*

"The Academy announced in its public session of the 27th March, 1820, that in that of March, 1822 it would award the prize of mathematics, consisting of a gold medal of the value of 3,000 franes, to the best work or memoir on pure or applied mathematics, which shall have appeared or been communicated to the Academy during the space of two years which are accorded to competitors. "Many physico-mathematical researches, worthy of high praise, have appeared in that interval. But the importance of the discovery of the action of the voltaic pile on the magnetic needle, a discovery which furnishes a new principle to applied mathematics, and which has already given rise to interesting applications of analysis, has determined the commission to award to it the prize of mathematics. The commission charged with the examination of articles for the prizes of mathematics is in the habit of adjudging those prizes without the co-operation of the Academy. But as the discovery in question is not explicitly comprised in the programme, it has been thought that the authorization of the society should be invoked for awarding the prize to this admirable discovery. This proposal having been submitted to the deliberations of the Academy, was unhesitatingly adopted."

A place having soon afterwards become vacant among the correspondents of the Academy for the section of physics, the nomination of M. Oersted to supply it took place 9th June, 1823. In the sequel, the highest scientific distinction at the disposal of the Academy was conferred on him, 11th April, 1842, by his elec tion as one of its eight foreign associates, to replace the distinguished botanist de Candolle.

The just eclat which had attended the discovery of Oersted, by no means diminished his desire of sometimes placing himself in personal communication with the savants of other countries. In 1822 he again went to Germany, where, independently of those who more peculiarly ranked as savants, Goethe, the illustrious poet, to whom nothing in the domain of intellect was alien, received him with distinction; as is testified by the manner in which Oersted's discovery is spoken of in several passages of his writings.

Oersted was now, for some time, engaged in thermo-electric experiments with Seebeck, and afterwards came to Paris in 1823. The Academy shared the pleasure which he experienced on taking his place in its ranks, and, during his sojourn, was entertained by several series of experiments which he performed in its presence, not the least curious of which were those executed in common by himself and Fourier.* In these, bars of bismuth and of antimony soldered together alternately and forming a closed circuit, were employed. By heating or cooling the solderings, electrical currents were produced which appeared more abundant but less intense than the currents developed by weak hydro-electric action, and gave occasion to many interesting observations.

Towards the middle of summer Oersted passed into England and Scotland, and was received, as he had been in France, with a cordiality and attention which testified the high estimation in which the author of the discovery of electro-magnetism was equally held in those countries. On his return to Copenhagen, he resumed his life of labor with more ardor than ever. The north of Europe then exhibited the spectacle of a brilliant scientific arena. At Stockholm, Berzelius, one of the princes of chemistry, at Copenhagen, Oersted, one of the princes of physics, formed, as it were, two centers of labor and discovery, around which gravitated, like so many brilliant satellites, men destined themselves to a just and well-earned celebrity-Arfvedson, Nordenskiold, Bonsdorff, Mitscherlich, Gustave and Henry Rose, &c.

The noble emulation which established itself between the laboratories of the

two capitals is easily conceived. Oersted reapplied himself to chemistry. Resuming at the end of a quarter of a century his investigations of 1799 on alumina, he accomplished, in 1824, a work which placed him in the rank of the

* See Annales de chim. et de physique, t. xxxii, p. 375, (April, 1823.)

0

most eminent practical chemists, and obtained, after prolonged efforts, the chloride of aluminum. No one before him had effected the decomposition of alumina. Yet he did not succeed in insulating the aluminum; this last and important step was reserved for M. Vöhler, the distinguished chemist of Gottingen. Still later, our young and learned colleague, M. Henri Sainte-Claire Deville, has formed of aluminum a new and valuable element of metallurgic industry.

One of the last labors of Oersted relates to the celebrated diamagnetic discoveries of our illustrious colleague M. Faraday, whose experiments had already added so many curious facts to electro-magnetism, as well as to the researches made on the same subject by some German savants, especially by M. Reich, of Friburg.

