STRUVE, FRIEDRICH-GEORG-WILHELM, a celebrated astronomer, was b. at Al tuna, April 15,1793, edttcated at the university of Dorpat (Russia), and appointed to a post in the observatory of that place in 1813. He became director of the Dorpat observatory in 1S17, and continued with the utmost assiduity his observations and re searches double and multiple stars, adding immensely to our knowledge of these systems; and earning for himself the reputation of beino. one of the most skillful of practical astronomers. '1 he instrument with which lie observed was a Fraunhofer's (q.v.) refractor, of 10 in. aperture, and 131 ft. focal length; and with this telescope, in gleaning from the depths of space the materials for his three important works on double stars (1822 and 1828, 1S37 and 1840, 1852), he examined no fewer than 120,000 of these twinkling luminaries. His investigations have led him to the conclusion, that the number of true double stars is much larger than was previously supposed (see STARS). Struve also executed a number of important geodetic operatic ,s, such as the triangula tion of Livonia, in 1816-19, and the measurement of an arc of 'the meridian in the Baltic Provinces, iu 1822-27; which was subsequently (1828-56) extended by him in conjunction with Hansteen (q.v.) and Selander, to the North Cape; and Tenner
southward to Ismail in Turkey. This latter undertaking, the most extens:ve trigono metrical operation ever performed, when completed, gave the length of a meridian arc of 20', and enabled geometers to determine with increased accuracy the exact form of the earth. Meanwhile, Struve had been appointed, in 1839, director of the best organ ized observatory in the world, that of Pulkova (q.v.), and also chosen correspondant in the astronomical section of the academy of sciences of Paris. He died at St. Peters burg Nov. 23, 1S64.—His son, OTTO-WILHELM STRUVE, also an eminent astronomer, was born at Dorpat, May 7, 1819, was educated under his father's direction, became his chief assistant at Pulkova, and the director of the observatory after his death. He has made numerous astronomical discoveries, among which are more than 500 new double stars, and (1847) a satellite of Uranus, and has written numerous important papers, the most noticeable of which set forth his researches on the inner or dusky ring, and on the variation in breadth of the bright rings of Saturn, and on the periodic motions of double stars.