Part 18

The world at this time, awakening from a long state of barbarism, was seized by a sort of idolatry and hunger for knowledge, and learning was the fashion of the day. Men of talent devoted their whole lives to science, with an abnegation of every other pursuit unknown in the present age, and were honoured by the great and followed by their disciples with a reverence merited by their enthusiasm and diligence, as well as by the benefits they conferred on their fellow creatures, in enlarging their sphere of knowledge, and bringing from the chaos of ignorance, truth, or the image of truth, to the light of day. Descartes was one of the most celebrated of the Frenchmen of genius of that time. He was not content with being the most eminent mathematician of his age, but he combined a system of philosophy, which, though false, obtained vogue, and secured to him a greater temporary reputation than if he had merely enounced truths, independent of the magic of a theory. The war of his partisans and their antagonists spread his fame: geometry and mathematics obtained more attention than they had ever done; and discoveries were made that excited the ambition of every fresh student to penetrate further than his predecessors into the secrets of the system of the universe. Étienne Pascal found men in Paris, with whom he allied himself in friendship, deeply versed in physics and mathematics, and he also applied himself to these sciences. He associated with Roberval, Carcavi, Le Pailleur, and other scientific men of high reputation--they met at each other's house, and discussed the objects of their labours; they detailed their new observations and discoveries; they read the letters received from other learned men, either foreigners, or residing in the provinces: the ambition of their lives was centred in the progress of science; and the enthusiasm and eagerness with which they prosecuted their researches gave an interest to their conversations that awoke to intensity the curiosity of Pascal's almost infant son. Adding youthful fervour to abilities already competent to the formation of scientific combinations and accuracy, the young Blaise desired to make discoveries himself in causes and effects. A common phenomenon in sound obtained his earliest attention. He observed that a plate, if struck by a knife, gave forth a ringing sound, which he stilled by putting his hand on the plate. [Sidenote: 1635. Ætat. 12.] At the age of twelve he wrote a little treatise to account for this phenomenon, which was argued with acuteness and precision. His father wished, however, to turn his mind from the pursuits of science, considering the study of languages as better suited to his age; and he resolved that the boy should no longer be present at the philosophical meetings. Blaise was in despair: to console him, he was told that he should be taught geometry when he had acquired Latin and Greek: he asked, eagerly, what geometry was? His father informed him, generally, that it was the science which teaches the method of making exact figures, and of finding out the proportions between them. He commanded him at the same time neither to speak nor think on the subject more. But Blaise was too inquiring and too earnest to submit to this rule. He spent every moment of leisure in meditation upon the properties of mathematical figures. He drew triangles and circles with charcoal on the walls of his playroom, giving them such names as occurred to him as proper, and thus began to teach himself geometry, seeking to discover, without previous instruction, all the combinations of lines and curves, making definitions and axioms for himself, and then proceeding to demonstration: and thus, alone and untaught, he compared the properties of figures and the relative position of lines with mathematical precision.

One day his father came by chance into the room, and found his son busy drawing triangles, parallelograms, and circles: the boy was so intent on his work that he did not hear his father enter; and the latter observed him for some time in silence: when at last he spoke, Blaise felt a sort of terror at being discovered at this forbidden occupation, which equalled his father's wonder at perceiving the objects of his attention. But the surprise of the latter increased, when, asking him what he was about, Blaise explained in language invented by himself, but which showed that he was employed in solving the thirty-second proposition of Euclid. His father asked him, how he came to think of such a question: Blaise replied, that it arose from another he had proposed to himself; and so going back step by step as to the figures that had excited his inquiry, he showed that he had established a chain of propositions deduced from axioms and definitions of his own adoption, which conducted him to the proposition in question (that the three angles of every possible triangle are equal to two right angles). The father was struck almost with fear at this exhibition of inborn genius; and, without speaking to the boy, hurried off to his intimate friend M. le Pailleur; but when he reached his house he was unable to utter a single word, and he stood with tears in his eyes, till his friend, fancying some misfortune had occurred, questioned him anxiously, and at length the happy parent found tongue to declare that he wept for joy, not sorrow. M. le Pailleur was not less astonished when the circumstances narrated were explained to him, and of course advised the father to give every facility for the acquirement of knowledge to one so richly gifted by nature. Euclid, accordingly, was put into the boy's hands as an amusement for his leisure hours. Blaise went through it by himself, and understood it without any explanation from others.[53] From this time he was allowed to be present at all the scientific meetings, and was behind none of the learned men present in bringing new discoveries and solutions, and in enouncing satisfactory explanations of any doubtful and knotty point. Truth was the passion of his soul; and, added to this, was a love of the positive, and a perception of it, which in the exact sciences led to the most useful results. At the age of sixteen he wrote an "Essay on Conic Sections," which was regarded as a work that would bestow reputation on an accomplished mathematician; so that Descartes, when he saw it, was inclined rather to believe that Pascal, the father, had written it himself, and passed it off as his son's, than that a mere child should have shown himself capable of such strength and accuracy of reasoning. The happy father, however, was innocent of any such deceit; and the boy, proceeding to investigate yet more deeply the science of numbers and proportions, soon gave proof that he was fully capable of having written the work in question.

