technic School, at a time when there was no Professor of Mathematics. He finished his scientific studies by himself, and that too without the luxury of the thousand tutors which are given to the candidates of the present day, studying the writings of the original authors-the treatises of Euler, Lagrange, and Laplace, and not the manuals of the second and third order in which the youthful intellect finds nothing to excite it. Arago did not at first understand all that he read, but he was encouraged by the sentiment of D'Alembert, "Go on, and the light will come to you." In 1803, when he was in his seventeenth year, and self-educated, he was received at Toulouse by the younger Monge, the first of his class; and at the end of a year, his devotion to the study of the sciences, and his acquirements, which greatly surpassed those of his comrades, induced him, with the advice of the celebrated Monge the elder, to attach himself to the Observatory at Paris, where he devoted himself to inquiries of the highest importance to astronomy and physics. As the basis of the decimal system of weights and measures established by the National Convention, who adopted as an invariable unit of measure the ten-millionth part of the arch of a terrestrial meridian, it was necessary to determine with great accuracy this minute fraction. Delambre and Mechain had already measured the part of the meridian between Dunkirk and Barcelona, but it was necessary to continue the measurement to the Balearic Islands in the Mediterranean. This arduous task was intrusted to M. Biot, and to Arago, who was his junior by twelve years, and to two Spanish commissioners, MM. Chaix and Rodriguez. On this great errand the two French philosophers set out for Spain in 1806, on a footing of perfect equality, and commenced a journey which, as far as Arago was concerned, was marked with adventures the most curious and often the most dramatic. Biot and Arago were stationed on the summit of Mount Galatzo, one of the highest of the Catalonian branch of the Eastern Pyrenees, while the Spanish commissioners occupied the summit of Mount Campecey in Iviça. The tents in which they dwelt were pitched on high peaks, which often had little more than twenty square yards of surface to allow them to make the fire-signals to one another during night which were necessary for fixing their respective positions. In these cold and desolate regions our astronomers remained for several months, exposed to the severe cold which prevails on those lofty summits, and to the fierce blasts which occasionally sweep over them. The tents in which they lived were frequently blown down, and their lives were endangered by the attacks of robbers, the chief of whom afterwards became the protector of the men of science. In order to give an idea of the risks to which they were exposed from the ferocity and ignorance of the mountaineers of Catalonia, Arago used frequently to describe the state of civilization in Spain scarcely fifty years ago. In 1807 the tribunal of the Inquisition still existed in Valencia. It did not, it is true, condemn its victims to be burned alive; but a woman having been accused of sorcery, it was decided by that terrible tribunal that she should be paraded through the streets of the town sitting astride upon an ass, with her face turned to its tail, and having the upper part of her body naked down to her girdle. The poor woman was smeared with honey, and when a drapery of hen-feathers had been thus made to adhere to her body, she was exposed to the gaze and ridicule of the mob. Here is an example," exclaimed Arago, in describing this scene, "of the kind of spectacle which was presented to the people at the beginning of the nineteenth century, in one of the principal towns of Spain, the seat of a celebrated university, and the residence of numerous citizens distinguished by their knowledge, their bravery, and their virtues. Let not the friends of humanity and civilization be disunited, but form an indissoluble band, for superstition is ever on the watch and ready to seize her prey." 66 In the month of April, 1807, the work of our astronomers was sufficiently advanced to permit M. Biot to return to Paris to give an account of the results which had already been obtained. The operations which were necessary to unite the island of Majorca with Iviça and Formentara were thus left in the hands of Arago and M. Rodriguez, and they succeeded in obtaining by a single triangle the measure of a parallel amounting to a degree and a half. At this time the rumors of the war which broke out between France and Spain began to create a suspicion in the minds of the inhabitants of Majorca, that the fires which blazed at the signal-stations on Mount Galatzo were telegraphic messages sent to the invading army, and that the instruments, and all the proceedings of the astronomers, boded mischief to