Berzelius travelled the path of Science together with other distinguished men, who likewise advanced chemistry with giant steps. This was a time such as no other science has yet known, for no other has grown up from its childhood to a certain maturity in so incredibly short a space of time.

Berzelius was born almost in the same year as H. Davy and Gay-Lussac. However similar were the labors of these three men in science, they were in other respects very different.

Davy's brilliant discoveries, especially that of the metallic nature of the alkalies, gave chemistry an extraordinary impulse, and caused great enthusiasm in its pursuit. He achieved great things by his discoveries, the further following out of which, however, he left to others. He died in the prime of life; but in a certain degree his intellectual blossom was already past. Born poor, he had attained to great honors and great riches, which were perhaps obstacles to his being subsequently as active for science as formerly. It is, moreover, in the highest degree to be regretted that, in the latter years of his life, his very extraordinary talents were entirely enstranged from that science for which he might have achieved so much.

Gay-Lussac commenced his scientific career with the discovery of an important law in physics, but he afterwards applied himself wholly to chemistry, and advanced it as much by accurate investigations as brilliant discoveries. To him is owing, among other important facts, the law, so important for the doctrine of definite proportions, that gases unite in simple relations of volume, a discovery, however, of which he did not at first make the many applications that were possible. But the most brilliant researches of Gay-Lussac are indisputably,-besides those published in common with Thénard on physico-chemical subjects, -the two sets of researches upon cyanogen and iodine. independently of the extremely importance influence which these researches exercised upon the whole range of chemistry, they may be regarded as models of investigation, both as regards the total results, the strict consistency of the reasoning, and the admirable description. As often as they are read, even at the present day, they will be regarded with astonishment.

Even

But when, soon after the appearance of his paper upon cyanogen, Gay-Lussac undertook, in conjunction with Arago, the editorship of the "Annales de Chimie et de Physique," his scientific activity became gradually less. The first volumes of this Journal certainly contain several small papers and remarks which call to mind the author of those on Iodine and Cyanogen; but after a few years he ceased to write almost altogether; and it is perhaps more to be sincerely regretted than in the case of Davy, that GayLussac, who died but a short time since, and after Berzelius, should already in the vigor of life have renounced his active scientific career, which seemed to promise so much.

It was not so with Berzelius. He also, He also, after years of poverty, gradually attained, if not to great wealth at least to external honors, without having sought them in the least. But these could not estrange him from science; on the contrary, he took advantage of every higher position for its benefit. Science was always the sole object of his endeavours, and he never employed them for a purpose foreign to it. So completely was his whole life dedicated to science, that, even under the sufferings resulting from a painful disease during his latter years, his whole thoughts remained bent upon it alone.

Such men present in their inspired labors, as it were, the type of the true man of science; and who does not feel himself happy to meet them in life?

ART. XI.-Correspondence of M. Jerome Nicklès, dated Paris, October 30, 1853.

OBITUARY.-FRANÇOIS ARAGO.-Death has recently made grievous inroads into the ranks of French science. We have seen the fall, successively, of Laurent, Auguste de St. Hilaire, the Botanist, Adrien de Jussieu, the last male descendant of the brilliant dynasty of the Jussieus, who died in July last, President of the Academy of Sciences, and member of the Botanical Section. A loss, still more recent, has increased this list of the dead-a loss irreparable, for it is that of a man, who was at the same time an illustrious philosopher, a champion of popular progress, and a distinguished citizen.

François Arago was born on the 26th of February, 1786, at Estagel, a small village of 3000 inhabitants, situated near Perpignan (Eastern Pyrenees). His father was Treasurer of Perpignan. With a moderate patrimony, and a numerous family, he could not give his children a liberal education; but Madam Arago was able to supply it, and devoted herself to their instruction; and she afterwards had the richest recompense which a mother can look for: her sons were all men of distinction. Besides François, who immortalized himself by his discove ries, we see Jacques and Etienne, who are distinguished in literature; Jean and Joseph, who were brave officers in the Mexican service; and last, Victor Arago, the youngest, now commandant of the Artillery.