Étienne Pascal was rewarded for all his self-devotion by the genius of his son. His daughters also profited by his care, and became distinguished at once by their mental accomplishments and their personal beauty. A disaster that occurred, which at first disturbed the happiness of the family, tended in the end to establish it, and to bring into greater notice the talents and virtues of the individuals of which it was composed.

[Sidenote: 1638. Ætat. 15.]

The finances of the government being at a low ebb, through mismanagement and long wars, the minister, cardinal de Richelieu, sought to improve them by diminishing the rate of interest towards the public creditor. Of course this act excited considerable discontent among holders of public stock; riots ensued, and some men, in consequence, were imprisoned in the Bastille. Among these was a friend of Étienne Pascal, who openly and warmly defended him, while he cast considerable blame on several government functionaries, and in particular the chancellor Séguier. This imprudence endangered his own liberty; he heard that he was threatened with arrest, and to avoid it left Paris, and for several months hid himself in Auvergne. He had many friends however among noble patrons of learning, and the duchess d'Aiguillon, in particular, interested herself in his favour. Richelieu, as is well known, was very fond of theatrical representations, and a tragi-comedy by Scuderi, was got up for his amusement. Jaqueline Pascal, then only fourteen years old, was selected to fill one of the parts: she at first refused, saying that the cardinal gave them too little pleasure for her to try to contribute to his; but the duchess saw hopes for the father's recall in the daughter's exertions, and persuaded Jaqueline to undertake the part. She acted charmingly, and at the end of the piece approached the cardinal, and recited some verses written for the occasion, asserting the innocence of her father, and entreating the cessation of his exile. The cardinal delighted, took her in his arms, and kissing her again and again, said, "Yes, my child, I grant your request; write to your father, that he may safely return." [Sidenote: 1639. Ætat. 16.] The duchess followed up the impression by an eulogium on Pascal, and by introducing Blaise; "He is but sixteen," she said, "but he is already a great mathematician." Jaqueline saw that the cardinal was favourably inclined; and with ready tact, added, that she had another request to prefer. "Ask what you will, my child," said the minister, "I can refuse you nothing." She begged that her father, on his return, might be permitted personally to thank the cardinal. This also was granted; and the family reaped the benefit. The cardinal received the exile graciously; and, two years after, named him intendant of Normandy at Rouen. Étienne removed with his family, in consequence, to that city. He filled the situation for seven years, enjoying the highest reputation for integrity and ability. About the same time, his daughter, Gilberte, formed an advantageous marriage with M. Périer, who had distinguished himself in a commission entrusted to him by the government in Normandy, and who afterwards bought the situation of counsellor to the court of aids of Clermont-Ferrand.

[Sidenote: 1641. Ætat. 18.]

Blaise, meanwhile, was absorbed in scientific pursuits. To the acquisition of Latin and Greek was added the study of logic and physics; every moment of his time was occupied--and even during meals the work of study went on. Charmed with the progress his son made, and his apparent facility in learning, the father was blind to the ill-effects that such constant application had on his health: at the age of eighteen, Pascal began to droop; the indisposition he suffered was slight, and he did not permit it to interfere with his studies; but neglected, and indeed increased, it at last entirely disorganised his fragile being. From that hour he never passed a single day free from pain. Repose, taken at intervals, mitigated his sufferings; but when better he eagerly returned to study--and with study illness recurred.

[Sidenote: 1642. Ætat. 19.]

His application was of the most arduous and intense description. At the age of nineteen he invented his arithmetical machine, considered one of the most wonderful discoveries yet put into practice. A machine capable of automatic combinations of numbers has always been a desideratum; and Pascal's was sufficiently well arranged to produce exact results--but it was very complex, expensive, and easily put out of order, and therefore of no general utility, though hailed by mathematicians as a most ingenious and successful invention. It cost him intense application, both for the mental combinations required, and the mechanical part of the execution:--his earnest and persevering study, and the great efforts of attention to which he put his brain, increased his ill health so much that he was obliged for a time to suspend his labours.

