, each between two different stars, to be examined by Hooke. Thus the affair rested for some time with outward decency, but not without some inward animosity. In 1673 Hevelius published the first part of his "Machina Cœlestis," as a specimen of the exactness both of his instruments and observations; and sent several copies as presents to his friends in England, but omitted Hooke. This, it is supposed, occasioned Hooke to print, in 1674, "Animadversions on the first part of the Machina Cœlestis;" in which he treated Hevelius with great disrespect, and threw out several unhandsome reflections, which were greatly resented; and the dispute grew afterwards so public, and rose to such a height, that, in 1679, Halley went at the request of the royal society, to examine both the instruments and the observations made with them. Halley gave a favourable judgment of both, in a letter to Hevelius; and Hooke, merely from his mode of managing the controversy, was universally condemned, though the preference has since been given to telescopic sights. Hevelius, however, could 'not be prevailed with to make use of them: whether he thought himself too experienced to be informed by a young astronomer, as he considered Hooke; or whether, having made so many observations with plain sights, he was unwilling to alter his method, lest he might bring their exactness into question; or whether, being by long practice accustomed to the use of them, and not thoroughly apprehending the use of the other, nor well understanding the difference, is uncertain. Besides Halley's letter, Hevelius received many others in his favour, which he took the opportunity of inserting among the astronomical observations in his "Annus Climactericus," printed in 1685. In a long preface prefixed to this work, he spoke with more confidence and greater indignation than he had done before; and particularly exclaimed against Hooke's dogmatical and magisterial manner of assuming a kind of dictatorship over him. This revived the dispute, and caused several learned men to engage in it. The book itself being sent to the royal society, an account was given of it at their request by Dr. Wallis; who, among other things took notice, that "Hevelius's observations had been misrepresented, since it appeared from this book, that he could distinguish by plain sights to a small part of a minute." About the same time, Molyneaux also wrote a letter to the society in vindication of Hevelius against Hooke's " Animadversions." Hooke drew up an answer to this letter, which was read likewise before the society; in which he observed, "that he was not the aggressor, and denied that he had intended to depreciate Hevelius."

In 1679, Hevelius had published the second part of his "Machina Cœlestis;" but the same year, while he was in the country, he had the misfortune to have his house at Dantzic burnt down. By this calamity he is said to have sustained several thousand pounds damage; having not only his observatory and all his valuable instruments and astronomical apparatus destroyed, but also a great number of copies of his "Machina Cœlestis;" which accident has made this second part very scarce, and dear. In 1690, were published a description of the heavens, called, "Firmamentum Sobiescianum," in honour of John III. king of Poland; and "Prodromus astronomiæ, & novæ tabulæ solares, unà cum catalogo fixarum," in which he lays down the necessary preliminaries for taking an exact catalogue of the stars. Both these works, however, were posthumous; for Hevelius died January 28, 1687, which was the day of his birth, on which he entered upon his 77th year. He was a man greatly esteemed by his countrymen, not only on account of his skill in astronomy, but as an excellent and worthy magistrate. He was made a burgomaster of Dantzic; which office he is said to have executed with the utmost integrity and applause. He was also very highly esteemed by foreigners; and not only by foreigners skilled in astronomy and the sciences, but by foreign princes and potentates: as appears abundantly evident from a collection of their letters, which were printed at Dantzic in 1683.'

HEWSON (William), an eminent anatomist, was born at Hexham, in Northumberland, November 14, 1739. He attended the grammar school of that town until he was apprenticed to his father, a surgeon and apothecary of reputation; after which he resided some time with Mr. Lambert, surgeon, at Newcastle. In 1759 he was sent to London, and resided with that distinguished anatomist, Mr. John Hunter, attending the lectures of his no less celebrated brother, Dr. Wm. Hunter. Young Hewson's assiduity and skill having attracted the attention of the teachers, he was appointed to superintend the dissecting room, while Mr. Hunter went abroad with the army in 1760; and in 1762, after studying a year at Edinburgh, he became associated with Dr. Hunter, and occasionally delivered the anatomical lectures; and when Dr. Hunter's spacious establishment was completed in Windmill-street, Mr. Hewson was allotted an apartment in the house. Here he pursued his anatomical investigations, and "his experimental inquiries into the properties of the blood;" an account of which he published in 1771, and he communicated to the royal society several papers containing an account of his discoveries of the lymphatic system in birds and fishes, for which he received the Copleyan medal, and was soon after elected a fellow of that body. In 1770, his connection with Dr. Hunter was dissolved, and he began a course of anatomical lectures alone in September 1772, in Craven-street; and published a second edition of his "Experimental Inquiry," which he dedicated to sir John Pringle, as a testimony of gratitude for the undeviating friendship of that illustrious physician. In the spring of 1774, he published his work on the "Lymphatic system." At this time his anatomical theatre was crowded with pupils, his practice was daily increasing, and his ardour for experimental research undiminished, when he was seized with a fever, occasioned by a wound received in dissecting a morbid body, which terminated fatally on the Ist of May 1774, in the thirty-fifth year of his age. His papers, which were afterwards collected together, were originally published in the 23d, 24th,

Martin's Bigg. Philos.-Ward's Gresh, Professors. - Moreri. - Saxii Qoom,

25th, and 28th volumes of the Philosophical Transactions, annis 1768-73.1

HEXHAM, ROGER of. See ROGER.

HEYLIN (Dr. PETER), an English divine, descended from an ancient family at Pentre-Heylin in Montgomeryshire, the son of Henry Heylin, gent. by Elizabeth, daughter of Francis Clampard, of Wrotham in Kent, and was born at Burford in Oxfordshire, Nov. 29, 1600*. In 1613 he was entered of Hart-hall in Oxford, and two years after chosen a demy of Magdalen-college. He had, while at school, given a specimen of his genius for dramatic poetry, in a tragi-comedy on the wars and fate of Troy; and now composed a tragedy, entitled "Spurius," which was so approved by his society, that the president, Dr. Langton, ordered it to be acted in his apartments. After this, he read cosmographical lectures in the college, which being a very unusual thing, and he very conversant in that branch of science, so much recommended him to the society, that he was chosen fellow in 1619. In 1621 he published his "Microcosmus, or Description of the World;" the chief materials of which were the lectures just mentioned. It was universally approved, and so speedily sold, that, in 1624, it was reprinted in the same size, but with considerable additions, and again presented to prince Charles, to whom it had been dedicated. It was soon after put into the hands of the king, who seemed at first greatly pleased with it; till meeting with a passage in it, where Heylin gave precedency to the French king, and styled France the more famous kingdom, he took so much offence, that he ordered the lord-keeper to suppress the book. Heylin, to