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on those we have just mentioned, and much remains to be done to make us 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 inexplorable 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 resistance 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 atmosphere; 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 better 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 volca

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 explanation 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. Chemical changes are constantly going on in our rocks and mountains, tending to the ruin of the high lands, the filling up of vallies, 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 renovat

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ing below as the chemical 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 connection 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 che-, mists, effected the amalgamation of ammonia, as it has been called, by the Voltaic instrument. This is an extraordinary experiment, and one of the greatest chemical 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 crystalline texture. As soon as it is separated from the battery, its decomposition commences, as if it had no independent existence; hydrogene 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 hydrogene with nitrogene. -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 hydrogene 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 hydrogene 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 hydrogene, without supposing that water in different electrical states constitutes the ponderable matter of oxygene and

hydrogene. 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 oxygene. 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 oxygene, he has shewn to be simple, and to be contained in muriatic acid gas united to hydrogene. 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 oxygene 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, oxygene 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 oxygene, and which are proved to be decomposed in the experiment. The facts respecting muriatic gas are equally clear. When equal volumes of oxymuriatic gas and hydrogene are inflamed together, this gas alone is formed; there is no deposition of water, and no water can be procured from it, excepting when compounds are used known to contain water or oxygene. Sir H. Davy does not assert, that oxymuriatic gas may not contain oxygene, he merely maintains, that it has not yet been decompounded, and that till it has been decompounded, it must be considered as a simple substance. The name oxymuriatic is evidently not very consistent with its simple nature, and he has accordingly discarded it and substituted chlorine, which expresses a physical quality of the gas. The same necessity of change for extending to all substances containing chlorine, a total reform in this part of nomenclature became absolutely necessary; and we are happy to say, has been effected on the most philosophical principles. The new names proposed by Sir H. Davy for this class of bodies are independent of theory, and will not require change whatever discoveries may be hereafter made relative to their composition, which is a great advantage in a progressive science like chemistry. A superficial observer might perhaps complain, that as these names convey no information respecting the constituent parts of substances, they are of no assistance to the student, and a great burthen to the memory. But such an objection, were it correct, is of little importance; their advantage is, that they convey accurate ideas, and cannot retard the progress of discovery. The object of science being truth, that nomenclature is best, which most promotes its acquisition.

Sir H. Davy considers chlorine and oxygene analogous to each other, and to be similar acidifying principles ; he has accordingly placed them together in his Elements in one class, in opposition to all other substances. Chlorine like oxygene is attracted by the positive pole of the Voltaic battery, and repelled by the negative. Both form acids by union with certain inflammable substances. The metallic combinations of both are also allied in many properties : and there are triple combinations of chlorine with carbon and hydrogene, very similar to certain vegetable substances, of which carbon, hydrogene, and oxygene are the constituent parts.

This doctrine respecting chlorine, appears to us one of the most perfect parts of the whole theory of chemistry. Satisfied with embracing the known, it does not extend to the unknown; nothing in it is taken for granted, and nothing imagined; it rests wholly upon sound logic and true philosophy. The fate of all new doctrines is opposition, and this doctrine is not an exception. The very few who are dissatisfied with it, defend the old hypothesis, as the phlogistians did their expiring creed. Since they are obliged to acknowledge that muriatic acid gas is not a simple substance, they call it a compound of an unknown basis and water; and since they will not grant oxymuriátic gas to be a simple substance, they call it a compound of the same unknown basis and oxygene; and this unknown basis, say they, is muriatic acid. Assertions and imaginations of such a description might, among the alchemists, very well pass for sound arguments and realities, but in the present state of the science, they are unworthy of serious consideration. One of the most interesting parts of Sir H. Davy's work, is

chemical attraction and the laws of combination and decomposition.” In this chapter he developes the doctrine that bodies combine only in certain definite proportions, and contro

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verts the opinion that they are capable of uniting in all quantities. His arguments are facts, which are alone deserving of confidence in an experimental science. By an appeal to facts, the accuracy of which cannot be doubted, he has satisfactorily shewn that a substance either combines with one quantity of another, or with a double, triple, or quadruple quantity of it

, or. to express it more concisely, with some multiple or divisor of that quantity. Thus there are four distinct combinations of oxygene and nitrogene, viz. nitrous oxide, nitrous gas, nitrous acid

gas, and pale nitric acid : the first is composed of one quantity or proportion of nitrogene and one proportion of oxygene, the weights of which are to each other as 26 to 15; the second consists of one proportion of nitrogene, the number of which is 26, and two proportions of oxygene, which are equivalent to 30, or twice 15, the third contains four proportions of oxygene to one of nitrogene, and the fourth five to one. He has also proved that the relation of the proportions, or of the saturating powers of substance, is constant and regular, so that their states being ascertained in respect to neutrality, or the excess of one ingredient or the other, the composition of bodies may be calculated on a few data, and chemistry be reduced almost to a mathematical science. Thus, oxygene combines with twice its volume of hydrogene and twice its volume of chlorine, to form water and euchlorine; and two volumes of hydrogene require two volumes of chlorine, to form muriatic acid gas. Thus there are two combinations of phosphorus and chlorine, the one a liquid, and the other a solid body, and both decompose and are decomposed by water; the hydrogene of which, uniting with the chlorine, forms muriatic acid gas, and the oxygene uniting with the phosphorus in one instance, forms. phosphorus acid, and in the other phosphoric ;-or in other words, the phosphorus which was combined with two proportions of chlorine, can only acquire by the decomposition of water two proportions of oxygene, and that which in the solid substance was united with three proportions of chlorine, cannot by the decomposition of water, acquire less than three proportions of oxygene.

We shall give another example, and from Sir H. Davy's work. “There is not,” says he,“ perhaps in the whole series of chemical phenomena, a more beautiful illustration of the theory of definite proportions than that which is offered in the decomposition of hydrophosphorous acid (which consists of four proportions of phosphorous acid and two of water). Four proportions of the acid contain four proportions of phosphorous and four of oxygene; two proportions of water contain four proportions of hydrogene and two of oxygene. The six proportions of oxygene unite

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