Soon after this, a question, involving very important consequences in physics, agitated the scientific world, and the position of the two Pascals was such, that their attention could not fail to be drawn to the consideration of it. The mechanical properties of the atmosphere had previously been inquired into by Galileo, who recognised in it the quality of weight. This philosopher, however, notwithstanding the wonderful sagacity which his numerous physical discoveries evince, failed to perceive that the weight of the atmosphere, combined with its fluidity and elasticity, opposed a definite force to any agent by which the removal of the atmosphere from any space was attempted. This resistance to the production of a vacuum had long been recognised, and was in fact expressed, but not accounted for, by the phrase, "nature's abhorrence of a vacuum." Whatever meaning he may have attached to it, Galileo retained this phrase, but limited its application, in order to embrace the phenomenon, then well known, that suction-pumps would not raise water more than about thirty-five feet high; and although "nature's abhorrence of a vacuum" raises the water thirty-five feet, to fill the space deserted by the air, which had been drawn out by the piston, yet above that height a vacuum still remained; which fact Galileo expressed by saying, that "thirty-five feet was the limit of nature's abhorrence of a vacuum."

That Galileo should have missed a discovery as important as it was obvious, is the more remarkable from the circumstance of its having been actually suggested to him by one of his own pupils. A letter from Baliani to Galileo is extant, dated in 1630, in which the writer says that Galileo, in one of his letters to him, having taught him that air has sensible weight, and shown him how that weight might be measured, he argued from thence that the force necessary to produce a vacuum, was nothing more than the force necessary to remove the weight of the mass of atmosphere which presses round every object, just as water would press on any thing at the bottom of the sea.[54]

Torricelli, the pupil of Galileo, next took up the problem. He argued, that if the weight of the atmosphere were the direct agent by which the column of water is sustained in a pump, the same agent must needs exert the same amount of force in sustaining a column of any other liquid; and, therefore, that if a heavier liquid were used, the column sustained would be less in height exactly in the same proportion as the weight of the liquid forming the column was greater. Mercury, the heaviest known liquid, appeared the fittest for this purpose. The experiment was eminently successful. The weight, bulk for bulk, of mercury was fourteen times greater than that of water; and it was found that, instead of a column of thirty-five feet being supported, the column was only thirty inches, the latter being exactly the fourteenth part of thirty-five feet.

Various ways of further testing the evident inferences to be drawn from this beautiful experiment, were so obvious, that it is impossible to suppose the illustrious philosopher to whom we are indebted for it, would not have pursued the inquiry further, had not death, almost immediately after this, prematurely removed him. The experiment became known, and excited much interest in every part of Europe; and Mersenne, who had an extensive scientific correspondence, having received an account of Torricelli's investigation, communicated the particulars to Pascal. Always reluctant to surrender long established maxims, the philosophers of that day rejected the solution of the problem given by Torricelli, and still clung to the maxim that "nature abhors a vacuum." The sagacity of Pascal, however, could not be so enslaved by received notions; and he accordingly, assisted by M. Petit, applied himself to the discovery of some experimental test, of a nature so unanswerable as to set the question at rest. The result was the celebrated experiment on the Puy de Dôme, the first and most beautiful example of an "experimentum crucis" recorded in the history of physics.

Pascal argued, that if the weight of the incumbent atmosphere were the real agent which sustained the mercury in Torricelli's tube, as it was inferred to be by that philosopher, any thing which would diminish that weight, ought to diminish in the same proportion the height of the mercurial column. To test this, he first conceived the idea of producing over the surface of the mercury in the cistern in which the end of the tube was immersed, a partial vacuum, so as to diminish the pressure of the air upon it. But, apprehending that this experiment would hardly he sufficiently glaring to overcome the prejudices of the scientific world, he proposed to carry the tube containing the mercurial column upwards in the atmosphere, so as gradually to leave more and more of the incumbent weight below it, and to ascertain whether the diminution of the column would be equal to the weight of the air which it had surmounted. No sufficient height being attainable in Paris, the experiment was conducted, under Pascal's direction, by his brother-in-law, M. Périer, at Clermont, on the Puy de Dôme, a hill of considerable height, near that place. The experiment was completely successful. The mercurial column gradually fell until the tube arrived at the summit, and as gradually rose again in descending. Bigotry and prejudice could not withstand the force of this, and immediately gave way. The maxim of nature's abhorrence of a vacuum was henceforth expunged from the code of natural science; and, what was still more conducive to the advancement of all true science, philosophers were taught how much more potent agents of discovery, observation and experiment, guided by reason, are, than the vain speculations in which the ancients had indulged, and from the baneful influence of which scientific inquirers had not yet been emancipated.

[Sidenote: 1647. Ætat. 24.]

