“I have delayed writing to you,” Jacqueline says, addressing her sister, {39a} “because I wished to tell to you at length of the interview of M. Descartes and my brother, and I had no leisure yesterday to say that on the evening of Sunday last M. Habert {39b} came, accompanied by M. de Montigny, a gentleman of Brittany, with the view of letting me know, in the absence of my brother, who was at church, that M. Descartes, his compatriot and good friend, had expressed a strong desire to see my brother, for the sake of the great esteem in which both he and my father were everywhere held, and that he begged to be allowed to wait upon him next day at nine o’clock in the morning, if this would not inconvenience him, whom he knew to be an invalid. When M. de Montigny proposed this, I felt hindered from giving a definite answer, because I knew that my brother was reluctant to force himself to conversation, especially in the morning. Nevertheless, I did not think it right to refuse, so we arranged that he should come at half-past ten next day. Along with M. Habert and M. de Montigny there were also a young man in the dress of a priest, whom I did not know, M. de Montigny’s son, and two or three other young people. M. de Roberval, whom my brother had informed of the intended visit, was also present. After some civilities, talk fell upon the instrument [probably that which Pascal had used in the experiments], which was very much admired, while M. de Roberval showed it. Then they spoke of the idea of a vacuum; and M. Descartes, on hearing of the experiments, and being asked what he thought was within the tube (_dans la seringue_), said with great seriousness that it was some subtle matter, to which my brother replied what he could. M. Roberval, believing that my brother had difficulty in speaking, took up the reply to M. Descartes with some heat, yet with perfect civility. M. Descartes answered with some harshness that he would talk to my brother as much as he wished, because he spoke with reason, but not to any one who spoke with prejudice. Thereupon, finding from his watch it was mid-day, he rose, being engaged to dine at the Faubourg Saint Germain. M. Roberval also rose, in such a way that M. Descartes conducted him to a carriage, where the two were alone, and battled at one another more strongly than playfully, as M. Roberval, who returned here after dinner, told us. . . . I have forgotten to tell you that M. Descartes, annoyed at seeing so little of my brother, promised to return next day at eight o’clock. . . . He desired this, partly to consult regarding my brother’s illness, as to which, however, he did not communicate anything of importance, only he counselled him to remain in bed every day as long as he could till he was tired, and to take plenty of soup.