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missible argument, he has been laid under the necessity of advancing so many unsupported, nay unfounded, statements, by way of defence. There is one consideration, however, which even in retiring must afford him no small consolation, namely, that he had the honour of beginning this controversy himself.

In conclusion, I only beg to recall the attention of Mr. Ivory and others, who dote upon the analytical theory of sound, to an objection I formerly stated, and which, so far as I know, had not been before attended to; namely, that in all these fluxionary investigations, each small cylinder of air is supposed to vibrate so as to have its variable length exactly proportional to its velocity in every part of a vibration. Consequently, when the velocity becomes nothing, at the turn of each vibration, the length of the cylinder is also nothing; that is, the cylinder is annihilated at the turn of each vibration. Now, I would ask these philosophers, if this circumstance alone would not be. fatal to the fluxionary investigations, although all other objections were laid aside?

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A New System of Geology, in which the great Revolutions of the Earth, and Animated Nature, are reconciled at once to Modern Science and Sacred History. By Andrew Ure, M.D., F.R.S., &c. London: Longman, Rees, Orme, Brown, and Green. 8vo. pp. 680; with seven plates and fifty-one wood-cuts. 1829.

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WE gladly embrace the earliest opportunity of presenting our readers with an analysis of this interesting, and in many respects original, work. The author has been long esteemed among men of science for his able and intrepid refutation of numerous errors current in some of our chemical systems; and he has now directed, with a no less steady aim, the same vigilance of observation and logical acumen towards the mystifications of the mineral world. Though the book now before us has not in the least a controversial texture, yet its author. could not possibly avoid noticing, in his introductory dissertation, the chimæras of cosmogony which at no distant date fluttered in many a geognostic head; and there is something

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truly picturesque in the athletic nonchalance with which he strangles them at a grasp, instead of nibbling at their wings and claws, as the rival partisans of those reveries were wont to do.

But Dr. Ure's present labours are not all of the Augean kind. Not content with removing much of the rubbish which has been heaped around rational geology, he has apparently got a glimpse of the true architecture of the globe, and has delineated some of its outlines with a powerful hand.

The great mystery of the mineral kingdom is to be found in the remains of the tropical plants and animals so profusely buried in the secondary and diluvial strata, not only of our temperate countries, but of even the circumpolar zones. Their delicacy of fabric, integrity of form, and posture in the earth, repel the idea of their having been transported to their present sites from the distant equatorial regions, by any aqueous catastrophe. They are undoubtedly buried in the spot where they grew and perished. It is to this enigma of the high temperature which anciently prevailed in our parallels of latitude, that Dr. Ure has concentered all his faculties of research and illustration, and to certain sudden crises of refrigeration which seem to have supervened at distant intervals, the last of them being the Noachian Deluge. That prior to this event, the terraqueous equilibrium was unstable, many great geological phenomena clearly attest; and the Doctor, in discriminating them, endeavours to shew whence that instability proceeded.

These propositions, as now picked out by us in an insulated form, may have somewhat of a hypothetical aspect, but no such impression will be felt in studying the work itself, since they spontaneously result from the phalanx of facts which he has embodied in their service.

There is one thing which we like exceedingly in the Doctor's schemes of induction: the documents subservient to them are neither got up nor trimmed by himself, but are taken, without distinction, from every record of genuine observation, whatever may have been the theoretical creeds of their authors.

It is amusing enough in this tesselated scheme of induction, to see conclusions legitimately drawn from facts which were originally advanced in support of entirely different views. But such is the influence of our author's logical collocations, that we can rarely help assenting to them, as highly probable, at least, if not absolutely true; and this is nearly as much as can be said for all physical doctrines not directly drawn by geometry from observation or experiment.

It strikes us that the title of this work might have very properly been, Geological Physics, or the Philosophy of Geology: for not more than one-half of it is occupied with geological details, and even these are subordinate to general inductions.

The introduction is in reality an elaborate philosophical discourse, in which several important preliminary questions are discussed: such as the visionary spirit of cosmogonists, ancient and modern; the connexion of geology with Scripture history, and of science with revelation in general; the illogical procedure of geognostic theorists, exemplified particularly in the Huttonian and Wernerian systems, as expounded by Playfair and D'Aubuisson; the new era of practical geology, commencing with Mr. Smith's sections of English strata, and the foundation of the Geological Society of London; the importance and uses of organic remains, &c.

One of the author's motives for publishing the present work will receive the unqualified approbation of all good members of society," a wish to lead popular students of philosophy to the moral and religious uses of their knowledge;" and, consequently, to expose the fallacies of our modern Pyrrhonists who ransack nature apparently with no other end than to call in question or vilify the wisdom and goodness of the Creator. Under this head, we find the limits of final causes well defined, and their temperate application ably vindicated.

Among the champions who have figured in the arena of cosmogony few have been more extolled than Professor Playfair, the eloquent historian of physical science; yet in our humble apprehension, few have so frequently violated every rule of induction as he has done in his geological speculations. We feel, therefore, truly grateful to Dr. Ure for the moral courage with which he has dispelled this illusion of a great name, so injurious to the advancement of truth.

