Leiden

Teaching Physics at the University of Leiden.

‘As I talk to people who have made very little progress in mathematics I have been obliged to have several machines constructed to convey the force of propositions whose demonstrations they had not understood. By experiment I give a direct proof of the nature of compounded motions, oblique collisions, and the effect of oblique forces and the principal propositions respecting central forces.’

Willem ‘s Gravesande to Newton (1718), quoted in Snobelen (1998).

‘s Gravesande’s remark to Newton in this letter of 1718 points to the difficulty Newtonians faced when trying to popularize Newton’s works. The importance of experiments for teaching Newtonian concepts to young undergraduate students is clearly visible in the books published by Willem ‘s Gravesande (1688-1742 ) and Petrus Van Musschenbroek (1692-1761), two Leiden professors whose works were collected by Worth. As Ruestow (1973) states, ‘both ‘s Gravesande and Musschenbroek were, from the beginning of their academic careers, to be counted among the advance party of Newtonian on the continent’. ‘s Gravesande was the author of a popular and effective Newtonian textbook, Physices elementa mathematica, experimentis confirmata, sive introductio ad philosophiam Newtonianam which was published at Leiden in 1720 and quickly translated into English; Musschenbroek was known as the author of the equally experiment-dependent Physicae experimentales (Leiden, 1729). Worth bought two of ‘s Gravesande’s works, his earlier Essai de Perspective (The Hague, 1711) and his 1732 edition of Newton’s Arithmetica Universalis (Leiden, 1732) and two of Musschenbroek’s: his Catalogus præcipuorum instrumentorum physicorum (Leiden, 1720) and the Physicae experimentales (Leiden, 1729).

‘s Gravesande and Musschenbroek were certainly in the vanguard of introducing Newtonianism into the Dutch universities but seeds of Newtonianism had already been planted in the Netherlands prior to their activities. The University of Leiden had been introduced to a version of Newtonianism by the Scottish Newtonian Archibald Pitcairne during his short stay there and in Amsterdam Pitcairne’s colleague, David Gregory, had made contact with more informal circles of mathematical amateurs. Vermij (2003) has demonstrated the role played by men such as Adriaan Verwer in the growth of Newtonianism in the Dutch republic prior to rise of ‘s Gravesande and Musschenbroek and has pointed to the impact made by the second edition of the Principia in 1713. As Vermij points out, the fact that the second edition was pirated at Amsterdam within a year of its publication is an indication that the booksellers felt there was a ready market for it.

‘s Gravesande’s Essai de perspective (The Hague, 1711), titlepage.

Having studied Law at Leiden Willem ‘s Gravesande was initially based at The Hague where he continued his mathematical studies by producing his Essai de Perspective in 1711. A trip to England in 1715 to mark the coronation of George I led to his election as a fellow of the Royal Society and his time in England enabled him to forge friendships with Desaguliers and Newton. His friendship with the latter was particular fruitful for Newton actively lobbied for him to be given a position at the University of Leiden. Newton’s recommendation worked and in 1717 ‘s Gravesande was appointed professor of astronomy and mathematics – a position he held until his death in 1742. His Physices elementa mathematica of 1720 was a two-volume work, heavily illustrated, which comprised his lectures to his students – he would later publish an abridgement of it in 1723 under the title ‘Philosophiae Newtonianae institutiones, in usus academicos. The original publication sold well and further editions were published in 1725 and 1742. Yet strangely Worth bought neither the original Latin version, nor the English translation. This may possibly have been because he had already purchased textbooks in English by Desaguliers and William Whiston and did not feel the need for ‘s Gravesande’s work. There might also have been another reason: ‘s Gravesande’s Essai de Perspective (1711) might be attractive to Worth but ‘s Gravesande 1722 ‘conversion’ to the Leibnizian camp on the issue of vis viva would have been less appealing to him. Carolyn Iltis (1973) has outlined the hardened intellectual battle lines which formed in the 1720s between the followers of Newton and Leibniz over the issue of vis viva. ‘s Gravesande’s decision to perform free-fall experiments which were evidently designed to challenge his erstwhile associates, Desaguliers, Henry Pemberton and Samuel Clarke was very unusual indeed in a writer who had not only been instrumental in introducing Newtonianism to Leiden but who continued to teach Newtonian physics there. It reminds us yet again that Newtonianism meant different things to different people.

Petrus van Musschenbroek, Physicae experimentales, et geometricae,de magnete (Leiden, 1729), title label on spine.

Worth was on somewhat firmer Newtonian ground with ‘s Gravesande’s colleague, Petrus van Musschenbroek (1692-1761). Musschenbroek had followed in similar footsteps to ‘s Gravesande: both had been taught by Boerhaave at Leiden; both had travelled to England in 1715 and had met Newton there. In 1719, having obtained his doctorate in philosophy Musschenbroek initially taught at Duisburg and then was appointed professor of mathematics and philosophy at the University of Utrecht. Moving to Leiden in 1740 to take up the professorship of mathematics and philosophy there he worked alongside ‘s Gravesande, finally succeeding him as professor of astronomy following the latter’s death in 1742. His Physicae experimentales, a large collection of experiments which had formed the basis of his lecture course at Utrecht, proved to be a popular text, and was reprinted and epitomized again and again. As the illustration demonstrates, Worth evidently considered it an important text as he had his copy gold-tooled. The experimental basis of the Dutch Newtonians and their interest in instrument making were evidently areas in which Worth had a keen interest.

Sources

de Pater, C (1975) in Th. H. Lunsingh Scheurleer, and G. H. M. Posthumus Meyjes, (eds) Leiden University in the Seventeenth Century. An Exchange of Learning (Leiden).

Illtis, Caroline (1973), ‘The Leibnizian-Newtonian Debates: Natural Philosophy and Society Pyschology’, The British Journal for the History of Science, 6, no. 4, pp 343-77.

Ruestow, Edward G. (1973), Physics at Seventeenth an Eighteenth-Century Leiden: Philosophy and the New Science in the University (The Hague).

Snobelen, Stephen D. (1998), ‘On reading Isaac Newton’s Principia in the 18^th Century’, Endeavour 22 no. 4, pp 159-163.

Vermij, Rienk (2003), ‘The Formation of the Newtonian Philosophy: The Case of the Amsterdam Mathematical Amateurs’, The British Journal for the History of Science 36, no. 2, pp. 183-200.