MUSSCHENBROEK, PETRUS VAN

(b. Leiden, Netherlands, 14 March 1692; d. Leiden, 19 September 1761)

physics.

Musschenbroek belonged to a well-known family of brass founders and instrument makers who were originally from near Tournai in Hainaut and who settled at Leiden in the latter part of the sixteenth century. His grandfather, Joost Adriaensz(1614–1693), manufactured lamps, especially church lamps, and was also a gauger of weights and measures. He was succeeded in his craft by his sons Samuel (1639–1681) and Johan (1660–1707). In accordance with the spirit of the times, they turned their skill to the making of scientific apparatus such as air pumps, microscopes, and telescopes. Christiaan Huygens mentions one of them as a maker of microscopes (letters of 1678 and 1683, Oeuvres complètes, VIII, 64, 422: see also bid., XXII, 762). Swammerdam used a microscope made by Samuel (Boerhaave, in his preface to the Biblia naturae, 1737); and the anatomist Regnier de Graaf employed anatomical injection spouts also made by him. Leeuwenhoek’s aquatic microscope (letter to the Royal Society of 12 January 1689) was made by Johan. Many of Johan’s instruments are still preserved; the extant instrument made by Samuel is an air pump of 1675.

In 1685 Johan married Maria van der Straeten; they had two sons, Jan (1687–1748) and Petrus. Jan, who succeeded his father in the workshop, obtained a good education at the Latin school and studied under Boerhaave. He was offered teaching positions but preferred to remain an instrument maker. This may well have been due to his friendship and collaboration with ’sGravesande, who based his physics lectures on experiments and had many of his instruments constructed by Jan. They can be studied in ‘sGravesande’s Physices elementa mathematica experimetis confirmata (Leiden, 1720–1721; 2nd ed., 1742); some seventy-five of them still exist. The popularity of this book brought numerous orders to Jan from universities and amateurs; many of his instruments were imitated, for instance, by George Adams for the cabinet of George III of England. His workshop on the Rapenburg (now no. 66) was famous. Albrecht von Haller, who visited him between 1725 and 1727, especially admired Jan’s magic lantern. Apart from catalogs of his works—as many as 200 items—he published only a description of new air pumps and of “agreeable and instructive”experiments to be performed with them (1736).

Petrus, not yet fifteen when his father died, owed his further education to his brother. He studied at the University of Leiden and in 1715 received his doctorate in medicine. He then made a study trip to London, where he met Desaguliers, then famous as lecturer and demonstrator of scientific experiments, who visited Holland in 1730. Back in Leiden he practiced medicine and shared with his brother both the friendship and the philosophy of ‘sGravesande. In 1719 Petrus received his doctorate in philosophy and accepted a professorate in mathematics and philosophy at Duisburg, where in 1721 he also became extraordinary professor of medicine. From 1723 to 1740 he occupied the chair of natural philosophy and mathematics at Utrecht, in 1732 also holding the chair of astronomy. Here he lectured on experimental philosophy, presenting views like those of ‘sGravesande and Newton and often using apparatus made by his brother.

Musschenbroek became increasingly famous, especially because of his lecture notes collected in ever larger volumes; the Epitome elementorum physicomathematicorum conscripta in usus academico (Leiden, 1726), Elementa physicae (Leiden, 1734), Institutiones physicae (Leiden, 1748), and the posthumous twovolume Introductio ad philosophiam naturalem, edited by J. Lulofs (Leiden, 1762), were widely used and translated into Dutch, English. French, and German. He refused offers of academic chairs at Copenhagen in 1731 and at Göttingen in 1737; but at the end of 1739 he accepted a chair at Leiden, where he taught from 1740 until his death. In 1742, after the death of ‘sGravesande, Musschenbroek became his logical successor in the teaching of experimental physics. The excellence of his lectures maintained the reputation that Leiden had acquired under Boerhaave and ‘sGravesande, and students interested in experimentation came from all parts of Europe. One of them was Jean-Antoine Nollet (in 1736), who became the leading exponent of this school in France.

