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udden change from the Greek to the Italian Campania. But if he afterwards found three one above the other, the intermediate one being e, as in the former example, the lowest was e uppermost Italian, he would then perceive the is former opinion, and would begin to suspect tastrophes, by which the cities were inhumed no relation whatever to the fluctuations in the the inhabitants; and that, as the Roman tongue tly intervened between the Greek and Italian, so : dialects may have been spoken in succession, and e from the Greek to the Italian may have been ual, some terms growing obsolete, while others oduced from time to time.
antiquary could have shown that the volcanic is of Vesuvius were so governed as that cities e buried one above the other, just as often as any n occurred in the language of the inhabitants, then, the abrupt passage from a Greek to a Roman, and
Roman to an Italian city, would afford proof of ions no less sudden in the language of the people. in Geology, if we could assume that it is part of the £ Nature to preserve, in every region of the globe, an Ken series of monuments to commemorate the vicissiof the organic creation, we might infer the sudden pation of species, and the simultaneous introduction of s, as often as two formations in contact are found to de dissimilar organic fossils. But we must shut our to the whole economy of the existing causes, aqueous, ous, and organic, if we fail to perceive that such is not plan of Nature.
shall now conclude the discussion of a question with ich we have been occupied since the beginning of the fifth apter-namely, whether there has been any interruption, om the remotest periods, of one uniform and continuous stem of change in the animate and inanimate world. We were induced to enter into that enquiry by reflecting how much the progress of opinion in Geology had been influenced by the assumption that the analogy was slight in kind, and still more slight in degree, between the causes which pro(28) HC XXXVIII
duced the former revolutions of the globe, and those now in every-day operation. It appeared clear that the earlier geologists had not only a scanty acquaintance with existing changes, but were singularly unconscious of the amount of their ignorance. With the presumption naturally inspired by this unconsciousness, they had no hesitation in deciding at once that time could never enable the existing powers of nature to work out changes of great magnitude, still less such important revolutions as those which are brought to light by Geology. They therefore felt themselves at liberty to indulge their imaginations in guessing at what might be, rather than enquiring what is; in other words, they employed themselves in conjecturing what might have been the course of Nature at a remote period, rather than in the investigation of what was the course of Nature in their own times.
It appeared to them far more philosophical to speculate on the possibilities of the past, than patiently to explore the realities of the present; and having invented theories under the influence of such maxims, they were consistently unwilling to test their validity by the criterion of their accordance with the ordinary operations of Nature. On the contrary, the claims of each new hypothesis to credibility appeared enhanced by the great contrast, in kind or intensity, of the causes referred to and those now in operation.
Never was there a dogma more calculated to foster indolence, and to blunt the keen edge of curiosity, than this assumption of the discordance between the ancient and existing causes of change. It produced a state of mind unfavourable in the highest degree to the candid reception of the evidence of those minute but incessant alterations which every part of the earth's surface is undergoing, and by which the condition of its living inhabitants is continually made to vary. The student, instead of being encouraged with the hope of interpreting the enigmas presented to him in the earth's structure-instead of being prompted to undertake laborious enquiries into the natural history of the organic world, and the complicated effects of the igneous and aqueous causes now in operation-was taught to despond from the first. Geology, it was affirmed, could never rise to the rank
of as and a Spond from
se to the
of an exact science; the greater number of phenomena must
The course directly opposed to this method of philosophising consists in an earnest and patient enquiry, how far geological appearances are reconcilable with the effect of changes now in progress, or which may be in progress in regions inaccessible to us, but of which the reality is attested by volcanos and subterranean movements. It also endeavours to estimate the aggregate result of ordinary operations multiplied by time, and cherishes a sanguine hope that the resources to be derived from observation and experiment, or from the study of Nature such as she now is, are very far from being exhausted. For this reason all theories are rejected which involve the assumption of sudden and violent catastrophes and revolutions of the whole earth, and its inhabitants-theories which are restrained by no reference to existing analogies, and in which a desire is manifested to cut, rather than patiently to untie, the Gordian knot.
We have now, at least, the advantage of knowing, from experience, that an opposite method has always put geologists on the road that leads to truth-suggesting views which, although imperfect at first, have been found capable of improvement, until at last adopted by universal consent; while the method of speculating on a former distinct state of things and causes has led invariably to a multitude of contradictory systems, which have been overthrown one after the other have been found incapable of modificationand which have often required to be precisely reversed.
The remainder of this work will be devoted to an investigation of the changes now going on in the crust of the earth and its inhabitants. The importance which the student will attach to such researches will mainly depend on the degree of confidence which he feels in the principles above expounded. If he firmly believes in the resemblance or identity of the ancient and present system of terrestrial
changes, he will regard every fact collected respecting the cause in diurnal action as affording him a key to the interpretation of some mystery in the past. Events which have occurred at the most distant periods in the animate and inanimate world will be acknowledged to throw light on each other, and the deficiency of our information respecting some of the most obscure parts of the present creation will be removed. For as, by studying the external configuration of the existing land and its inhabitants, we may restore in imagination the appearance of the ancient continents which have passed away, so may we obtain from the deposits of ancient seas and lakes an insight into the nature of the subaqueous processes now in operation, and of many forms of organic life which, though now existing, are veiled from sight. Rocks, also, produced by subterranean fire in former ages, at great depths in the bowels of the earth, present us, when upraised by gradual movements, and exposed to the light of heaven, with an image of those changes which the deep-seated volcano may now occasion in the nether regions. Thus, although we are mere sojourners on the surface of the planet, chained to a mere point in space, enduring but for a moment of time, the human mind is not only enabled to number worlds beyond the unassisted ken of mortal eye, but to trace the events of indefinite ages before the creation of our race, and is not even withheld from penetrating into the dark secrets of the ocean, or the interior of the solid globe; free, like the spirit which the poet described as animating the universe,
-ire per omnes
Terrasque, tractusque maris, cœlumque profundum."
"To go through all lands, and the tracts of the ocean, and the boundless heaven."