ON February 5 occurs the centenary of the birth of the distinguished German astronomer, Friedrich August Theodor Winnecke, who at the early age of twenty-eight years was elected an associate of the Royal Astronomical Society, and was for a time the vice-director of Pulkova Observatory. The son of a pastor, Winnecke was born in a village in Hanover, and after leaving school studied at Gottingen and Berlin, coming under the influence of both Gauss and Encke. At the age of twenty-one years he became an assistant at Bonn to Argelander, who was then engaged on his great star maps. A visit by Wilhelm. Struve to Bonn led to Winnecke in 1858 becoming a member of the staff at Pulkova, where he worked under both Wilhelm and Otto Struve, until in 1865 he was overtaken by severe mental illness. During those years he had observed the comets of 1856 and 1862, watched in Spain the total solar eclipse of 1860, made notable observations on Mars and compiled the first Pulkova General Catalogue of Stars. When he regained his health, he settled at Carlsruhe, and after the conclusion of the Franco-German war was appointed to the chair of astronomy at Strasbourg and charged with the task of erecting an observatory. He spent some ten years there, when to the great loss of astronomical science he was attacked by melancholia and from that time until his death at Bonn on December 2, 1897, the cloud which settled on his mind never lifted. He had been a frequent contributor to German, English and Russian astronomical publications, and was widely known as a great teacher of practical astronomy.