The appearance of François Arago on the arena of Science was most opportune. His father had destined him to the law; but the young man had other tastes. He met, one day, an officer of engineering drawing a plan on the ramparts of the city, and enquired of him how he could obtain the right of wearing so fine a uniform. "Become a scholar of the Ecole Polytechnique," was the reply. From that time the career of the young man was determined. Having no instructors, he gave himself to books, and in 1803, at the age of 17 years, he entered this National School.

At the end of a year he had left behind him all his fellow students, and was detached by Monge to the Observatory of Paris, where he commenced his researches in Physics and Astronomy.

SECOND SERIES, Vol. XVII, No. 49.-Jan. 1854.

15

In 1806, he left for Spain, where he continued under the direction of M. Biot, the measure of the meridian of France, which had been interrupted by the death of Mecham. On the demand of the National Convention which established the Decimal system, Delambre and Mechain undertook the measurement of an arc of the meridian between Dunkerque and Barcelona. It was this measurement that MM. Biot and Arago continued to the Balearic Islands. This journey in Spain was full of dramatic incidents to Arago. Encamped on the summits of the elevated peaks of Catalonia, our observer had to contend in turn with the wind, the cold, and hunger, and also with brigands, the chief of whom ended by becoming the Protector of our young savants.

A year after their departure for Spain, MM. Biot and Arago had nearly completed the measurements as regards Spain. The former then returned to Paris, and Arago went on to Majorca to continue his operations. But the war was on the point of breaking out between France and Spain; and the night signals, the instruments, and the movements of the young Frenchmen who remained at work about the summit of Galatzo, rendered him an object of suspicion to the Majorcans, and Arago was arrested and thrown into the citadel of Belver. He managed to escape, and embarked with his papers and instruments for Algiers. The French Consul made him reëmbark for Marseilles, but at the moment of entering the Gulf of Lyons, the vessel was captured by a Spanish corsair and conducted to Rosas; Arago and his companions were at first imprisoned and then thrown into the Pontoons of Palamos. At last, through the reclamation of the Dey of Algiers, to whom the vessel belonged, Arago and his associates were returned to Algiers. But a revolution had there taken place, and the Dey had just been decapitated; the new Dey was unwilling to let Arago go away, whom he supposed to be possessed of treasures, and under the direction of the Danish Consul, and Arago was consequently thrown into slavery. Finally, after a series of vicissitudes of various kinds, he succeeded again in quitting Algiers, and on the 2nd of July, 1809, he entered the lazaretto of Marseilles, with all his instruments which he had succeeded in preserving.

France had believed him dead. The first letter which arrived for him at the Lazaretto was one from Humboldt, who knew him only from his misfortunes, and from that time a friendship commenced between these two great men which continued to the end. On the 17th of the September following, Arago entered the Institute: he was then 23 years old. Already he had made with Biot an extensive work on the determination of the coefficient for tables of Astronomical refraction; he had measured the refraction of different gases, a research that before had not been attempted; he had determined the relation between the weight of air and that of mercury, and found a specific value for the coefficient in the formula for calculating the heights of mountains from barometric observations; he had also made an important investigation on the velocity of light, and numerous observations towards the verification of the laws of libration; and finally he completed the triangulation prolonging the meridian of France to the island of Formentosa.

In 1812, the Bureau des Longitudes charged him with the delivery of a course of lectures on Astronomy at the Observatory, which was

continued until 1847, presenting in them the most arduous details of the science. On the 7th of June, 1830, he was named perpetual Secretary of the Academy of Sciences, replacing Fourier. From this moment a new life actuated the Academy, and it was under the impulse received from Arago that this illustrious society attained in a great degree to that distinguished standing and authority now accorded to it by the scientific world.

The revolution of 1830 broke out, and Arago entered political life. Named a member of the Chamber of Deputies, he took his seat among the republicans; and being a great orator, he was not slow to acquire influence in the parliamentary debates. It was on his Report, that a national recompense was voted to Daguerre, the inventor of Photography, and to Vicat, the inventor of hydraulic cements. He voted the

printing of the works of La Place and those of Fermat; he defended the railroads against the coalition of the "maitres de porte"; he protected electric telegraphs against the adverse intentions of the administration represented in the Chamber of Deputies by M. Pouillet, the physicist; in a word, in all circumstances, Arago was at the head of Progress.