"The theory of Hutton was passing fast into oblivion, like its visionary predecessors*, when it was re-embodied, for a season, by the eloquence of Playfair. Delighted with the imposing boldness of the Huttonian creed, the Professor undertook its exposition with the ardour of a mineralogical neophyte. Bringing to the task the joint resources of dialectics and geometry, he produced those Illustrations of the Huttonian Theory which have been so highly celebrated by his literary friends, though they will probably add nothing to his fame as a philosopher."

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The cosmologies of Leibnitz, Whiston, Demaillet, Buffon, Dolomieu, Bertrand, &c.

After a few introductory remarks, Dr. Ure quotes a passage from the illustrations, on which he comments in the following terms:

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"Had the Professor regarded the hypothesis of his friend, Dr. Hutton, with equal impartiality as that of Werner, he would not have expended any refined analysis in its support. That the planets had at one time an actual figure infinitely more irregular than the present, is certainly a very strange proposition for a modern philosopher to make, one equally extravagant with any Epicurean fiction in Lucretius. After an indefinite period, it appears that one of them at least, the earth, became sufficiently regular for an abode of living beings. Their habitation has, however, a precarious existence. The progress of waste will eventually crumble down its mountains, and strew their detritus over the bottom of the sea, converting our imperfect spheroid into the perfect form of equilibrium. This geometrical symmetry which conspiring physical forces tend, by this creed, to produce, should some day cover the whole land with a winding-sheet of water, universally fatal to organic motion and life. This mortal consummation, however, they propose to obstruct from time to time, by fortuitous explosions from the central fires, upheaving mountains and plains, as they are wanted, to rescue the world from a watery grave. The probability of such a mode of salvation is rapidly diminishing; for it is admitted by the theoretic votaries both of Vulcan and Neptune, that these igneous eruptions are becoming vastly feebler and less frequent than they in ancient times; that volcanic fires are fast expiring, and only a few smoking spiracles remain to attest their former activity. In this predicament, the Huttonians can hold forth to proselytes but slender hopes of the duration of their system. The casual convulsion of a dying power is a very precarious resource, and can be little relied on for resisting the steady pace of destruction. The earth of the Huttonians must become a

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Mr. Playfair's two travellers, the celestial and, terrestrial, would have found a better coincidence, and one more to their credit, as philosophers, by tracing at once the actual and only beneficial form of the earth, and its fellow planets, to that perfect Wisdom which created all things in conformity to their destined ends, and which provides, with unwearied beneficence, for the wants and well-being of every organic tribe.

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I have no desire to fatigue my readers with a detailed examination of the theory propounded by Hutton, and embellished by Playfair. Its defects and inconsistencies, and 'in

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deed its whole hypothetical tenor are now so notorious, that no practical naturalist of eminence will venture to adopt its conclusions. My sole object, here, was to unveil its vain spirit of theoretic cosmogony; to exhibit its efforts to build a Babeltower that should make a name, and enfranchise it from the control of a creating and directing Providence. The world, according to Hutton, shows no trace of a beginning, or of an end; but has been the theatre of an indefinite series of transformations in time past, and will continue to be so in time to come. The mountains of a former earth were worn down and diffused over the bottom of a former ocean. There they were exposed to the agglutinating power of subjacent internal fires; and after due induration, were heaved up by the explosive violence of the same force, into the inclined or nearly vertical positions, in which the great mountain strata now stand..

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"The mountains of gneiss and mica slate, allowed by every practical geologist to be primitive, are barren in animal exuvia. Now these most distinctly stratified rocks were formed, it is said, at the bottom of the Huttonian sea, by the same process calcareous and other secondary strata that are replete with shells. Whence do these organic ruins come, and why are they absent in the former class of rocks, both of them formed in the same sea, and under similar circumstances? They cannot reply that the epoch of the gneiss and mica-slate formations was anterior to the existence of animals; for their theory affirms, that the present earth sprung up out of a preceding one, by a spontaneous growth or transition, without the intervention of a divine creative energy. They tell us, that in an indefinite series of ages, the mountain masses of the preexisting globe became submarine concentric layers of rock, which were thence elevated by catastrophe into the present dry lands. Their marine deposition was slow and tranquil, disturb ing the general economy of nature no more than at present, and, consequently, not interfering with the production of marine testaceous animals, nor with the distribution of their shelly exuviæ. Hence, should these beds be eventually indurated and heaved up by the subjacent fires into the nearly vertical mountain schists of a new earth, they must contain the organic witnesses of their submarine formation. But since our actual mountains of gneiss and mica-slate are destitute of these internal witnesses, as also of their basis, carbonate of lime, they CALORIE9) 1 been formed at the bottom of an ocean teeming ith animal life. Devoid of organic remains, they indicate a sea devoid of vital energy. The first appearance of shelly strata is coincident with a specific exertion of creative power,

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