Oersted presented his first results to the Royal Society of Sciences of Copenhagen, 30th June, 1848, and gave a review of them in the Compte Rendu of the transactions of the society. He soon afterwards drew up a more complete memoir, which has been published in French.* Therein he recognizes a decreasing magnetic progression which includes the magnetic bodies properly so-called, the attractable diamagnetic bodies, the repellable 'diamagnetic bodies. The magnetism of these last may, according to him, be considered as negative, if we regard the magnetism of iron and of the attractable diamagnetic bodies as positive. Oersted showed herein that, experiment in hand, he always kept himself abreast of the progress of physics, and particularly of electro-magnetism.

In effect, the weight of years never relaxed the activity of Oersted. Were I to undertake a bare enumeration of the researches and writings of every kind which he executed at Copenhagen during the last twenty-five years of his life, I should much exceed the time at my disposal. But, while omitting this long catalogue, in which are numbered nevertheless important memoirs on electricity and magnetism, on the compressibility of liquids and of gases, on the heat developed by the compression of water, on capillary phenomena, works of literature and philosophy, &c.,† I feel bound to point out what contributed in quite * See Annales de Chimie. et Physique, 3d series, t. xxiv, p. 424, (December, 1848.) The following note, for which I am indebted to M. de la Roquette, makes us acquainted with one of these last works:

"Oersted published, about 1850, two volumes under the title of Aanden i Naturen, a philosophic work which appears to me of high import; it forms a series of treatises in which the author introduces us, in a manner at once philosophic and popular, to the study of nature, by revealing to us the eternal spirit which determines all its phenomena, and the relation under which this spirit exists towards the material and intellectual world. The following is the substance of the tracts or chapters of which the work is composed:

"Vol. I. (1) of spirit manifested in matter. The author develops what is constant or immutable in the continual changes of bodies; it is the single thought or design which exists therein. The unity of this thought pertains to nature, for the natural laws, which are constant and invariable, are laws of reason; not of the reason which is in us, but of that which prevails in the entire universe. It is the assemblage of laws determining the activity of an object, which constitutes its real essence. These laws, which may be properly called the ideas of nature, form in every object a unity which may be qualified as the essential meaning of the object or its idea. This idea does not exist solely in the thought; it is realized, on the contrary, in the acting forces of the objects. The being of the object is thus an animated or living idea. In order to place these interesting reflections within the reach of all, the author has recourse to the form of dialogue, like Plato, Fontenella and Fenelon; his style is at once simple and clear, rich and varied. (2) The fountain and the jet d'eau. He here characterizes the different impressions produced by this phenomenon. (3) The relation between the conception of nature by thought and that which is effected by help of the imagination. (4) Superstition and incredulity in their relations to the natural sciences. (5) All existence considered as the empire of spirit. (6) The culture of the sciences represented as a worship offered to God.

"Vol. II. (1) The relation of the natural sciences to poetry. (2) The relation of these sciences to different important notions of religioh. (3) Of the salutary influence which the study and employment of the natural sciences must exert on the intellectual development of man. (4) Two discourses on occasion of the reunion of the Scandinavian naturalists. (5) On the passage from the school to active life. (6) Comparison of ancient and modern times; the author here demonstrates that neither the world nor humanity have deteriorated; that the temperature of the air has not changed; (the physical state of Greenland was, six

a special manner to the honor of Oersted, by observing that, in him, the favors of fortune never weakened his devotion to the duties of the savant, and that after having made a discovery whose brilliancy rendered it difficult further to augment his reputation, he believed that he still owed to science and his country the constant tribute of assiduous labor.

It was one of the happy events of Oersted's life that he witnessed, in 1829, under the reign of Frederic VI, the founding at Copenhagen of a Polytechnic School. Of this he was named director, an honorable title which he retained till his death. We will not examine whether this Polytechnic School, in which courses were appropriated to the arts and trades, entirely resembled our own. In such a country as Denmark, less extensive than civilized, it is necessary to unite many branches in order to compose a solid faggot. The object was, in the main, analogous, and the very name of the school was a memorial of the first journey of Oersted to Paris, as well as an homage rendered to the celebrated school of Monge and Fourcroy. In the Danish institution, Oersted continued to profess physics till his last year, with unremitting zeal, animation and success. As director, he treated the pupils with a mixture of kindness, sagacity and firmness which secured their unreserved devotion and willing obedience.

