MUSSCHENBROEK, PETER VAN, an eminent natural philosopher, was born at Leyden in March 1692. Studying at the university of his native city, he became a proficient in classics under Perizonius and Gronovius, and in natural philosophy, chemistry, and medicine, under Senguerd, Bidloo, Le Clerc, Burman, Albinus, Boerhaave, and Rau. The teacher, however, from whom he derived the most profit was the eminent mathematician Gravesande. A scientific partnership was formed in 1717 between the master and the pupil, for the prosecution of natural philosophy according to the principles of Newton, and in opposition to those of Descartes. Gravesande concentrated his attention on the theoretical part of the study; Musschenbroek conducted the experiments; and both, by their separate investigations, corrected or confirmed the results obtained by each other. The consequence was, that the downfall of Cartesianism, and the establishment of Newtonianism, were very much accelerated in Holland. In increasing the knowledge, and in determining the future studies of Musschenbroek, the effect was also great. An inaugural dissertation which he delivered in 1718, on the occasion of taking his degree, brought out into full prominence his taste and talent for experimental science. It was entitled De Aeris Præsentia in Humoribus Animalium, and was full of experiments, carefully prosecuted and clearly explained. His fame was now established. He was appointed professor of natural philosophy and mathematics, and professor extraordinary of medicine in the university of Duisburg in 1719. In 1723 he was promoted to the chair of natural philosophy and mathematics at Utrecht. He was now placed in his proper sphere, and began to prosecute his favourite studies with increased vigour. His first important production was Epitome Elementorum Physico-Mathematicorum, 12mo, Leyden, 1726, a work which was afterwards gradually altered as it passed through several editions, and which appeared at length in 1762, under the new title of Introductio ad Philosophiam Naturalem. The publication in 1729 of his next great work, Physica Experimentales et Geometricæ Dissertationes, raised his reputation to its acme. It threw new light on the subjects of the magnet, capillary attraction, and the cohesion of bodies. Scarcely less instrumental in advancing science was his Latin edition, in 1731, of the Italian work Saggi di Naturali Esperienze fatte nell' Accademia del Cimento. The numerous notes which he appended to this translation contained, amid many other curious investigations, a description of a new instrument, the pyrometer, which he had invented, and of several experiments which he had made on the expansion of bodies by heat. His great eminence was acknowledged in this same year by an invitation from the King of Denmark to Copenhagen. He declined this honour, 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 took possession of the mathematical chair at Leyden in 1739. Here he resolved permanently to settle. Offers of preferment from Berlin, Madrid, and St Petersburg, were tendered to him in quick succession; yet, declining all these honours, he continued peacefully to instruct his pupils, and to pursue his favourite investigations till the day of his death in September 1761.
Musschenbroek is also the author of Elementa Physica
8vo, 1734, translated into English by Colson, in 2 vols. 8vo, 1744. He contributed a dissertation on Barometers to the Memoirs of the Academy of St Petersburg, and several papers on Meteorology to the Memoirs of the French Academy of Sciences, and to the Transactions of the Royal Society of London.