Such is the theory of the Count de Buffon, a gentleman of great ingenuity, taste and erudition; whose works, so long as he confined himself to facts and reasoning, have been universally admired; but whose theories have been as much ridiculed by others as he ridiculed those of Burnet and Whiston. Soon after the publication of this theory, Buffon was summoned before the Faculty of Theology at Paris, and there informed that fourteen propositions in his works were reprehensible and contrary to the creed of the church. One of these, which related to geology, was, "That the waters of the sea were concerned in producing the mountains and valleys of the land." And it is curious to remark that this, which was almost the only correct geological proposition in the whole work, Buffon publicly renounced! Upon this theory of Buffon I would take leave, upon the highest modern authority, further to observe, that "from a long series of observations, made with powerful telescopes, Herschel discovered that the solar light and heat do not emanate from the body or nucleus of the sun, but from certain phosphoric and pyrophoric clouds, which are produced and developed in its atmosphere. That this immense ocean of light is violently agitated over its whole surface, causing those corrugations of its disc which he has so well described,—and which indeed, may be observed through a telescope of moderate powers, by even an unpractised eye. When this superficial structure is broken through and widely separated, we may discern the black veil of subjacent solar clouds, or even the solid dark nucleus of the sun itself. Hence Herschel accounts for the dark spots which are frequently observed on the sun's disc, and for the shelving margins which surround them.—Across these excavations of the phosphoric film, bridges of luminous matter, are seen to stretch, which extending in breadth, finally cause the dark chasm to disappear, and restore to the sun all its original brightness. The area of one of these black spots is often much greater than the whole surface of the terrestrial globe. When the storm subsides in the solar atmosphere, the equilibrium of its clouds replaces the layer of light. It is well known that these spots, first observed by Gallileo, led to the discovery of the sun's motion round its axis, and showed that this motion is accomplished in twenty-five and a half days."

Had Buffon been acquainted with these great excavations of luminous matter, he would probably have ascribed them to a projection of the solar substance giving origin to some new planet or comet, and causing diminution of the sun's heat proportional to the darkened portion of its orb. But Herschel has shown, on the contrary, that the seasons in which the solar spots are most abundant, are characterized not by decreased light and heat to the earth, but apparently by an opposite result. He hence infers, that these spots correspond, and are owing to an increased activity in the vibratory motions, by which the sun excites the ether, diffused through space.

The new improvements in optics, afford a very unexpected means of determining whether it be true, as Herschel imagined, that the solar light does issue from an incandescent solid or fluid. When such a body, raised to a very high temperature, becomes luminous, the rays which fly off in all directions, do not come from the outer surface only, but also proceed, as the rays of heat do, from a multitude of material points placed beneath or within the surface, to a certain depth, extremely small indeed, but actually existing. Now, such of those rays as traverse the envelope of the heated mass obliquely, acquire and preserve a peculiar property, which can be rendered sensible by experiment; they are polarised. But if the same mass, instead of being rendered luminous by its proper temperature, be only covered with an exterior film of flame, which is the source of its light, the rays do not then possess this property.

Science has thus been enabled to submit to this singular test, the light which the sun sends to us. M. Arago, the author of this beautiful experiment, has in fact discovered that the rays of the sun, when transmitted even obliquely, are not polarised.

These results are fatal to the theory of Buffon. Those who belong to his school, if any remain, can no longer contend for the sun as the eternal furnace from which to make ignited spheres; but on the contrary, the nucleus of that luminary may possibly enjoy a habitable planetary temperature.

In 1788 Werner published, by his lectures, his famous theory of the earth. He supposed that at some former period this globe had, for a long time, been covered with water to a greater depth than the original altitude of the highest mountains. That this immense body of water was then tranquil, or nearly so, and contained in solution all the materials of all the rocks of which the present crust of the earth is composed. That in this state, chemical deposites, exhibiting more or less of a crystalline structure, were first gradually made, and invested the nucleus of the earth. That these chemical deposites constitute the primitive rocks, including the granite and trap, and are distinguished by their crystalline form, and by the total absence of organic remains. That during this period, most of the highest mountains were formed; but by a gradual subsidence of the waters the summits of these mountains were left naked, the tranquillity of the waters was disturbed, and currents were consequently produced. That by these currents the naked rocks were worn and partially disintegrated; and the grains or fragments thus produced, were diffused through the mass of water. That the rocks formed at this period would, of course, consist partly of chemical and partly of mechanical deposites. That they would also lie over the primitive rocks, but in consequence of the diminished altitude of the waters, they would appear at a lower level, often resting on the declivities of primitive mountains. That as organic remains make their first appearance in the rocks of this period, it is inferred that the rocky shores which had recently emerged from the great deep, were then passing into a habitable state. That the level of the great ocean continuing to sink, more extensive portions of the earth were left exposed to the increasing violence of the currents, and the solution, which was originally chemical, now became, in a great degree, composed of grains, or comminuted fragments, detached from the older rocks, and that hence the minerals of this period consist of mechanical deposites; that they lie over the two preceding classes and at a lower level, in consequence of the greater subsidence of the waters.

That extensive portions of the globe having now become dry, new species and genera inhabited the waters and dwelt upon the land, while numerous vegetables adorn the shores and other parts of the earth. Hence these rocks abound with organic remains, both animal and vegetable.

Doctor Hutton published his theory about the year 1795; he supposed that all the solid parts which form the crust of the present globe, have proceeded from the disintegration and destruction of former continents, by the gradual action of the atmosphere and water; that the ruins of those ancient continents were transported by water, and deposited at the bottom of ancient seas; and that these heterogeneous materials thus deposited, were consolidated by the action of subterraneous fires; and, by the same agents, were subsequently elevated to form the present continents. That gneiss and other stratified rocks were only softened, elevated, and sometimes variously inclined; while granite and other unstratified minerals were completely fused, and in many cases forced upwards by this powerful agent through the incumbent strata. That as this earth had arisen from the ruins of an anterior world, so that had originated from the ruins of a former one, and so ad infinitum.

Each of the two last theories obtained numerous advocates; and a flame of controversy respecting them was kindled, that for some years blazed throughout Europe with great fury. As usual, both parties claimed the victory; but impartial readers appear to think that while each party may lay some claims to correctness, yet as an entire theory both are in the wrong.

(To be continued.)