Villebressieu, who reportedly describes Descartes as “a special friend” (Baillet 1691, 1:258), was a physician, chemist, and engineer of Grenoble. He seems first to have attracted Descartes’ respect for his work with a camera obscura, which reversed the image, and suggested an intromissionist theory of perception. He spent time in Holland with Descartes, who appreciated his practical ability in following instructions on how to apply prescribed principles and insights, for example, in polishing lenses and mirrors. While with Descartes, Villebressieu worked under him, apparently with success and growing responsibility. Later, he became widely known for his machines and inventions, some of which he made during his time with Descartes – for example, a double spiral for scaling a tower, a rolling bridge, and a practical wheelchair. They did much together in optics, with Descartes often amazing his pupil with novel effects. Traveling together in Holland, Villebressieu invented a new way of representing complex planar perspectives that promised great savings in time and effort for engineers, painters, and others.

See also Machine, Optics