Spreading scientific philosophies with instruments: the case of Atwoods machine

We study how the paradigm of Newton’s science, based on the organization of scientific knowledge as a series of mathematical laws, was definitively accepted in science courses - in the last decades of the XVIII century, in England as well as in the Continent - by means of the “universal” dynamical machine invented by George Atwood in late 1770s just for this purpose. The spreading of such machine, occurred well before the appearance of Atwood’s treatise where he described the novel machine and the experiments to be performed with it, is a quite interesting historical case, which we consider in some detail. In particular, we focus on the “improvement” introduced by the Italian Giuseppe Saverio Poli and the subsequent “simplifications” of the machine, underlying the ongoing change of perspective after the definitive success of Newtonianism. The case studied here allows to recognize the relevant role played by a properly devised instrument in the acceptance of a new paradigm by non-erudite scholars, in addition to the traditional ways involving erudite scientists, and thus the complementary role of machine philosophy with respect to mathematical, philosophical or even physical reasoning.

💡 Research Summary

The paper investigates how the Newtonian paradigm—characterized by the organization of scientific knowledge into a series of mathematical laws—became firmly entrenched in university curricula during the last decades of the eighteenth century in both England and on the Continent. The authors argue that the decisive catalyst was not a series of philosophical treatises or elite lectures alone, but the widespread adoption of a “universal” dynamical apparatus invented by George Atwood in the late 1770s.

The study begins with a broad cultural background: after Newton’s death, his ideas were disseminated through the Royal Society, popular lecturers, and a growing network of scientific societies. Figures such as John Theophilus Desaguliers in England, Willem Jacob Gravesande in the Netherlands, and Jean‑Antoine Nollet in France played pivotal roles in translating, teaching, and experimentally demonstrating Newtonian concepts for audiences that could not follow the original mathematical texts. This “machine philosophy”—the use of physical instruments to convey abstract theories—emerged as a complementary strategy to textual exposition.

Atwood’s machine was designed to provide a clear, repeatable demonstration of the relationship between force, mass, and acceleration (Newton’s second law). By suspending two masses on a string and adding a small auxiliary weight, the apparatus produced a constant acceleration that could be measured directly with simple timing devices. Crucially, the machine required no sophisticated calculus to interpret the results; the proportionality of acceleration to the added force was evident to any observer.

The authors highlight that Atwood’s device began to circulate before Atwood himself published his treatise describing it. Italian physicist Giuseppe Saverio Poli introduced a series of “improvements” that simplified the pulley system, refined the scale graduations, and reduced manufacturing costs. Poli’s version made the apparatus accessible not only to university laboratories but also to private academies and amateur societies across Italy, Spain, and the Austrian lands. Subsequent “simplifications” by other educators stripped away non‑essential components, producing a minimal version focused solely on measuring the gravitational acceleration. These streamlined models further lowered the barrier to entry for students and non‑specialists.

The paper then surveys the textbook landscape of the period. In England, Desaguliers’ two‑volume A Course of Experimental Philosophy (1734, 1744) combined theoretical exposition with detailed instructions for constructing and using experimental devices, including Atwood’s machine. In the Netherlands, Gravesande’s Physices Elementa Mathematica (1720) and the later works of Pieter van Musschenbroek propagated Newtonian mechanics through a blend of Latin text and illustrated apparatus, while the Musschenbroek brothers’ workshop mass‑produced the necessary instruments. In France, Nollet’s Leçons de physique expérimentale (1743‑48), heavily supported by Voltaire, featured hundreds of experimental setups, though the adoption of Newtonian astronomy lagged behind due to lingering Cartesian influence.

Through this comparative analysis, the authors demonstrate that the physical instrument functioned as a “translator” of abstract law into tangible experience. Students who struggled with the mathematical formalism could nonetheless observe the proportionality of force and acceleration directly, internalizing the Newtonian worldview without needing to master the underlying calculus. This experiential learning reinforced the textual and lecture‑based transmission, accelerating the acceptance of Newtonian mechanics among the broader scholarly community, including those outside the elite academic circles.

Finally, the paper concludes that the case of Atwood’s machine exemplifies the broader role of well‑designed scientific instruments in paradigm shifts. While traditional channels—philosophical debate, textbook publication, and elite lecturing—remain essential, the “machine philosophy” provides a complementary pathway that engages non‑erudite scholars through hands‑on demonstration. The diffusion of Atwood’s apparatus, its Italian improvement, and subsequent simplifications illustrate how an instrument can become a catalyst for the institutionalization of a new scientific paradigm, shaping the way future generations learn and accept foundational physical laws.