Through dark retreats pursue the winding ore,
Search Nature's depths, and view her boundless store;
The secret cause in tuneful numbers sing,

How metals first were framed, and whence they spring:
Whether the active sun, with chymic flames,

Through porous earth transmits his genial beams;
With heat impregnating the womb of night,
The offspring shines with its paternal light:
Or whether, urged by subterraneous flames,
The earth ferments, and flows in liquid streams;
Purged from their dross, the nobler parts refine,
Receive new forms, and with fresh beauties shine :-
Or whether by creation first they sprung,

When yet unpoised the world's great fabric hung:
Metals the basis of the earth were made,

The bars on which its fixed foundation's laid:
All ~~-~nd conses they disdain to own,
And from th' Almighty's fat sprung alvii.

Thomson, in his beautiful Hymn to the Sun," extends the penetrating influence of that luminary, not to the formation of metals only, but to the production also of the precious stones. See this quoted in Pp. xlii.

Minerals are usually arranged under four classes; earthly, saline, inflammable, and metallic'.

This is the arrangement of Professor Werner, and approaches much nearer to a natural order than that of Haiy. He distributes all the known mineral substances among four classes. The first comprehends the acidiferous bodies, being those into the composition of which any acid enters; this is again subdivided into four orders, according as the acid is either free or combined with an earth, with an alkali, or with a compound alkalino-earthy base. The second class, entitled earthy substances, is not subdivided into orders or genera, but consists of forty-two species, with an appendix of twenty-six other substances, the claims of which to the rank of species are considered as dubious. The third class takes the non-metallic combustibles,

I. Earthy. This class is distinguished by its being in general brittle, not remarkably heavy, as usually possessing white or light colours, disposed to crystallize, uninflammable in a low temperature, insipid, and inodorous. The earthy minerals are either SILICEOUS, in the form of pebbles, gravel, sand, sand-stones, pudding stones, &c.; or are CALCAREOUS, as limestone, chalk, spar-marble, alabaster, &c.; or ARGILLACEOUS, as clay, fullers' earth, lithomarga, boles, slate, &c.; or MAGNESIAN, as steatites, asbestus, serpentines, &c.; or BARYTIC, as the baroselenite or ponderous spar, &c. In these compounds, in which more than one of the earths are found, the earth from which each substance derives its genuine distinction is most abundant, so there are also others in which the earths STRONTIA, YTTRIA, and JARGONIA, are most predominant. Most of the PRECIOUS STONES are compounds, in which different combinations of one or more of the other earths, lime, alumine, magnesia, and sometimes a small portion of iron, are united to a large portion of pure quartz, or silex, in a crystalline form; hence result the opal, garnet, catseye, onyx, sardonyx, &c.

The ruby has been found to be formed of alumine and magnesia, with chromic acid, and the emerald is supposed to be the same compound with the acid in a

The fourth and last class is the metallic, in which the native metals and their ores are arranged in three orders, denoting the difficulty or ease with which they are reduced to the metallic state, and these orders are again subdivided into twenty-two genera. Mr. Arthur Aikin disapproves of both these systems, points out their deficiencies, and endeavours to supply them in his general synopsis. See his useful Manual of Mineralogy,' 12mo, the Introduction to which is highly valuable to the student.

different degree of oxidyzement. The chrysolite appears to be composed of lime and the phosphoric acid. Th' unfruitful rock itself, impregned by thee,

In dark retirement forms the lucid stone.
The lively diamond drinks thy purest rays,
Collected light, compact; that, polished bright,
And all its native lustre let abroad,

Dares, as it sparkles on the fair-one's breast,
With vain ambition emulate her eyes.
At thee the ruby lights its deepening glow,
And with a waving radiance inward flames.
From thee the sapphire, solid ether, takes
Its hue cerulean; and, of evening tinct,
The purple-streaming amethyst is thine.
With thy own smile the yellow topaz burns;
Nor deeper verdure dies the robe of Spring,
When first she gives it to the southern gale,
Than the green emerald shows. But, all combined,
Thick through the whitening opal play thy beams;
Or, flying several from its surface, form

A trembling variance of revolving hues,
As the site varies in the gazer's hand.

THOMSON.

II. The class of saline minerals is characterized by being moderately heavy, white, sapid, soft, and possessing some degree of transparency.

III. The characters of the inflammable class are, lightness and brittleness: the individuals in this class are mostly opaque, scarcely ever crystallized, and do not feel cold. Here may be placed the bitumens, amber, jet, petroleum, coal, &c. In this class may also the diamond be placed.

IV. The metallic class contains many genera, characterized by opacity and great specific gravity: they generally possess a peculiar lustre, are tough, and in some degree malleable, cold, and not easily inflamed.

■ The Sun,

Metals.

And now the regions deep explore,

Where metals ripen in vast cakes of ore.
Here, sullen to the sight, at large is spread
The dull unwieldy mass of lumpish lead.
There, glimm'ring in their dawning beds, are seen
The light aspiring seeds of sprightly tin.
The copper sparkles next in ruddy streaks;

*

*

The silver then, with bright and burnished grace,
Youth and a blooming lustre in its face,

To th' arms of those more yielding metals flies,
And in the folds of their embraces lies.

GARTH.

The limits of our Introduction precluding us from noticing more at length the three first classes of minerals, we shall confine our attention to a short account of the METALS. The most popular and pleasing description of them, and the best adapted to the purposes of our volume, we find in a valuable work lately published by MR. GEORGE GRAVES, entitled the Naturalist's Pocket Book, p. 307; from this interesting publication, therefore, we select the following slight sketch.

The metals having never been decomposed, are supposed, when pure, to be simple substances. The number of known metals is twenty-seven: they are found in a native state, either simple, consisting of only one substance; or compound, when composed of two or more substances. All the metals are much heavier than the earths, the heaviest of the latter not exceeding five times the weight of water, and the

lightest of the metals being six times heavier than water. Those metals that are capable of extension by being beaten with the hammer, are termed malleable; and those which do not possess this property are called brittle. The malleability of metals adds greatly to their usefulness, and, being fusible, man is enabled to free them from earths and extraneous substances without these properties, he could hardly reduce them to his service.

MALLEABLE METALS.

1. Platina. This is the heaviest of metals, being twenty-three times heavier than water; its colour is a dull tin white; it is capable of great extension, but is difficult of fusion; in hardness it nearly equals iron. This metal is principally confined to South America it is usually found in small grains, mostly in the vicinity of the gold mines; it is met with alloyed with magnetic iron, gold, copper, lead, and several other metals.

C

2. Gold is nineteen times heavier than water, is very soft, ductile, and flexible; its colour varies from pale yellow to deep orange; it is capable of great extension, and its tenacity is very great. Gold is ge nerally mixed with some other metal, as tin, copper, silver, &c.; it is found in veins, in the beds and sands of rivers and mountain streams, in several parts of Europe, Asia, Africa, and America: from South America we obtain the greater part of the gold now in use; it occurs in small grains or lumps, from the weight of a few grains to fifty pounds; it sometimes, though but rarely, occurs in this kingdom, as also in