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devotional or even scientific feeling, we look abroad into the natural world under the present state of things; and behold in what an infinite multiplicity of shapes, and forms, and textures, and modifications, this same degraded substrate of matter is rendered the basis of beauty and energy, and vitality and enjoyment; equally striking in the little and in the great; in the blade of grass we trample under foot, and in the glorious sun that rouses it from its wintersleep, and requickens it into verdure and fragrancy; from the peopled earth to the peopled heavens; to the spheres on spheres, and systems on systems, that above, below, and all around us, fulfil their harmonious courses, and from age to age

In mystic dance, not without song, resound

His praise who, out of darkness, called up light. Had the real order of nature been attended to, instead of the loose suggestions of fancy, we should have heard but little of this controversy; for it would have made us too modest to engage in it: it would have shown us completely our own ignorance, and the folly of persevering in so fruitless a chase. Let us then, in as few words as possible, and in order to excite this modesty, attempt that which has been too seldom attempted heretofore, and see how far the subject is unfolded to us in the book of the visible creation.

It has already appeared to us that matter in its simplest and rudest state is universally possessed of certain active properties, as those of gravitation and repulsion, which, in consequence of their universality, have been denominated essential *: but it has also

* Vol. I. Ser. 1. Lect. iv. pp. 75. 80.

mass.

appeared to us that there is an insuperable difficulty in determining whether these properties belong to common matter intrinsically, or are endowments resulting from the presence and operation of some foreign substance, such as the ethereal medium of Sir Isaac Newton, and which, if it exist at all, is probably a something different from matter, or if material, different from common, visible, and tangible matter.

It has appeared to us next, that common matter, in peculiar states of modification, is also possessed of peculiar properties, independently of the general or essential properties which belong to the entire

Thus iron and iron ore give proofs of the possession of that substance or quality which we call magnetic; glass, amber, and the muscular fibres of animals, give equal proofs of that substance or quality which we denominate electric or voltaic; and all bodies in a state of activity, of that substance or quality which is intended by the term caloric. But what is magnetism? What is voltaism? What is caloric ?

There is not a philosopher in the world who can answer these questions: we know almost as little of them as of gravitation, and can only trace them by their results. We can, indeed, collect and concentrate them, invisible and intangible as they are to our senses; and we have hence some reason for believing them to be distinct substances rather than mere qualities; and, quently, often denominate them auras.

But are these auras material or immaterial ? Examined by the common properties of matter, as weight, solidity,

conse

* Vol. I. Ser. 1. Lect. v. p. 87.

impenetrability, they appear to be the latter; for they are all equally destitute of these properties, so far as our experiments have extended; and hence they are either immaterial substances, or material substances void of the general qualities that belong to matter in its grosser forms.

Let us ascend to the next step in this wonderful and mysterious scale. It appeared from the remarks offered in a former lecture*, that, independently of that general influence and power of attraction which every particle of matter exerts over every other particle, there are some bodies which exert a peculiar power over other bodies, which separate them from their strongest and most stubborn connections, and as completely run away with them as the fox runs away with the young chicken. And we here behold another power introduced, and of a still higher order; a power, too, of the most complex variety, and which in different substances exhibits every possible diversity of strength.

Let us take a single example of this curious phænomenon, and let us draw it from facts that are known to almost every one. The water of the sea, and of various land-springs, as that at Epsom, for example, is loaded with a certain portion of sulphuric acid, or oil of vitriol; thus impregnated, as it flows over a soil composed either wholly or in part of the earth called magnesia, it evinces a peculiar attraction for this substance, separates it from the bed on which it has been quietly reposing, and so minutely dissolves it, as still to retain its transparency. But the attraction of the sulphuric acid for the magnesia is much less than its attraction for the fixed alkalis, potash and soda: and hence, if, to the water thus impregnated, we add a certain quantity of either of the two latter substances, the connection between the acid and the magnesia will immediately cease: the former will evince its preference for the alkali employed; and the magnesia, no longer laid hold of by the sulphuric acid, will be precipitated, or, in other words, fall by its own weight to the bottom of the water in the form of a white powder, and may be easily collected and dried. And this, in reality, is the usual mode by which this valuable earth is obtained in its pure state.

* Vol. I. Ser, 1. Lect. v. p. 94.

But the sulphuric acid having thus shown a stronger attraction for an alkali than for an earth, is there no substance for which it discovers a stronger attraction than for an alkali? There are various : it may be sufficient to mention caloric or the matter of heat. And hence, exposed to the action of heat, it soon becomes volatile, unites itself to the heat, flies off with it in vapour, and now leaves the alkali behind as it before left the magnesian earth. Glass-manufacturers take advantage of this superior attraction of the mineral acids for heat compared with their attraction for alkalis, and employ, in their formation of glass, common sea-salt, which is a combination of an acid and an alkali;

drive off the former from the latter by the aid of a very powerful fire, and then obtain a substance which is absolutely necessary for the production of this material.

These curious and altogether inexplicable properties and preferences we call chemical affinities

and chemical elections: and there are numerous instances in which the substances, thus uniting themselves together, evince an order and regularity of the most wonderful precision, and which is nowhere exceeded in the developement of the most delicate organ of animated nature. And I now particularly allude to the phænomena of crystallization ; the different kinds of which, produced by the consolidation of different substances, uniformly maintain so exact an arrangement in the peculiar shape of the minute and central nucleus, or the two or three elementary particles that first unite into a particular figure, and follow up with so much nicety the same precise and geometrical arrangement through every stage of their growth, that we are able, in all common cases, to distinguish one kind of crystal from another by its geometrical figure alone; and with the same ease and in the same manner as we distinguish one kind of animal from another by its general make or generic structure. The form of these elementary particles we can no more trace to a certainty than the bond of their union; but there is great reason for believing them to be spheres or spheroids, as first conjectured by that most acute and indefatigable philosopher Dr. Hooke, and since attempted to be explained by Dr. Wollaston in one of the Bakerian lectures. *

Such are the most striking powers that occur to us on a contemplation of the unorganized world. From unorganized let us ascend to organized nature. And here the first peculiar property that astonishes us is the principle of life itself; — that wonderful

* Phil. Trans. 1813, p. 51.

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