Primarily a lecturer and author, Musschenbroek tended more to supervise than to become involved in the construction of apparatus. He devised many of his experiments, in the process consulting records of other experimenters, among them those of the Accademia del Cimento. Musschenbroek translated their accounts into Latin, adding reports concerning his own work (1731). Many of his instruments were made by his brother Jan; but those of other craftsmen —for instance, Jan Paauw—were also employed. The Musschenbroeks never made barometers or thermometers; these were supplied by Gabriel Daniel Fahrenheit in Amsterdam and by others.

The experiments can be studied in Musschenbroek’s books, which contain many fine illustrations; they deal with the mechanics of rigid bodies, air pressure, heat, cohesion, capillarity, phosphorescence, magnetism, and electricity. Many of these experiments have become classics in elementary instruction. One of the better-known apparatuses is the pyrometer (the name was given by Musschenbroek), first described in the Tentamina of 1731; it consists of a horizontal metal bar fixed at one end and connected at the other end to wheelwork that shows the expansion of the bar when it is heated. It was originally used without a thermometer, which was not mentioned until the Introductio of 1762. Musschenbroek’s best-known experiment is that with the Leyden jar, discussed below.

Underlying Musschenbroek’s lectures demonstrated with experiments was the experimental philosophy. This philosophy, which he proclaimed in Holland along with Boerhaave and ‘sGravesande, was set forth in their books and in academic lectures such as Musschenbroek’s inaugural address at Utrecht, Oratio de certo methodo philosophiae (Leiden, 1723). The principal source of inspiration was Newton; but Galileo, Torricelli, Huygens, Réaumur, and others were important to this school. Since the mind, Musschenbroek states in his Elementa physicae (1734), has no innate idea of what bodies and their qualities are, we can obtain knowledge about them only by observation and experiments. But we must be extremely careful, use good instruments, and take into consideration all circumstances—atmospheric pressure, temperature, locality, and weather. Thus we can discover the laws that govern the behavior of bodies, provided the results of experiments, repeated over and over again, are the same, and specific causes are admitted only when the phenomena investigated leave no doubt. The stress is therefore on induction; but deduction, for example, by means of mathematics, is admissible, as Newton had shown, provided such deductions are constantly tested by experiment. The success of such reasoning on the basis of careful experimentation finds its guarantee in the infinite wisdom of the Supreme Being. This philosophy inspired the founding of many amateur societies in Holland and abroad for experimental study.

Musschenbroek is generally credited with originating the Leyden jar. He knew that a charged conductor surrounded by air loses its charge very rapidly, especially in a rainy climate like that of Holland. He had a gun barrel suspended by two silk lines and the barrel charged by means of a rapidly rotating glass globe rubbed by hand. A brass wire from the barrel led a few inches through a cork into a bottle and extended into water in the bottle. Thus the water was charged. Musschenbroek’s assistant, Andreas Cunaeus, accidentally took hold of the bottle, thus giving it the necessary outer coating. Then he touched the wire with his other hand—and received a fearful shock. He had unintentionally experienced the effect of a true capacitor.

This accident occurred in January 1746. Musschenbroek reported the experiment to Réaumur, who showed the letter to Nollet. Musschenbroek’s other collaborator, Jean Nicolas Sebastien Allamand (who later wrote a biography of ’sGravesande), wrote directly to Nollet. The latter, quite excited about this “Leiden experiment,” reported to the Académic des Sciences at its April meeting. Nollet continued to write on and repeat the “experience nouvelle mais terrible” in a sensational way. Thus the bouteille de Leyde became widely known during 1746. Musschenbroek first described it in the Institutiones physicae of 1748.

As to the priority of the experiment, in 1744 Georg Matthias Bose in Wittenberg had published the drawing of “fire” from electrified water in a glass, an experiment that Musschenbroek knew and wanted to repeat. Early in 1745 Allamand had received a terrible shock in the same way that Cunaeus did the following year, and he had reported on it in the Philosophical Transactions of 1746. And on 4 October 1745 J. G. von Kleist, dean of the cathedral at Kammiń (now Kamien Pomorski), made a similar experiment. This was reported to other Germans interested in electricity and was published by J. G. Krüger in his Geschichte der Erde (Halle, 1746), but it passed unnoticed for a long time. Yet it was Musschenbroek’s communication which, through Nollet, made the capacitor known, so that there were soon improvements in its construction, and Benjamin Franklin analyzed the experiments on “M. Musschenbroek’s wonderful bottle” in his third and fourth letters to Peter Collinson (1747, 1748). In them he established that the charge is not in the wire or the water, but in the glass. He also corresponded with Musschenbroek and in 1761 visited him in Leiden.