The revolution of 1848 brought Arago into the Provisional Government. He had just completed his eulogy of Bailey, the Astronomer, the friend of Franklin, who took an active part in the revolution of 1789, of which he was a victim. Reasoning by analogy, Arago looked for a like fate. This fear was happily exaggerated. Times had changed as well as circumstances, and the only analogy between the two men, Bailey and Arago is in that both were astronomers and both perpetual Secretaries of the Academy of Sciences.

After the coup d'etat of December 2, 1851, Arago refused to take the oath of allegiance, which was required of him in his capacity as director of the Observatory, and thus made manifest once more that politics ought to be kept aloof from Science.

A life of so much labor had worn down his health. Although attacked with diabetes, he still contemplated putting the last touch to his unfinished works. Bright's malady set in and aggravated his situation, which was complicated with dropsy of the abdomen, attended with effusions, and swelling of the extremities. All announced his approaching end: yet his mind was not for a moment obscured. Shortly before his death, although blind, he superintended in some difficult researches; he asked M. Babinet to prepare for him a table of more accurately determined numbers for the lengths of undulations, that he might bring to completion a memoir on interferences; and he finished the editing of his Physical researches on the Planets, &c. &c. He died in the midst of these arduous occupations, on the 2nd of October, at the age of 67 years, a few minutes after having shaken the hand of M. Biot.

We have mentioned some of the works which Arago accomplished in his younger days. These works were completely eclipsed by the discoveries to which his name has since become attached, which embrace the following principles:

1. The discovery of chromatic and rotatory polarization. 2. That of Electro-magnets.

3. That of the magnetism which is developed when bodies are revolved near a magnet.

Arago was an Encyclopedic genius. Science, Literature, Political and Social economy, his vast intelligence embraced all with equal abil. ity. His powerful faculty of assimilation, popularization, and of appli cation of principles, placed him every where in the first rank. Whether Orator or Professor, he shone with brilliancy both in political and scientific assemblages. He was distinguished for the perspicuity and elegance of his style, and occupies an eminent place among the prose writers of France.

In the midst of so much grandeur, Arago led a most modest life. He considered as lazy whoever did not work fourteen hours a day; and such days were for hin days of repose. Although so absorbed with his occupations, he still found time to appear in the society of Paris as one of its most spirited conversationists.

While devoted to continued labor, he completely forgot his own interests, and had only what was barely necessary for the support of his family. He left two children, one Emanuel Arago, an eloquent orator of the bar of Paris and of Republican assemblies, the other Alfred Arago, a distinguished painter. If he has not bequeathed to them a fortune, he has left an immortal name: he has created by his genius a renown more illustrious than all the renown ever gained by arms—which for a long time enjoyed the privilege of giving fame, but now yields the right to the peaceful conquests of science.

Academy of Sciences.-For some weeks past, there has been little of interest brought before the Academy of Sciences. The visits of several foreign savants, MM. Richard Owen, Magnus, Rammelsberg, Kölliker, etc., have afforded some little variety. But the new scientific communications are few at the present time. I therefore leave this subject to my next letter, when I shall also be able to state who is Perpetual Secretary in place of Arago.

Views on the origin of terrestrial magnetism.—The earliest view of terrestrial magnetism supposed the existence of a magnet at the earth's centre. As this does not accord with the observations on declination, inclination and intensity, Tobias Meyer gave this fictitious magnet an eccentric position, placing it one-seventh part of the earth's radius from the centre. Hansteen imagined that there were two such magnets, different in position and intensity. Ampère set aside these unsatisfactory hypotheses by the view, derived from his discovery, that the earth itself is an electro-magnet, magnetised by an electric current, circulating about it from east to west, perpendicularly to the plane of the magnetic meridian; and that the same currents give direction to the magnetic meridian, and magnetise the ores of iron; the currents, being thermoelectric currents, excited by the action of the sun's heat successively on the different parts of the earth's surface as it revolves towards the

east.

A long time before the discovery of electro-magnetism, Biot was occupied with this subject, and regarded the terrestrial magnetism as the principal resultant of all the magnetic particles disseminated in the earth. M. Gauss adopts this view, as an interpretation of the fact,