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and seditious, and those who were supposed to have actively engaged in them pursued by the vengeance of the government. Stephen Pascal was signalled out, although, it afterwards appeared, unjustly, as one of these, and an order immediately issued for his arrest,—which, however, by the timely warning of a friend, he succeeded in eluding, and betook himself for refuge to the solitudes of his native district. It is difficult to conceive a more cruel and tyrannous exercise of authority under any regular and peaceable form of government than is here exhibited to us; and, as if still more to bring out the fearful chances of such an absolute power lodged in the hands of an individual, the following story as to the manner in which the afflicted father was restored to his disconsolate children is related by the Abbe Bossut. 'The cardinal having taken a fancy to have Scudery's tragi-comedy of "L'Amour Tyrannique" acted before him by young girls, the Duchess d'Aiguillon, who was charged with the conduct of the piece, was desirous that Jaqueline Pascal, then just thirteen years of age, should become one of the actresses. Her elder sister, who in her father's absence was the head of the family, replied with indignation, that " the cardinal had not been sufficiently kind to them to induce them to do him this favour." The duchess, however, persisted in her request, and made it to be understood that the recall of Stephen Pascal might be the reward of the favour which she solicited. The friends of the family were consulted, and they agreed that Jaqueline should accept the part assigned to her. The representation of the piece took place on the 3rd of April, 1639. The little Jaqueline played her part with a grace and accomplishment which charmed all the spectators, aud especially the cardinal himself. She was skilful enough to take advantage of the momentary enthusiasm. Approaching the cardinal on the conclusion of the play, she recited the following verses:—
'Ne vous etonnez pas, incomparable Armand,
* These verses have been thus rendered :—
Oh! marvel not, Armand, the great, the wise, If I have slightly pleased thine ear—thine eyes; My sorrowing spirit, torn by countless fears, Each sound forbidden save the voice of tears;— With power to please thee wouldst thou me inspire, Recal from exile now my hapless sire. N. S.—VOL. IV. N N
The tyrant was taken in the pleasant lure that had been laid for him. 'He took the girl in his arms,' continues the abbe, 'and embracing and kissing her while she repeated trie verses, replied, "Yes, my child, I grant you what you ask; write to your father that he may return with safety." The Ducbess d'Aiguillon, immediately taking up the conversation, spoke in praise of Stephen Pascal: " He is a thoroughly honest man; he is very learned; and it is a great pity he should remain unemployed. There is his son," added she, pointing to Blaise Pascal, "who, although he is only fifteen, is already a great mathematician." Encouraged by her first success, Jaqueline again ventured to address the cardinal; "I have still another favour, my lord, to ask you." "What is it, rny cbild? ask what you will; you are too amiable to be refused anything." "Permit my father to come in person and thank your eminence for your kindness." "Certainly," said the cardinal, "I wish to see him; and let him bring his family along with him." As soon as the father received the grateful intelligence, he returned with all diligence to Paris, and immediately on his arrival hastened with his three children to Rue], the residence of the cardinal, who gave him the most flattering reception. "I know all your merit," said Richelieu; "I restore you to your children, and commend them to your care; I am anxious to do something considerable for you."'
In fulfilment of this promise, Stephen Pascal was appointed, two years afterwards, Intendant of Rouen, in Normandy, the duties of which office he is said to have discharged during the seven following years with an ability and disinterestedness which recommended him alike to the district and the court. His family accompanied him to the country; and in the same year, 1641, his elder daughter was married to M. Perier, who had distinguished himself in a commission with which the government had entrusted him in Normandy, and who subsequently became counsellor to the Court of Aides in ClermontFerrand.
Blaise Pascal, now reputed a geometrician of the first class. followed with a consuming ardour his favourite studies. At the age of nineteen he invented the Arithmetical Machine which bears his name. Some of the finest years of his life be devoted to the improvement of this contrivance; and he has himself informed us that one of his main reasons for doing so was, that it might be serviceable to his father in the discharge of his official duties. There can be no doubt, however, that he permanently injured his health in this laborious task, while he never succeeded in it to his wishes. The great Leibnitz took up the project of Pascal, and is understood to hare executed two models of a calculating-machine, at once more simple and effective than that of Pascal. But greatly as both these illustrious attempts merit our admiration, they failed in proving of any practical benefit to the world. It was reserved to our distinguished countryman, Mr. Babbage, at once to conceive and bring to practical completion such a calculating-machine as truly deserves the name, which not only computes, unaided, the problems given to it, but, moreover, 'corrects whatever errors are accidentally committed, and prints all its calculations?
