1911 Encyclopædia Britannica/Musschenbroek, Pieter van

MUSSCHENBROEK, PIETER VAN (1692–1761), Dutch natural philosopher, was born on the 14th of March 1692 at Leiden, where his father johann Joosten van Musschenbroek (1660–1707) was a maker of physical apparatus. He studied at the university of his native city, where he was a pupil and friend of W. J. s’G. Gravesande. Graduating in 1715 with a dissertation, De aeris praesentia in humoribus animalium, Musschenbroek was appointed professor at Duisburg in 1719. In 1723 he was promoted to the chair of natural philosophy and mathematics at Utrecht. In 1731 he declined an invitation to Copenhagen, and was promoted in consequence to the chair of astronomy at Utrecht in 1732. The attempt of George II. of England in 1737 to attract him to the newly-established university of Göttingen was also unsuccessful. At length, however, the claims of his native city overcame his resolution to remain at Utrecht, and he accepted the mathematical chair at Leiden in 1739, where, declining all offers from abroad, he remained till his death on the 9th of September 1761.

His first important production was Epitome elementorum physico-mathematicorum (12mo, Leiden, 1726)—a work which was afterwards gradually altered as it passed through several editions, and which appeared at length (posthumously, ed. by Johann Lulofs, one of his colleagues as Leiden) in 1162, under the title of Introductio ad philosophiam naturalem. The Physicae experimentales et geometricae dissertationes (1729) threw new light on magnetism, capillary attraction, and the cohesion of bodies. A Latin edition with notes (1731) of the Italian work Saggi di naturali esperienze fatte nell-l’Accademia del Cimento contained among many other investigations a description of a new instrument, the pyrometer, which Musschenbroek had invented, and of several experiments which he had made on the expansion of bodies by heat. Musschenbroek was also the author of Elementa physica (8vo, 1729), and his name is associated with the invention of the Leyden jar (q.v.).