The Royal Society in the eighteenth century cuts a poor figure in comparison with its robust parent of the seventeenth century. Contemporary satirists and modern historians alike have found little to recommend the weak and well-padded institution. After Newton's death in 1727, it was no longer the centre for natural philosophy, and even during his tenure as President the Society did not escape censure. Fascination with monstrous curiosities and antiquarian puzzles replaced serious scientific work, according to various detractors. Recently scholars (...) have begun to re-evaluate this caricature and point to the myriad ways in which the Society cultivated natural philosophy and natural history during the eighteenth century. This essay focuses on one of the Society's frequently overlooked strengths: its extensive correspondence. (shrink)

In this paper, I will examine John Smeaton’s contribution to the vis viva controversy in Britain, focusing on how the hybridization of science, technology, and industry helped to establish vis viva, or mechanic power, as a measure of motive force. Smeaton, embodying the ‘hybrid expert’ who combined theoretical knowledge and practical knowhow, demonstrated that the notion of vis viva possessed a greater explanatory power than momentum, because it could be used to explain the difference in efficiency between overshot and undershot (...) waterwheels. Smeaton’s conclusions were correct since waterwheel efficiency was already measured in terms that were proportional to vis viva, not momentum, as a result of the industrial applications of waterwheel technology, which favored measuring efficiency by the product of mass and vertical displacement. Toward the end of the eighteenth century, the loss of motive force in the inelastic collision driving the undershot wheel began to be seen as equivalent to the expenditure of labor in the manufacture of commodities, further underlining how strictly scientific conclusions about motive force could have their origin in industrial practices. (shrink)

Newton wrote in thePrincipiathat all bodies are to be regarded as subject to the principle of gravitation. Every body, however great or small, is related to every other body in the universe by a mutual attraction. It was this postulated universality of the force of gravity which contributed so greatly to the order and unity of the Newtonian world. This unity was, for its followers, an untested article of faith for nearly a century after thePrincipia. During this time the evidence (...) of gravitational attraction continued to be drawn from the motions of the earth, moon, planets, comets, and falling bodies—phenomena which span an intermediate range of masses, sizes, and distances. In three domains of experience, involving the extreme upper and lower limits of masses and dimensions, the action of gravity had not yet been observed: the gravity of the “fixed” stars; the mutual attraction of terrestrial bodies; and the gravitation of light. The task of deducing observable consequences from each of these supposed instances of universal gravitation fell to the Reverend John Michell (1724–1793), a teacher at Cambridge (1749–1763) and afterwards Rector of Thornhill, Yorkshire. His renowned London friend Henry Cavendish (1731–1810) encouraged him in these researches and became involved in the resulting observational and experimental questions. The immersion of Michell and Cavendish in gravitational studies was an essential feature of their commitment to a unified Newtonian world. Their commitment had yet a broader significance: Newton's theory of gravitation inspired their image of physical reality, and it served as their model of an exact science. This paper is an attempt to relate the personal friendship of Michell and Cavendish, their scientific collaboration, and their common Newtonian philosophy. Its chief focus is on Michell's 1784 plan for weighing the stars by the gravitational retardation of their light; his project of weighing the world by means of a torsion balance is treated by way of an epilogue. (shrink)