their country. Arago was therefore denounced as a spy, and his life was saved a revolution had taken place in the palace; the Dey who had rescued him from the hulks at Palamos had been beheaded, and the new Dey threw difficulties in the way of the departure of Arago, whom he believed to be laden with riches. At this time there was a desire for a war against France; and Arago would have been thrown into the slave-prison, where, opposite the coast of France, so many men and women of all nations have been martyred, had not the Danish Consul taken the philosopher under his protection. Fortunately for our friend, the brutal Dey was hung, and Arago again quitted Algiers on the 21st June, 1809, after a detention of more than six months. On the 1st of July, when the vessel in which he had embarked was in sight of Marseilles, it narrowly escaped from an Eng only from his having been arrested by the authorities. He was imprisoned on the 2d June in the citadel of Belver; but as he was scarcely safe under the protection of its ram- | parts, behind which he continued to work, he resolved to make his escape; and having embarked for Algiers, with his instruments, on the 28th July, he succeeded in reaching it, after a favorable passage, on the 3d August. After a residence of ten days in that city, he embarked for Marseilles in an Algerine frigate, procured for him by the French Consul; but no sooner had this vessel reached the Gulf of Lyons, and was in sight of the coast of Provence, than it was captured by a Spanish privateer, and carried to Rosas on the 16th of August. In this new position Arago was obliged to assume the character of a travelling merchant, and by the aid of a thou-lish cruiser which had given it chase; and sand devices he was not discovered by those who had known him when in Mount Galatzo, and who had been more and more convinced that he was a political spy. He was at first confined in a windmill, but on the 25th of September he was imprisoned, along with the Algerine crew, in the Fort of Trinity, from which, after three weeks' confinement, he was transferred, on the 17th of October, to the hulks at Palamos, where he endured a thousand tortures, and was almost starved for want of food. Indignant at the insult offered to his flag by the Spanish privateer, the Dey of Algiers demanded and obtained from the Spanish Government the liberation of Arago and the whole of the crew; but his activity on this occasion was not roused by the consider ation that a French philosopher had been taken prisoner in one of his ships. The ship had in its cargo two real lions, which the Dey had sent as a present to the Emperor Napoleon, and as one of them had been killed by the Spanish sailors, his threat of reprisals was more energetic and successful than it would otherwise have been. Anxious to return to his native country, after so many misfortunes, Arago again embarked for Marseilles, on the 28th November, 1808; but, just as the ship was about to enter the harbor, a violent hurricane drove it to sea, and cast it on the precipitous coast of Sardinia, which was then at war with Algiers. Being thus prevented from landing, the vessel, in a shattered condition, made for the coast of Africa, and on the 5th December reached Bougia, about three days' journey from Algiers. Assuming the dress of a Bedouin Arab, and protected by a Marabout, Arago arrived in Algiers on the 25th December; but, unfortunately for our pilgrim philosopher, with all his instruments, and manuscripts, and plans, saved from so many disasters, Arago entered the Lazaretto of Marseilles on the 2d July, thus gloriously terminating a career of labor, misfortune, and suffering, which, in the cause of science, he had endured for nearly three years, and to which few philosophers have ever been exposed. Having received no intelligence concerning him since the return of Biot, his friends in France believed that he was dead. His poor mother had even in her hands the watch which Arago had been obliged to sell at Rosas. She had caused many masses to be said for her favorite son, and, as he himself had often with much feeling told his friends, she caused as many to be said in gratitude to Heaven for having restored her child. pre Afflicting as had been his misfortunes to himself and his family, they were but the lude to a glorious career. The first letter which he received in the Lazaretto of Marseilles was from the illustrious Humboldt, who knew him only by his misfortunes; and from that hour there commenced between these distinguished men a friendship which, to use the words of Arago, "continued during fortyfour years without a cloud to disturb it ;" a sentiment reciprocated with equal warmth by his friend. On his arrival in Paris, where his scientific labors had been appreciated, and his sufferings deplored, he was specially honored with the patronage of Laplace, Legendre, and