whale, the cow whale in particular, it certainly belongs; and though said, either to be the cause or effect of disease, may be classed with such animal juices as the musk and the civet. Three hundred and sixty ounces of ambergris have been found in one whale; and on analyzation it has been proved to have the same principles as other bitumens, that is to say, an acid spirit; a concrete acid salt; an oil and a charcoal residuum; and therefore, it is ranked as a bitumen.

Petroleum, is a liquid bitumen which runs between rocks and stones. It is distinguished into varieties. The lightest, most transparent, and most inflammable, is called naptha. The heavy, black, thick and tenacious, so as to stick to the fingers, is the petroleum. The pissasphaltum, is of a consistency between the common petroleum and the asphaltum, or bitumen of Judea.

The bowels of the earth, we thus see, are replete with combustion and inflammable substances. They do not, as philosophers supposed, terminate in a clear, crystaline fountain, in which there is nothing to be tasted but the waters of life. On the contrary, every thing would

would seem to prove, they are like the stomach of an animal, in which is constantly flowing all sorts of impurities. From the earth, therefore, we preceive, there is something like an analogous perspiration, which, when regular, passes off like insensible perspiration in an healthy body; but, when obstructed, or increased to a violent degree, produces effects similar to those of a febrile heat in the body; and a concussion ensues, which commonly is succeeded by a vast effusion of watery vapours, and great falls of rain, similar to the profuse quantities which break out from the human body after a shaking fit. Two observations confirm this; first, that earthquakes are commonly preceded by a great drought, and a series of fine weather: and secondly, that they are succeeded by great rains.

But the cause of the internal commotions of the earth, or rather the origin of the fires which occasion them, is not easily explained. It is well known that martial pyrite being moistened, will acquire heat; but, that this heat may burst into actual flame, the concourse of open air is absolutely requisite: however, if we suppose the heated pyrite to have been in contact with black wad and petroleum, we may suppose the flame to arise, as we see it produced by art, in

the

the desiccation of that substance, and its mixture with the mineral oil.* That ore, when heated, affords dephlogisticated air, of which a very small quantity is sufficient to produce flame: This flame once produced, may be supported by dephlogisticated air from other ores; and the phlogiston may be supplied by pyritæ, bitumenous schistus, bitumen and coal.

The existence of subterraneous fire, therefore, may readily be explained in our present state of knowledge relative to dephlogisticated air, since we can easily imagine, that much dephlogisticated air may be detached from variety of bodies within the bowels of the earth, by means of heat; and that such dephlogisticated air, will serve to keep those very fires burning, which are the instrumental means of its production from the divers minerals which contain that pure respirable fluid. This indeed, Lavoisier, as we formerly remarked, has demonstrated, in employing vital, or dephlogisticated air, instead of common air, as aliment to fire. By this means he succeeded in melting platina. Glasses had often been used, and had produced remarkable effects, in fusing bodies that had long been deemed infusible or refractory. But Lavoisier's method proved, that dephlo

Kirwan. † Cavallo.

dephlogisticated air augments the activity of heat, and manifests the power of fire, in the most eminent degree.

The inflammable bodies which we have thus mentioned, and which are supposed to have generated in a long period of time, from animal and from vegetable substances, meeting with acids and other substances in the bowels of the earth, and there undergoing various changes, until they acquire the form in which they present themselves to us; are still capable of further corroboration, from the great chymical difference between the mineral and the organic kingdoms. Vegetable and animal bodies furnish an inflammable fat, or oily substance. Mineral bodies are unfurnished with such substance. And hence it is, that animal bodies are susceptible of fermentation, while mineral bodies are not so. And yet a sort of doubt, in one particular instance, is thrown upon this hypothesis. All strata, accompanying coal, says Whitehurst, are universally charged with vegetable forms, which plainly indicate, that all coals were originally derived from vegetables. But may not the same be said of iron, for the same strata, also produce iron stone; and wherever vegetables are observed to decay

ap

in stagnant ditches, the waters in the ditch pear ochrey? It is worthy of notice also, that superior strata universally contain iron stone, coals, and vegetable impressions, but no marine production whatever; whereas inferior strata, which are lime stone, contain the exuviæ of marine animals, but no vegetable forms. An extraordinary bed of coal, likewise, near the village of Ninkerich, belonging to the Prince of Sarrebrück, begins at the side of a mountain, at the height of 200 feet from the plain, and continues upwards. The vegetable remains which are in and about it, are prodigious.

But this is a subject which we must examine a little more closely. Vegetables, as I have above said, have been considered as the cause of the formation of pit coal. A few forests, however, being buried in the earth, are not sufficient to form the masses of coal which exist in its bowels. A greater cause, more proportioned to the magnitude of the effect, is required; and we find it only in that prodigious quantity of vegetables which grows in the seas, and is still increased by the immense mass of those which are carried down by rivers. These vegetables, carried away by the currents, are agitated, heaped together, and broken by the