The study of physics next engaged the active and restless curiosity of Pascal; and here a more successful reward awaited his labours. The attention of scientific men had already been drawn to several phenomena bearing upon the fact of atmospheric pressure. It had been found by the workmen engaged in the construction of the fountains at Florence for Cosmo de Medicis, that they could not raise water by means of a sucking pump beyond the height of thirty-one feet. Galileo was applied to for a solution of the difficulty. Imbued with the notion which had prevailed from all ages that the water follows the piston, because nature abhors a vacunm, he replied thai, this abhorrence of nature, in obedience to which the water at first rises, has yet a limited sphere of operation, and that it ceases to act beyond thirty-one feet. Somewhat dissatisfied himself, however, as might be conceived, with this explanation, he engaged his pupil Toricelli to investigate the subject, and endeavour to find a more rational and satisfactory cause of the phenomenon. Toricelli immediately suspected that the weight of the water had something to do with the particular degree of elevation at which it stood in the pump, and that of course a heavier fluid would not stand so high. He accordingly experimented with mercury, and the result of his experiment is so well known, and has been so popularly applied in the construction of the barometer, as scarcely to require mention. Having taken a tube of glass three feet in length, and completely closed at the bottom, he filled it with mercury, and then applying his finger to the higher end, and reversing the tube, he plunged it into a small basinfull of mercury, withdrawing his finger as he did so. After a few oscillations, the mercury settled at thirty inches, and he was hence, of course, led to the conclusion that the water in the pump, and the mercury in the tube, at the respective heights of thirty-one feet and thirty inches, exerted the fame pressure upon the same base, and that both were necessarily counterbalanced by some fixed and determinate force. But what was this force? Learning from Galileo that the air was a heavy fluid, he formed the belief and gave publicity' to it, that the weight of the atmosphere pressing upon the water in the reservoir, and the mercury in the basin, was the counteracting cause which sustained both suspended at their respective elevations. He did not live, however, to verify the important conclusions to which he had thus come. It remained to Pascal to place, by a series of novel experiments, the matter beyond all doubt.
Having heard from M. Mersenne of the experiments that had been made in Italy, he repeated them at Rouen with the same results, but without reaching at first any satisfactory explanation. He was at once led, indeed, from his own observation, to conclude that the ancient dogma of nature's abhorrence of a vacunm wasameve figment; ignorant, however, at this time of the suggestion of Toricelli as to the pressure of the atmosphere, he failed to strike into the right path of discovery. But shortly after he had published his views and researches on the subject, in 1647, he became acquainted with those of Toricelli, and at once entering into them, very soon formed the conception of an experiment which should leave the matter in no question. If the weight of the air was the cause of the suspension of the mercury in the tube of Toricelli, as he suggested, the mercury ought to stand at a less elevated height, according as the column of air which pressed upon the surface of the basin in which the tube stood was increased or diminished. If, on the contrary, the atmospheric pressure had nothing to do with the phenomenon, the mercury would always remain at the same elevation, whatever the height of the column of air. Pascal endeavoured himself so far to cany out this experiment, but the variation was too insignificant at ordinary heights to warrant any conclusive inference. He accordingly communicated with his brother-in-law in Auvergne, in order that he might try the experiment during an ascent of the Puy-de-Dome, a mountain of that province, about 3000 feet in height. 'Some circumstances,' says the Abbe Bossut, from whom we have borrowed much of the previous detail,' retarded the execution of the project, but at length, on the 19th of September, 1648, it was performed with all possible exactitude, and the results which Pascal had predicted occurred from place to place. In proportion as they ascended the mountain, the mercury fell in the tube, the difference of level at its base and summit being upwards of three inches. In returning, the party renewed their observations with the same results.' When Pascal received information of these interesting particulars, he immediately computed the proportional fractional rise of the mercury within small elevations, and making the experiments again for himself on the heights at his command in Paris, he found the results to correspond with his calculations. He was thus left in no doubt as to the correctness of Toricelli's suggestion, and all who merely sought to arrive at the truth were convinced that he had established it by the most satisfactory demonstration.
After he had thus ascertained that the atmospheric pressure was the true cause of the suspension of the mercury in Toricelli's tube, Pascal immediately saw that the column of mercury would also fluctuate with the changes of the weather. In order to verify this fact M. Perier made a series of observations at Clermont during the years 1659, 1650, and the three first months of 1651. M. Chanut, also, the French ambassador in Sweden, was engaged to make a similar course of observations at Stockholm, in which he was assisted by Descartes, who happened to be then resident in that city. It was fully proved by these observations that the column of mercury varied in length according to the temperature, the winds, the moisture, and other circumstances connected with the state of the atmosphere; and the Toricellian tube thus became adapted to the popular use, in which it is now so familiar to all, of indicating the changes of weather dependent upon the variations of the atmospherical column.
These discoveries made an extensive sensation in the scientific world, and greatly added to the reputation of Pascal. His triumph, however, was by no means unmixed. So ancient and venerated a dogma as nature's abhorrence of a vacunm was not so easily exploded. A degree of sacredness seemed to invest it from its very antiquity, and the Jesuits came to its Tescue. When Pascal published his first experiments on the subject, made at Rome, in a work entitled 'Experiences nouvelles touchant le vide,' P. Noel, a Jesuit, who was then rector of the College of Paris, violently attacked it. 'All the prejudices of a bad philosophy, and all the virulence of error,' were summoned to the assault. Pascal readily repelled the objections of the Jesuit; but the strength of the obstacles he had to encounter was thus painfully manifested to him. When his further discoveries became known, the Jesuits renewed their attacks, accusing hiin of appropriating the labours of Toricelli. He replied in a letter, giving a minute account of all his proceedings, and thus in the most effective way vindicating his distinctive claims to be reckoned as a discoverer along with the Italian. There can be no doubt that it is from this period we must date Pascal's relations of hostility to the Jesuits which have become so immortalized by the 'Provincial Letters.' These repeated assaults upon the value of his scientific labours