idea presented itself to our author that the by a dipping needle placed vertically, so magnetic needle while under the influ- that its axis of rotation is continued in a ence of a glass or metal plate, might be car-plane perpendicular to one of the radii of ried round or in some way affected by the the disc. No action is experienced by a rotation of the plate. In order to perform similar needle placed at the centre of the this experiment, an apparatus consisting disc. There was also a second point nearer chiefly of a clock made of copper with the the margin than the centre where no change exception of two or three steel pivots, was was produced by the disc on the position of constructed for the purpose of giving a mo- the needle; but between these neutral points tion of rotation to the plate laid horizon- the lower pole is constantly attracted totally on the top of a vertical revolving axis. wards the centre of the disc, while beyond Immediately above this was placed a glass that point it is repelled. These experiments receiver, within which the needle was sus- were announced to the Academy of Sciences pended so as to take its place horizontally on the 7th March 1825; and they were exwithin a short distance of the revolving hibited in London in the following April by plate. M. Gay Lussac. They excited great interest throughout Europe. Messrs. Babbage and Herschel, Barlow, Nobili, Christie, and Messrs. Prevost and Colladon took up the subject and obtained many important results. When the apparatus was prepared, and the copper made to revolve under the needle in its place, with a sheet of paper intervening to prevent disturbance from aerial currents, the needle was gradually drawn out of the magnetic meridian with a force proportional to the velocity of the copper plate, and as this new force is opposed by the magnetic action of the earth, which constantly tends to keep the needle in its place, the needle must finally take a position of equilibrium depending on the ratio of these forces. In very rapid rotations, however, the inferior influence of the earth is completely overpowered, and the needle turns continually round. In such cases the needle will take a fixed position by increasing its distance from the revolving plate, the velocity remaining the same, so that the deviation of the needle may be made very small by increasing that distance. In consequence of M. Arago having discovered in 1820, contemporaneously, we believe, with Sir H. Davy and Dr. Seebeck, the power of the electric current to impart magnetism to iron and steel needles, his friends have claimed for him a share in the discovery of the Electric Telegraph. We have not seen sufficient evidence, nor do we believe that any exists, to place the name of any single person in the history of science, as the discoverer of the Electric Telegraph. Although so much has been done by individuals, both as discoverers of principles and inventors of methods, yet we are not aware of any person having claimed for himself the invention of this noble apparaIn studying the influence of plates of va- tus. If, however, we are to give the invenrious metals, Arago found the results so de- tion of the steam engine and steam vessels pendent on the purity of the materials, that to Papin and others, who originally sughe did not publish them, but limited his at-gested the idea, we can have no hesitation tention chiefly to the determination of the in assigning the invention of the Electric components of the force developed by rota- Telegraph to a humble Scotsman who has ion, in the direction of three lines parallel to left us only the shadow of his name. Just three co-ordinate planes perpendicular to one hundred years ago, a contributor to each other. The component perpendicular the Scotch Magazine, dating from Rento the revolving plate he found to be a repul- frew, published to the world the invention sive one by its action on a long magnet, of the Electric Telegraph, in terms so dissuspended vertically by a thread to the extinct that they must take away from every tremity of the arm of a balance in equilibri- claimant any other merit than that of simum with a weight at the other extremity.lifying it, and employing the known princiWhen the plate revolves the magnet is re- ples of electricity and magnetism, discopelled, and the equilibrium of the balance vered since the time of its inventor. Aloverset. The second component is horizon- though this is not the place to discuss the tal and perpendicular to a vertical plane history of that invention, we shall give our abutting against the projection of the pole readers the gratification of reading this reof the needle. This is the force which, act-markable production.* ing in the direction of a tangent to the axis, produces the rotation of the needle. The third component is parallel to the radius which abuts against the projection of the pole of the needle. It may be determined "Renfrew, Feb 1, 1753. "SIR,-It is well known to all who are conversant in electrical experiments, that the electric power may be propagated along a small wire, from lone place to another, without being sensibly abated Among the interesting inquiries of Arago of battle, and while military officers who relating to magnetism, we cannot omit his assisted them-men of tried courage-grew views respecting what has been called by pale and fled from the scene, the two savans Humboldt magnetic storms or disturbances in went on coolly making their calculations the magnetic atmosphere, extending them- and observing the temperature and pressure selves to great distances in our-atmosphere, with boilers every moment on the point of exhibiting themselves in irregular move- explosion.