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the stones which are called precious, from their beauty and rarity. The common uses of stone in building, and the several degrees of them, from the coarsest rock to the finest marble, are well known: but still, the situation of the stone, as it 'lies in the earth, compared with the property of that stone, which is most ordinary, is worthy of particular consideration. Beds of stone, as they lie in the quarry, are parted here and there- with perpendicular cracks, by means of which the largest masses become accessible, and subject to such forces as will separate and raise them up; and unless the beds of stone had been thus naturally parted, all the art of man would have been insufficient to extract stones from the earth, for the common uses of life. Some are of such a grain that they will split like wood, and may be shivered even without a tool, into thin plates, by the force of the weather. But wonderful above all js the property of the limestone; which, when its native moisture is totally expelled by fire, imbibes water with such force that it falls into an impalpable powder, and forms a cement, by which separate stones are indissoluby joined into one body: and it holds them together more firmly at the end of a thousand years than it did at first. This is a discovery of such importance in the art of building, that it is probably, as ancient as the art itself. The use of stone and mortar is spoken of as known before the building of Babel: and how it could be found out, doth not appear; because, I think, there is no operation in the common course of nature which could lead to it.

It would answer no purpose here to recount the various sorts of opaque stones; some curious for their beauty, others excellent for their use. The flint enables us to produce fire, of which no creature but man hath the use and management. The fiercest of wild beasts fly from the sight with terror; and dread that fire which is kindled by man, as man himself dreads the fire of lightning which is sent from heaven.

In regard to the common stones of the earth, there is a certcin fact which must excite the curiosity of those who attend to it. Of the pebble kinds, the greater part are formed out of fragments of stone, spar, and marble rounded by trituration in water; of which kind millions are agitated to and fro, and worn by the motion of the tides upon the shores of the sea. The inland parts of the earth, to the greatest depths, contain these pebbles; which, being the production of the sea, could never have been formed where they are found, and must, therefore, have been originally lodged by water in places which are now remote from the sea. The same may be said of an immense quantity of sand, which, though it is now lying in dry beds of earth, has the certain marks of trituration by water.

Metals and minerals, which are the more valuable productions of the earthy are, in 'form and appearance, but another kind of stones; under which name they are mentioned in the book of Deuteronomy; where Moses commends the promised land to the people, as a land whose stones are iron, and out of •whose hills they might dig brass; not in the form of brass, but of stones, out of which brass might be extracted, and compounded by the labour of man, and the rules of art. All the treasures of the earth are found in an imperfect state, , which calls forth the arts of chemistry, and makes work for the fires of the refiner; but, when due pains have been bestowed upon them, then we discover what a pure and splendid

nature is given to them by the Creator. Who would think, that hurnished gold, and polished steel, should have been in an obscure state, 1 iIre the stones of the earth? The mind of man, improved by education, is just as different from the same mind in the state of nature.

Such is the richness and brightness of the several kinds of metals, that it hath been the custom with men, from time immemorial, to give to the metals of the earth the same names as to the lights of heaven, according to their colour and their dignity. Gold is allied to the sun, from its yellow colour, and its splendor; silver to the moon, from its whiteness, and as being next in dignity to the sun. Mercury or quicksilver takes its name from the planet nearest to the sun; copper from the planet next in order; iron, tin, and lead, Were given to the remaining planets more remote from the sun.

The natural history of the metals seems to have had a considerable share in the mythological mysteries of heathenism*. But leaving these fanciful doctrines of men, w,ho gave the honour of God's works to their idols, we may go on from the metals to the gems, which are of an higher order, and a more refined nature. Here the glory of the terrestrial, approaches very near to the glory of the celestial bodies; especially in the diamond, the prince of precious stones; which vies in purity and brightness with the matter of the heavens, and appears like embodied light; insomuch that, if the fluid of light could be fixed into an ice, as the fluid of the water is, we may imagine that something like the diamond would be produced. It is remarkable, that the brighest matter of the earth is united with the richest, for the formation of a precious stone; the various sorts which receive their colour from some metal; as the ruby from gold; the emerald from copper; whence emeralds were commonly found in the copper mines of Cyprus*. When the metals are united to a chrystalline, or pellucid basis, they form a gem; but, if to an opaque earthy matter, they form the high-coloured earths of the painters, which all derive their beauty from some metallic mixture. It is further remarkable, that the chrystalline matter, and the metal which gives it colour, are united in nature by the mediation of water : whereas, if we attempt to unite them by art,in the artificial gems, we are obliged to have recourse to the violence of fire, to diffuse the colouring parts through the crystal. This, and some other like instances of the difference between the chemistry of art and the chemistry of nature, should make us cautious of pronouncing too hastily concerning subterraneous productions, lest we take that for the effect of fire, which was, in reality, the effect of water.

* Copper had its name from the Island of Cyprus, where the use of brass was said to have been first invented; (In Cypro, ubi prima fuit aeris inventio. Plin. Lib. 34, cap. 2.) and hence we may account for the mystical dedication of that Island to Venus, the Cyprian goddess, (Diva potens Cypri. Hor.) who agrees in name with a planet in the heavens, and with the ore of Cupper in the« earth. On this plan, it is very probable that the fable of Jupiter's burial in the island of Crete might, at the bottom, be nothing but a mythological mode of signifying to those who were in the secret, that tin was found under ground in that island.

Instead of naming the several minerals which are dug out of the earth, I shall rather direct your attention to two which are of more consequence than the rest: these are salt and sulphur. Salt preserves from * Theophrastus.

putrefaction; and, being soluble in water, it keeps the sea sweet and wholesome. Where the heats are greater, .the sea has more salt; because there is more danger of putrefaction; which teaches us, that the sea was not salted, by accident, but by design *. As the doctrine of truth in the Gospel saves the world from moral corruption, so doth salt preserve it from natural corruption; whence the one is used as a figure of the other. Ye are the salt of the earth, said Christ to his preachers; without you the world would be as putrid as flesh is found to be without the use of salt.

The other mineral substance is sulphur; of universal effect, as the cement of nature for uniting theparts metals into masses, or mineralizing them, and giving them many of their properties. It is also the grand combustible of the world ; which, as it descended from the heavens in rain for the destruction of Sodom, so is it now the chief cause of those dreadful commotions which happen in the earth. When iron and sulphur and water meet together, a fermentation ensues, which, if strong enough, breaks out into actual fire and flame. It hath pleased God, for wise ends, to lodge these different principles'near to each other, in many places, that their mixture may present to our sight one of the most tremendous appearances in nature. When the sun shines upon the calmness of the ocean, we understand that God is benevolent as well as great; and, when the volcano rages, we are to learn that he is just and terrible in his wrath and vengeance. When the law was given on mount Sinai, the whole mount trembled, and burned with fire, and there were thunders and light

* The late Dr. Halley, supposing that the sea grew salt by accident, in tract of time, from the waters washing away some salt from the land, proposed a new method for finding the age of the world, from the saltness of the sea. See Vhys. Disq. where some iarther observation* are made on this subject.

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