1. The variety of fossils	11. Of stones
2. The general properties of metals	12. Of petrifying springs
3. Of the nutrition and generation of metals	13. Of copper springs
4. Of gold, silver, platina, copper, iron, tin, lead	14. Of lime
5. Of steel	15. Of precious stones
6. Of quicksilver	16. Of the loadstone
7. Of mines	17. Of inflammable fossils
8. Of mundic	18. Of amber
9. Of the fissures of the earth	19. Of linum asbestum
10. Of salts

1. Among the bodies that remain to be considered, those which seem to bear the nearest resemblance to plants, are fossils, comprehending under the name, all bodies that are dug out of the earth. These have frequently, been, for order’s sake, divided into three classes: such as are capable of liquefaction; such as are reducible to a calx; and such as are inflammable. Of the first class, are metals: gold, silver, platina, copper, iron, tin, lead, quicksilver. However these differ in other respects, they all agree in the following particulars: that they are heavier than any other bodies yet known; that they are malleable; and that they are capable of liquefaction.

2. It is not improbably supposed, all metals consist of particles so heavy, that they cannot be totally torn asunder or dissipated by fire, or put into so rapid a motion as to inflame. It only sepa­rates them so far as not to resist a hard body, which is what we term liquefaction. Their malleableness, or bearing to be wrought by the hammer, may spring from the figure of their parts, per-. haps oblong or square, which may occasion their cohering’ so strongly, as not easily to be separated. And it is probable the pores, either of their constituent particles, or of the whole mass, are few and small, which may account for their being SO much heavier than any other known bodies,

This is the radical character of metals. The weight of gold to that of glass is as nine to one; and the weight of tin, the lightest of all metals, is to that of gold as seven to nineteen: which con­siderably surpasses the weight of all stones and other the most solid bodies. Nor is there any body in nature but a metal, that is one third of the weight Of ‘gold.

The specific weight of the several metals, and of the granite water and air, stands thus:

Gold, - 19636 Iron, - - 7852

Quicksilver, 14019 Tin, - - 7321

Lead,. - 11345 Granite,- 3978

Silver - 10535 Water, - - 1000

Copper, - 8843 Air, - - 3/11

3. The nutrition of metals seems to consist only in the accre­tion of homogeneous parts, which is not improbably supposed to continue, while they lie in their native bed. Many suppose, that they have lain there ever since the flood, if not ever since the creation. Whether they have or not, they seem to grow as long as they remain therein. And after these beds have been emptied by miners, in a time they recruit again. Yea, the earth, or ore of allum will recruit again above ground, if it be exposed to the open air. And so in the forest of Deane the best iron, and in the greatest quantities, is found in the old cinders melted over again.

However, it has long been disputed, whether metals are ge­nerated, or were all originally produced at the creation: and whether there be any general seeds of metals, as some suppose antimony to be. This is indeed a fossil of a very peculiar na­ture. It is a kind of undetermined, metallic substance, mixed with stony and sulphureous particles, so that it is hard to reduce it to any class. It is found in mines of all metals, but chiefly in silver or lead mines. That in gold mines is counted the best. It has also its own peculiar mines. It lies in clods of several sizes, nearly resembling black-lead, but is full of small threads, like needles, brittle as glass. It melts in the fire, though with some difficulty. Its uses are very numerous. It is a medicine of sovereign use in many cases, when warily and properly administered. It is a common ingredient in burning concaves, serving to give the composition a finer texture. It makes a part in bell-metal, in order to render the sound more clear. It is mingled with tin, to make it more hard, as well as of a brighter colour, and in lead, in casting of printers’ letters, to render them more smooth or firm. It is also a general help in casting of metals, and especially in casting cannon-balls.

4. Gold is either found in small grains in the sand of rivers, (formerly in several of the rivers of Europe) or is dug out of the earth, in small pieces of a tolerable purity. Sometimes it is also found like the ore of other metals, in a mass of earth, stone, or sulphur. In this state it is of all colours, red, white, black ash, making no ostentation of its real value.

The chief properties of gold are, 1. It is the heaviest, though not the hardest of bodies. 2. It is the most ductile and malleable of all metals, of which goldbeaters and wire-drawers give us an abundant proof. But this depends altogether (incomprehensible as it is) on its being free from sulphur. For mix but one grain of sulphur with a thousand of gold; and it is malleable no longer. 3. It is more fixed in the fire than any other metal. Lay a quan­tity of gold two months in the intensest heat, and when it is taken out, there is no sensible diminution of its weight. And yet in the focus, of a large burning glass, it volatilizes and eva­porates. Yea, many thousands of moidores were wholly consum­ed, others half, or a quarter consumed, ‘by the flames which broke out, (luring the late earthquake at Lisbon. Gold may likewise by a glass’ be fused into a sort of calx, and then vitrified. But if the same be fused again with grease, ft is restored into gold. 4. It is dissolveable by no menstrum known, but aqua regia or mercury. The basis of aqua regia is sea-salt, the only salt which has any effect on gold. But this has its effect, how­ever applied, whether in a fluid or solid form. 5. It readily and spontaneously attracts and absorbs mercury. But as soon as the mercury enters it, the gold becomes soft like paste. 6. It with­stands the violence both of lead and antimony. All metals but gold and silver melted with lead, perish with it and evaporate: and all but gold, if melted with antimony. Thus melt gold, sil­ver, copper and tin with antimony, and all the rest rise to the top, and are blown off with bellows, but the gold remains be­hind. Hence antimony is used as the test of gold.

The malleableness or ductility of gold, is beyond all imagina­tion. By exact weighing and computation it has been found, that there are gold leaves, which in some parts of them are scarce 350000th part of an inch thick. And yet this is a notable thick­ness in comparison of that of the gold spun on silk in gold-thread. It has been proved that the breadth of these gold plates is only the 96th part of an inch, and in their thickness, the 3072d; so that an-ounce of gold is here extended to a surface of 1190 square feet.

How thin must it be when thus extended! In some parts it has been computed, its thickness is only the 3,150,000th part of an inch ! And yet with this amazing thinness, it is still a perfect cover for silver : nor can the best eye, or even the best microscope discern the least chasm or discontinuity. Nay, there is not an aperture to admit alcohol of wine, one of the subtlest fluids in nature: no, nor light itself. So closely connected are the particles, notwithstanding their inconceivable thinness.

Silver approaches the nearest to gold in ductility and resisting fire. Like the ore of all other metals, it is found in the earth, under different forms and colours. But it usually affects some-what of a pointed regular form like crystals. It is never found in sand or grains, as native gold is. It is sometimes ash-coloured, sometimes spotted with red and blue, sometimes -of changeable colours, many times almost black.

Although the history of fossils has been diligently cultivated, especially j)y the ‘moderns, yet it must be owned, that andst the vast variety of them, there is still room for new inquiries. No wonder therefore, that among the great variety of salts, ores and other concretes, new mixtures should daily be discovered. But that among bodies so simple as metals, any should still remain unknown, will appear extraordinary.

Yet so it is there has been discovered in New Spain, an ori­ginal metal between gold and silver, the Spaniards call it platina, from the resemblance in colour which it bears to silver. It is of an uniform texture, bright and shining. It takes a fine polish, and does not tarnish nor rust. It is very hard and compact, but extremely brittle, and malleable but in a small degree. it is found chiefly in small grains, yet not pure, but mixed with a shining black sand. There are likewise usually mixed with it, a few,, shining particles of a golden colour.

