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our perambulations must-not extend far out of the beaten track. I cannot, however, help observing, that in the arduous undertaking we have commenced, you will understand it is not my intention to run from London to Oxford, and from Oxford to Edinburgh, from Edinburgh to Paris, and so on, in so many days; nor simply to calculate as to the probability of our reaching a particular place in so many hours. We travel for mental improvement; to study men and manners ; to inspect minutely the wonderful phenomena of nature, the ingenious productions of art, and, above all, to know ourselves. În the various countries we shall traverse there will be many subjects for contemplation, many calls upon our patience and forbearance; many incentives to that charity, which beareth all things;' and many demands upon our liberality both of
purse and mind. The man who travels need not forget his country, but he should forget its prejudices; he should, in fact, become a citizen of the world. The man who cannot accommodate himself in some degree to the customs and manners of the different nations through which he travels ; who is disgusted in one place at the light-hearted gaiety of this people ; at the gravity of another; the superstition of a third, and so on, had much better remain at home. Sterne has given a humourous list of travellers. If I recollect right, he mentions“ idle travellers, inquisitive travellers, lying travellers, proud travellers, vain travellers, and splenetic travellers ;" to which he subjoins the following—“ Travellers of necessity,” as he calls them. “ Delinquent and felonious travellers, unfortunate and innocent travellers, simple travellers, and sentimental travellers ;" to which, with his permission, we will add, intelligent travellers. Under this last class, dear Edward, we will endeavour to arrange ourselves ; our time must not be wasted either in merely seeing sights, as some would call the inspection of the phenomena of nature, or the productions of art. Our mornings must be devoted to study ; your classical learning will be kept up, but I shall begin you with a course of mathematical instruction ; from that we will proceed to scientific inquiries, which depend on a knowledge of mathematical learning ; nor will theology, political economy, and other subjects that comprise the education of a gentleman, be neglected. But I am not now detailing the prospectus of a boardingschool.
“ You have then made up your mind to endure with for
titude all the hair breadth 'scapes we are doomed to encounter, as I dare say, we shall hardly quit the British Isles with. out putting your courage to the proof.” “ Indeed," replied Edward, " I fatter myself I shall not be a troublesome, though I fear you will find me an inquisitive traveller." '
DR. WALKER.-" I shall be always happy to answer your questions, whenever their solutions lie within my knowledge; and in order to convince you how anxious I am, that you should possess that sort of general information, which will add considerably to the pleasure of our present intended tour, and which will so greatly enlarge your understanding, I shall volunteer a geological description of the earth upon the surface of which we are about to peregrinate; as to its productions they will present themselves to our view on every side, and then we will descant on their nature and properties.”
6 INDEPENDENT of the practical utility of geology, to mining and farring,” pursued Dr. Walker, “it is a study which opens to the traveller new sources of amusement and delight; för amidst the sublime imagery of a inountainous country, the feelings naturally exalted, are yet more raised and refined by the contemplation of its uses and subserviency to life.
66 We learn that certain rocks are more prolific in mineral treasures than others; that some yield nothing useful ; that veins of the metals pursue certain courses ; that coal is accompanied by favourable and unfavourable indications. The farmer is enabled by geology, to ameliorate his land ; for it teaches him whence to procure mineral manures, and where to look for those associations of strata which are called for in agricultural improvements. The architect who knows any thing of geology will not construct a monument intended to last for ages, with a perishable stone, when he can select a material of lasting durability. In order to explain the subject of geology according to the several opinions of different men, I shall give you an outline of Burnet's Sacred Theory of the Earth, which begins with the separation of elements from a fluid mass ;- the heaviest particles are supposed to have sank and formed a nucleus; the water and air took their
respective stations; and upon the water the air afterwards deposited a rich unctuous shell or crust that contained in itself the elements of vegetation, and clothed the whole with a beautiful verdure. Mountains, seas, protuberances, or inequalities were then unknown; the equator was coincident with the plane of the ecliptic, and all the charms of spring were perpetual. Many centuries, however, did not glide away before the sun tore the aforesaid crust, or exterior, into large cracks and fissures, which gradually increased till they extended themselves to the great aqueous abyss. The con. sequences may be easily anticipated. The waters finding vents thus made, rose higher and higher; the shell was utterly broken up and destroyed, and that universal deluge took place, of which we have an awful description in Ger. vi. and vii. From this flood, the state of the world is divided into Diluvian and Antediluvian. By this catastrophe, the
. globe of the earth was not only shook and broke in a thousand places, but the violence of the shock it then underwent, shifted its situation; so that the earth which before was placed directly under the zodiac, became thenceforth oblique to the same; whence arose the difference of seasons, which the antediluvian earth was not exposed to. But at length dry land began to appear, owing to a gradual subsidence of the waters, which retired into caverns and crevices origi. nally existing in the nucleus, or formed by the disruption of the crust. Upon the increasing dry land, vegetation began again to exist; and our present islands and continents were formed, while the sea still occupies in parts its original bed. Such is a brief outline of Burnet's romance, which will still be read with some profit, though certainly with more pleasure, even in these times of advanced physical knowledge. It may not be improper to notice to you, that the theory of Burnet, who may be justly said to have adorned the latter half of the 17th century, is nothing more than Des Cartes primitive world of concentric strata of divers heterogeneous matter.
