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Memoir on the General Principle of Naiural Philosophy. By M.

G. LAME, Professor at the Polytechnic School. The discovery of ether is due to the physical theory of light; the idea of luminous undulations, defended by Euler and Young, has had a definite triumph by the discoveries of Arago and of Fresnel ; since the fruitsul theories of the latter, the more recent works of MM. Hamilton and Lloyd, Brewster, Babinet, Seebeck, and the mathematical researches of MM. Cauchy, MacCullagh, and Neumann, it is no longer possible to doubt the existence of ether. The physical theory of electricity, excited by the discovery of Ersted and the works of Ampere, all conjoin at the present day to make all the electrical phenomena depend on the mutual actions of ether and the ponderable matter; and it is evident that to this preconceived idea are due the greater parts of the discoveries of MM. Becquerel, De la Rive, Faraday, and Savary. In fine, the physical theory of heat, since the works of MM. Melloni and Forbes, is in vain defended against the idea of vibrations.

In resuming the subject, the general principle, towards which the three partial theories of natural philosophy at the present day converge, attributes to ether, to its own repulsions, and to the actions which the ponderable matter exercises on it, all the phenomena which depend on these theories. The propagation of the vibrations of the etherial fluid gives light, and all the radiations. The increase or diminution of the masses of ether, which form the atmospheres of ponderable atoms produces electricity and chemical phenomena. In fact the vibratory movement of these atmospheres gives heat.

This principle contains in itself all the hypotheses elaborated by the philosophers who occupy themselves on the different departments of philosophy ; it embraces and explains sufficiently the phenomena of all classes. This generality does not show, without doubt, its real existence, but it gives to it, at least, as much of certainty as to the original ideas of modern discoveries, since these ideas are found to be comprised in the complete expression of the principle which it contains. The consequences deduced from this principle present themselves with a probability then sufficient to attract the attention of philosophers.

One of these consequences is the existence of a pressure exercised by the ether on itself, on all other bodies, and in the interior of all the millions of other ponderables. The non-manifestation of this pressure results from the fact that there is no body in existence entirely deprived of ether; and that because all the particles of the fluid communicate freely among them, by the layers which sej te the ponderable atoms, whose complete contact nowhere exists. This pressure ought to surpass in greatness the cohesion of all the trans

('omptes Rendus, Jan, 3, 1842,

parent solids, for it is that which maintains them : as the atmospheric pressure maintains the liquids which evaporate in a vacuum. But again, if we take a glimpse at any kind of barometer which can give us the exact amount of this pressure, there exists the means of proving its variation ; such is, amongst others, the measure of the co-efficient of the dilatation of the gases. If the pressure of the ether is greater at the present day than at the epoch when M. Gay Lussac measured it for the first time, in an exact manner the dilatation of the gases, the two fixed points of the thermometer, ought to approach each other; which explains in a very simple manner the non-agreement of the co-efficient measure at two epochs. In fact, after the actual memoir :

1st. The tension of the vapour of water, measured at a determined temperature, is only the excess of its total elastic force on the pressure of the ether in vacuo ; and if the pressure augments, the vapour ought in reality to be raised in temperature, inasmuch as its measured tension remains constant. That is to say, that the fixed point for the ebullition of water, under a barometric pressure of om:76, ought to be higher.

2nd. The fusion of a solid takes places when the resultant of the interior repulsive forces surpasses a little the pressure of the ether ; that is to say, that the degree of the fusion of a solid, under the pressure of the ether, is analogous to that of the ebullition of a liquid, under the atmospheric pressure. Then, if the pressure of the ether is augmented, the temperature of melting ice ought to be raised.