When exposed by itself to the fire, it is extremely, hard to melt. It has been kept for two hours in an air furnace, in a heat that would melt cast iron in fifteen minutes, without being either melted or wasted. But when exposed to a proper heat -with gold, silver, copper, lead, or tin, it readily melts and incorpo­rates with them. Having been kept in an assay-furnace with lead for three hours, till all the lead was wrought off, it was found remaining at the bottom, without having suffered any alte­ration or diminution. A piece of it having been put into strong aquafortis, and kept in a sand heat for twelve hours, yet when taken out it was no ways corroded, and was of the same weight as when put in. It has been said to be heavier than gold: but that is a mistake. Its specific gravity is to that of water, as fifteen to one. Yet an equal mixture of gold and platina, was near as heavy as gold itself, being to water as nineteen to one. It appears then, that no known body comes so near gold in fixed­ness and solidity. If it could be made as ductile as gold it would not easily be distinguished from it.

Platina is likewise found in large, hard masses: these masses are with great labour, reduced into small grains, which are after­wards ground with mercury to extract the gold; and it is not to be brought into fusion by the greatest degree of fire procurable in the ordinary furnaces. It entirely resists the vitriolic acid, which dissolves or corrodes every other known metallic body except gold. Nay, it resists the marine fumes, and the regal cement, so called, from its being supposed to purify gold from all heterogeneous metallic matters. It also resists the force of the vitriolic and flutrous acids, though applied in such a manner as to be capable of perfectly dissolving all other known metallic bodies. It follows from other experiments, that platina contains nò gold; for it cannot,, any more than the common metallic substances, prevent a small portion of gold mixed with it from being disco verable. It farther appears, that platina, like gold, is not acted on by the simple acids which dissolve every metallic body besides:that aqut regiae, the solvents of gold, prove menstrua for platina; and that consequently the common methods for assaying and puri­fying gold by aqua fortis, aqua regiz, or the regal cement, can no longer be depended on : that it differs from gold, in giving no stain to the solid parts of animals, not striking a purple colour ‘with tin, not being revived from its Solutions by inflammable spirits, not being totally precipitable by alcaline salts; that in certain circumstances it throws out gold from its solutions; that these properties afford means of distinguishing a small portion of gold mixed with a large one of platina, or small portion of platina with a large one of gold; and that platina contains no gold except­ing the few particles distinguished by the eye. That platina is precipitated from its solutions by the vitriolic acid, and by the metallic substances, which precipitate gold, though scarce totally by any: and that its precipitates resist vitrification, and this per­haps is a more perfect manner than precipitates of gold itself. It is therefore a simple metal of a particular kind, essentially distinct from all those hitherto known, though possessed of some properties generally supposed peculiar to gold. Many of its cha­racters have been already pointed out; others result from com­bining it with the several metals, with each of which, notwith­standing its resistence to the most intense fires by itself, or with unmetallic additions, it melts perfectly ; occasioning remarkable alterations in their colours, texture, and hardness. It melts with equal its weight of each of the metals, with one more readily than with another. With some it becomes fluid, in a moderate fire; but a strong one is requisite for its perfect solution. Composi­tions of silver, copper, lead, with about one third their weight of platina, which had flowed thin enough to run freely in the mould, and appeared to the eye perfectly mixed, on being digested with aquafortis till the mestruum ceased to act, left several grains of platina in their original form. Upon viewing these with a micros­cope, some appeared to suffer no alteration; others exhibited an infinite number of minute, bright, globular protuberances, as if they had just begun to melt. Platina hardens and stiffens all metals; one more than another, lead the most. In a moderate quantity it diminishes, and in a large one destroys the toughness of all the malleable metals, but communicates some degree of this quality to cast iron. Tin bears much the least, and gold and silver the greatest quantity without the loss of their malleability. A very small portion of platina scarce injures the colour of copper and gold : a larger renders both pale, a far less quantity has less effect on copper than on gold. It debases and darkens, in proportion to its quantity, the colour of the white metals; that of silver much the least, and of lead the most. It in good measure preserves iron and copper from tarnishing; scarce alters gold or silver in this respect; makes tin tarnish soon, and lead exceeding quick. .

Copper comes next to silver in ductility. Brass is an artificial metal, composed of copper fused with lapis caliminaris. Iron is less ductile than any of these, and contains more dross. It like-wise easily rusts, whereas silver seldom rusts, and gold seldom either rusts or cankers. It resembles lead, but is considera­bly harder and not near so heavy. Indeed it seems to be a sort of imperfect metal, generated of two different seeds, that of silver and that of lead, which makes it a kind of compound of both. And it is sometimes found in silver mines, sometimes in’ lead mines, though it has also mines of its own. It is the lightest of all metals, very little ductile or elastic, but the most fusible of all. It is scarce dissolvable with acids, but easily mixes with other metals.

Of all the substances concurring to form the terrestrial globe, iron seems to have the greatest share: as it not only abounds in most kinds of stone, but enters greatly into the composition of clay. This may be judged, from the similitude of colour between clay and dry iron ore, from the easy vitrification of clay, from the resemblance of vitrified clay to clinkers of iron, from its deep red colour after calcination, and, lastly, from its yielding pure iron, by being burnt with oil.

Dr. Lister has shewn that stones out of the human bladder, being calcined, iron may be extracted from them by a loadstone. And there is scarce any terrestrial substance either in men, brutes, or plants, which after burning do not exhibit some metal­lic particles. Dr. Bucher says, that out of brick-earth, mixed with any fat or oil, and calcined in the fire, he hath produced iron: The spirit of vitriol being mixed with iron, after fermenting, produces a green vitriol like the natural one. But if for spirit of vitriol, you use oil of vitriol, which is the most acid part of that mineral, there happens immedi­ately a small fermentation, which is quickly over. That fermentation begins again in a few days, under the form of a white smoke, which rises to the surface, and the whole mass of iron turns into a very white pap which smells like common sulphur. When the fermentation is over, the iron, instead of turning into green vitriol, becomes on a sudden white vitriol Mean time there is on its surface a black dust, which it has thrown up. It seems this would have made it green. For if white vitriol be mingled with this dust, it acquires a green colour.

White-lead is thin plates of lead dissolved in vinegar. Red-lead is com­monly calcined. Black.lead (very improperly so called) is only a talky kind of earth. for it is only the iron that causes the redness of the bricks and it can be extracted from them again. Moreover, metals are dissolved by the salts and moisture in the earth, and so mix with the nutricious juices of vegetables; hence it may in some pects be said, that we eat metals with the greatest part of our food.

The arbor martis is a germination of iron, resembling a natural plant. The manner of its discovery was this. One poured oil of tartar on iron filings, dissolved in spirit of nitre in a glass. Presently the liquor swelled much, though with little fermen­tation, and was no sooner at rest, than there arose a sort of branches adhering to the glass, which increased till they covered it all over. And these branches were so perfect, that one might even discover a kind of leaves and flowers thereon. The expe­riment has since been frequently repeated, and with the same success.