* ments of the magnetic needle, and termina- Numerous and valuable as are the scienting in a display of the aurora borealis. In tific researches of Arago, of which he has electrical storms, on the other hand, the dis- himself given an account, yet we should turbances have a limited range, terminating form an imperfect estimate either of his in thunder, and lightning, and rain. genius or of his labours were we to measure When the construction and safety of steam them by his published writings. In early boilers had become objects of national im- life, when fame is the lofty stimulus to portance, Arago and Dulong were, in 1820, genius, the young philosopher is little scruemployed by the government to make ex- pulous about the form or manner in which periments on the subject, and they drew up he presents his achievements to the world. tables exhibiting the elastic forces of steam To gain the victory-to announce it to the at different temperatures. This task, which world, and to receive the laurel, are the sole was executed with much ability, was as objects of his desire. If he has competitors dangerous as it was difficult. The bursting in the race of ambition who carry less of boilers to which they were constantly ex-weight than himself, and who have more posed, and that too in a limited locality, was leisure and greater instrumental resources, more hazardous than that of shells in a field he is compelled to work under a higher have been touched. And then, by some practice, they may come to understand the language of the chimes in whole words, without being put to the trouble of writing down every letter. by the length of its progress. Let then a set of wires, equal in number to the letters of the alphabet, from the horizontal wire A to the bell A, another be extended horizontally between two given places, from the horizontal wire B to the bell B, &c. Then parallel to one another, and each of them about an let him who begins the discourse bring the wires in inch distant from that next to it. At every twenty contact with the barrel, as before; and the electric yards end, let them be fixed in glass or jeweller's spark breaking on the bells of different size, will incement, to some firm body, both to prevent them form his correspondent by the sound what wires from touching the earth, or any other non-electric, and from breaking by their own gravity. Let the electric gun-barrel be placed at right angles with the extremities of the wires, and about an inch below them. Also let the wires be fixed in a solid piece of "The same thing may be otherwise effected. Let glass at six inches from the end; and let that part of the balls be suspended over the characters as before, them which reaches from the glass to the machine, but instead of bringing the ends of the horizontal have sufficient spring and stiffness to recover its sit-wires in contact with the barrel, let a second set uation after having been brought in contact with this reach from the electrified wire, so as to be in contact barrel. Close by the supporting glass, let a ball be with the horizontal ones; and let it be so contrived suspended from every wire: and about a sixth or an at the same time, that any of them may be removed eighth of an inch below the ball, place the letters of from its corresponding horizontal by the slightest an alphabet, marked on bits of paper, or any other touch, and may bring itself again into contact, when substance that may be light enough to rise to the elec- left at liberty. This may be done by the help of a trified ball; and at the same time let it be so contri-small spring and slider, or twenty other materials, ved that each of them may reassume its proper place which the least ingenuity will discover. In this when dropt. All things constructed as above, and the minute previously fixed, I begin the conversation with my distant friend in this manner. Having set the electrical machine a-going as in ordinary experiments, suppose I am to pronounce the word Sir; with a piece of glass, or any other electric per se, I strike the wire S, so as to bring it in contact with the barrel, then i, then r, all in the same way; and my correspondent almost in the same instant observes these several characters rise, in order, to the electric balls at his end of the wires. Thus I spell away as long as I think fit; and my correspondent, for the sake of memory, writes the characters as they rise, and may join and read them afterwards as often as he inclines. Upon a signal given, or from choice, I stop the machine; and taking up the pen in my turn, I write down whatever my friend at the other end strikes out. way the characters will always adhere to the balls, excepting when any of the secondaries is removed from contact with its horizontal; and then the letter at the other end of the horizontal will