Jacques Rohault - Traité de Physique - 1676

ROHAULT (Jacques). TRAITÉ DE PHYSIQUE. 1676.
In Paris, at the shop of Charles SAVREUX, with Guillaume DESPREZ, at the foot of Notre-Dame tower, on the Archbishopric side
422 pages, 3 ff. (complete). FOURTH EDITION, revised and corrected. Numerous figures in the text
- second part: cosmography
- third part: terrestrial beings
- fourth part: the animated body
In-12 calfskin, spine with 4 raised bands, gilt tooling, 2 ink stamps on the title page, light damp stain with no damage to the text in the lower margin of part of the work, tips trimmed, 2 worn corners with leather loss at the joints and on the boards.

The French physicist Jacques Rohault was born in Amiens in 1618, or in December 1617, into a prosperous family. After classical studies with the Jesuits, he educated himself in physics and mathematics, gaining such notoriety that he became the mathematics professor to the Dauphin and to the princes of Conti. His teaching is very oriented toward geometry and particularly toward the civil and military applications of this discipline. Also self-taught in philosophy, he seems to have been initiated by Claude Clerselier, an admirer of Descartes, whose daughter Rohault married.

Jacques Rohault applies his pedagogical talents to the teaching of the great experiments of physics of his time, repeating at Notre-Dame de Paris the demonstration of the weight of air performed by Blaise Pascal at the Tour Saint-Jacques. This experimental teaching (for which Rohault made his own instruments) continues in the form of weekly meetings, the “Rohault Wednesdays.” At each of these meetings, Rohault performs an experiment inspired by Pascal’s or Descartes’ physics, or sometimes his own, and discusses it with his listeners. It is on this occasion that he becomes a promoter of Cartesian physics, a stance which, given his fame, contributes to the importance given to Cartesianism. He dies in Paris in 1672.

The Treatise of Physics is thus the continuation of this pedagogical and experimental work, a kind of formalization of this teaching. He then develops four well-defined parts, each marked by the will to demonstrate experimentally. He also adds data relating to the circulation of blood and especially to magnetism, for which he resorts to a combination of affinities. He interprets the experimental results mainly according to the texts of Descartes and Copernicus, but Rohault does not strictly follow Descartes’ interpretations and emphasizes their mechanistic side.