Monge; and such was the estimation in which he was held by the philosophers in Paris, that at the age of twenty-three, when a vacancy took place in the section of Astronomy in the Academy of Sciences by the death of Lalande, he was elected on the 17th of September, 1809, by forty-seven out of fifty-two votes. In asking the question, how it happened that | "He had, indeed," says M. Barral, "executed, in concert with M. Biot, a very laborious and very delicate work, on the determination of the coefficient of the Tables of Atmospheric Refraction, so useful in the correction of astronomical observations. He had measured the refractive powers of different gases, that is to say, the action which they exercise in causing the rays of light to deviate from their path; an inquiry which had not previously been attempted. He had determined the ratio of the weight of air to that of Mercury, and obtained a direct value of the coefficient of the formula by which the heights of mountains are computed by simple barometrical observations. By placing a prism before the object-glass of the telescope attached to the mural quadrant of the Observatory, he had done much on the subject of the velocity of light, and proved that the same tables of refraction would serve for the light coming from the sun and for that coming from the stars. This was the first step to a truth now well demonstrated, that the sun is but a star among the innumerable stars which people the firmament. He had, along with M. Bouvard, made numerous observations relative to the verification of the laws of libration, and computed tables eminently useful to astronomers. And finally, he had completed the most laborious triangulation which had ever been executed, for prolonging the meridian of France to the Island of Formentara. Thus might Arago, at the age of twenty-three, have rested himself, without any person having the right to say that he had not paid his tribute to science; but he did not sleep in the academician's chair." Leaving to a future part of our article an account of the leading scientific discoveries of Arago, we shall now follow him in his more public career as a professor in the Polytechnic School, a Director of the Observatory, a Member of the Board of Longitude, Perpetual Secretary for the Mathematical Sciences to the Institute, Minister of War and Marine in the Provisional Government of 1848, President of the Executive named by the Constituent Assembly, and when called upon as Director of the Observatory to take the oath of allegiance to the government of the Emperor. Although Arago, when a pupil at the Po lytechnic School, had fearlessly given his suffrage against the assumption of the imperial crown by Bonaparte, and was the first on the list to record his negative, yet that great man, who knew the value of an honorable action, and occasionally overlooked it even when directed against himself, never resented this act of juvenile hostility; but, recollecting the courage of the scholar in exercising a right which he himself would in similar circumstances have exercised, appointed him one of the professors of the Polytechnic School soon after his admission to the Academy; and about the same time he named him one of the astronomers of the Imperial Observatory, in which he resided till his death. He was also appointed to the situation of examiner of the sub-lieutenants of engineers and artillery who had finished their education at His popularity in these situations was very the school of application established at Metz. great. From the extent and variety of his acquirements, Arago was able to give successively five different courses of lectures. Ever anxious as every great man must be who has been permitted to make grand discoveries, to assist those who seem destined for the same high position, he delighted in patronizing youthful genius, and well merited the affection of his pupils. He never failed to defend the Polytechnic School against the attacks of its enemies; and on a very late occasion, in the last work which issued from his pen, he resisted the introduction of certain changes which he thought not only unnecessary, but calculated to injure the character of an institution which had been the envy and admiration of Europe. In 1818 or 1819, he was appointed by the Board of Longitude to execute, along with M. Biot, the geodetic operations on the coasts of France, England, and Scotland. It was on this occasion that M. Biot measured the length of the pendulum at Leith, and in Unst, one of the Shetland Isles; and the results of the operations of the two astronomers in these localities, as well as of their joint operations in Spain, were published in 1821 in an interesting work, which does equal honor to its authors and to the nation at whose expense the operations were carried on, and the work given to the public.