WINLOCK, Joseph, astronomer, born in Shelby county, Kentucky, 6 February, 1826 ; died in Cambridge, Massachusetts, 11 June, 1875. He was graduated at Shelby college, Kentucky, in 1845, where he was appointed professor of mathematics and astronomy. In 1852-'7 he was one of the computers in the office of the "American Ephemeris and Nautical Almanac" in Cambridge, Massachusetts, and then he was appointed professor of mathematics at the United States naval academy, Annapolis, Maryland, but he soon returned to Cambridge as superintendent of the "Nautical Almanac." In 1859 he relinquished this office to take charge of the mathematical department of the United States naval academy; but on the removal of that institution to Newport, Rhode Island, at the beginning of the civil war, he resumed charge of the "Almanac." He was appointed in 1866 professor of astronomy in Harvard, and director of the observatory, and subsequently he was professor of geodesy in the Lawrence scientific and mining schools of the university. His first work after taking charge of this observatory was the reduction and publication of the unfinished work of his predecessors, thus completing the volume on sun-spots, the catalogue of zone stars, and of polar and clock stars that has since been published. Meanwhile the instrumental appliances were carefully studied and largely increased, not only by the accumulation of new forms, but by the introduction of improved apparatus of his own device. The meridian circle was procured through his influence at a cost of $12,000. In 1870, when the new instrument was ready for use, it was directed upon the zone of stars between 50, and 55º of north declination, which was the field assigned to the Harvard observatory by the Astronomische Gesellschaft. His other work included a catalogue of new double stars and much labor on stellar photometry, he was further active in the efforts that have resulted in furnishing standard time to Boston. In 1872 he began the preparation of a series of astronomical engravings to represent the most interesting objects in the heavens as they appeared in the powerful instrument of the observatory. Thirty-five plates were completed at the time of his death, and included representations of the planets, sun-spots, protuberances, and corona; the moon's craters and geography, seven of the most famous clusters and nebulae, the Donati comet of 1858 and Coggia's comet of 1874. He held the office of consulting astronomer of the United States coast survey, and in 1874 was appointed chairman of the commission that was established by act of congress for making inquiries into the causes of steam-boiler explosions. Professor Winlock had charge of the party that was sent by the United States coast survey to Kentucky to observe the total solar eclipse of August, 1860, and conducted the expedition to Spain, under the same auspices, to observe the eclipse in December, 1870. The degree of A. M. was conferred on him by Harvard in 1868, and he was a member of various scientific societies, including the American academy of arts and sciences. In 1863 he was named by act of congress as one of the corporate members of the National academy of sciences. His published works consist chiefly of a set of "Tables of Mercury," of other publications from the office of the "American Ephemeris," and of brief papers in astronomical journals and in the proceedings of scientific societies of which he was a member.