Grandamy was a physicist and astronomer, described, by contrast to Mesland and Vatier, who were far more positively disposed to Descartes’ philosophy, as among those Jesuits who only “sampled” it, or who only praised his good intentions and efforts, without going any further. He was the inventor of a nonmagnetic needle received by Descartes through Mersenne. As the rector of the Collège de La Flèche, he was a correspondent of Descartes, also conveying to him important letters from Mesland. He was the recipient, among other Jesuits, of a copy of the newly published Principles of Philosophy when Descartes briefly returned to Paris in 1644.

See also Jesuit; Mesland, Denis; Vatier, Antoine