A friend of mine showed me an experiment of the same kind. In a glass placed over a moderate fire, there was a continual budding of silver, in the form of a branch. When this was clipped off with scissors, and a little crude mercury added,, in a small time there arose another branch of true silver, which had suck­ed in and converted into metallic springs, a considerable portion of the quicksilver. The increment of new silver branches ceased not, as long as the fire was continued and fresh mercury sup­plied, for the due nutriment of this mineral vegetation. The ingredients were only aquafortis, quicksilver, and a small quan­tity of silver, far less than you may reap in a small time front these silver sprigs. Yet far more expense is blown away in smoke, than can be recovered from this silver harvest.

Not much unlike this was an experiment made by a gentle­man, who kept in a cabinet some pieces of fire-stone from a coal-pit, and some large pieces of crude allum-stone, such as it was when taken out of the rock. After a time both these had shot out tufts of long and slender fibres: some of which were half an inch long, bended and curled like hairs. And as often as these tufts were wiped off, they sprouted out again.

But both of these fail short of what is related by a curious natu­ralist. “Having extracted the salts out of a quantity of fern-ashes after the common method, most of the water being evaporated, I had. several pounds of salt, most of which being dried, I exposed the rest t the air. Having put it into a large glass, I forgot it for five or six weeks: looking after it then, I was saluted with a pleasing spectacle. The lixivium had deposited a large portion of salt, out of which sprung at a small distance from each other, about forty branches, which exactly resemble fern, putting out many leaves on each side, from one stem. They were of different sizes, but the figures of all were precisely the same. And these artificial vegetables, taking case not to shake them, I preserved for many weeks.”

And yet the following ‘account is stranger still. “ I mixed equal parts of sal ammoniac and potashes, which Were put into a tall glass body, with plenty of volatile salt sublimated. I expected no unusual appearance from this, having often repeated the operation. Being called out just as the salt began to appear, how was I amazed at my return, to See in the glass head a forest in perspective, so delineated, as scarce to be equalled by the greatest masters. They were a representation of firs, pines, and another sore of tree I had never seen. But of this delightful spectacle I was soon deprived by the sublimation of more ‘salts.

“ The next day I related this to Sir Robert Murray. He told me, one Davison, an experienced chemist, at Paris, had fre­quently shewed him in a glass a great company of firs and pines, full as lively as any can be painted. But in a little time they dis­appeared. He produced them again at pleasure. But herein his operation differed from mine: the substance tout of which he raised those shapes was of a more fixed nature; that which afforded mine, was volatile to the highest degree. Again, he could constantly and regularly produce those beautiful repre­sentations: whereas mine unexpectedly appeared; nor have I any hope of seeing them again.”

Sal ammoniac is made of the soot arising from the clung of four-footed animals, as sheep, oxen and camels, so long as they feed only on green vegetables. This dung is collected in the four first months of the year, when all these feed on fresh spring grass. This, in Egypt, is a kind of trefoil or clover. But when the cattle are fed on hay, and the camels on bruised date-kernels, their excrements are not fit for this purpose.

The nitre of Egypt was well known to the ancients. it is produced in two lakes near Memphis. One of them is four or five leagues long and one league broad: the other, three leagues long, and one and a half broad. In both, the nitre is covered by a foot or two of water. They cut it up with long iron bars, sharp at the end. And what is taken away, is replaced in one or two years, by new nitre, coming out of the earth.

5. If iron in melting be carefully purged from its dross, drawn into plates, and plunged red-hot into cold water, it grows harder, and is termed steel. But it is considerably softened again, if it is put into the fire, and afterward left to cool gra­dually in the air.

6. Quicksilver differs from all metals, in that it is naturally liquid. Its properties are, 1. It is the heaviest of all bodies, but gold and platina. 2. It is the most fluid of all. The particles even of water, do not divide so easily as those ‘of quicksilver they have hardly any cohesion. 3. Of all bodies it is divisible into the minutest parts. Being on the fire. it resolves into an almost invisible vapour. But let it be divided ever so much, it still retains its nature. For the vapours of distilled quicksilver, received in water or on moist leather, become pure quicksilver. And if it be mixed with lead or other bodies, in order to be fixed, it is easily by fire separated from them again, and reduced to its ancient form. 4. It is extremely volatile, being con­vertible into a fume, even in a sand-heat. 5. Of all fluids it is in equal circumstances the coldest and the hottest. This depends on its weight; for the heat and cold of all bodies, is (cæteris paribus) as their weight. 6. It is dissolvible by almost all acids, but vinegar. And hereby we discover, if it be sophisticated with lead. Rub it in a mortar with vinegar. If it be mixed with lead it grows sweetish: if with copper it turns greenish or bluish. If there be no adulteration, the quicksilver and vinegar will both remain as before. 7. It is the most simple of all bodies, but gold and platina. 8. It has no acidity at all, nor does’ it cor­rode any body.

But it may be observed of metals in general, there is great uncertainty and inconstancy in the metallic and mineral king­doms, both as to colour, figure, and situation. A marcasite, for instance, may have the colour of gold and silver, and yet afford nothing but a little vitriol and sulphur: while what is only a pebble in appearance, may contain real gold.

It is common also to find the same metal shot into many dif­ferent forms, as well as to find different kinds of metal of the same form. There is the same uncertainty as to their place. Sometimes they are found in the perpendicular fissures of the strata, sometimes interspersed in the substance of them; and the same metals in strata of very different natures. - They are likewise frequently intermixed with each other; so that we seldom find any of them pure and simple, but copper and iron, gold and copper, silver and lead, tin and lead in one mass: yea, sometimes all fix together.

What distinguishes them from all other bodies, as well as from each other, is thcir heaviness: each metal having its peculiar weight, which no art can imitate.

But who can reckon the various ways, wherein metals are useful to mankind Without these we could have nothing’ of culture or civility; no tillage or agriculture; no reaping or mowing, no ploughing or digging, no pruning, or grafting, no mechanic arts or trades, no vessels or utensils of household stuff, no convenient houses or edifices, no shipping or navigation. What a barbarous and sordid life, we must necessarily have lived, the Indians in the northern parts of America, are a clear demonstration.

And it is remarkable, that those which are of most necessary use, as iron and lead, are the most plentiful. Those which may better be spared, are more rare. And by this very circumstance they are ‘qualified to be made-the common measure and standard of the value of other commodities, and to serve for money, to which use they have been employed by all civilized nations in all ages.

All metals are liable to-rust. Gold itself rusts, if exposed to the fumes of sea-salt. The great instrument in producing rust. Is water: air, only by the water, it contains. Hence in dry air metals do not’ rust; neither, if they are well oiled: water not being able to penetrate oil. Rust is only the metal under another. form. Accordingly rust of copper may be turned into copper again. Iron, if not preserved from the air by paint, will in time turn wholly into rust.

7. Mines in general are cavities, within the earth, containing substances of various kinds. These the miners term loads: if metallic, they are said to be alive; if not, to be dead bodies. In Cornwall and Devonshire the loads always run from east to west. Mines seem to be, or to have been, channels of waters within the earth, and have branches opening into them in all directions. Most mines have streams running through them: where they have not, probably the water has changed its course. The springs in these parts are always hard, abounding either with stony or sulphurco-saline particles. These particles are either of a vitriolic or an arsenical nature. The first concretes into white cubes, resembling silver, the second into yellow ones resembling gold. Both these are by the miners termed mundic.

8. MUNDIC is variously coloured on the outside with blue, green, purple, gold, silver, brass and copper colours. But within it is either of the colour of silver, of brass, or gold colour, or brown. The other Colours are no more than a thin film or sediment, which water, variously impregnated, deposites upon the surface.