The ascending variation of the fixed point of melting ice ought to be much greater than the variation in the same direction of the fixed point of ebullition. From some experiments of verification in which I have been assisted by M. Cobart), I have proved that the tension of the vapour of water, at the temperature of melting ice, is still at the present day 5" ", as M. Gay Lussac found it at an epoch but little removed from that in which he measured the dilatation of the gases. We may, then, say at the present day, as then, that the temperature of melting ice is that where the tension of the water is 5mm. This concordance proves that the resultant of the repulsive forces in the ice, and the elastic force of the vapour of water, at the temperature in which ice melts, preserve a small constant difference, whatever be the variation which this temperature may undergo through a change in the pressure of the ether.

However, it is sufficient to consult the table of the tensions of the vapour of water, in order to see that if these tensions represent the excesses on the pressure of the ether, an augmentation in this latter pressure ought to raise the temperature at which the measured tension is 5mm; that is to say, the zero of the thermometer, of a quantity of from seventy to eighty times greater than the correspondent variation of the point of ebullition, or of the temperature at which the measured tension of the vapour of water is of 760mm. Thus the two fixed points of the thermometer ought to approach each other.

It is to be presumed, then, that the non-accordance of the number found, during twenty-five years, by M. Gay Lussac, to express the co-efficient of the dilatation of gases with that found at a later period by M. Rudburg, and verified by M. Regnault, results entirely from variations of this nature. The difference of the two results explain themselves, by admitting that the pressure of ether has undergone on the earth, in a quarter of a century, an augmentation equivalent to a pressure of eight or nine-tenths of a millimeter in height of the mercury : a small increase, but which will suffice, however, to bring nearer to each other the two fixed points of the thermometer by 24 degrees, taken on the old divisions ; for by dividing the total dilatation of the air between the two fixed points, obtained by M. Rudberg by 97.75, and not by 100, we re-obtain the number given by M. Gay Lussac.

Professor STEINHEIL on a simple Method of Showing the Existence

of Induced Counter-Currents by Direct Experiment. From ihe Gelehrte Anzeigen, Munich, Dec. 1, 1837. Translated by W, LETTSOM, Esq.

Between the poles of a compound horse-shoe steel magnet let tliere be adapted a rotating anchor of soft iron, surrounded with covered wire. The ends of this wire dip down into mercury cups separated by a partition, the cups themselves being brought into connection with the terminal wires of a battery. Between one of the above caps and the battery a multiplier is to be inserted.

As soon as the battery is set in action, the anchor between the poles begins to rotate; and let us suppose the needle of the multiplier to be deflected at ihe same time to the right. Now break off the connection with the battery, and spin round ibe anchor by the application of some mechanical force in the same direction in which it was previously impelled by the battery : the needle of the multiplier will be deflected in the opposite direction ; that is to say, to the left, and the amount of this deflection increases with the rapidity of the notion imparted to the anchor.

By the rotation of the anchor, caused by the battery, there are, therefore, currents of opposite signs called forth, and in which the compter-current is stronger the more rapid the motion is, or the greater the strength of the magnet is, and from which there must naturally result a proportionate, and not an accelerated velocity; and as a further proof of this, it may be added, that the velocity of the rotating apparatus is increased the very instant that the magnetic power is reduced by the application of an anchor—that is to say, while we weaken the magnet, we reduce the power of the induced counter-current.

This experiment appears so convincing, and so irreconcilable with Moser's views on electro-magnetic machines--namely, tbat the

action is not called into play the very instant the circuit is completed, and that it is the rapidity in the succession of these inpulses which limits the effect (see Moser, Repertorium der Physik, vol. i, Berlin, 1837, p. 281), that we cannot but hold that philosophy to be in error; and are led to think, with Jacobi, that the absence of the power once expected from these machines, arises from the countercurrents induced in the copper helices by the motion of the rotating magnets.

Experimental and Theoretical Researches in Electricity, Magnetism,

&c. Seventh Memoir. By WILLIAM STURGEON, Superintendent and Lecturer of the Royal Victoria Gallery, Manchester; formerly Lecturer on Experimental Philosophy at the Hon. East India Company's Military Academy, Addiscombe ; &c.

SECTION I.

