seen by the work before us, and was shown by the success of his lectures; for if his subject were not of that popular nature to arrest the attention of those who sought for mere amusement, he retained, to the end of his course, all whose object was the acquisition of useful and liberal knowledge.

The subject was selected for an early place in the scheme of lectures, as one of a peculiarly valuable character; it is a subject that is, at the present period, rapidly rising from the state of a crude mass of various ill digested opinions and conceptions to the rank of science; while the numerous facts and inferences with which it is crowded, render it an object of interesting study to all liberally educated persons, and of value in innumerable practical cases. It is also a subject that has as yet excited but little attention among us; while mineralogy, that is little more than the alphabet of this more extended branch of knowledge, has been an object of much study, little attention has hitherto been paid in this country to the generalization of the important facts that geology presents to our view, and still less is known of the inferences to be drawn from the observation of the phenomena that occur in our hemisphere, when compared with the results found to arise from similar circumstances observed in other parts of the globe. The want

of this last important branch of knowledge has been very severely felt; we have every where instances of immense expense laid out in the search of metals in strata in which they are never worked to profit, or of coal in primitive and tertiary formations; and at the very time of the delivery of the lectures, a corporate body of our city was preparing to bore for water, in the hopes of obtaining an overflowing spring, through a mass of diluvial gravel resting upon primitive rock. The absurdity of such undertakings is manifest to the merest tyro in geology; and yet we find them continually entered into, not only by persons in other departments most intelligent, but even in cases where the habitual prudence of moneyed men might probably have been expected to dictate their obtaining the best advice from competent judges. We, therefore, are of opinion, that in selecting geology for a portion of their first winter's course, the associates acted wisely, and provided for the public instruction upon a subject more neglected than almost any other in the circle of the sciences.

The time has been, when the very name of Geology excited a smile. This arose from the fact, that it is the very last of all scientific subjects into which the beautiful process of reasoning by induction has been introduced. It was the practice of the ancient philosophers, to assume for the explanation of natural

phenomena, hypotheses that had no foundation but in their own imagination, and no evidence but in their fortuitous coincidence with the facts themselves. Bacon exposed the fallacy of such a mode of proceeding, and showed that no proposition should be used in philosophical reasoning, unless it could be deduced from a comparison and collation of the facts themselves. In this way general propositions may be obtained, that, by comparison with each other, furnish the evidence of others still more general, and the process of generalization may be extended, until we reach those abstract propositions that are styled "Laws of Nature." By an inverse process, these laws and propositions, that in assemblage are called theories, may be employed to explain newly observed phenomena, and to predict the result of new combinations.

Such is the fate of discoveries, that they frequently appear to arise as much from the general state of science, as from the genius of their inventors; and thus it happened, that while Bacon was engaged in illustrating the principles of this method, Galileo was actually making its application. The pride and obstinacy of pretenders to learning resisted the introduction of this beautiful method into every branch of science; near a century elapsed after its use in physical science by Galileo, before it was recognised as the only legitimate logic in Natural Philosophy; Reid and Stewart were still later in introducing it into Moral Science; Chemistry was not entirely stripped of hypothetical propositions before the time of Sir Humphrey Davy; and we are at this moment witnessing the triumph of the logic of Bacon, in Political Economy, and in the science of which we are treating. To recapitulate the many vague and wild hypotheses with which this unfortunate branch of knowledge was loaded, until its very name became an object of ridicule, would far exceed our limits. They have been held up to merited derision in the playful work of our countryman Knickerbocker. We may, however, regret, for the honour of our nature, that the list of the fabricators of these falsely called theories of the earth, should begin with Plato, Aristotle, and Pythagoras, contain Descartes, Burnet, Whiston, and Buffon, and terminate with Playfair and Werner; names in other respects so distinguished.

Perhaps no small part of the errors into which philosophers have run in this respect, arises from our scanty knowledge of the globe we inhabit. We are acquainted with little more of it than its mere crust, for the labour of man has never yet penetrated to a depth much greater than the 50,000th part of its diameter. Still, however, this mere superficial view

presents us with numerous and interesting phenomena, whence, by the process of induction, we may legitimately seek to obtain information in respect to the age, and original form of the globe, and to the convulsions and revolutions it has undergone.

Reasonings drawn from various astronomical phenomena, teach us that the earth we inhabit is a body nearly spherical; inferences of the same fact have been obtained from its actual circumnavigation; that it is flattened at the poles is shown theoretically upon the principles of gravitation and centrifugal force, and the result is confirmed by experiments with the pendulum, and by the measurement of degrees upon the surface. Its density has been determined by Cavendish and Maskelyne; and the deduction from their experiments, that its strata become more and more dense as the centre is approached, has been confirmed by Sabine in his examination into its shape; and yet, although we have thus not only measured, but weighed it, and determined the ratio of the weight of its different layers, we are profoundly ignorant of their nature.