There are few copper loads, if any, but have this semi-metal (whichis a kind of wildmock copper) attending uponthem. There­fore, in searching for copper, it is reckoned a great encourage­ment to meet with mundic. The mundic does not intimately incorporate itself with the ore of copper; for copper in its mineral state, being usually of a close consistence, repels the mundic, which is therefore easily separated from the ore.

Cornish waters are infected by mundic, more or less, according to the quantity which they pass through, and the disposition of the mundic, either to retain or to communicate the noxious par­ticles of which it consists. Arsenic, sulphur, vitriol, and mercury are the constituents of mundic, yet these pernicious ingredients are so bridled and detained by their mutual action and re-action, and by mixing with other minerals, that the water is not poisonous, generally speaking, even in the mine where it proceeds directly from the mundic.

Mundic resembles plants, animals, mouldings, carvings and sundry more varieties, too numerous to insert. Shall we attribute this to a plastic power superintending the congress of fossils, and sporting itself with such representations Or shall we rather say, that the great power which contrived and made all things, needing no delegate, artfully throws the flexile liquid materials of the fossil kingdom into various figures, to draw the attention of mankind’ to his works, and thence lead them to the acknow­ledgment, and adoration of an intelligent being, inexhaustibly wise, good and glorious Doubtless these are the works of that same lover of shape, colour and uniformity that paints the pea cock’s train, that veins the onyx, that streaks the zebra: it is the same band whose traces we may discover even among the meanest and most obscure fossils. God loves symmetry, gracefulness, elegance and variety, and distributes them for his complacency as well as glory, limits them not to plants, and animals, and open day light, but like a great master habitually imparts them to all his works, though in the deepest ocean, and in the most secret parts of the earth.

9. Although fissures are the natural result of a moistened and mixed congeries of matter, passing by approximation of parts into a state of solidity, we are by no means to conclude them useless, or the works of chance. No, the Great Architect, who contrived the whole, determined the several parts of his scheme so to operate, as that one useful effect should become the bene ficial cause of another. Hence it happens, that matter could not contract itself into solid large masses, without leaving fissures between them: and yet the fissures are as necessary and useful as the strata through which they pass. These are the drains which carry off the redundant moisture from the earth, which but for them, would be too full of fins and bogs for animals to live, or plants to thrive on. Through these fissures the rain which sinks beneath the channels of rivers, not having the advantage of that conveyance above ground, returns into the sea, bringing the salts and mineral juices of the earth into the -ocean, enabling it to supply the firmament with proper and sufficient moisture, and preserving that vast body, the sea, wholesome, fit for fish to live in, and sailors to navigate.

In these fissures the several ingredients which form the richest loads, by the continual passing of waters, and the menstrua of metals, are educed out of the adjacent strata, collected and con­veniently lodged in a narrow channel, much to the advantage of those who search for and pursue them. For if minerals were more dispersed, and scattered thinly in the body of the strata, the trouble of finding and getting at metals, those necessary instru­ments of art and commerce, and the ornaments of life, would be endless, and the expense of procuring, would exceed the value of the acquisition; without these, neither metals, marbles, salts, earths nor stones, could be so easily or in such plenty, provided, as is necessary for the-use of man.

‘Earth is certainly the general food and stamen of all bodies, yet we know of itself it can do nothing: it must be Connected by a cement, or it cannot form Stone; it must be softened and atten­uated by moisture and warmth, or it cannot enter into the alimen­tary vessels of plants and animals. The parts of earth which constitute the solids of any plants are exceeding fine, and the common mass in which we plant trees, is for the most part gravel, clay, and sand, which promote vegetation, but are too gross to enter into, and become the constituent parts of them. Water must therefore be considered as the vehicle of more solid nourishment, and the parent of the fluids: the earths, salts, and oils, are the great instruments of the increase of solids. To trace fertility a little farther: when the earth is softened and diluted heat rarefies and evaporates the mixture; the salts con­tained and dissolved, are always active and promote motion; the elasticity of the air quickens and continues it: the oils supple the passages, of which some are fitted to secrete, arrest, and deposite the nutritious particles as they pass; some adapted (by the same secret hand, which conducts every part of the opera­tion) to throw off the redundant moisture by perspiration: the earthly mixture composes the hard and solid parts, and the genial, little atmosphere of every plant gives spirit, colour, odour and taste. Herbs and fruits being thus fed and matured, make tile earth they contain better prepared to pass into the still more curious and highly organized parts of animals. It is easy to see that this is rather a detail of the several materials, and well known instruments, conducing to fertility, than the cause. Fertility is owing to the concert, fitness and agreement of all these, with some volatile active principle, of which we know nothing at all. But whence that agreement results, how the materials ferment, replace, connect, and invigorate one another, how the vessels choose and refuse, (if I may so say) in order to produce the fertility desired, is known only to the infinitely wise Disposer of all things, ever attentive to the nurture and support of what he has created. But to whatever cause the fertility of earth is to be assigned, earth it must be owned is a most fruitful universal ele­ment. Animals, plants, metals and stones arise out of it, and return to it again; there, as it were, to receive a new existence, and form new combinations, the ruins and dissolutions of one sort affording more and more materials for the production of others.

In stones and metals, we admire the continuity, hardness and lustre of earth; in plants, the rarity, softness, colours and odours: in animals, the lush, tile bone, and an infinite number of fluids, in which this supple clement can take place: but the greatest wonder is, that earth is capable of being subtalized to such an exquisite degree, as by uniting and communicating with spirit, to perform all animal functions given it in charge by the soul. This is the highest and utmost refinement, which in this state of being, earth is capable of; but that it may be still-farther refined, in order to be qualified for a future, incorruptible, and more glorious state, is one of the greatest truths which we owe to revelation.

10. To the second class of fossils belong those which. are reduced by fire to a caix. Such are, i. Salts, all fossils which whether they have a salt taste or no, are soluble in water. Com­mon salt is heavier than water, and if quite pure, melts when left in the open air. If the water it is dissolved in be boiled and evaporated, it remains in the bottom of the vessel. It is well known to preserve flesh from putrefaction, and to be with great difficulty dissolved by fire. Probably it is composed of pointed particles, which fix in the pores of flesh, and by reason of their figure are easily divided by water, though not by fire. It ever comes purer out of the fire. Yet it will fuse in a very intense heat.

All salt dissolves by moisture: but moisture -only dissolves a certain quantity. Yet when it is impregnated with any salt, as much ‘as it can bear, it will still dissolve a considerable quantity of another kind of salt. It seems, the particles of this, being of different figures, insinuate into the remaining vacuities. Thus when a cup of water will dissolve no more common salt, allum will dissolve in it. And when it will dissolve no more allum, saltpetre will dissolve, and after that, sal ammoniac.

The most remarkable salt mines in the world, are in the village Willisca, five leagues from Cracow in Poland. They were first discovered above 500 years ago, in the year 1251. Their depth and capacity are surprising. They contain a kind of subterranean republic, which has its laws, polity, carriages, and public roads for the horses which are kept there, to draw the salt to the mouth of the quarry. These horses after once they are down, never see the light of the day again. But the men take frequent occa­sions of breathing the upper air. When a stranger comes to the bottom of this abyss, where so many people are interred alive, and where so many were born, and have never stirred out, he is surprised with a long series of lofty vaults, sustained by huge pillars, which being all rock salt, appear by the light of flambeaus, that are continually burning, as so many crystals, or precious stones of various colours.

