Her chief amusement during her leisure hours was sweeping the heavens with a small Newtonian telescope.
Thus rational mechanics, based on the Newtonian Laws, viewed as mathematics is independent of its supposed application, and hydrodynamics remains a coherent and respected science though it is extremely improbable that any perfect fluid exists in the physical world.
In the appended treatise Sur la Cause de la pesanteur, he rejected gravitation as a universal quality of matter, although admitting the Newtonian theory of the planetary revolutions.
James Keill (1673-1719) applied Newtonian and mechanical principles to the explanation of bodily functions with still greater accuracy and completeness; but his researches have more importance for physiology than for practical medicine.
The principal literary results of his early years here were the Discours en vers sur l'homme, the play of Alzire and L'Enfant prodigue (1736), and a long treatise on the Newtonian system which he and Madame du Chatelet wrote together.