by the same bodies when acting in masses, which produce chymical phenomena when acting by their particles; it is not therefore improbable, that the primary cause of both may be the same, and that the same arrangements of matter, or the same attractive powers, which place bodies in the relations of positive and negative, i. e. which render them attractive of each other electrically, and capable of communicating attractive powers to other matter, may likewise render their particles attractive, and enable them to combine when they have full freedom of motion." This ingenious speculation, which the author justly complains has been attacked and misrepresented by those who did not understand his views, has good analogies in its favour. Heat and light are the common effects of strong electrical and chymical action. Those bodies which in masses most powerfully excite each other electrically by contact, when their particles have freedom of motion, most readily combine chymically, as the acids and alkalies; the metals and sulphur-and when the natural electrical state of a body is artificially exalted, its chymical attraction also is exalted, and when the former is destroyed, the latter, too, is no longer exerted. No finer illustration can be given of these truths than the effects attending the action of the Voltaic battery.

Sir H. Davy has used this instrument with the greatest success, and by opposing the superior electrical attractions to the natural chymical ones, he has penetrated into the compo sition of various bodies, that had long baffled all research. By the same methods, from the fixed alkalies, which are well known to be corrosive, dull, and very soluble substances, he has extracted bodies of metallic lustre, exhibiting the colour and splendour of silver, and like metals, perfect conductors of heat and electricity. They are, nevertheless, the lightest bodies in nature, and the most inflammable substances known: the basis of potash takes fire on water and ice, and both of them decompose all bodies known to contain oxygen; so that no little ingenuity of contrivance was necessary to preserve them, and prevent their return to their original state by the absorption of oxygen. The discoverer of these bases of the fixed alkalies, considers them as metals, and has, accordingly, called them potassium and sodium. But his views and his names, though now generally adopted, have met with some weak opposition from those on whom the extraordinary features of the new bodies made the deepest impressionnamely, their lightness and inflammability connected with their alkaline origin. We must acknowledge, that his reasons for this classification appear to us perfectly conclusive.

It is founded on obvious analogies of the most decisive character. Were minute differences to be taken into account, there would be as many classes of bodies as there are now individuals. The principle of scientific arrangement is to go from the more general, or common properties, to those which are less common and particular, and thus kingdoms, classes, orders, &c. are arrived at. To determine the propriety of Sir H. Davy's classification, we must inquire what are the characters essentially constituting the class of metals. Certainly those are not the properties to seize in making a classification, which are constantly varying, and are different in almost every individual, as colour and specific gravity; but those which uniformly exhibit themselves in all metals, as opacity, the metallic lustre, the power of freely conducting electricity and caloric, and the power of forming chymical combinations with certain substances. If these latter are considered essential characters to the exclusion of the former, as we do not hesitate in asserting that they should be, no doubt will remain respecting the metallic nature of the bases of the fixed alkalies: and there is no less propriety, we conceive, in the names given by Sir H. Davy to these bodies, than in the places he has assigned them. Aware of the evils of the French nomenclature, founded upon hypothetical views, he has purposely avoided names connected with theory, and has chosen such as may remain unchanged during the perpetual fluctuation of systems. This being the case, we cannot but reprobate the vain spirit of innovation that invents names without discovering things; and makes distinctions where there are no real differences. Thus, in France, some chymists, in pursuance of their particular views, have thought proper to call the bases of the alkalies, metalloids, instead of metals; and what is more to be wondered at, these terms have constantly been imported into use by some in our own country. Names, to the true philosopher, who looks and examines beyond names, signify but little, but, to the superficial inquirers, who are satisfied with their acquisition, they are of great importance. And those given by discoverers should be held as sacred as the names given by parents to their children, not to be trifled with, and altered, at every one's capricious taste, but only to be changed when called upon by absolute necessity.

A rapid and brilliant course of discovery was the consequence of the decomposition of the fixed alkalies, and the further application of the Voltaic battery to the chymical analysis. The alkaline earths had long been suspected to contain metallic matter, and this suspicion was verified by

Sir H. Davy, who, by various ingenious devices, separated their bases from oxygen, and examined them sufficiently to ascertain their metallic nature, and some of their physical qualities, and showed that they approached the common metals in density and fixedness in the fire, though they greatly exceeded them in their affinity for oxygen. The decompos sition of the common earths, and the demonstration of the metallic nature of their bases soon followed; but his experi ments were not so satisfactory on this subject as on those we have just mentioned, and much remains to be done to make tis acquainted with the character of these new metals. The speculations arising from these discoveries are very curious, and promise to throw much light upon various subjects hitherto but little understood. They do not concern the surface of our globe, as much as the hidden depths and inex plorable heights.

There are two kinds of phenomena equally mysterious and wonderful, viz. volcanoes and meteoric stones. Earthquakes and volcanoes have long been the admiration of philosophers, and the terror of the vulgar.

Various attempts in all ages have been made to explain their origin, and all the causes hitherto assigned have been equally inadequate. The very existence of meteoric stones has only lately become credible, but no sooner was it believed, than their formation was attempted to be explained: some supposed them to be particles from the moon, sent to our earth by the projectile force of volcanoes; others imagined that they were formed in the higher regions of our atmo sphere; and the idea that they were the fragments of broken planets had its supporters.