11. To this class, secondly, belong STONES, which are hard, rigid, void of taste, reducible to dust by the hammer, and into a calx by fire. It is probable, that stones, like salts and most fossils, are generated from a fluid, which gradually hardens into stone, by the evaporation of its finer parts.

Mr. Tournefort observed, that in tile famous labyrinth of Crete, several persons had engraved their names in the living rock, of which its walls are formed: and that the letters so engrav en, instead of being hollow, as they were at first, stood out from the surface of the rock. This can no otherwise be accounted for, than by supposing the cavities of the letters filled insensibly, with matter issuing from the substance of the rock, even in more abundance than was needful to fill those cavities. Thus is the wound of a knife healed up, much as the fracture of a bone is consolidated, by a callus formed of the extravasated nutritious juice, which rises above the surface of the bone. Such callus’s have been observed to be formed on other stones, which were reunited after they had been accidentally broken. Hence it is manifest, that stones grow in the quarry, and consequently are fed; and that the same juice, which nourishes them, serves to rejoin their parts when broken. There is then no room to doubt, that they are organized, and draw their nutricious juice from the earth, which is first filtrated and prepared in the surface of the stone, and thence conveyed to all the other parts.

Doubtless the juice which filled the cavities of those letters was brought thither from the root of the rock, which grew as corals do, or sea mushrooms, which every one allows to grow: and yet they are true stones.

Indeed there are some species of stones, whose generation can no otherwise be accounted for, than by supposing them to come from a kind of seeds, which contain their organized parts in, minature. But many sorts of stones were once fluid; witness the various foreign bodies found therein.

That even pebble stones grow, may be proved to a demonstra­tion, by an easy experiment. Weigh a quantity of pebbles and bury them in the earth. After a time dig them up, and on weighing them again, you will find they have gained a very con­siderable addition.

The vegetable mould or surface of the earth, is made up of sands, clays, marls, loams, rotten stalks, and leaves of herbs, serving both as a proper bed and covering, and as a receptacle and conductor of moisture to tile roots of trees and plants. Sands and pebbles may be considered as drains, for carrying off the redundant moisture, to places where it may be ready to supply the place of what is continually rising in exhalations. But lest tile strata of sand should be too thick, small ones of clay are often placed between, to prevent the moisture from departing too far from where it may be of use. And lest these thin partitions of clay should let the particles of sand insinuate into them, and thereby let the moisture pass through, thin crusts of a ferrugine­ous substance are placed above and beneath each of these claycy strata: by which means the clay and sand are effectually kept asunder.

Supposing some stones are organized vegetables, and are produced from seed, yet most sorts of stones seem to be unor­ganized vegetables. Other vegetables grow by a Solution of salts, attracted into their vessels. Most stones grow by an accretion of salts, which often shoot into regular figures. This appears by the formation of crystals upon the Alps. And that stones are formed by the simple accretion of salts, appears from the tartar on the inside of a claret vessel; and still more clearly, from the formation of a stone in the human body. The air is in many places impregnated with such salts or stony particles: and these ascending from the cavities of the earth, may petrify wood. In this case the petrifying quality is not originally, either in the earth or the water: but in the rising steams impregnated with saline or stony particles.

12. Many waters are generally supposed to turn other bodies into stone. This is ascribed to the lake Loghmond in Scotland, and Lough-Neagh in Ireland. But it is a mistake. There is not in reality any such transmutation in those bodies. Only the stony particles floating in the water, lodge in the pores, or on the surface of them. Petrifactions therefore are nothing more than incrustations of stony particles, which surround and partly insi­nuate into the bodies immersed.

With regard to Lough-Neagh, some think the petrifying qua­lity, to be not only in the water, but in the adjacent soil. Many pieces of petrified wood are thrown up daily, in breaking up new ground, which that water never touched. They are often found two miles from the Lough, in great numbers, and deep in the ground, altogether like the Lough-Neagh stones. That these were once wood is certain. They burn clear, and may be cut with a knife, though not so easily as other wood.

Petrifying springs are impregnated, some with particles of stones, others with serrugineous and vitriolic particles. When the stony ones drop on wood, or other vegetables, they coagu­late upon it, and by degrees cover it with a stony coat. If this be broke before the wood is rotted away, you find it in the heart of the stone. If the wood is rotted, you will find a cavity in the stone; but this also in time will be filled up with stony particles. Sometimes indeed these waters penetrate the pores of the wood, fill them up with their stony particles, and by their burning qua­lity proceeding from lime-stone, destroy the wood, and assume the shape of the plant.

Metallic particles mostly act, by insinuating into the pores of wood or other vegetables, without increasing their bulk, or alter­ing their texture, though they greatly increase their weight. Such is the petrified wood in and near Lough-Neagh. It does not shew any outward addition of matter, and preserves the grain of wood. All the alteration is in the weight and closeness, by the mineral particles pervading and filling the pores.

That there are mines near the Lough, we may gather from the great quantity of iron-stones found on its shores, and from the yellowish ochre and clay in many places near it. Now, whatever springs run through these, will be impregnated with metallic particles. And if they rise in the middle of a river or lake, and in their course meet with wood or other vegetables, these parti­cles will insinuate and lodge themselves in their pores, and by degrees turn them into stone.

That such springs are under this lake, appears from hence, that in the great frost, 1740, though the lake was frozen over, so as to bear men on horseback, yet several circular spots remained unfrozen. Hence it appears, that this petrific quality is not in all parts of the lake, but here and there only. As to the trees which are found petrified and buried at a small distance from the lake, probably it was broader once than it is now, so that what was then under water, is now dry land. If so these trees might have been petrified in the part which was then overflowed, though it is now dry.

13. It is certain, that water impregnated with metallic parti­cles, when falling on wood or other vegetables, will coagulate upon it, as was observed above, and cover it with a metallic coat. It is also certain, that the vegetables included therein, are gradually destroyed, till the same matter which first formed the crust, takes up the whole space which they occupied before. But it is not only wood and other vegetables, which are capable of being thus acted upon, first crusted over and then destroyed. A shovel of iron some years since lying in the water, in the county of Wicklow, in Ireland, was observed to be incrusted with copper, which gave occasion to an important discovery. A gentleman, who visited the place on purpose to examine the truth of what was commonly reported, observes, “ I saw the iron bars impregnated with copper. I was an eye witness to the change in all its progress: an*o were thousands beside. I saw the masons laying a chain of new stope troughs, for the copper water to run through. I saw the men also laying the iron bars on wooden rafters, in those troughs. I saw the iron bars lifted up out of some troughs, where they had lain from one to eight months: and saw them incrusted over with copper, and corroded more or less, (some of them to very thin plates) according to the time they had lain in the water. I saw some of the troughs emptied, wherein the bars were wholly dissolved: and the labourers were throwing up with shovels the copper, which lay on the stones in the bottom of them. It was like mud, as it lay wet on the stones in the bottom of them. It was like mud, as it lay wet in the heap, but became dust as it dried. I also saw several pieces of copper, which had been made out of their copper-mud.

