resume the history of opinions respecting the deluges of history and geology.

Writers upon the deluge early perceived the difficulty of finding water enough on the surface of the globe to cover its continents. Hence they resorted to subterranean abysses of vast extent; and for a long time this opinion seems to have been taken for granted; so that philosophers had little to do, except to point out a method by which these internal waters could have been forced out so as to deluge the surface. Hutchinson, Catcott, and recently Kirby, imagined, that as the waters were driven out, by internal heat according to the latter author, and by the pressure of the air on the surface according to Catcott, the air would rush inward to supply its place, and to prevent the falling back of the waters; and though such an effect must have taken place in defiance of the laws of gravity, yet it corresponds very well with the other parts of their hypothesis, and Mr. Kirby has advanced a principle which makes such apparent inconsistencies no real inconsistencies. "It must always be kept in mind," says he, "that this was not an event in the ordinary course of nature, and a result of the enforcement of her established code of laws, but a miraculous deviation from it, in which their action was suspended, and in consequence of which, perhaps, some were abrogated and new ones enacted in their room." (Br. Tr. p. 15.) We have no objection to considering the Noachian deluge as miraculous. But after this admission it seems very absurd to attempt, as these authors do, to explain the manner in which the event took place, any further than to state the facts just as they are delivered to us in the inspired record and then when their hypotheses are shown to be in violation of the laws of philosophy, to escape from the difficulty by terming the event a miraculous one. But if we have any reason to suppose this event was brought about by natural agencies, then our reasoning concerning their modus operandi must be in accordance with the known laws of nature. We ought either to discard all reasoning on the subject, or to reason according to the principles of correct philosophy.

Other writers have invented more ingenious expedients for forcing the water out of the bowels of the earth. Hooke, a distinguished mathematician and philosopher, whose posthumous works were published at the commencement of the eighteenth century, imagined the globe was compressed so as to force the water out, just as the juice of a lemon is driven out by squeezVOL. IX. No. 25.

14

ing it in the hand; and thus, to say the least, he showed how the depressed portions of the surface might have been inundated. Subterranean agencies, according to him, the same that produce earthquakes, occasioned the depressions and elevations of the crust, which caused the waters to flow out.

Ray, a distinguished naturalist and the contemporary of Hooke, had recourse to the hypothesis of a shifting of the centre of gravity of the earth, somewhat after the manner in which Dr. Halley explains magnetism by a mass of metallic iron in the earth, which has a revolution distinct from that of the earth, and is of irregular form. As the attracting centre changed, it would cause the waters successively to deluge and desert the different parts of the surface.

Sir Henry Englefield has made some curious calculations to show how a slight expansion of the waters within the globe might produce a general deluge. He assumes that the solid crust of the globe is 1000 miles thick, and that beneath this is an abyss of waters 2000 miles thick, leaving a solid central nucleus 2000 miles in diameter. Assuming that the temperature of the whole globe before the deluge was 50° (Fahrenheit) and that from some cause it was suddenly raised to 83°, he finds, since water expands one 25th of its bulk from freezing to boiling, that this increase of heat would be sufficient to deluge the earth. If the cause of the elevation of the temperature were then removed, the waters would contract to their original bulk, and leave the continents again dry. The great difficulty with this hypothesis, besides its unsupported assumption of a vast internal ocean, is, that several of its conditions (as for instance the accession to, and subsequent abstraction of temperature from the waters,) would demand as great an exercise of miraculous power as to produce a deluge without the intervention of means.

In our own day and country, Dr. Silliman has suggested a very ingenious hypothesis to bring the waters of the earth's abysses over the dry land. He supposes vast galvanic arrangements to exist in the bowels of the earth, which might have generated vast quantities of hydrogen, oxygen, and carbonic acid by decomposition, and that these gases, occupying the upper portions of subterranean cavities, would, as they accumulated, force the waters out and cause them gradually to overflow the land, but after their escape the waters would flow back again into these internal reservoirs.*

* American Journal of Science, Vol. 3, p. 51.

This notion of vast subterranean accumulations of water, however, though quite plausible at the beginning of the present century, has probably been abandoned by nearly every able geologist, since the recent astonishing discoveries concerning central heat. Ingenious therefore as several of the modes are that have been mentioned for forcing out these waters, proposed though they have been by men of the most powerful and logical minds, it is no longer necessary to spend any time in proving them unfounded.

The famous Dr. Halley ascribed the deluge to a comet impinging obliquely against the earth. This would change the axis of rotation as well as the length of the day and the year, and the powerful agitation thus given to the waters would drive them with violence over the dry land. This change of the earth's axis, whereby the former equatorial regions have been brought into the northern hemisphere, has been a favorite notion with cosmologists ever since the time of Allessandro degli Alesandri who suggested it in the fifteenth century; and even in our day, it has been advanced with confidence. It was among the fancies of Dr. Samuel L. Mitchell of New York ;* although both Newton and La Place had shown its extreme improbability; and we find it in the recent Geologie Populaire of M. N. Boubee of France.