During his third journey, Oersted found himself crossing the channel from France to England, on his forty-sixth birthday, 14th August 1823; it is an anniversary which the people of the north style the day of one's fete. Accustomed in Denmark to pass it in the bosom of his family and friends, he was now left to his solitary thoughts; and these naturally reverting to his country, inspired him with the design of founding something on his return which should be at once a profitable and pleasant memorial of the vows which on this occasion he addressed to his distant home. The plan of a society for the promotion of the study of nature formed itself in his mind, and was so thoroughly wrought out during the short navigation, that nothing was required on landing at Dover but to reduce it to writing. The plan met with cordial acceptance in Denmark, and by aid of the new association, courses of natural history were established not only at Copenhagen, but in other cities of the country; nor has this institution since ceased to bear the useful fruits which Oersted had anticipated.

He was also member of a literary society. In connection with this a monthly publication was edited, in which he often inserted articles on the most varied subjects, not excepting religious and philosophical ones. He belonged, moreover, to an association established for the right use of the liberty of the press. In fact, his co-operation seems to have been claimed almost universally at Copenhagen, nor was a sense of its value without frequent manifestations in other cities of Denmark, and even in those of the neighboring countries. To the last, he was accustomed to make numerous excursions as well into the north of Germany as into the Scandinavian peninsula, in attendance on the assemblages of naturalists which were held at different places. It was a cherished idea of his that, through these assemblages, not only might the exchange of scientific views be facilitated and a more intimate union among the representatives of science be cemented, but that their benefits might be extended to a wider circle by expositions placed within the reach of all and contributing to introduce, even among the popular masses, the habit of comprehending and mutually exchanging their idioms and forms of literature; especially was it his hope that the three Scanhundred years ago, the same that it is to-day;) the olive had in France, eighteen hundred years ago, the same limit in the north which it has at present; the men of antiquity were not stronger and attained not a more advanced age than those of modern times; the human far from retrograding, has made sensible progress in regard to morals. (7) The relation of the natural sciences to different ages and to their philosophy; * Christianity and mental cultivation as lending each other mutual support."

race,

The interest which this work excited in Germany led to its translation under the title of Der Geist in der Natur, (The Soul in Nature). [It was also translated into English.]

dinavian nations might thus become, as it were, three branches drawing in common their intellectual nourishment from the same radical stock.

It was never the misfortune of Oersted to witness any diminution of reputation. In 1846, in the sixty-ninth year of his age, he again traveled into Germany, France and England. In an interesting notice of Oersted read 7th November, 1851, before the Royal Society of Sciences of Copenhagen, M. Forchhammer, who had accompanied him, tells us that this journey resembled an ovation. In England, especially, Oersted was received by the most eminent politicians and men of science with a distinction which has rarely been the portion of a stranger, and, above all, of a simple savant. His purpose was to take part in the meeting at Southampton of the British Association for the Advancement of Science. In one of the sessions of that body, Sir John Herschel, made an address to him, remarkable for the signal and intelligent justice which it rendered to his scientific labors.

Honored in his public, Oersted was happy in his private life. His younger brother, whom he had taught to read under the roof of the wig-maker of Rudkjöbing, ever continued to be his faithful and intimate companion. The latter had himself acquired great celebrity by his labors in philosophy and jurisprudence, and had filled the position of president of the Royal Society of Copenhagen. Only with the death of the elder brother terminated the auspicious habit, contracted in childhood, of daily exchanging their impressions and ideas. In 1814, Oersted had espoused Mademoiselle Brigitte Ballum, daughter of a Lutheran minister of Kjedby, in the isle of Möen, and found in her an accomplished companion, whose character, admirably adapted to his own, formed their mutual happiness. Of five daughters and three sons born of this union, only three of the former and two of the latter survived Oersted, to be the consolation of their mother. One of his daughters is married to M. Sharling, professor of chemistry in the University of Copenhagen, long known for important researches on respiration.*

Around Oersted, however, there existed a still more extensive family. It was composed, we might say, of the whole city of Copenhagen, where he was as much loved as esteemed, as much esteemed as admired. Of this his fellowcitizens gave him a touching proof in the latter days of his life. The day (7th November, 1850) which marked the fiftieth anniversary of his entrance upon public duties, and was what is called in the north his jubilee, was celebrated by a general festival in Denmark, with the somewhat quaint forms of Teutonic good-fellowship, but accompanied by a substantial testimonial of gratitude to the man who was regarded as the honor of the whole nation. It had been determined by the friends, the pupils, and indeed the simple admirers of the philosopher, to make this the occasion of securing to him for the remainder of his life the possession of Fasanenhof, (Pheasant-court,) a delightful summer residence in the garden of Fredericksburg The choice of the dwelling was so much the more delicate and so much the more pleasing to Oersted from its having been previously the habitation of Ochlenschläger, the friend of his youth.

