HEVE'LIUS, JOANNES, or more properly JOANNES REVEL, a Polish astronomer of great eminence, was born at Danzig, of a noble family, January 23, 1611. After visiting the principal countries of Europe (1630-34), he returned to his native city, and was occupied in busiocss or public affairs till ]639, when, by the advice of Cruger, whose pupil he had been, he applied himself almost exclusively to the study of astronomy. In 1641 ho built an observatory iu his own house, and furnished it with a quadrant and sextant of three and four feet diameter, together with large telescopes constructed by himself. His scientific pursuits did not however preclude his being elected consul in 1651, to which distinction his rank in society and philosophic character entitled him, and of which he continued to discharge the duties to the time of hls death. In 1647 he published a description of the moon, under the name of 'Selenographia' (Gedsni, folio), to which was added a representation of the other planets as seen by the telescope. In 1654 appeared his treatise De Motu Lunn Libratorie' (Gedatii, folio), in the form of a letter to Riccioli, wherein ho gave an explanation of the libration of the moon. (Montucla, 'Hist.. des Math6m.; tome IL p. 638.) To these succeeded an account of the cclipace of 1654 : a treatise, 'De Nature Saturni Faciei ejuaque Pha sibus ' (1656); Observations on the Transit of Mercury' in 1661, to which he added an account of the transit of Venus in 1639, se observed by liorrox (Gedani, 1661); ' Observations of the Comets of 1664 and 1665; published in 1665 and 1666 ; and in 1668 appeared his Cometo graphia.' In 1672 appeared an epistle to Oldenburg on the comet of that year ; and in 1673 the first part of the Machina Ccelestis ' was published. it was this last work which gave rise to public controversy between Hevelius and Dr. Hooke, who published • Animal in Mach. Celeat. lievelii; Loud., ]674, in 4to. Hevelins always imagined that better observations could be made with plain sights than with tele scopes. Hooke recommended the use of the latter to Hevelins on the receipt of a copy of his' Cometographia; and some correspondence took place, which was increased into a quarrel by the dictatorial manner of Hooke in the work just cited. Halley was requested by the
Royal Society of London to visit Hevelius at Danzig, and judge of the goodness of his observations. This voyage, which was made in 1679, produced a report from Halley highly favourable to Hevelius. In 1664 Hevelius was elected a member of the Royal Society of London. In 1679 he sustained considerable loss by the destruction of his house and observatory by firo. The whole of his iustrumeats and library were destroyed, including most of the copies of the second part of his ' Machina Ccelestis; which had only been published that year. This second pert is now extremely rare. This accident appears only to have had the effect of increasing his ardour in the pursuit of astronomy, for ho shortly after erected a new observatory, thoogh on a less magnificent scale; and by 1685 he had another volume of observations ready for publication. He had now been occupied forty-nine years as an observer, and had attained sixty-three years, the climacteric, as it used to be called, of life, for which reason this volume (the last pub lished during his lifetime) is entitled Annus Climactericus.' His posthumous works are Firmameatum Sobieskiauum' (1690) and •Prodromus Astronomic's' (1691). Hej died at Danzig, universally respected, in 1637.88, and in his seventy-sixth year. Duriog his life time he carried on an active correspondence with most of the learned men of Europe. The letters of his correspondents, and numerous observations, in 17 folio volumes, were purchased of his family by M. 'Mille in 1725, and some of these were published by J. P. Kohlius in the supplement to the ninth volume of the ' Acta Eruditorum,' sect. viii. p. 359: the rest are at the Royal Observatory at Paris. His relation, J. E. Olhoff, published a considerable number of letters written to him in 1683.
Hevelius comes next to Flamsteed among the men of his day, as a diligent and accurate observer of the heavens. His Firinementum Sobieskianum' is a standard catalogue of stars, containing the places of 950 stars known to the ancients, 603 observed by himself, and 373 southern stars by Halley. For a full account of all his labours, see Delambre, 'Hist. Astron. Mod.,' vol. ii. pp. 434-484 ; see also Weidler, 'Hist. Astron.,' p. 485.