Whiston improved upon this cometic theory of Halley. He thought that the mere appulse of a comet to the earth sufficient to produce the deluge without actual collision. And by a display of mathematical learning of a high order, he made it probable that a comet did actually pass near the earth just previous to the deluge. This he thought would produce a gradually increasing tide, both in the waters upon and within the earth, until the comet had reached its nearest distance from the earth, when the waters would gradually decrease. This theory certainly seemed very plausible; and even Mr. Greenough, late president of the London Geological Society, although he does not avow his belief in it, yet shows it more favor than any other, and says, "we need not be deterred from embracing that hypothesis under an apprehension that there is in it any thing extravagant or absurd." However, since the time when he advanced this sentiment, he has entirely changed his opinion re

* Cuvier's Theory of the Earth, p. 410. New York 1818. Greenough's Geology, p. 198. Loudon 1819.

specting the geological evidence of a general deluge, as we shall see further on.

It is true that some twenty years ago there was no extravagance or absurdity in supposing that the appulse of a comet to the earth, and especially its collision with our globe, would produce a terrific effect upon its fluid portions and even solid parts. But from more recent observations it appears certain, that some comets, and probably all, consist of matter so attenuated, that were our globe to come into direct collision with one, it is doubtful whether we should be conscious of it. They have probably "no more solidity or coherence than a cloud of dust, or a wreath of smoke," "through which the stars are visible with no perceptible diminution of their brightness."* These discoveries, admitted now by the ablest astronomers, have doubtless given the final quietus to this cometic theory of the deluge; though we perceive that some geologists on the continent of Europe still cling to this hypothesis.

Another hypothesis that has been very much in vogue, and has received the support of several able geologists, supposes the sea and land to have changed places at the deluge; that the former continents were deluged by being sunk beneath the ocean, while our present continents were raised at the same time. It was adopted by Hooke in his work on earthquakes. "During the great catastrophe," he says, "there might have been a changing of that part which was before dry land into sea by sinking, and of that which was sea into dry land by raising, and marine bodies might have been buried in sediment beneath the ocean, in the interval between the creation and the deluge." These views, with the exception of that part which deposites the fossiliferous strata between the creation and the deluge, were adopted and defended towards the close of the last century by M. De Luc, professor of Philosophy and Geology at Göttingen. More recently this hypothesis, just as it was described by Hooke, has been defended with no small ability of certain kind, and with the most dogmatic assurance, by Granville Penn. He assumes as demonstrated truth, that "there

* Whewell's Bridgewater Treatise, p. 152, 153. Philadelphia 1833. + Hooke's Posthumous Works, p. 410, as quoted by Lyell.

Letters on the Physical History of the Earth. By J. A. De Luc, F. R. S. With Introductory Remarks, etc. by Rev. H. De La Fite. London 1831. (See Letter 6.)

have been two and only two, general revolutions in the substance and circumstances of this globe; so that all effects discoverable, or appearances discernible which are truly attributable to general revolutions, must find their causes in those binary revolutions or in the period of time intervening between them."* He then attempts to show that the remains of tropical animals. and plants were drifted into the northern hemisphere in the period between the creation and the deluge, and deposited so as to form the fossiliferous strata of our present continents. At the deluge, he maintains that the earth that then was, was literally destroyed, or sunk beneath the waters, while our present continents were lifted up. These views have been lately echoed by Fairholme in a smaller work more adapted to general circulation. Both of these writers belong to Great Britain; the work of the latter only, has been reprinted in this country.

The works of Penn and Fairholme above alluded to, furnish the best example of physico-theology modernized, that we have seen. They were compelled to pay so much deference to the advanced state of science at the present time, as to knock off some of the Hutchinsonian protuberances; yet they have not gone into the core of the system to make any reformation there. Their works are distinguished, in the first place, by great positiveness of opinion. Where the ablest geologists hesitate and wait for further light, they cut the knot at once. And yet it is quite clear from the books themselves, (we have no other means of judging,) that their knowledge of geology is mostly literary; that is, obtained by reading. The relative importance of facts is so often presented by them in such a manner, as to betray at once their want of practical acquaintance with the subject. Nay, this is shown by their very positiveness on many points, which all working geologists know to be quite problematical. Secondly, these works are distinguished by very great severity and intolerance towards the leading geologists of the last half century. A powerful attempt is made to exhibit the Mosaical and mineral geologies as at variance in their fundamental principles; so that the one or the other must be abandoned.

And

A Comparative Estimate of the Mineral and Mosaical Geologies. By Granville Penn, Esq. In two Volumes, 8vo. Second Edition. London 1825. (See Vol. 2.)

General View of the Geology of Scripture, etc. By George Fairholme, Esq. 1 vol. 12mo. Philadelphia 1833. (See chap. 6 et seq.)