* Immediately after the publication of this * Recueil des Observations Géodésiques, astronomiques et Physiques, exécutée par ordres du Bureau de Longitude, en Espagne, en France, en Angleterre, et en Ecosse, &c., ouvrage faisant suite au tome troisième de la Base du Système Métrique, en 4to avec Figures. Paris, 1821. work, namely, in 1822, Arago was appointed! a member of the Board of Longitude; and such was his anxiety to make his talents useful in every situation which he occupied, that in the Annuaire, or Almanac, published annually by the Board, he contributed every year from 1824 to 1853* inclusive, valuable scientific notices, chiefly on astronomy and meteorology, but often on mechanics and civil engineering, and sometimes interesting biographical notices, either pronounced at the grave of distinguished individuals, or read in the Academy of Sciences. When Arago was appointed one of the astronomers of the Observatory, the Board of Longitude requested him to deliver a course of lectures on Astronomy. This course was begun in 1812, and continued till 1845. It was attended by persons of all ranks, philosophers, politicians, and workmen, who flocked to listen to the eloquence of the astronomer. Arago had a peculiar facility in bringing down the higher parts of astronomy to the comprehension of ordinary minds, a faculty so rare that some of the most distinguished astronomers have failed in making their science intelligible or interesting to a public auditory. Arago adopted a method which, we believe, had been tried before, by one of his predecessors. When he began to give his course on astronomy, he glanced around his audience to look for some dull aspirant for knowledge, with a low forehead, and other indications that he was among the least intelligent among his hearers. He kept his eye fixed upon him; he addressed only him; and by the effect of his eloquence and powers of explanation as exhibited on the countenance of his pupil, he judged of their influence over the rest of his audience. When he remained unconvinced, the orator tried new illustrations till the light beamed from the grateful countenance. Arago had nothing to say to the rest of his audience. The orator and his pupil were the Siamese twins united by an intellectual ligament. Next morning, when Arago was breakfasting with his family, a visitor was announced. A gentleman entered-his pupil of the preceding evening-who, after ex pressing his admiration of the lecture, thanked Arago for the very particular attention which he had paid him during its delivery. "You had the appearance," said he, "of giving the lecture only to me." After the entrance of the Allies into Paris, Arago shut himself up in the Observatory, and refused to see any of the distinguished sovereigns, or other great men who then sojourned in the capital. Humboldt had in vain asked leave to introduce to him the King of Prussia. One day Arago had just risen from table, and had gone into the billiard-hall with his friend. The noise of a carriage was heard at the door, when instantly entered Humboldt, accompanied by a gentleman in a cap and travelling-dress. "I am setting out for Berlin," said Humboldt, "and I could not think of going without taking leave of you. Monsieur accompanies me, and I asked him to come in with me, that he might not be kept waiting in the carriage." Arago saluted the stranger, showed him to a chair, and, without taking any further notice of him, entered into a long and interesting conversation with Humboldt. At the end of an hour, Humboldt took leave of Arago, and the stranger saluted him and retired with his companion. Scarcely had they gone when Arago said smilingly to his two friends, "This excellent friend of mine believes undoubtedly that I have not recognized the King of Prussia." When the conqueror of Waterloo occupied the Elysée, Napoleon had abandoned every hope of power in Europe, and looked to America as a place of refuge which he might reach without difficulty, and where he might reside in freedom. With this view he developed his future plans to the celebrated Monge. "Idleness," said he, "will be to me the most cruel of tortures. Condemned no longer to command armies, I see that it is only the sciences which can powerfully divert me from mental cares; to learn only what has been done by others would not answer my purpose. I would wish in my new career to leave behind me works and discoveries worthy of myself. I wish to have a companion who will initiate me into the sciences. We shall afterwards explore together the new continent from Canada to Cape Horn, and in this long journey we shall study together all the great phenomena of the physics of the globe, upon which the scientific world have not yet come to a decision." Transported with enthusiasm, Monge exclaimed, "Your companion, Sire, is already found. I will accompany you." Napoleon nished at the number of restrictions