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JOHN POND (c. 1767-1836)

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Originally appearing in Volume V22, Page 60 of the 1911 Encyclopedia Britannica.
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JOHN POND (c. 1767-1836), English astronomer-royal, was born about 1767 in London, where his father made a fortune in trade. He entered Trinity College, Cambridge, at the age of sixteen, but took no degree, his course being interrupted by severe pulmonary attacks which compelled a long residence abroad. In 1800 he settled at Westbury near Bristol, and began to determine star-places with a fine altitude and azimuth circle of 22 ft. diameter by E. Troughton: His demonstration in 18o6 (Phil. Trans. xcvi. 420) of a change of form in the Greenwich mural quadrant led to the introduction of astronomical circles at the Royal Observatory, and to his own appointment as its head. He was elected a fellow of the Royal Society on the 26th of February 18o7; he married and went' to live in London in the same year, and in 1811 succeeded Maskelyne as astronomer-royal. During an administration of nearly twenty-five years Pond effected a reform of practical astronomy in England comparable to that effected by Bessel in Germany. In 1821 he began to employ the method of observation by' reflection; and in 1825 he devised means (see Mem. Roy. Astron. Soc. ii. 499) of Combining two mural circles in the determination of the place of a single object, the one serving for direct and the other for reflected vision. Under his auspices the instrumental equipment at Greenwich was completely changed, and the number of assistants increased from one to six. The superior accuracy of his determinations was attested by S. C. Chandler's discussion of them in 1894, in the course of his researches into the variation of latitude (Astron. Journ. Nos. 313, 315)/ He persistently controverted (1810-1824) the reality of J. Brinkley's imaginary star-parallaxes (Phil. Trans. cviii. 477, cxiii. 53). Delicacy of health compelled his retirement in the autumn of 1835. He died at Blackheath on the '7th of September 1836, and was buried beside Halley in the churchyard of Lee. The Copley medal was conferred upon him in 1823, and the L'alande prize in 1817 by the Paris Academy, of which he was a corresponding member. He published eight folio volumes of Greenwich Observations, translated Laplace's Systkme du monde (in 2 vols. 8vo., 1809), and contributed thirty-one papers to scientific collections. His catalogue of 1112 stars (1833) was of great2 (After Wossidlo. From Strasburger's Lehrbuch der Botanik.) Potamogeton natans. 1, Apex of flowering shoot. 3, Flower viewed from the side. 2, Flower viewed from above. 4, Diagram of flower. axillary or terminal spikes; they have four stamens, which bear at the back four small herbaceous petal-like structures, and four free carpels, which ripen to form four small green fleshy fruits, each containing one seed within a hard inner coat; the seed contains a large hooked embryo: An allied genus Zannichellia (named after Zanichelli, a Venetian botanist), ' occurring in fresh and brackish ditches and pools in Britain, and also widely distributed in temperate and tropical regions, is known as horned pondweed, horn the curved fruit.
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