Second Memoir concerning the Natural, Chemical, and Medical History of Human Urine. By M. M. FOURCROY and VAUQUE LIN. In this valuable paper, the properties of the particular substance which gives to the urine its character, viz. the urée, are considered. To procure it, the urine of an adult, 7 or 8 hours after a repast, is evaporated till it has acquired the consistence of a thick syrup. On cooling, the whole mass concretes into granular chrystals, which are a mixture of all the salts with the proper urinary matter. To obtain the latter, 4 times its weight of alcohol is thrown at different times on the mass slight heat is applied: the greater part dissolves, and gives a dark brown colour to the liquor; and there remains a saline matter almost white.

The brown solution in alcohol is poured into a glass retort, and distillation is carried on till it acquires a syrupy consist ence. This is the urée: of which the foetor is insupportable, and analogous to that of the arsenical sulphurets.

Bed...s.

ART. XV. Nouveaux Principes de Geologie, &c. i. e. New Principles of Geology, compared to and put in Opposition with those of the antient and modern Philosophers, &c. By P. BERTRAND, Inspector General of Bridges and Roads. 8vo. pp. 550. Paris. 1798. Imported by De Boffe, London. Price 7.

sewed:

TOTWITHSTANDING the wonderful progress made of late years in chemistry, in the analysis of mineral bodies, and in the knowlege of the different ways in which they are found disposed in several parts of the globe, the tracts on general geology, which have been given to the public, continue still to be rather poetical dreams, than sober philosophical lucubrations. This prevalent fault we rather ascribe to the daring impatience of writers, than to the abstruseness of the subject; though it is no doubt one of the most complicated and dark in the whole department of natural sciences. If the writers of these works would confine themselves to proceeding step by step, drawing only immediate and necessary consequences from accurate observations, and leaving to future ages the care of advancing farther in proportion to the knowlege thus acquired, the real progress of geology would be greater; and many general facts would be better ascertained by this safe and impartial method, than they now are by the continual attempts. of these authors to square them to their fanciful systems. From the impatience to give general theories before solid foundations have been laid for them,,airy hypotheses are successively

created

created and obtruded on the public; each destroying the former, and itself enlarging but little, if at all, the boundaries of science. The only advantages, perhaps, resulting from these wild attempts, consist chiefly in the objections against the preceding systems; and occasionally in some fortunate observation, or conjecture; which deserves to be kept in store, even after the illusory vision, which it is made to prop, has vanished and sunk into oblivion.

These general reflections are peculiarly applicable to the publication which we are now examining. The system proposed in it will be found as wild and chimerical, as any of its most visionary predecessors; and the objections to the system of M. La Metherie (the last and most fashionable geological author) are by far the most useful result of M. BERTRAND'S meditations.

We shall begin by giving the outlines of this new theory of the earth; which, from the neologic and figurative expressions frequently used by the author, and from the incoherence of his reasoning, is in some measure rather darkened than illustrated by his explanations. In order to convey it with some clearness to our readers, we shall divide it into epochs

1st Epoch. Motion, heat, light, and life, are not necessary companions of matter, but local temporary accidents immobility, cold, and darkness, are on the contrary the most natural state of things throughout the immensity of space. Besides those heavenly bodies which now enjoy light and life, an infinite number of other worlds exist; resting invisible in darkness and inactivity, and waiting for some favourable circumstance which may bring to them light and motion. Water (according to this author) is the original substance of our planetary world, and undoubtedly of any other world: but this water, before motion and heat are communicated to it, is only a solid mass of ice. Gravitation being the only force inherent to matter, when it acts alone, as it does in these frozen dead worlds, it tends only to keep the parts of matter united and motionless; every other motion, which may set them in activity, must be ascribed to mechanic impulsion and projection.

2d Epoch. It is difficult to conceive that a comet, of the order of those which move round our sun, could be strong enough to impart this princip'e of motion and life to our globe, and to the others of our planetary system. M. BERTRAND supposes the existence of comets of a superior and unknown order; which, wandering about a great many worlds, finally end their career, and fulfil their destination, by striking one of the dead and frozen; breaking it in pieces; and mixing their

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their materials with those of the till then lethargic mass. These fragments acquire, by this impulsion, a common projectile motion in the same plane, and in the same direction. The light, heat, and life, brought by this energetic comet, mixing with the original ice, form new combinations; afford causes of intestine motions; and begin by these means a new order of things: which M. BERTRAND calls vital and organic constitution, and which he supposes to be different in every planet, since their density is not the same.

3d Epoch. The ice, by the medium of heat as a dissolvent, being reduced to primordial matter, all antient combinations were destroyed, to give room to new combinations of a different order. The first, perhaps the only, conversion of this regenerated element was the calcareous earth; the species of earth from which, in his opinion, every other earth is originally formed. This deposition of calcareous matter, being equal every where, could not but produce a regular nucleus in our globe; and this nucleus being equally covered by water, the structure of our planet was far different from what it now is. No spot of ground could be out of the water; no mountains, no valleys, could be formed by such an homogeneous equal deposition. How, then, were they produced?

