CELSIUS, seTsffis, the name of a Swed ish family, several members of which attained celebrity in science and literature: 1. MAGNUS CELSIUS : b. in the old province of Helsingland 1621; d. 1679. He became professor of mathe matics in the University of Upsala and published two works on the antiquities of his native province and was the discoverer of the Helsing runes. Besides mathematics and archaeology, he cultivated poetry with some success, and was so skilled in practical mechanics that he himself made all the scientific instruments he required in his astronomical observations, etc. 2. His son, Nu.s b. 1658; d. 1724; also filled the mathematical chair in Upsala University. 3. OLAF CELSIUS, another son of Magnus: b. 1670; d. 1756. He early became famous as an earnest student of the Oriental languages and of botany. He was successively appointed to the chairs of Greek, Oriental languages and theol ogy, and filled the office of provost of the cathedral at Upsala. He devoted a good deal of attention to the study of runology and was among the first to recognize the genius of Lin naeus, whom he liberally patronized. In 1745— 47 he published his voluminous work, botanicon,) a description of all the plants men tioned in the Bible. 4. ANDERS CELSIUS, son of
Nils Celsius, and the most distinguished of the family; b. 27 Nov. 1701; d. 1744. After being appointed professor of astronomy at the Uni versity of Upsala, he traveled in Germany, Eng land, France and Italy. At his instigation the observatory at Upsala was built, and he became its first director. In 1736 he took part in the famous expedition that was undertaken by Maupertuis, Clairaut, Camus and others for the purpose of measuring a degree of the merid ian in Lapland. For his services in this expe dition he received a pension from the French king. He is best known at the present day as the constructor of the Centigrade thermometer.
He urged the adoption of the Gregorian calen dar. He published observationibus pro figura Telluris) (1738). 5. OLAF CELSIUS the younger, son of the Orientalist and naturalist, and cousin of the preceding: b. 1716; d. 1794. He became bishop of Lund, and devoted him self to history and poetry. His principal his torical works are (Ecclesiastical History of the Kingdom of of Gustavus I) ; (History of Erik XIV.)