“This water is supposed to flow over a vein of copper in the neighbouring mountain, it is of a sharp, acid taste, and of a blue colour. It is received and collected in those troughs ‘wherein the iron bars were placed: which’ after lying in the water, often not above three months, are entirely consumed: then at the bottom of the troughs, a quantity of topper is found, in the form of coarse sand. And it is remarkable, that there is a greater quantity of this copper, than there was of iron.

But by what principle is this effect produced In order to discover this I made the following experiments.

“ 1. Some small iron nails ‘put into the water, were in four minutes covered with a substance of a copper colour. And during that time the nails gained four grains in weight. The water had the very same effect on silver and tin, but not on gold. Hence we observe, the colour and increase of weight were owing to the adhesion of the particles of the matter dissolved in the water by an acid, which could not penetrate gold.

“ 2. In order to determine the quantity and quality of this matter, I put two drachms of small iron nails into three ounces of the water. After they had lain therein four and twenty hours, I found the surface of the water covered with a thick scum, exactly like that which covers a chalybeate spaw. I observed, likewise, it had lost the blue colour, and sharp, vitri­olic taste. It was quite transparent, and at the bottom lay a brown powder, which when dried, weighed fourteen grains. This powder, melted without any flux, poduced twelve grains of pure copper. The nails also (which had lost eight grains) were in several places covered with a solid lamina of pure copper. The water being afterward filtrated and evaporated, afforded a pure green vitriol.

“ 3. From the spring water treated in the same manner, I obtained a blue vitriol, the basis of which is copper. From all these experiments it appears, that a mineral acid is the active principle in this water, which being diffused through the copper ore, unites itself with that mind and forms a vitriol. This is dissolved by the water, and remains suspended therein, till it meets with the iron in the trough, and by which it is more strongly attracted than by the copper. Therefore, it quits the copper, corrodes the iron, and changes it into a vitriol, which is again dissolved ‘and carried off in the stream. Meantime the copper, deserted by its acid, falls by its specific gravity to the bottom of the trough.

“It appears then, upon the whole, that this admirable process of nature, whereby one metal seems to be turned into another, is no more than a simple precipitation of the copper, by means of them.”

In the Lower Egypt, there is a vast sandy desert, called the Desert of St. Macarius. One large plain herein is called by a name which signifies, The sea without water. This is strewed over with limbs of trees which are entirely petrified: very probably by means of the nitre, with which this whole country abounds.

The change of wood into stone is not the only wonder here. The sand is also changed into eagle-stones. These stones are found two or three fingers breath beneath the surface of the earth, in little mines, some paces long and broad, about half a mile from each other. It is thought that in these places, there oozes out of the earth, a sort of metallic matter, which ferments with the burning sand, and in fermenting assumes Some kind of roundish figure, and attaches to itself more and coarser sand. Afterward it hardens by degrees, and grows black through the heat of the sun.

The eagle-stone when in the mine is soft and brittle as an egg, and of a bright yellow or violet colour, but after being exposed to the air, it turns brown or black, and hardens gradually. Like­wise after a few days, most of these stones, will, if struck, sound like little bells.

Not far off is a vast heap of sand, which they call the Eagle-stone Hill, because it is covered over with great rocks of the very same matter whereof the small eagle-stones are formed.

But what shall we judge of those petrified shells, which have been dug up in many places Some indeed are not petrified. Near Reading, in Berkshire, for succeeding generations, a con­tinued body of oyster-shells have been Lund through the cir­cumference of five or six acres of ground. Beneath is a hard, rocky chalk, on which the shells lie in a bed of green sand, about two feet thick. Above are various strata for at least eighteen feet. The shells are so brittle, that in digging, one of the valves will frequently drop from its fellow. But several are dug out entire; nay, some double oysters, with all their valves united.

In a quarry at the east end of Broughton, in Lincolnshire, there is a clay under the stone, in which are numberless frag­ments of the shells of shell-fish of various kinds. And there are sometimes found whole shell-fish, with their shells on, in their natural colours, only bruised and broken, and some squeezed flat by the weight of earth, which was cast upon them at the deluge.

There is another quarry, south of the town, of a blue, hard stone, (probably a pure clay in some antediluvian lake) in which are numberless shell.fish of various sorts, but so united to the stone, that it is hard to get them out whole. They are all in the furface of the quarry, within a foot of the top. On the surface there are many shell-fish, half in the stone, half out. That part which is within the quarry is whole, but is a hard stone. That which is without, is all consumed, but a little of the edges, which are plain shell.

Some of the shell-fish in this quarry are half open, and filled with the matter of the bed on which they lie. Some of them are broken, others bruised: the edge of one fish is sometimes thrust into the sides of another. One shell of some is thrust half way over the other, and so they are petrified together.

Among these there are several great horse-muscles, such as breed in rivers and ponds. And in the fields and stones near Bramby and Frodingham is found a sort of fish bending like a ram’s horn, and creased like one on the outside. The bed wherein, it seems, this fish bred, is about a foot thick; in which are millions of the fish, sticking half within the stone, half without. And this shell being extremely durable, even the part sticking out, is not consumed, as it usually is in others, but remains whole and entire.

14.From stone burnt to dust arises lime, which has this re­markable property, that if cold water he poured upon it, it presently heats and boils up. In order to account for this, some have supposed, that some subtle matter is lodged, in the pores of the lime, (perhaps many of those particles of fire, whereby the stone was reduced to dust) which when the water insinuates into those pores, occasions the same kind of ebullition, as if it was poured on any other burning substance.

15.Most precious stones are transparent, and strike the eye with vivid and various colours. Probably they were once fluid bodies, which while in that state were mixed with metallic or mineral juices. Their transparency likewise makes this pro­bable, and so does their outward configuration. For many bodies hardening into solids shoot into crystals, just as is observed of several kinds of precious stones: and to this their inward struc­ture answers. For in many we may observe the thin plates. or coats one over the other, just as we see in those mineral sub­stances, which were once fluid. Their colours might be owing to some mineral juice or exhalation, which tinctured them before their pores were fully closed. This is the more probable, because many gems lose their colour,, if they lie long in the fire: and because, generally, coloured gems are found over metallic or mineral

Dr. Boerhaave takes crystal to be the basis of all precious stones, which assume this or that colour, from the metallic or mineral steams mixed with the primitive crystalline matter. But how is crystal itself formed An Italian writer gives a parti­cular account of this. In the Val Sabbia, says be, I observed some parts of a meadow bare of all herbs. Here, and no where else thereabouts, the crystals are genenated. And whenever there is a serene and dewy sky, if all the crystals that can be found over night, are taken away, others will be found in the same place in the morning. Having observed, there is no sign of any mineral steam near, I conclude they are produced by steams of nitre. These may at the same time hinder vegetation in those places, and coagulate the dew that falls thereon. As nitre is the natural coagulum of water, so it ever retains’ its sex-angular figure. The largest crystals known were found in the mountains of Grimiule, between vast strata of Stones. The biggest of them was near three feet in length, and little, less in circumference. It weighed two hundred and fifty pounds: others weighed less and less, to those of ten pounds, which were the smallest there. They were of the same figure; sexangular columns, terminated by sexangular pyrands at one end, and at the other fixed to the rock. They were in general perfectly clear throughout, but in some the bass was foul, in others the point.

