Hevelke, John, an eminent astronomer, was born at Dantzig on the 28th of January 1611. He studied in Germany, England, and France, and everywhere obtained the esteem of the learned. He was the first who discovered a kind of libration of the moon, and made several important observations on the other planets. He also discovered several fixed stars, which he denominated the Firmament of Sobieski, in honour of John III., king of Poland. His wife was also skilled in astronomy, and made part of the observations published by her husband. In 1673 he published a description of the instruments with which he made his observations, under the title of Machina Celestis, and in 1679 he published the second part of this work; but in September the same year, whilst he was at a seat in the country, he had the misfortune to have his house at Dantzig burnt down. By this calamity he is said to have sustained a loss of several thousand pounds; for not only were his observatory and all his valuable instruments and apparatus destroyed, but also a great number of copies of his Machina Celestis; an accident which has rendered the second part very scarce, and consequently very dear. Hevelius died on the 28th of January 1687, his birth-day, at the age of seventy-six. He was a man greatly esteemed by his countrymen, not only on account of his skill and reputation in astronomy, but as an excellent and worthy magistrate. He was appointed a burgomaster of Dantzig; an office which he executed with the utmost integrity and approbation. He was also highly esteemed by foreigners, not only by those who were skilled in astronomy and the sciences, but by foreign princes and potentates; as appears from a collection of their letters to him, which was printed at Dantzig in the year 1683. The printed works of Hevelius are, 1. Selenographia, Dantzig, in folio; 2. Letters to Eichstadt on an Eclipse of the Moon, to Gassendi and to Boulliau on an Eclipse of the Sun, 1649, and to Riccioli on the Libration of the Moon; 3. Letter to Nucerius on Eclipses, 1654; 4. De Nativa Saturni Facie, 1656; 5. Mercurius in Sole visus, 1662; 6. Historia mirae Stella in collo Ceti, 1662; 7. Prodromus Cometicus, Descriptio Cometae, Mantissa Prodromi Cometicet, 1665 and 1666, in folio; 8. Cometographia, 1668, in folio; 9. Machina Celestis, pars prior, 1673; 10. Epistola de Cometa anni 1672, Id. anni 1677, in 4to; 11. Machina Celestis, pars posterior, 1679; 12. Annus Climactericus sive Observationum quadragesimus nonus, 1685. The posthumous works of Hevelius are, 1. Prodromus Astronomiae, 1690; 2. Uranographia seu Firmamentum Sobescianum, 1690; together with Excerpta ex Litteris illustrium et clariss. Virorum ad Jo. Hevelium perscriptis, judicia de rebus astronomicis ejusdemque scriptis exhibentia, Dantzig, 1684, in 4to.