“ Leibnitz about this time published' his · Protogea,' in which he supposes the earth to have been in a state of combustion for many ages, and at length to have gone out for want of fuel. A glassy crust was thus formed, which gave rise to sand and gravel; other kinds of earth resulted from sand and salt ; and as the globe cooled, the water which had before been kept in the state of steam, assumed fluidity, and falling to the earth, produced the ocean.
“ Whiston's New Theory of the Earth,' leaves us bewildered and perplexed, and is principally deserving notice as accounting for the deluge by the approach of a comet towards the earth. This comet coming below the moon, would raise a prodigious and strong tide in the small seas, which, on his hypothesis, were in the antediluvian globe of the world; and also in the abyss, which was under the upper crust of the earth. This tide would rise during the approach of the comet, and would be greatest when the comet was at its least distance from the earth. By the force of the tideand the attraction of the comet, the abyss put on an elliptic figure; the outward crust of the earth, incumbent on the abyss, accommodating itself to that figure, which it would not do while it held solid and conjoined, at last broke, and hence the words of Moses, the
fountains of the great deep being
“ The same comet, in its descent towards the sun, passed so close by the body of the earth, as to involve her in its atmosphere and tail for a considerable time; and, of consequence, left a vast quantity of its vapours both expanded and con-densed on her surface; but a great part of these being afterwards rarefied by the solar heat, would be drawn up again into the atmosphere, but afterwards returning in violent rains, make good what Moses intimates by the windows of heuven being opened, and particularly by the forty days rain ; for, as to the following rain which with this made the whole time of raining 150 days, Whiston attributes it to the unlucky eart! coming a second time within the atmosphere of the persecuting comet, on its return from the sun.
Lastly, to remove the waters, he supposes a mighty wind to have arisen, which dried up some, and forced the rest into the abyss again, through the clefts by which they had come up; only a good quantity remained in the alveus of the great ocean, now first made, and in the smaller seas, lakes, &c. Whiston only proposed this theory hypothetically at first; that is to say, he only supposed such a comet, because it would feasibly and philosophically account for the phenomenon of the deluge; but upon reconsideration, he thinks there actually was such a comet near the earth at that time, and that the great comet of 1688 is the same.
“But no one has proceeded to the forming a theory of the earth, with the pomp and circumstance of Buffon. It merits åttention, as Mr. Brande says, not on account of its ac
cordance with present appearances, or as affording plausible solutions of observed phenomena, but from the eloquence with which it is adorned, the extent of information it displays, and the popularity it derived from these sources.
“ Buffon supposes the planets in general to have been struck off from the sun by a comet ; that they consisted of fluid matter, and thence assumed a spherical form: and that by the union of centrifugal and centripetal forces, they are restrained in their present orbits. The earth gradually cooled, and the circumambient vapours condensed upon its surface, while sulphureous, saline, and other matters penetrated its cracks and fissures, and formed veins of metallic and mineral products. The scorified, or pumice-like surface of the earth, acted upon by water, produced clay, mud, and loose soils, and the
atmosphere was constituted of subtle effluvia, floating above all the ponderous materials. Then the sun, the winds, the tides, the motion of the earth, and other causes, became effective in producing new changes. The waters being greatly elevated in the equatorial regions, and mud, gravel, and fragments being transported thither from the poles, the highest mountains were formed between the tropics, the lowest towards the poles ; and the tropical seas were studded with an infinity of islands. The surface of the earth, once even and regular, became now rough, and irregular ; excavations were formed in one part, and land was elevated in another; and during a period of ages, the fragments of the original materials, the shells of various fish, and different other exuviæ, were ground up by the ocean, and produced calcareous strata, and other lowland depositions; these relics of marine animals which we find at such heights above the present level of the sea, as to render it more than probable, that the ocean once entirely overwhelmed the earth.
“ From these phenomena, Buffon draws a series of curious and minute conclusions, which our limits forbid us even to particularize; but cvery one who now contemplates the earth's surface, traces upon it marks of the direst and most unsparing revolutions, which, from the present order of things, it appears impossible should re-occur, except by the united and continuous agency of the most active powers of destruction. Buffon says this arose from the soft state of the former crust of the earth, and those causes, now imbecile and slow in their operation, were then more effectually, exerted, and results were obtained in a few years, for which