On a Peculiar Class of Voltaic Phenomena. The great interest excited by the developement of those facts which show the various means by which modifications of chemical action on metallic bodies by acid menstrua are produced, having induced the British Association to grant pecuniary aid to Professor Schöenbein to enable him to pursue those experimental enquiries in which he had previously been so successfully engaged on this subject, it cannot be presuming too much to suppose that the Association would be desirous of becoming acquainted with every fact connected with so interesting a branch of physical science. And as I think it possible that Professor Schöenbein may not be in possession of some particular facts of this class, which were discovered several years ago, and as the theoretical views which accompanied the publication

of those facts appear to me to be applicable to every phenomenon of this peculiar class hitherto made public, I now venture to introduce them to the notice of the British Association,* simply as adscititious data, independently of which any historical view of the discoveries which have been made in this class of phenomena, and of the theoretical notions which have been advanced for their explanation, must necessarily be incomplete.

347. The experiments to which I allude were published in the year 1830, in a pamphlet, a copy of which accompanies this paper ; and as the experiments are clearly described, and the theoretical views which I then entertained respecting them are unequivocally stated in the original, 1 cannot do better in this place than to refer to them as they stand in a note commencing at page 77 of that work.+ This theory of the electro-chemical action of the simple metals on acid and other solutions was republished in the “ Annals of Electricity,"

• The first section of this Memoir formed the substance of a paper which was read at the Glasgow Meeting of the British Association, 1840.

+ The reader is referred to rol. I of the Annals for a perasal of the theory alladed to.

&c., for October, 1836, commencing at page 11 ; and a more extended application of that theory commences at page 17 of the same number.

348. Having thus directed the attention of the Association to the character of the phenomena which I had discovered and published more than ten years ago,* it will appear obvious, by comparing them with the extensive series of facts which have subsequently been developed by various experimenters, that the whole are belonging to one and the same class of phenomena : that they have an electric origin: and are particular cases of, and easily traceable to, the same general laws of electro-chemical action which I have so clearly portrayed in the pamphlet already referred to.

19. We must not, however, overlook the labours of Bergman and Keir, the latter of whom has given a long list of discoveries of this class of facts,† all of which are as highly important as any that have been subsequently developed. Mr. Keir clearly describes some of those facts which have appeared as novelties within the last few years; and has shown that iron acquires that altered state by the action of nitric acid, which Sir John Herschell met with in his experiments, and has called the prepared || state ; and what Schöenbein and

others call the peculiar, or the inactive state. 350. The fact, also, that iron in certain conditions will not precipitate copper from its sulphate and other solutions, as recently observed by M. Schöenbein, was one of the many beautiful phenomena discovered by Keir, and clearly described in the Philosophical Transactions for 1790. Keir describes a number of similar experiments on the solutions of various metallic salts, and the phenomena in every case are obviously of the same class, and easily shown to be of electrical origin.

351. I have looked very attentively to the experiments of Herschel, Schöenbein, Andrews, Noad, &c., and I have repeated and varied many of them, and instituted others to a considerable extent, in order that I might be enabled to ascertain how far those theoretical laws which I had set forth would become applicable to the phenomena by the severest test which they could present. The electrochemical phenomena developed by the action of two distinct metals, or by the action of two pieces of the same kind of metal, in acid or in alkaline solutions, are so easily traced to voltaic electricity, that no difficulty whatever is presented to their explanation. Sir Hum

Sir J. Herschel's paper on this subject, which is next on record, is dated August 19, 1833. See Annales de Chemie, or Philosophical Magazine, for October, 1837.

Philosophical Transactions of the Royal Society of London, 1790, p. 353 ; also Hutton's Abridgment of do., vol. xvi, p. 694 : and Annals of Electricity, vol. v, p. 427.

Kier calls that iron which is active in nitric acid, fresh iron ; and that which has become inactive, altered iron. See Annals of Electricity, vol. v,

| Philosophical Magazine, for October, 1837, p. 330.

p. 439.

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