immediately drop from its ball. But I mention this only by way of variety. "Some may perhaps think, that although this electric fire has not been observed to diminish, sensibly, in its progress through any length of wire that has been tried hitherto; yet as that has never exceeded some thirty or forty yards, it may be reasonably supposed, that in a far greater length, it would be remarkably diminished, and probably would be entirely drained off in a few miles by the surrounding air. To prevent the objection, and some longer argument, lay over the wires from one end to the other with a thin coat of jeweller's cement. This may be done for a trifle of additional expense; and as it is an electric per se, will effectually secure any part of the fire from mixing with the atmosphere I am, &c., C. M."-The Scots Magazine, Feb. 1753, vol. xv. pp. 73, 74. "If any body should think this way tiresome, let him, instead of the balls, suspend a range of bells from the roof, equal in number to the letters of the alphabet; gradually decreasing in size from the bell A to Z: and from the horizontal wires, let there be *Notices on this subject will be found in the Ananother set reaching to the several bells; one, viz.Inuaire for 1829 and 1830. mental pressure, and by prematurely disclos- volumes will embrace his historical eloing his discoveries to enable his rival to oc- ges and biographical notices, preceded by cupy the very heights at which he aimed. memoirs of his youth. Two volumes will Time, however, soon reduces this morbid as- be occupied with nineteen scientific memoirs, piration after fame, and we believe there are of which only six or seven have been pubfew successful discoverers who have not with- lished. Two volumes will form a treatise held from the public large portions of their on physical astronomy, a work of which the researches, in the hope, frequently a vain highest expectations have been formed. Othone, of finding leisure to correct and extend er three volumes will comprehend the scithem. If Arago had not published so early his paper on chromatic polarisation, he might have anticipated Biot in many of his great discoveries; but, on the other hand, he ran the risk of losing the priority which he possessed, unless he had couched his results in an anagram, or lodged them in a sealed packet with the Academy. entific notices which have appeared in the Annuaires, including a new edition of the remarkable one on Thunder, which Arago had prepared on his deathbed. The last volume will contain reports made to the different legislative assemblies on the subject of fortifications and other public works. M. Barral, formerly a pupil of the Polytechnic School, and Professor of Chemis try, has undertaken the duty of editing the works of his friend and there is reason to believe that they will very soon be in the possession of the public. It is doubtless, from causes of this nature, that Arago has left behind him so many unpublished memoirs, and so many undescribed inventions and discoveries. When, in 1850, he himself made this announcement to the Academy, it was in terms, and under circum- Although these volumes will form the stances, which deeply affected his colleagues true monument to the memory of their disand his audience. "The bad state of my tinguished author, yet the friends of Arago health," he said, "and the great change which have, with great propriety, resolved to erect, my sight has almost suddenly experienced, in honour of him, a more public memorial. have inspired me with a desire, I may We trust that this will neither be a marble almost say, have imposed upon me the du- bust in the Institute, which private friends ty, of promptly giving to the public the sci- may supply, nor a colossal figure in bronze, entific results which I have obtained, and nor a sepulchral column over his ashes, but which, for a long time have slumbered in a noble building erected in the heart of my manuscripts. I have resolved to com- Paris, at whose base the youth of France mence with Photometry, a science which, may kneel, or within whose precincts they born in the middle of our Academy, has re- may imbibe those ennobling sentiments, mained stationary amidst the progress which or study those immortal truths which will has been made in optics during the last half ever be associated with his name. century. In publishing the results of re- It is difficult to draw in a few definite searches pursued interruptedly for many lines the character of a man like Arago, fong years, and with instruments improved presented to us as it is under so many or invented by myself, it appears to me that phases, and viewed from so many points of my communications should not bear upon sight. A child of the first revolution—a insulated facts, but should rather embrace stripling during the consulate and military general results mutually connected, so as to sway of Napoleon-a public teacher under form each a chapter in science." With these the restoration-a legislator under the unpreliminary observations, our great philoso- constitutional regime of Louis Philippe-a pher entered upon the subject of his me- cabinet minister under the provisional govmoirs, and at successive sittings of the Acad- ernment-a deputy under the second repubemy, he continued