Pascal had hardly escaped from boyhood at this time; his invention, his patience, the admirable system he pursued of causing all his opinions to be supported by facts and actual experiment, deserved the highest praise and honour. It is mortifying to have to record that his discovery was disputed. The jesuits accused him of plagiarism from the Italians; and Descartes declared, that he had first discovered the effects produced by the weight of the atmosphere, and suggested to Pascal the experiment made on the Puy de Dôme. [Sidenote: 1651. Ætat. 28.] Pascal treated these attacks the contempt which his innocence taught him that they deserved; and published an account of his experiments without making the slightest allusion to them. Descartes was a man of eminent genius--his industry and penetration often led him to make the happiest conjectures; but, more intent on employing his bold and often fortunate imagination in the fabrication of ingenious theories than on applying himself with patience and perseverance to the discovering the secrets of nature, he sometimes threw out a happy idea, which he did not take the pains to establish as a truth and a law. The honour of invention is due to those who seize the scattered threads of knowledge which former discoverers have left, and weave it into a continuous and irrefragable web. [Sidenote: 1653. Ætat. 30.] Pascal followed up his experiments with the utmost hesitation and care, only deciding when decision became self-evident. Two Treatises, one "On the Equilibrium of Liquids," another "On the Weight of the Atmosphere," which he subsequently wrote, though they were not published till after his death, display his admirable powers of observation, and the patient zeal with which he followed up his discoveries. At the time that he wrote these treatises he was engaged on others, on geometrical subjects: he did not publish them; and some have been irrecoverably lost. Every subject then interesting to men of science employed his active mind. His name had become well known: he was consulted by all the philosophers and mathematicians of the day, who proposed questions to him; and his thoughts were sedulously dedicated to the solution of the most difficult problems. But a change meanwhile had come over his mind, and he began to turn his thoughts to other subjects, and to resolve to quit his mathematical pursuits, and to dedicate himself wholly to the practice and study of religion.

This was no sudden resolve on his part--piety had always deep root in his heart. He had never, in the most inquisitive days of his youth, applied his eager questionings and doubts to matters of faith. His father had carefully instilled principles of belief; and gave him for a maxim, that the objects of faith are not the objects of reason, much less the subject of it. This principle became deeply engraven in his heart. Logical and penetrating as his mind was, with an understanding open to conjecture with regard to natural causes, he never applied the arts of reasoning to the principles of Christianity, but was as submissive as a child to all the dicta of the church. But though the so to call it metaphysical part of religion was admitted without a doubt or a question, its moral truths met with an attention--always lively, and at last wholly absorbing; so that he spent the latter portion of his life in meditating, day and night, the law of God.

This change began first to operate at the age of four-and-twenty. His zeal overflowed to, and was imbibed by, all near him. His father was not ashamed to listen to his son's exhortations, and to regulate his life hereafter by severer rules. His unmarried sister, Jaqueline--the heroine of the tale previously narrated, who possessed singular talents--listened to her brother with still greater docility and effect: an effect rather to be deplored than rejoiced in, since it caused her to renounce the cultivation of her talents, and the exercise of active duties, and to dedicate herself to the ascetic practices of Catholicism.

Meanwhile the health of Pascal suffered severer attacks, and his frail body wasted away; so that before he attained the prime of life he fell into the physical debility of age. He resided at this time in Paris, with his father and his sister Jaqueline. To benefit his health, he was recommended to suspend his labours, to enjoy the recreations of society, and to take more exercise: accordingly, he made several tours in Auvergne and other provinces. [Sidenote: 1651. Ætat. 28.] The death of his father broke up the little family circle. Jaqueline Pascal had long entertained the desire of becoming a nun: on the death of her father she put her resolve in execution, and took the vows in the abbey of Port Royal aux Champs. [Sidenote: 1653. Ætat. 30.] The other sister resided with her husband at Clermont. Pascal, left to himself, devoted his time more earnestly than ever to studious pursuits, till the powers of nature failed; and he was forced, through utter inability, to abandon his studies. He took gentle exercise, and frequented society. Though serious even to melancholy, his conversation pleased by the depth of understanding and great knowledge that it displayed. Pascal himself felt the softening influence of sympathy: he began to take pleasure in society--he even contemplated marrying. Happy had it been for him if this healthy and sound view of human duties had continued: but an accident happened which confirmed him as a visionary--if we may apply that term to a man who in the very excess of religious zeal preserved the entire use of his profound arts of reasoning, and an absolute command over his will: yet when the circumstances of his exclusive dedication of himself to pious exercises are known, and we find that a vision forms one of them, that word cannot be considered unjust--nor is it possible to help lamenting that his admirable understanding had not carried him one step further, and taught him that asceticism has no real foundation in the beneficent plan of the Creator.

[Sidenote: 1654. Ætat. 31.]