If a solution of allum is permitted to crystallize quietly, it shoots into planes, of eight, six, four and three sides. But beside this, particles when excited to action by a certain degree of heat, arrange themselves into regular and delightful star-like figures of different sizes. Many of these have long streaming tails, and resemble comets. Others shoot into an infinite number of paral­lel lines, beautiful beyond description. These configurations are no less constant in their forms, than the crystals on which they grow. And they are equally transparent, but the figures produced are so extremely different, that every’ considerate observer must judge them to be owing to some very different property in nature. But what property Who can determine Indeed how little do we know of the most common things The very elements that surround us, the fire, the water, the air we breathe, the earth we tread upon, have many properties beyond our senses to reach, or our understanding to comprehend.

Dr. Borlase range’s crystal itself and all gems under the head of spar,, which, says he, are only finer and purer substances of the spar-kind.

All spar has been in a state of fluidity. In some are found straws and other light bodies. Yet time adds nothing to their firmness: but they are as hard when first consolidated, as ever they will be. But why do we find no spars in their fluid state Because while the matter of them remains incorporated with the water, it is not to be distinguished. from it, and as soon as it is deserted by the water, wherein it swims, it commences stone. It is by water that the sparry atoms are washed out of their repositories, and are collected into a transparent or opaque juice. As soon as the redundant water is drained off or evaporated, the stony parts accede to a closer union. They are assisted therein, either by cold compressing the parts, or by sudden evaporating heat. Thus the stone is formed, so much water resting in the pores as is necessary to fix it into a consistency. Hence may arise some queries.

1. Whether spar is not the universal gluten of stones distin­guished. from each other, by various mixtures of earthy, mineral, or metallic particles, but all united by the sparry liquor Per­haps there is scarce any sand, stone, or ore, which either by the naked eye or glasses, may not be discerned to have a portion of spar, clearer or opaque, in its composition.

2. Whether these and all other sorts of stones are not conti­nually forming in the earth

3. Whether there are not quarries of stone, which, when left unwrought for a considerable time, yield a fresh supply of stone, in those’ channels, which had been before thoroughly cleared

A very peculiar kind of precious stone is what is termed a turquois. It is of the opaque kind, and commonly of a beautiful blue colour. And yet it has lately been made very probable, that these shining stones are originally no other than the bones of animals. In the French mines they are frequently found in the figure of teeth, bones of the legs, &c. And turquoises half formed, are composed of laminæ, like those of bones, between which petrifying juice insinuating, binds them close together. And the more imperfect the stones are, the more distinguishable are the different directions of the fibres and their larninæ, and the nearer resemblance they bear to fractured bones.

The blue turquois, is indeed no other than fossil bone, or ivory saturated with copper dissolved in an alkaline menstruum; the green turquois is the same substance, intimately penetrated by a cupreous matter dissolved in an acid menstruum.

16. The loadstone is found in iron mines, and resembles iron both in weight and colour. Its most remarkable properties are, turning to the poles, and attracting iron. As to the former, when it moves without hinderance, it constantly turns one end to the north, and the other to the south: only declining a little to the cast or west. If two loadstones are brought within a certain distance of each other, that part of the one which is toward the north pole of the earth, recedes from that part of the other which respects the same pole. But it accedes to it, if the south­ern pole of the one, be turned toward the south pole of the other. The needle touched with the loadstone, when on this side the equinoctial line, has its north point bending down-‚ward; on the other side, its south point: under the line, it turns any way, and is of no use.

As to its attractive power, it not only sustains another toad­stone, (provided the north pole of the one be opposed to the south pole of the other) but iron also. Likewise if steel-dust be laid upon a loadstone, it will so dispose itself, as to direct its parti­cles straight to the poles, whence they will be moved round by little and little, till they are parallel to the axis of the loadstone, It communicates its virtue to iron, and if it be armed with (that is, fixed in) iron, its force is greatly increased. It looses its force either by fire, or by letting two loadstones lie together, with the north pole of one opposed to the north, or the south pole of one to the south of the other. These plain phænomena of the ‘load-stone we know: the cause of them we know not.

From late observations it appears, that the loadstone is a true iron ore, and is sometimes found in very large pieces, half load-stone, half common ore. In every one, 1. There are two poles, one pointing north, the other south; and if it be divided into ever so many pieces, the two poles will be found in each piece. 2. If two loadstones be spherical, one will conform itself to the other, as either would do to the earth, and will then approach each other: whereas in the contrary position, they recede from each other. 3. Iron receives virtue, either by touching, or by being brought near the stone: and that variously, according to the various parts of it which it touches. 4. The longer the iron touches the stone, the longer it retains the virtue. 5. Steel receives this virtue better than iron. 6. In these parts the south pole of a loadstone lifts more iron than the north pole. 7. A plate of iron interposed hinders the operation of the loadstone; but no other body; no, not glass itself. 8. A touched wire, if bent round in a ring, quite loses its virtue. But though bending thus destroys its virtue by day, it will not destroy it in the even­ing. Where is the philosopher in the world, who can account for this 9. Loadstones without any known cause, act sometimes at a greater distance than at other times. That of the royal society will keep a key suspended to another, sometimes at the height of ten feet, sometimes not above four. As strange as it is, the variation of the needle is different at different times of the day. 10. If a touched wire be split, the poles are’ sometimes changed (as in a split loadstone). And yet sometimes one half retains the same poles, and the other half has them’ changed. 11. Touch a wire from end to end with the same pole of the load-stone, and the end first touched turns contrary to the pole that touched it. But touch it again from end to end with the other pole of the stone, and it will turn just the contrary way.

12.Touch a wire in the middle with one pole of the stone, and the pole of the wire will be in that place: the two ends will be the other pole. 13. The poles of a small loadstone may pre­sently be changed, by applying them to the opposite poles of a large one. 14. Iron bars which stand long in an erect position, grow permanently magnetical; the lower end of them being the north pole, and the upper the south pole. 15. The same effect follows, if you only hold them perpendicularly: but if you invert them, the poles will shift their places. 16. Fire, which deprives a loadstone of its attractive virtue, soon gives verticity to a bar of iron, if it be heated red hot, and then cooled in an erect pos­ture, or directly north and south. 17. A piece of English okcr, thus heated and cooled, acquires the same verticity. 18. The verticity thus acquired by a bar of iron, is destroyed by two or three smart blows on the middle of it. 19., Either a piece of iron or a loadstone. being laid on a cork that swims freely in the water, which ever of the two is held in the hand, the other will be drawn to it. This proves that the iron attracts the stone, just as much as it is attracted by it. 20. Draw a knife leisurely from the handle to the point Over one of the poles of a loadstone, and it acquires ‘a strong magnetic virtue. ‘But this is immediately lost, if you draw it over the same pole from the point to the handle. Lastly, a loadstone acts with as great force in vacuo; as in the open air.