week after week,-with- lic, and a dying man under the second out the aid of diagrams or instruments, empire, we find him carried, a patriot, to without looking into his MSS.,-without his grave by the representatives of all the consulting even a memorandum,-to de- conflicting opinions, and all the antagonist scribe in detail long series of experiments authorities of his country. Through what and calculations, and to expound those great dangerous quicksands must such a course physical truths to which they led. These have lain? How many Charybdises must memoirs we are happy to announce will the pilgrim have crossed, and how many speedily be given to the world. M. Gide, the Scyllas evaded in so stormy a passage to celebrated publisher of the Travels and Cos- the grave. It would be difficult to delineate mos of Humboldt, has given 120,000 francs, in its noble outline and godlike form the chaabout £5000, for the copyright of Arago's racter of the patriot and the philanthropist, works, printed and in MS. They will be two inseparable names, but that statesman published in twelve volumes octavo. Three is, doubtless, deserving of the double title who has lived simply and died in poverty-man, subject, like every other judge, to the who has refused salaries that he had earned, influences around him. How different is and emoluments that he had won, and who the conduct of some of our own self-conhas spent his life in developing the only stituted arbiters of science, who, with no true sources of national greatness, and social country in their heart, have, under the imregeneration-the education of the common- pulse of an ignoble personality, transferred wealth-the advancement of science, litera- to foreign claimants discoveries which have ture, and the arts-the simplification of been made at home. knowledge, and the diffusion of it among One of the brightest phases in the characall classes of the people. In this its highest ter of Arago was his ardent love of science, meaning Arago was a statesman, and one of his admiration of those who advanced it, that honoured group whose destiny it has his zeal to encourage youthful genius, and been to take an efficient part in these various to patronise the ingenuity and inventions of branches of their country's service. But in the humblest artizan. In the name of the thus serving his country, he became the youth and the workmen of Paris, M. Barral benefactor of the human family. Every has expressed the affection and gratitude step in the patriot's career, though primarily which they owe him. M. Flourens has taken for his country, is ultimately taken recorded in eloquent terms the sentiments for mankind. The lesson which is taught, of the Academy which he adorned; and the and the example which is set on the Seine veterans of science who have mourned his or on the Thames will be learned and imi- loss in the different capitals of the civilized tated on the Mississippi, and on the Volga. world will doubtless join in the glowing The law of truth and justice which triumphs sentiments of the chief whom they honour, over European anarchy, will yet tame the the illustrious Baron Humboldt, the father ferocious Tartar, and fix the wandering of the republic of science :-"But that," says Arab. he, "which characterised this singular man It is, however, in his character as a philo- was not only the fire of genius which producsopher and as a Perpetual Secretary of the ed, and the penetration which enabled him to Institute that Arago is best known and most develop new creations as things that had appreciated in England. He was personally been long achieved by human intelligence; it acquainted with the greater number of our was the attractive union of the energy and distinguished men, and received as a foreign elevation of an empassioned character, with member into almost all our Societies. His the most affectionate gentleness of disposigenius-his talents-his discoveries- his tion. I am proud to think that, by my tenmanly character-his high estimate of intel- der devotions and my respectful admiration, lectual worth, were universally admired, I have belonged to him during forty-four and if we ever heard a sound not in unison years; that my name will be sometimes with the language of praise, it was but the pronounced beside his great name; and expression of regret that so distinguished a that all my works bear testimony to my philosopher should have been exposed to gratitude and warm affection." the political convulsions which had been so long desolating his country. After such expressions of admiration and friendship from authorities so high, we As an editor of the Annales de Chimie et should scarcely have ventured to add a few de Physique and of the Comptes Rendus, words of our own, had we not been placed &c., Arago was specially called upon to toward Arago in a relation very different decide in cases of disputed inventions and from theirs. Forty years have elapsed discoveries. We all know how complicated since the writer of these lines became acsuch questions become when discussed under quainted with Arago, when engaged in the the influence of national and personal feel- same inquiries with himself. The tie creating, and we have seen how these feelings ed by similarity of