Musschenbroek married Adriana van de Water (d. 1732) in 1724 and Helena Alstorphius in 1738. A son, Jan Willem (1729–1807), wrote the family history.

BIBLIOGRAPHY

I. Original Works. There is no modern critical bibliography of the Musschenbroeks’ works. For a preliminary listing see D. Bierens De Haan, Bibliographie néerlandaise historique-scientifique (Rome, 1883; repr. Nieuwkoop, 1960), 202–204. Petrus’ main literary production consists of a gradual extension of his Utrecht lecture notes published first in the already mentioned Epitome of 1726. These include Beginsels der natuurkunde (Leiden, 1736; 2nd ed., 1739); Essai de physique … avec une description de nouvelles sortes de machines pneumatiques et un recueil d’expériences par Mr. J. Musschenbroek, translated by P. Massuet, 2 vols. (Leiden, 1736–1739; 2nd ed., 1751); The Elements of Natural Philosophy, translated by J. Colson, 2 vols. (London, 1744); Grundlehren der Naturwissenschaft nach der zweiten lateinischen Ausgabe, translated by J. C. Gottsched (Leipzig, 1747); and Cours de physique expérimentale et mathématique, translated by Sigault de la Fond, 3 vols. (Paris, 1769), with a preface by J. Lulofs, a colleague of Musschenbroek’s at Leiden, and a description of the relation of these different books to each other.

See also Disputatio medica inauguralis de aeris praesentia in humoribus animalibus (Leiden, 1715; 2nd ed., 1749); Oratio de certo methodo philosophiae (Leiden, 1723), his inaugural address at Utrecht—on its influence on the spread of Newtonianism in France see Brunet, below; Physicae experimentales et geometricae, de magnete, tuborum capillarium vitreorumque speculorum attractione magnitudine terrae, cohaerentia corporum firmorum dissertationes ut et ephemerides meteorologicae ultrajectinae (anni 1728) (Leiden, 1729; Vienna-Prague-Trieste, 1754); Tentamina experimentorum naturalium captorum in Accademia del Cimento… quibus commentarios, nova experientia, et orationem de methodo instituendi experimenta physica additit P. v. M., 2 vols. (Leiden, 1731; Vienna-Prague-Trieste, 1756), French version in Collection académique (Dijon-Auxerre, 1755); Oratio de mente humana semet ignorante (Leiden, 1740), his inaugural address at Leiden; Oratio de sapientia divina (Leiden-Vienna, 1744); Institutiones logicae, praecipue comprehentes artem argumentandi (Leiden, 1746; Venice, 1763); and Compendium physicae experimentales conscripta in usus academicos, J. Lulofs, ed. (Leiden, 1762). Jan Musschenbroek’s writings are Liste de diverses machines de physique, de mathématique, d’anatomic et de chirurgie (Leiden, 1736); and Description de nouvelles sortes de machines pneumatiques tant doubles que simples (Leiden, 1738), also published in Dutch.

The only extant instrument of Samuel Musschenbroek, the air pump of 1675, was made for Professor Burchard de Volder and is in the Leiden Museum of Science, which also has a considerable number of Johan’s instruments, identifiable by the trademark of Samuel and Johan, an oriental lamp. The collection of Johan’s instruments includes the aquatic and other microscopes, as well as air pumps. The instruments gathered by Jan for ‘sGravesande have been to a great extent preserved at Leiden. Many other instruments made by Jan may still exist, but they cannot be identified with certainty because he seldom used the family trademark (see the books by Rooseboom, Crommelin, and van der Star), Many of Jan’s models are illustrated, however, in the Physices elementa of 1720–1721 and 1742. The university museum at Utrecht has an air pump and two microscopes by Jan, the first pyrometer made by Petrus, and three cylinders of Petrus’ friction meter. Instruments made by the Musschenbroeks and their imitations exist elsewhere-for instance, in the cabinet of George III. The Catalogus van Mathematische, Physische, Astronomische, Chirurgische, en andere Instrumenten te Bekomen in de Fabricq van Mr. J. H. Onderdewyngaart Canzius te Delft (1804) lists a number of Jan’s apparatuses, with reference to the pictures in ‘sGravesande.