Oersted was conducted thither on the day of his jubilee. At the same time the King raised him to the rank of councillor of private conferences, a title never before conferred on a professor of the university, and much higher than that of councillor of ordinary conferences, which Oersted had borne for ten years. His bust, executed by a celebrated statuary, was set up at Fasanenberg in presence of an immense crowd, in which were intermingled the most illustrious personages of the kingdom. The rector of the university formally presented

His treatise on respiration was published in 1843, some months before the researches of MM. Andral and Gavarret on the same subject. (See Comptes Rendus of the Academy of Sciences, t. xvii, p. 1205.) M. Alexandre Oersted, son of the celebrated jurist M. André Sandoe Oersted, and nephew of the renowned physicist, is at present professor of botany in the University of Copenhagen.

him with the gold ring of a doctor, on which was engraved a head of Minerva encircled with diamonds. The Seigniory of the association of students notified him that he had been elected an honorary member of that society, and a deputation of the Guild of arts and trades tendered him thanks for what he had done in behalf of the industry of the country.

To all the discourses addressed to him Oersted replied with a force, a composure and a choice of expressions which surprised the assistants. The choir of the students commenced and terminated the fête with a chant, the words of which had been composed by one of the best poets of Denmark. In the evening a procession with torches and a new chant by the students greeted the object of this enthusiastic commemoration.

The day on which classes so numerous and so diversified had vied with each other in testifying for him their affection and admiration must have been to Oersted one of the sweetest of his life. He had received from his sovereign and his fellow-citizens the most exalted testimonials of esteem with which any Danish savant had been ever honored, and, in spite of his modesty, his conscience could not have failed to insinuate to him that he was not unworthy of them. The hope of passing his last years, surrounded by his family and dedicated to a tranquil scientific activity, in the smiling retreat which his countrymen had thought proper to offer him, was calculated to blend the satisfaction of the heart with the consecration of his renown. Yet this pleasing hope was but a deceptive gleam, and although his mind, still vigorous, and his frame-replete with life, seemed yet to promise length of days, it was not granted to Oersted so much as to take possession of his new domicil, for before the return of spring he had ceased to live.

He died at Copenhagen, 9th March, 1851, at the age of seventy-three years and seven months, removed unexpectedly and in but a few days, by a simple catarrh contracted by studying of a morning in too cold an apartment. His death was a profound and general grief for the city of Copenhagen and for all Denmark. In that grief, this Academy, in common with the whole scientific world, bore no indifferent or simulated part.

Oersted was replaced in the list of our eight foreign associates by the celebrated chemist of Berlin, M. Mitscherlich, to whom crystallography is indebted for the most important progress it has made since Hauy. M. Mitscherlich had, in his youth, associated himself with the labors of the Scandinavian scientific school; and this choice, justified by other reasons, might be regarded as a new and last homage rendered to the memory of Oersted as well as to that of Berzelius.

No scientific body had been backward in crowning with its suffrage the great discovery of Oersted. To make an enumeration of more than fifty societies which inscribed his name among those of their correspondents or their foreign associates, would be little less than to draw up a complete list of the principal Academies of the two hemispheres. More than one sovereign had been emulous of associating himself with the movement of public opinion in his behalf. He was advanced to the class of grand-cross of the Danish order of Danebrog, grand-cross of the Swedish order of the Polar Star, member of the order of Merit of Prussia, and officer of the Legion of Honor.

Oersted was not only eminent as a physicist, profound as a thinker, he was a man of rare excellence of character. Author of one of the capital discoveries of the century, promoter of one of the schools which confer most honor on his country, founder of many important scientific and literary institutions, dear to the youth and to the public of Copenhagen, whom he had charmed during 50 years by a system of poetic and philosophic ideas in harmony with their natural instincts, * Two hundred thousand persons, preceded by the princes of the royal family, followed the body of Oersted to its resting place.