*

Let us digress to inquire how much we actually know in relation to it. Nearly three fourths of its surface are covered with water; the greatest part of this liquid mass is accumu lated in one vast ocean, occupying in one compact body nearly an entire hemisphere, and having various branches or gulfs; of these, the largest and most important is the Atlantic Ocean. The depth of this immense expanse of waters is hardly known to us experimentally; but the sublime calculus of Laplace has penetrated into its profoundest depths, and from the phenomena of the tides he has been enabled to infer the mean depression of its basin.

The portion of solid matter that is elevated above this ocean, is divided into two great continents of very unequal magnitude, nor is there apparently any symmetrical arrangement. The fancied opinion of a great girdle of mountains, constituting nearly an entire great circle of the globe, is unfounded in fact; and no other circumstance has ever been stated, approaching to the nature of such an arrangement. Yet, with this apparent irregularity in the general outline, and dissimilarity in the individual features, we find, at every step, instances of infinite wisdom, by which a succession of natural causes has been made to act for ages, to produce and maintain a state of things fitted in the highest degree for the comfort and well-being of the inhabitants, to whatever class they belong, or whatever place they hold in the scale of being.

* Vide MALTE BRUN's Geography, vol, 1.

The best interpreters of sacred writ, admit that it is not contrary to the Mosaic history to believe, as all the phenomena appear to declare, that the earth existed" without form, and void," long previous to the creation of man; and that the six days of creation may fairly, and in conformity with other similar passages, be construed to signify an equal number of indefinite periods of time. During these periods, the earth was, by a succession of changes, flowing from the action of causes, set in motion by the Deity" in the beginning," gradually prepared for the habitation of man. Originally, a fluid chaotic mass, of which its spheroidal figure is a satisfactory proof. The consolidation, appears to have been slow, whether arising from abstraction of heat, from chemical precipitation, or by deposit from a state of mechanical mixture. Whichever of these was the cause, or whether they were all combined, the waters would have held the higher place, and finally covered the whole solid nucleus. This primitive ocean, as we find from the deposits it has left, was peopled with vast numbers of organized beings; at the most distant periods; these differed widely in character from those now known to inhabit our globe. We may hence infer a great difference in the very nature of the fluid, and in the means of subsistence then provided. As the gradual change took place by which the surface was fitted to be raised above the level of the waters, the character of these inhabitants gradually changed, whole genera and species, nay, even entire families, disappeared, others took their place, and at every step we perceive a gradual approach to the genera and species that are found at present living. The period at last arrived, when the continents were to be raised above the level of the deep. They seem to have been speedily clothed with vegetation, but this was likewise composed of plants that do not now exist upon the surface of the land; we find their types, indeed, in the fragments of broken genera, but no living identical species. Over the face of these continents the water again made an irruption, overwhelming the forests, and depositing them in vast carbonaceous beds beneath it; covering them with its mechanical and chemical precipitates, filled with the remains of its animal inhabitants; a second, and perhaps a third time, do these alternations appear to have been repeated, and inquirers into the nature of the animal remains, pretend, by their means, to discriminate the character of the different floods to have been alternately fresh and salt. How, or by what means these great convulsions were effected, we cannot determine, yet we may fairly infer them to have been produced by the action of secondary causes still to be found in existence.

Since the discovery of the metallic bases of the alkalies and earths, and the investigation of their properties, a most ingenious hypothesis has been framed. It supposes, that at no great depth beneath the primitive ocean, were found great beds of these metals; that they were finally brought into contact with the water; the violent action that was the result would have produced phenomena similar to, but vastly more extended, than those of submarine volcanoes; the masses of solid earthy matter thus formed, would have elevated themselves, and lifted with them the incumbent and previously horizontal strata; in furnishing the other component part of the earths thus formed, large quantities of the water of the primeval ocean would have been consumed; these effects combined would at once account for the appearance of the continents, and repeated from time to time, may be considered as sufficient reasons for their present structure. In such conflicts of elementary bodies, the living animals of the vicinity must have been destroyed. These were replaced from time to time by others, and of this last fact, as we have stated, there is actual evidence. The atmosphere, impregnated with a predominating quantity of hydrogen arising from the decomposition of water, must have been unfit for the support of the life of terrestrial animals, and for this reason we find vegetables, of which it is the appropriate food, to have been first created. But in the period that occurred last before the date of the Mosaic history of the creation of man, we perceive proofs of the existence of numerous terrestrial animals, while man was not among the number. In every successive step of the creation, we find existing proofs of the gradual preparation of the earth for the habitation of our species, the most perfect of organized beings, and the image of the Creator. last the third day of the creation dawned, and the continents, nearly in the state in which we now found them, appeared; the waters of the ocean were collected in their basin; the earth brought forth the green grass, the grain bearing plants, and the trees with their various fruits; during this period the ocean recovered from its state of agitation, and was prepared for the reception of its present inhabitants, with which it was next stocked; and to conclude the preparation for the formation of man, terrestrial animals, and birds in their present forms and species, were created. Last of all man was formed, and though more perfect than any other terrestrial being, equally humble in his origin, he sprung from the same earth that had, at the command of the Almighty, given birth to every preceding creature, whether of species still continued, or of whose existence we know only