definite experiments in 1647, and published the results in the same year; and that he had then not mentioned the name of Torricelli, because, while he knew that the experiments were made in Italy four years before, he did not then know that the experimenter was Torricelli; but

that so soon as he learned this fact—which he and his friends were so eager to know, that they sent a special letter of inquiry to Rome—he was “ravished with the idea that the experimenter was so illustrious a genius, whose mathematical writings, already well known, surpassed those of all antiquity.”  He says, in conclusion, that it was only in the same year (1647), after the publication of his own researches, that he learned “the very fine thought” of Torricelli concerning the cause of all the effects which had been attributed to the horror of a vacuum.  But “as this was only a conjecture as yet unverified,” he then, with the view of ascertaining the truth or falsehood of it, conceived the plan of the experiments carried out by M. Périer at the top and the foot of the Puy de Dôme.  “It is true, sir,” he adds, “and I say it boldly, that this series of experiments was my own invention; and therefore I may say that the new knowledge thus acquired is entirely due to me.”

To this letter M. Ribeyre made a satisfactory and touching reply.  He expresses disapproval of the allusion of the Jesuit father, but as the discourse was otherwise free from offence, he was willing to attribute it to a “pardonable emulation among savants,” rather than to any intention of assailing Pascal.  He makes, in short, the best excuse he can for the Jesuit, and hastens to assure Pascal that his reputation needed no justification:—

“Your candour and your sincerity are too well known to admit any belief that you could do anything inconsistent with the virtuous profession apparent in all your actions and manner.  I honour and revere your virtue more than your science; and as in both the one and the other you equal the

most famous of the age, do not think it strange if, adding to the common esteem which all have of you, a friendship contracted many years ago with your father, I subscribe myself yours,” etc.