pole. The two wires would be ever afterwards in different electric relations to each other: one would be positive, the other negative; and thus the effects of memory would be shown, and future actions regulated.'-Elements of Electro-Biology.

We refrain from offering a remark upon the absurdity of this, being satisfied that the fallacy of such reasoning is too transparent to escape our readers.

As this is the only section of the present article in which the phenomena of animal electricity will be referred to, we cannot close it without a few remarks. The investigations of Galvani, of Humboldt, of Aldini, and more recently the delicate researches of Matteucci, Du Bois-Reymond and others prove beyond all doubt, that every motion of the body, and every emotion of the mind reacting on the material organism, produces an electrical disturbance, the weak manifestations of which can be measured by the delicate galvanometers we now employ. During life the struggle of antagonistic forces to maintain the requisite equilibrium produces a continual change of state, and consequently as continued an indication of electrical pulsation. When life has ceased, and the full play of chemical disintegration has set in upon the body, lying 'in cold obstruction,' this alldiffusive power is still detected in its wondrous workings, it is no less energetic in the disorganized mass than it was in the form in its full beauty of organization. So far from our philosophy leading us to the conclusion that life-vitality, is electricity, every step of our enquiry shows us that the physical force is infinitely inferior to that mysterious principle which human science cannot reach. Whether we examine life in the vegetable or in the animal worlds, it so evidently lies beyond the pale of the physical forces which human intellect may try and test its powers upon, that each true philosopher feels the strength of the words- Hitherto shalt thou come, but no further; and here shall thy proud waves be stayed.'

LIFE is beyond the search of the most exalted human intelligence. VITAL FORCE in its lowest development is infinitely superior to electricity in its highest manifestations, and it requires no great penetration to perceive subtile powers, which are not yet 'dreamed of in our philosophy, beyond these physical forces with which we are, as yet, so imperfectly acquainted, and these still inferior to that approach to spiritualization which we call life. We must return from this digression.

Volta had not been long engaged in the investigation of Galvani's phenomena of muscular contraction, when he began to doubt the correctness of his conclusions. By a very simple experiment he determined the fact that the contractions were

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due to some power developed by the heterogeneous metals. He touched the upper and under surface of the tongue with tin and silver respectively, and found when the two metals came in contact, that instead of the anticipated contraction, a peculiar taste was generated. This experiment was sufficient to prove that there was no discharge of animal electricity, but a manifestation of some mysterious power, generated between the moist surface of the tongue and the metals employed. The contest between Galvani and Volta was long continued, the result one side was the proof of an electrical power residing in the nervous and muscular fibres, which however was eclipsed by the startling discovery, on the other side, of a method for developing this force by a combination of dissimilar metals and a fluid.

on

Galvani, in the very height of a controversy which exhibited much of that bitterness which, it is to be regretted, so often marks the discussions of philosophers, left the field to his opponent; dying on December 4, 1798: his nephew Aldini, still exerting himself to sustain the cause of animal electricity.

Twelve months after the death of Galvani, Volta announced his discovery of the battery, and by the powers which he thus obtained, completely placed the theories of animal electricity in a state of temporary extinction. The pile of Volta, with its wonderful powers, which were capable of almost infinite multiplication, necessarily attracted the attention of all experimentalists. The pile or battery of Volta is too familiar to our readers to require any particular description. In all the various modifications of form, two dissimilar metals are employed, - one of which is oxidised by the action of the fluid in which they are placed. Amongst the more remarkable investigators of voltaic electricity, was Sir Humphry Davy, who, with the enormous battery of 2000 pairs of plates, placed at his disposal by the Royal Institution, produced some of the most brilliant results which have ever distinguished the labours of an English chemist. Not merely did he startle the aristocracy of science by the luminous arc which he exhibited between the charcoal poles of his battery-a radiance so intense that it appeared to the astonished crowds who flocked to his lectures as equal in brilliancy to the meridian sun-but he employed its powers upon some of the most intractable substances in nature, and succeeded in extending our knowledge; by the discovery of the metallic bases of the earths and alkalies. It is not our intention to trace out each step of progress in this highly interesting department of science; it is sufficient for the purpose we have in view, that we state the substantive proof, that at the quantity of electricity which is set in motion in the voltaic battery bears a direct relation to the amount of chemical change which one of the metals undergoes.

In 1806, Sir Humphry Davy, in his celebrated Bakerian Lecture,' directed attention to the remarkable character of electro-chemical decompositions; but notwithstanding the extensive researches of electricians, it was not until 1833, that the law determining these was correctly enunciated. In that year Dr. Faraday announced 'That for a constant quantity of elec'tricity, whatever the decomposing conductor may be, whether water, saline solutions, acids, fused bodies, &c., the amount of ' chemical action is also a constant quantity, i. e., would always be * equivalent to a standard chemical effect founded upon ordinary ' chemical affinity.'-Faraday's Experimental Researches in Electricity.

The definite chemical action of electricity was subsequently proved, and the law established that the chemical power of a current of electricity is in direct proportion to the absolute quantity of electricity which passes. On this point Dr. Faraday employs the following emphatic words,

'Now it is wonderful to observe how small a quantity of a compound body is decomposed by a certain portion of electricity. Let us, for instance, consider this and a few other points in relation to water. One grain of water, acidulated to facilitate conduction, will require an electric current to be continued for three minutes and three quarters of time to effect its decomposition, which current must be powerful enough to retain a platina wire, Toth of an inch in thickness, red-hot in the air during the whole time; and if interrupted anywhere by charcoal points, will produce a very brilliant and constant star of light. If attention be paid to the instantaneous discharge of electricity of tension, as illustrated in the beautiful experiments of Mr. Wheatstone, and to what I have said elsewhere on the relations of common and voltaic electricity, it will not be too much to say that this necessary quantity of electricity is equal to a very powerful flash of lightning. Yet we have it under perfect command; can evolve, direct, and employ it at pleasure; and when it has performed its full work of electralization it has only separated the elements of a single grain of

water.

