The revelations of this letter are very curious. The respectful desire of Descartes, already so distinguished, to make Pascal’s acquaintance, and to enter into conversation with him; his resentment of Roberval’s interference, and their earnest altercation, prolonged in the carriage after leaving Pascal’s house; the evidently serious character of Pascal’s maladies, and the watchful attention of his sister. It is clear through all that Descartes had been busily occupied with the same physical problems as Pascal, and that he was somewhat jealous of the results towards which Pascal and his friends were tending. Evidently there was a certain measure of unfriendliness between Roberval and Descartes. I am unable, however, to see any traces of a coterie surrounding Pascal and inimical to Descartes, as M. Cousin suggests. { 41} If such a coterie existed at this time in Paris, of which the “hasty and jealous Roberval” was the centre, and which delighted in “abusing Descartes, and attacking him on all sides,” Jacqueline’s frank and lively letter seems enough to show that while Roberval was Pascal’s friend and Descartes’s disputant, there was nothing in the meantime between Descartes and Pascal but courteous friendliness and a cordial feeling of mutual respect.
Descartes, however, in his retirement at Stockholm, plainly cherished the impression that Roberval’s intimacy with Pascal prevented the latter from doing full justice to his scientific position and suggestions; and having as yet heard nothing, in June 1649, of the special results of Pascal’s experiments on the Puy de Dôme in the preceding year, he wrote to his friend Carcavi to let him know about these.
“I pray you, let me know of the success of an experiment which Pascal is said to have made on the mountains of Auvergne. . . . I had the right to expect this of him rather than of you, because it was I who advised him two years ago to make the experiment, and who assured him that, although I had not made it, I had no doubt of its success. But _as he is the friend of M. Roberval_, _who professes not to be mine_, _I have some reason to think he follows the passions of his friend_.” { 42a}