studies, though at first have operated in the history of fluxions and strong, is often one which is most easily in the recent controversies respecting the dis-severed. Whether in the pursuit of fame covery of Neptune. Arago has been rashly we outstrip our friend, or are left behind in accused of always leaning to his country; the race, we reach the goal with some disbut though we do not concur in some of his turbance in the affections. The silver cord, decisions, nor admit the rules which some though neither enfeebled nor broken, may of his countrymen have laid down as the yet have given forth a discordant sound. basis of such adjudication, we yet regard That man indeed can have no feeling for his his decisions as the convictions of an upright mission who does not vindicate a right of discovery with all the energy which truth *Comptes Rendus hebdomadaires des Séances de and justice demand, and hence it is that, L'Académie. Par MM. Les Secrétaires Perpétuels, under peculiar circumstances, men of ardent 1835-1854. temperament have permitted such discus-) The attack upon the Institute as a body will no doubt be repelled by an elaborate exposure of its falsehoods. It is with the charges against the Academy of Sciences and M. Arago that we shall deal. This distinguished body is charged "with adopting in the present day new methods to gain an ascendency over the public!" It is described as an inferior body to the Academy under Lagrange and Laplace, as unjustly boasting of the superiority of its mathematicians, as having lost its preeminence in Europe, and as addressing itself to the populace and winning their sympathy by the tone of its periodicals. The older members, Biot, Thenard, Cauchy, Mirbel, Arago, and Chevreul, are down as belonging to another age; and Dumas, Elie de Beaumont, and Leverrier, the younger members, are denounced as "more devoted to politics than to physics." 66 set This change of character is ascribed to the admission of the public to its meetings, which is considered as no less a revolution is therefore with the deepest sorrow that we than that of the State in 1830! Profound mourn the double loss of a friend and of a discussions are now said to have disappearsage, and that we now express over his tombed, and the Academicians seek only the our admiration of his genius, our sympathy with his patriotism, our gratitude for his kindness, and our affection for his character. We could have wished to have here closed our account of M. Arago; but an attack has been made upon him in England by one of our most respectable Journals, so violent in its character, so false in its statements, and so vicious in the motives which have inspired it, that we owe it to the scientific character of our country to disavow it as the production of any English philosopher. Although the title of the article is The Institute of France, a subject not very interesting to the readers of the Quarterly Review, yet that title is assumed in order to introduce an account of the Academy of Sciences, and thus gain a position from which to throw dishonour on its Perpetual Secretary. Had the writer of this tirade subjected to criticism any of the works of Arago, or questioned the originality or value of any of his discoveries, or had he been led in political discussion to challenge his patriotism or denounce his republicanism, we should have been the last to interfere even with the licentiousness of literary criticism or the virulence of political slander. But the article to which we refer is an attack upon the entire life and character and motives of a great man; dictated by personal resent ment, pretending to instruct the public when its object is to wound the individual, and masking under the incense of praise the poison of its stiletto. favour of the crowd. The Comptes Rendus, the noblest scientific journal in the world, is said to have been established as a great instrument of domination," and to be often filled with worthless communications. M. Arago is declared to be "the promoter of this revolution." He is charged with ignorance of mathematics and of classical learning; with seeking for an easily won applause in the exposition of popular science; with exhibiting an intolerance without bounds when a republican; with leaguing himself with the ultra-liberal party; with addressing himself to false and vulgar patriotism; with claiming all discoveries for Frenchmen; with preferring the productions, of an ouvrier to those of a philosopher; with setting aside in the Academy important discoveries to announce showers of frogs to please "a gaping crowd;" and with "pulling down the pillars of the Temple of Science to make sport for the Philistines." Out of "a thousand of examples" of virulent discussions, in which the " rigour of philosophical disputation is exchanged for the heated declamation of popular demagogues," the critic gives one of a very gentle character on the authority of a Havre newspaper. M. Arago is next charged with voting for that distinguished naturalist, Charles Bonaparte, as a candidate for the Academy, in opposition to M. Delessert. The patronage of the numerous professorships possessed by the Academy is said to be so abused, that combinations are made in order that the success of an election may sooner |