The chief laws of magnetism ‘are these: 1. The’ loadstone has both an attractive and a directive power: iron touched by it has only the former. 2. Iron seems to consist almost wholly of attractive particles, loadstones of attractive and directive toge­ther, probably mixed with heterogeneous matter, as not having been purged by fire like iron. And hence iron, when touched, will lift up a much greater weight than the loadstone that touched it. 3. The attractive power of armed’ loadstones is, cæteris pan­bus, as their surfaces. 4. Both poles of the loadstone equally attract the needle till it is touched. Then it is that one pole begins to attract one end and repel the other. But even the repelling pole will attract upon contact, or at a very small dis­tance. But how odd are the following experiments ! I cut a piece, says Dr. Knight, of a loadstone, in an oblong square. In this I placed the magnetic virtue in such a manner, that’ the two opposite ends were both south poles, and the middle quite round was a north pole. I made the two opposite ends of another stone, north poles, the opposite side south poles. An irregular stone had two broad, flat surfaces opposite to each other. I made half of each of these surfaces a north pole, and the other half a south pole. So that the north pole of one surface was opposite to the south pole of the other. I took a stone that had a grain very apparent, running the lengthways of it. At one end of it I placed a north pole, surrounded by a south: at the other a south sur­rounded by a north pole: so that the edges of each surface had a different pole’ from that which occupied the middle.

Many varieties of this kind might easily be ‘devised. But these examples are sufficient to shew, how manageable the mag­netic virtue is, with respect to its direction; and how defective all the hypotheses are, which are brought to account for the phænomena of the loadstone.

Mr. Howard sailed to Barbadoes in company with another ship, commanded by one Groston. Suddenly a terrible clap of thunder broke Groston’s fore-mast, and did some damage to his rigging. When the noise was past, he was surprised to see Mr. Groston’s ship steering directly homeward. He tacked and stood after him, and found that Mr. Groston did indeed steer by the right point of the compass, but that the card was turned round, the north and south point having changed places. If he set it right with his finger, as soon as it was at liberty, it returned to its former posture. And on examination, he found every compass in the ship had undergone the same change.

An odd discovery has been lately made, that not only iron, as has been generally thought, but brass too, by being hammered and properly touched, will contract a true magnetic virtue. And perhaps it will be hereafter discovered, that other metals may receive the same.

Before closing this article, it may be proper to observe, first, The peculiar qualities wherewith some other stones are endued; and secondly, the remarkable uses they are of to us. As to the former, we nay observe, 1; The colour. The carbuncle and ruby shine with red, the sapphire with blue, the emerald with green, the topaz with a yellow or gold colour; the amethyst, is as it were tinctured with wine; the opal varies its colour like change­able taffeta, as it is variously exposed to the light. Observe, 2. The hardness wherein some stones exceed all other bodies, the diamond in particular, which is so extremely hard, that no art is able to counterfeit it. 3. As to the uses, some are serviceable for building, and for many sorts of vessels and utensils; for pil­lars and statues; for porticos, conduits, palaces, as free-stone and marble: some to burn into lime, some (with the mixture of kelp) to make glass, as common flints: some to cover houses, as slate; some for marking, as chalk, which serves also to manure land, and for medicinal uses; some to make vessels which will endure the fire. I might add the warming stone, digged in Cornwall: which being once well heated at the fire, retains its heat for a considerable time.

17. Of the third class are inflammable fossils, the chief of which are SULPHUR and EFRUMEN. Both are highly inflammable: but the substance of bitumen is more fat and tenaceous; whereas sulphur may easily be broken, and reduced to a fine powder.

The bitumen of the Latins was by the Greeks called asphaltos. It is a black, solid, brittle substance, resembling pitch. It is chiefly found swimming on the dead sea, where anciently stood Sodom and Gomorrah. It is cast up from time to time from the bottom to the surface, where it gradually condenses by the heat of the sun. It burns as violently as naphtha; but is of a firmer consistence.

Asphaltos is also a kind of bituminous stone, found near the ancient Babylon, and lately in the province of Neufchatcl, which properly mixed, makes an excellent cement, incorruptible either by air or water. With this, it is supposed, the walls of Babylon were built.

Yet seems to be formed in the earth of a bituminous juice. It is a light, smooth, pitchy stone. It is fissile, and works like amber: the best in the world is said to be found in Yorkshire. It readily catches fire,’ flashes and yields a bituminous smell.

Nearly resembling this, is the channel coal, found in several parts of Lancashire, which burns with an even, steady flame, like a candle or torch.

18. AMBER is a kind of fossil pitch, the veins of which run chiefly at the bottom of the sea. It is hardened in tract of time, and cast on shore by the motion of the sea. It was long thought that none could be found but in Prussia: but it has since been found in Sweden, on the shores of the isle of Beorkoo, though situate in a lake whose water is sweet. Nay, it is digged out of the earth, at a considerable distance from the sea, and not only in sandy, but in firm ground.

19. But the most extraordinary of all fossils is the ASBESTOS. It seems to be a species of alabaster, and may be drawn into fine silky threads, of a greyish or silver colour. It is indissoluble in water, and remains unconsumed even in the flame of a furnace.

A large burning-glass, indeed, will reduce it to glass globules; but common fire only whitens it. Its threads are from one to ten inches long, which may be wrought into a kind of cloth. This the ancients esteemed as precious as pearls. They used it chiefly in making shrouds for emperors or kings, to preserve their ashes distinct from that of the funeral pile. And the princes of Tartary at this day apply it to the same use. The wicks for their perpetual lamps were likewise made of it. A handkerchief of this was long since presented to the royal society. It was twice thrown into a strong fire, before several gentlemen. But in the two experiments it lost not above two drachms of its weight. And what was very remarkable, when it was red hot, it did not burn a piece of white paper, on which it was laid.

But there is a kind of asbestos wholly different from that known to the ancients. It is found so far as we yet know, only in the county of Aberdeen, in Scotland. In the neighbourhood of Achintore, on the side of a hill, in a somewhat boggy soil, about the edges of a small brook, there is a space ten or twelve yards square, in which pieces of fossile wood petrified lie very thick. Near this place, if the ground be dug into with a knife, there is found a sort of fibrous matter, lying a little below the surface of the ground, among the roots of the grass. This the knife will ‘not cut: and on examination it proves to be a true asbestos. It lies in loose threads, very soft and flexible, and is not injured by the fire.

Yet it is sometimes collected into parcels, and seems to form a compact body. ‘When this, however, is more nearly examined, it appears not to be a real lump, but a congeries resembling a pledget of pressed lint, and being put into water, it separates into its natural loose threads.

A stranger discovery still has been lately made. The proprie­tor of a forge, upon taking down his furnaces to repair them,, found at the bottom, a great quantity of a substance, which upon repeated trial, effectually answered all the Uses of the asbestos.’ it was equally well manufactured either into linen or paper, and equally well endured the fire. Upon prosecuting the inquiry, it appeared to him, that both the native ‘asbestos (at least one species of it) and this obtained from the forge, were nothing more, than what he terms calcined iron, deprived, whether by nature or by art, of its inflammable part: and that by Uniting the inflammable part, either with this, or. the fossile asbestos, it may at any time be restored to its primitive state of iron.

But it is certain, there is asbestos which has no relation to iron. Both in Norway and Siberia, there are petrifying waters which, pervading The pores of wood lying therein, fill it with stony particles; and when by a caustic, corrosive power, derived from lime, they have destroyed the wood, a proper asbestos remains, in the form of a vegetable, which is now no more. To which of these does the following belong

Signor Marco Antonia Castagna, superintendant of some mines in Italy, has found in one of them a great quantity of linum asbestum. He can prepare it so as to make it like either a very white skin, or a very white paper. Both of these resist the most violent fire. The skin was covered with kindled coals for some time: being taken out, it was soon as white as before: neither had it lost any thing of its weight. The paper also was tried in the fire, and without any detriment. Neither could any change be perceived, either with regard to its whiteness, fineness, or softness.