4th Epoch. A new comet of high degree approached our globe, near enough to influence its destinies; changed and slackened both the annual and diurnal motions of the planet; displaced the axis and the equator; altered likewise the points at which the spheroid was compressed or elevated; and, by these means displacing the waters, occasioned the sudden emersion of the first continents. The surface of these was already marked by declivities and valleys, the first occasioned by the general change of level; the second by the sudden retreat of the waters. These continents, however, being all composed of calcareous matter, what events caused the forma, tion of the other fossil substances which now exist?

5th Epoch. The first action of atmospherical powers, and of the solar rays on the virgin soil, occasioned a sudden eruption of all the vital forces, so long suspended and concentered. In this explosion of life, every particle of native soil was vivified; and numberless races of vegetables and animals were produced, of such sizes and in such numbers, that putrefaction and fermentation ensued. Some meteoric phænomenon having set fire to this monstrous heap of putrefied bodies, the horrid conflagration extended everywhere, even under the sea, and was the cause of most tremendous earthquakes; which broke all the strata, that till then had been horizontal, and lifted them up in every direction, even perpendicularly;

dicularly thus giving rise to the chains of mountains, and all, their different forms. The ashes of this almost general combustion, being the most saline of the then existing substances, formed a lixivium; which, filtering through the interstices of the broken strata that were yet of a soft consistence, produced the quartz and other similar substances which now compose them. Wherever this lixivial and quartzeous flux deposed large quantities of matter, the granite was formed. From the mixture of this Aux with loose ashes, the gneiss originated; and, by several such mixtures, the corneous, micaceous, and other schists were formed. The different sorts of lixivial. fluxes and vitreous salts, combined with other salts, and with the original calcareous substances, gave rise to new earths; which, though generally reckoned primitive, both by chemists and mineralogists, are nevertheless (according to M. BERTRAND) so many natural amalgams, which defy the present powers of chemistry; such are magnesia, barytes, argill, &c. residuum of the putrefied organic bodies, not being thoroughly burnt and converted into ashes, experienced only different de grees of fire and decomposition, and was turned into coals and bitumens. Such, according to our author, was the process by which nature, from this enormous putrefied dunghill, formed nearly all the fossil substances, except only the calcareous.

The

6th Epoch. The general combustion, by which in the pre-. ceding period so many wonders were effected, prepared also the way to another revolution. The fire, extending under the sea to an immense depth, consuming and volatilizing the earths, occasioned hollows and caverns of incalculable dimensions: which, being laid open by some violent shock, were filled by the waters of the ocean; and, by this sudden retreat of the watery element, vast portions of our globe were left dry and exposed to the atmosphere, while part of the old continents fell into the hollows and disappeared.

M. BERTRAND deems it very probable that a second change of the axis of our planet was the cause of this catastrophe; because the fossil organized bodies, found in different countries, seem to prove that a change of zones and climates has taken place, since the moment at which they were first inhabited by terrestrial vegetables and animals.

This, according to the author, is the epoch in which we live; and in which Nature, no doubt, fatigued and harassed by her first gigantic efforts, has lost much of her former energy. The organized bodies of this epoch are all new species, by no means comparable either in size, numbers, or prolific quality, to the first inhabitants of the globe. The means of destruction are likewise as much weakened as those

of

of production. Our present earthquakes, and our volcanoes, are microscopic objects in comparison with those of the former epochs. Those first earthquakes shook the globe, displacing and overthrowing every thing; the first conflagrations were (in the author's words) bottomless and boundless seas of fire; while our actual volcanoes he compares to chimneys.

M. BERTRAND assures us that the actual state of the globe has already lasted longer than any other of the former states; and that it is very probable, from the exhausted condition of nature, that it will continue to decay in peace till the planet is again cold, lifeless, and dry: but this is a mere probability, because, if partial nature be liable to decline, universal nature is always in full activity; and some new change of the axis of the earth may sink part of the existing continents, and may expose to the solar rays, and to the vivifying action of the atmosphere, the bottom of the Southern and of the Pacific

oceans.

We have now given the outlines of this author's hypothesis, faithfully extracted from his hook; and we are confident that no sensible reader expects that we shall dwell long on their refutation. If all that is gratuitous in his assertions, all that is contradicted by cool investigation, and all that is inconsistent with his own views, be taken away from his system, nothing we dare say, nothing-will remain of it. He himself is aware of the uncommon excentricity of his notions; since he tells us (page 482.) that, in these matters, truth can only be found in the most unlikely suppositions. What grounds, in fact, can we have for belief in the existence of invisible, motionless, dead, frozen worlds? in that of comets of a superior order, wandering through the wide space, without any proportionate center of attraction and motion? of primæval waters depositing only calcareous matter, though (even according to him) they must have contained those principles which in their progress gave rise to every other substance? What grounds for asserting the unaccountable production of such quantities of organized bodies, as can effect a change in the nature of minerals themselves, and be the cause of the formation of granites, &c.? There would be no end to the enumeration of all the absurdities of this philosophical romance, even when divested of the strange ideas which are suggested in the details; some of which not only offend by their improbability, but by their want of moral decency. We shall present our readers with a single instance, from chapter 27, where M. BERTRAND gives his opinion on the first formation of the organized bodies. He supposes that the virgin mud, fecundated by the solar rays, by the meteors, by the sideral influence, and perhaps by an unknown sexual influence,

brought