Another catalog that mentions instruments of Musschenbroek is Collectio exquisitissima Instrumentorum in Primis ad Physicam experimentalem Pertinentium, quibus, dom vivebat, Usus fuit Celeberrimus Petrus van Musschenbroek … quorum Auctio fiet … ad Diem 15 Martii et Seqq. 1762 (Leiden, 1762).

In the university library at Leiden there is much MS material by Petrus and some by Jan. They are listed in J. Geel, Catalogus librorum manuscriptorum qui inde ab 1741 bibliotheca Lugduno Batavae accesserunt (Leiden, 1852), 221–223. The municipal archives of Utrecht contain Petrus’ handwritten copy of the list of instruments he was authorized to buy for the Theatrum Physicum and the observatory at Utrecht.

II. Secondary Literature. No full-length modern biography of the Musschenbroeks exists, A concise sketch of their lives, based partially on the MS history by Jan Willem van Musschenbroek (Petrus’ son), together with a description of their extant instruments, can be found in M. Rooseboom, Bydrage tot de geschiedenis der instrumentmakerskunst in de Norrdelyke Nederlanden tot omstreekts 1840 (Leiden, 1950); supplemented by C. A. Crommelin, Descriptive Catalogue of the Physical Instruments in the National Museum of the History of Science at Leyden (Leiden, 1951); “Leidsche leden van het geslacht Musschenbroek,” in Leidsch Jaarboekje (1939), 135–149; and “Huizen der Leidsche van Musschenbroeks,”ibid., (1945), 127–133; and P. van der Star, Descriptive Catalogue of the Simple Microscopes in the National Museum of the History of Science at Leyden (Leiden, 1953). See also H. J. M. Bos, Mechanical Instruments in the Utrecht University Museum (Utrecht, 1968), where 22 of the ca. 100 mentioned instruments are copies of instruments described in Musschenbroek’s books; and E. J. Dijksterhuis, “Uit het Utrechts verleden der fysica,” in Nederlands tijdschrift voor natuurkunde, 22 (1956), 163–180; and A. Savérien, Histoire des philosophes, VI (Paris, 1768); A. N. Condorcet, “éloge de Musschenbroek,” in Oeuvres, II (1847), 125–127; and F. Boerne, Nachrichten von den vornehmsten Leben und Schriften jetz lebender berühmter Aertze und Naturforscher, I (Wolfenbüttel, 1749), 529–541

On Musschenbroek’s influence on the spread of Newtonianism see P. Brunet, Les physiciens hollandais et la méthode expérimentale en France au XVIII siécle (Paris, 1928), 68–100; and his L’introduction des théories de Newton en france au XVIII Siécle (Paris, 1931), 124, 326. The invention of the Leyden jar is discussed in C. Dorsman and C. A. Crommelin, “The Invention of the Leyden Jar,” in Janus, 46 (1957), 275–280; F. M. Feldhaus, Die Erfindung der elektrischen Verstärkungsflasche durch E. J. von Kleist (Heidelberg, 1903); and J. L. Heilbron, “G. M. Bose: The Prime Mover in the Invention of the Leyden Jar?”Isis, 57 (1966), 264–267. The original publications on this subject are G. M. Bose, Tentamina electrica in academiis regiis Londensi et Parisina primum habita omni studio repitata … (Wittenberg, 1744), 64; Tentamina electrica tandem aliquando hydraulicae chymiae et vegetabilibus utilia (Wittenberg, 1747), 36–37; J. A. Nollet, “Observations sur quelques nouveaux phénoménes d’élec tricité,” in Histoire de l’Académic des sciences for 1746, 1–33; and “Recherches sur la communication de l’électricité,”ibid., 447. See also J. Priestley, The History and Present State of Electricity (London, 1767); P. F. Mottelay, Bibliographical History of Electricity and Magnetism (London, 1922); and I. B. Cohen, Benjamin Franklin’s Experiments (Cambridge, Mass., 1941).

D. J. Struik