We have advanced, in the order of time, too rapidly, in our desire to render as distinct as possible the connexion of these physical forces as indicated by the present advanced state of our knowledge, and must now return to one of those starting points which mark the grand advances of human knowledge.

We have already seen each decided step in advance made by individual exertion, and we have already marked a certain order in time between the faint twilight, as it were, of a slowly as

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cending star, and the full development of each particular truth. Although there were numerous able experimentalists between Gilbert and Franklin, who added materially to our knowledge of electrical phenomena; yet these two names, and particularly the latter, stand out in brilliancy beyond all others. In like manner Volta and Davy mark the extreme ends of a line of progress; and in the ordinary sequence of events, Hans Christian Oersted boldly distinguishes a new and most important point of departure-important in all its relations to science, and of the highest interest, as leading by a few steps to one of the most wonderful applications which science has ever bestowed upon the altar of utility.

At the end of the last century, Denmark produced a knot of distinguished men-poets, sculptors, and philosophers. Amongst these, the names best known to the English reader are those of Thorwaldsen and Oersted; with the latter alone are we at present concerned.

Hans Christian Oersted was born in the little town of Rudkjaking, on the island of Langeland, in 1777, and he died at his country residence, near Copenhagen, on the 9th of March, 1851, aged 74; and of this period at least half a century had been spent in the closest contemplation of nature. In the strictest sense, Oersted was a philosopher, and consequently a poet. The high intelligence of a chosen mind,' to use Akenside's delicate expression, marks all his speculations. In his Essay On the Comprehension of Nature by Thought and Imagination,' this is manifested in a remarkable manner. As an investigator of natural science himself, he feels it still a duty to demonstrate how the truths which are obtained by reflection and observation of Nature, contain rich material for the imagination; and he contends that the practical character of the present century more than ever demands that the leaders in literature and science should enforce the necessity of reconciling the world of reason and imagination. A reconciliation not to be effected in a moment-but one which may be brought about as the fruit of repeated efforts. A succession of examples,' says Oersted, 'will serve to prove how the intuitive-the prophetic view of Nature-may be more exactly defined and further developed 'by means of the profounder knowledge which is derived from 'reflection.' We are desirous of giving a clear view of the mind of this departed philosopher of Denmark; and we cannot do so more pleasingly than by a short quotation from this Essay, which shows how poet-like his contemplative spirit dwells upon the theme-the improvement of our perceptions of the beautiful and sublime by the advance of knowledge.

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We need scarcely mention the vastness of the impression which the starry heavens produce, since it is so powerful as to be felt by every one. He ever, who seeks no more than the gratification of his sense, and whose dawning reason is but faintly traceable in his sensational apprehensions, must acknowledge that the canopy of heaven is the grandest object he knows: this vast extent, however, would be dead and blank to us were it not enlivened by the innumerable host of stars. Their light comes to us with double force from the darkness of the surrounding earth, when those objects which remind us of the trivial circumstances of daily life, or which are of transitory importance, and which would otherwise attract our attention on all sides, are invisible. This enlarges the scale of our ideas, and quickens our perceptions for the reception of that light which proceeds from a higher, a greater, and a less transitory world. The glorious nature of light is here wonderfully manifested; its animating and beneficial effects have in all times caused it to be the most beautiful emblem of life and virtue. Beneath the mild, clear, undazzling light of stars, which scarcely enables us to see anything around us, while, if I may so express myself, the light shines but to manifest itself, we feel as if Light and Life and Happiness dwelt far away above us in those distant regions; while, on the other hand, Darkness, Death, and Terror remained here on earth. This idea interpreted in one manner may be easily misunderstood; but the feeling which such a sight exercises upon the unperverted senses has nothing to do with these misconstructions. Added to all this, we have the deep, and, we may say, tangible silence of night, by which the ear receives as faint impressions of the world beneath us, as are conveyed to the eye by mild starlight. In short, it is not a mere flight of the imagination which causes our devotional feelings to be excited on a starlight night, but it springs from a feeling deeply rooted in our nature. How different is the impression of a moonlight night. The mild light of the moon's disk, unlike that of the sun, does not oblige us to lower our eyes, but rather draws them upwards to heaven. At the same time, it so far overpowers the light of stars that they no longer attract our notice, and sometimes become invisible. Moonlight also shows just so much of earth as to prevent our entirely forgetting it; thus, Fancy and Thought wrapt in mild enthusiasm, hover indefinitely between heaven and earth.'

Such is the strain in which Oersted proceeds, examining at every step the different feelings of man according to the amount of cultivation which each mind has received, and he concludes

'The better we understand these truths, the wider will be the view unfolded to us, and futurity promises to reveal still more secrets; the wonders of the globe, unravelled by science, prove that we are not isolated beings, but that we are related to the whole universe; and with the same comprehensive grasp though in a different direction -reveals the fundamental doctrine of universal attraction. The observant student is carried upwards, penetrated and animated by the