The inquisitive mind of man will be for ever speculating on the unknown, and endeavouring to reconcile it with the known. For the explanation of volcanoes, the very inflammable metals of the alkalies and earths appear far batter adapted, than any of the imaginary causes yet assigned. Nothing is required, but to suppose these bodies existing in the bowels of the earth. They would be inflamed by the influx of water, and such an inflammation may well be thought to produce the phenomena of earthquakes and volcanoes. And this supposition is equally consistent with the products of volcanoes and the mean density of the earth. Ascending to the higher regions, and to meteoric stones, these may be considered as coming into our atmosphere composed of the metals of those earths which they are found to contain; and thus, though their origin is left undetermined, their ignited state, their fused surface, and some other appearances connected with them, may be explained.

These discoveries of Sir H. Davy, while they offer expla nation of the destructive and terrible in nature, are also calculated to disclose the manner in which the harmony and order of the universe are preserved. Chymical changes are constantly going on in our rocks and mountains, tending to the ruin of the high lands, the filling up of valleys, and the overflowing of seas; but underneath, in the tranquil bosom of the earth, electrical changes produced by means of vast natural combinations of different strata and different fluids, may be in action, and as powerfully renovating below as the chymical changes are degrading above, and as rapidly preparing new continents as they are wasting the old. We have glanced at these hypothetical views, not because they are dwelt upon in Sir H. Davy's work, who is too judicious to mingle them with the established truths of science, but on account of their probable connexion with his discoveries, and the grandeur of the speculations they suggest.

Other substances besides those already mentioned have experienced the power of the Voltaic battery, and that of the alkaline metals. Berzelius and Pontin, two celebrated Swedish chymists, effected the amalgamation of ammonia, as it has been called, by the Voltaic instrument. This is an extraordinary experiment, and one of the greatest chymical wonders of the 19th century, already so prolific in wonders. When a globule of mercury moistened with liquid ammonia is negatively electrified by the battery, it greatly increases in volume, and acquires a butyraceous consistence and a crystals line texture. As soon as it is separated from the battery, its decomposition commences, as if it had no independent existence; hydrogen and ammonia are evolved, and the mercury returns to its former state. The different opinions which have appeared respecting this amalgam are noticed in the last division of the Elements, where its nature is ably discussed. From analogy it was inferred to consist of mercury and the metal of ammonia; and from direct experiments it was concluded to be a compound of mercury and hydrogen with nitrogen. The latter composition, however inconsistent with our established systems, is the only one warranted by facts. Granting this composition of the amalgam, which has perfectly metallic characters, a suspicion cannot but be formed of the compound nature of the other metals; and that hydrogen truly is, what the later phlogistians supposed to be the general inflammable and metallizing principle. But there are other experiments that warrant other views, and one in particular, which we cannot pass by, described by Sir H. Davy in his work, which is no less extraordinary than the amalgam

itself. When a globule of mercury was put into a vessel full of water, and the vessel connected with a powerful Voltaic combination, the globule became affected-it acquired polarity -oxide was formed at the positive pole, but no hydrogen evolved at the negative, except when the conducting power of the water was increased by the addition of salt, and then a vibratory motion which before appeared, ceased to be produced. The author has minutely examined all the circumstances of the experiment, and cannot account for the disappearance of the hydrogen, without supposing that water in different electrical states constitutes the ponderable matter of oxygen and hydrogen. Nothing prevents the adoption of this conclusion at present, but its immense importance, and the wary spirit of the philosopher

From the alkalies and earths Sir H. Davy extended his researches to the undecompounded acids, the boracic, fluoric, and muriatic. By means of potassium, he effected the decomposition of boracic acid, and both by analysis and synthesis proved it to consist of an inflammable basis united to oxygen. The same means applied to fluoric acid were not equally efficacious, and we still remain in a great measure ignorant of the nature of this body, which has not yet been obtained in an insulated state, but is always found combined with water, silex, or boracic acid.

He has been more successful with respect to muriatic and oxymuriatic gas. His discoveries have quite reversed the order of our notions respecting the composition of these bodies. The former, which was long considered as the simple substance, he has proved to be compounded; and the latter, which was supposed to be compounded, and to consist of muriatic acid and oxygen, he has shown to be simple, and to be contained in muriatic acid gas united to hydrogen. The series of facts by which he has arrived at these conclusions are of the most important and decisive nature. We shall not follow his route in the gradual development of his doctrines, but mention merely those facts which appear sufficient to establish their truth. Charcoal intensely ignited, remains unaltered in oxymuriatic gas; sulphur and phosphorus do not extract oxygen from it, but form with it peculiar compounds, and the metals do not become oxidated in it, but uniting with it, form that class of bodies formerly called dry muriats. To be brief, oxygen cannot be obtained from oxymuriatic gas, either by potassium, or the immense power of the Voltaic battery, and can only be procured when substances are used known to contain oxygen, and which are proved to be decomposed in the experiment. The facts respecting muriatic