which he made upon our éloges, and he at last told us that the experiment on which we placed such value had been published since 1807, in his treatise on Natural Philosophy. This rendered our discussion long and minute. Mrs. Young was present, without taking any part; but as we knew that the fear, really puerile, of passing for learned women, and the dread of receiving the name of bluestockings, made English ladies very reserved in the presence of strangers, our want of tact did not strike us till the moment Mrs. Young quickly left the room. We began to make excuses to her husband, when she appeared with an enormous quarto volume under her arm. This was the first volume of the treatise on Natural Philosophy. She placed it on the table, opened it, without saying a word, at page 787, and pointed to a figure where the curvilinear path of the diffracted fringe on which the discussion turned was theoretically established."* thanked his friend with emotion, and had | They paid a visit to our illustrious countrysome difficulty in making him understand man, Dr. Thomas Young, of which Arago that a septuagenarian would hardly be qua- has given the following interesting anecdote: lified for so difficult and fatiguing an enter-"Fresnel had about this time entered upon prise. Under this feeling, Monge applied to his brilliant scientific career, by his Memoir Arago as a suitable companion to Napoleon, on Diffraction. This work, which, in our and described to his colleague in glowing co-opinion, contained a capital experiment irrelors the grandeur of the transatlantic scheme, concilable with the Newtonian theory of light, and the honor of being associated with so became naturally the first topic of our conillustrious a personage. The young philoso-versation with Dr. Young. We were astopher was to receive a handsome sum in compensation for the loss of his appointments, and a large fund was to be devoted to the purchase of a complete collection of astronomical, physical, and meteorological instruments. The negotiation, however, romantic as it was, produced no result. The English and Prussian armies were now advancing by forced marches upon the capital, and Arago imagined that the Emperor had committed a great mistake in occupying himself and them with such unseasonable arrangements, in place of remaining at the head of the troops, and rallying them under the walls of Paris for a final effort to save their country. He therefore declared that he could not charge him self with scientific researches in the new world, when France might perhaps lose its independence and disappear from the map of Europe. Monge was confounded at the refusal of his young friend. He counted it almost a proof of mental aberration, and again urged Arago to agree to the proposal. The events of the war, however, extinguished all such projects, and on board the Northumberland a less pleasing voyage became the destiny of Napoleon. This was not the only refusal of Arago to quit his country. During the Restoration, he was invited by the Emperor Alexander to Russia to take the direction of the sciences in his empire; but even the hostility of the Government could not induce him to abandon France, and he replied to the offer of the Czar that as long as he had an inch of ground upon which to plant the foot of his telescope, he owed to his country the results of his labors. In 1816 our author established, along with Gay Lussac, the Annales de Chimie et de Physique, a monthly journal of science, which has had a most extensive circulation, and which, since the death of its distinguished editors, has been placed under the charge of MM. Chevreul, Dumas, Pelouz, Boussingault, and Regnault, all eminent members of the Academy of the Sciences, and well known throughout Europe by their discoveries. In the same year M. Arago visited London along with his distinguished friend, M. Gay Lussac. Although during the Restoration Arago took no very prominent part in the politics of the day, he yet exercised the privileges of a citizen, and maintained those liberal opinions which men of patriotic minds and ardent temperaments never fail to cherish. It was, however, not till the Revolution of 1830, when the elder branch of the Bourbons was expelled from France, that he was called from the peaceful pursuits of science into the arena of political strife, and rendered a real service to his country by the active part which he took in the Chamber of Deputies and in the Municipal Council of Paris, in favor not only of political ameliorations, but of measures advantageous to science and to the useful arts. He was elected a member of the Chamber of Deputies for the Lower Seine, and attached himself to the party of the extreme left, of which Lafitte and Dupont de l'Eure were the head. Though as a speaker he was fluent and eloquent, he seldom spoke but on subjects which he had well studied, |