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endangering vessels by suction, but rather a tumultuous movement of the water, which circulates in several quick eddies, varying with the force and direction of the winds and currents. When the wind and the current oppose each other, the Kalofaro becomes a scene of extensive and violent agitation, and will wheel round even ships of war upon its surface; but there is no appearance of an absorbing gulf answering to the ancient imagination, though smaller vessels are exposed to the peril of being driven ashore, or destroyed by the waves beating over them. In order to avoid the danger arising from Charybdis, the mariners of former times went as near as possible to the coast of Calabria, and sometimes went too near, provoking the dangers arising from Scylla; and hence the proverb still applied to those who, in attempting to escape one evil, encounter another:

:

Incidat in Scyllam, cupiens vitare Charybdim.
"Who flies Charybdis, upon Scylla strikes."

Brydone, after referring to the accounts given of it by the classical writers, remarks:"It certainly is not now so formidable, and very probably the violent motion, continued for so many ages, has by degrees worn smooth the rugged rocks and jutting shelves that may have intercepted and confined the waters. The breadth of the straits, too, in this place, I make no doubt, is considerably enlarged. Indeed, from the nature of things, it must be so; the perpetual friction occasioned by the current must wear away the bank on each side, and enlarge the bed of the water."

Of all the oceanic movements exhibited in the form of waves, tides, and currents, of which a summary notice has been given, the latter are the most influential in affecting the displacement of its waters. The tides alternately elevate and let down the surface, rather than produce an actual stream, except along shore, and in confined channels; for when we speak of the motion of a tide-wave, and of its rate of advance, we do not mean a shifting of the water from place to place, but the progressive elevation of its surface stratum. The influence of the winds in creating waves is very circumscribed in forcing the sea to change its situation, except where they are strong and permanent; and it is the upper stratum that they chiefly affect. It may here be mentioned that the common saying of the waves running "mountains high" is a popular exaggeration, for in the rudest parts of the deep, as the Bay of Biscay, the vicinity of Cape Horn, and the Cape of Good Hope, no wave rises more than thirty feet during the most violent storms. Currents, on the contrary, involve extensive areas of the ocean; extend in many instances to the bottom of the sea, and transfer its waters from one hemisphere to another— from the Pacific to the Atlantic, and to the Pacific again, in perpetual revolution-from the congelation of polar regions to the heat of the equatorial. Owing to the joint influence of winds, tides, and currents, there is no part of the ocean, for any long interval, in a state of rest—an obviously benign arrangement of Providence; for if it became for any length of time a vast stagnant pool, its waters, charged with an immense amount of decomposing animal and vegetable matter, notwithstanding their saltness, would soon become fœtid, would give off noxious exhalations, infect the whole atmosphere, and reduce the world to an uninhabitable desert. It has been wisely ordained, therefore, that the physical condition of this enormous mass of water should answer to the apostrophe— "Roll on, thou deep and dark blue ocean, roll!"

CHAPTER X.

CHANGES IN OCEANIC REGIONS.

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E have now arrived at a very interesting department of Physical Geography-the consideration of the changes to which the surface of the globe is subject, and of the causes which produce them, already indicated in the preceding pages. From the experience of many an individual life, it might be imagined, that "all things continue as they were from the beginning of the creation"-that an immutable character belongs to the earth's external aspect- so uniform are the appearances presented by nature during the course of man's threescore years and ten. The grandsire, trembling with age and infirmity, and living in a country distant from the centres of volcanic action, sees no alteration in the configuration of the hills and valleys with which he has been surrounded from his childhood. The stream wanders in the same channel, with as much transparency, and with as many circling eddies, now that he is old and grey-headed, as when in youth he romped upon its banks, and plucked with careless hand the daisy or the cowslip from its grassy slopes. There is, however, no part of the globe free from physical change, whether bare to the light and air of heaven, or lying a thousand fathoms deep below the waters, though it may require the lapse of ages to discover the signs of alteration, and though circumstances may forbid the mutation being the subject of sensible evidence. The bed of the ocean must of necessity be constantly undergoing changes, extensive and diversified, wrought in secret places, into which the inquisitive eye of man cannot penetrate, and which are often beyond the reach of his longest sounding-line. "All the rivers run into the sea, yet the sea is not full: unto the place from whence the rivers come, thither they return again." Denudation, or the carrying away a portion of the solid materials of the land through which they flow, is one effect of their action. It transpires with varying energy, according to the velocity of their current, and the nature of the contiguous soil; and the distribution of the material of which the land is robbed takes place under the control of these two particulars. The heavier debris of rivers may be generally deposited in their own channels, where there is a marked diminution in the power of the stream, arising from its course lying through an extensive level; but the finer particles are transported to a more distant locality, and are either deposited at the confluence of rivers with the sea, where the tides meet them with sufficient force to produce stagnation, or they are conveyed to a more remote resting-place by the tremendous rush of the fresh water into the bed of the deep, and the action of the oceanic currents.

According to Major Rennell, a glass of water taken from the Ganges in the floodseason will yield about one part in four of mud. The mean quantity of water discharged by the river throughout the year he estimated to amount to 80,000 cubic feet in a second, but to be 405,000 cubic feet when the river is in flood. Calculating upon these data, Sir C. Lyell states, that if the mud be assumed to be equal to one half the specific gravity of granite, a supposition below the truth, the weight of matter daily

carried down in the flood season would be about equal to seventy-four times the weight of the Great Pyramid of Egypt. He observes :- ."405,000 cubic feet of water per second gives in round numbers 100,000 cubic feet of mud per second, which ×86,400, the numbers of seconds in twenty-four hours, =8,641,100,000, the quantity of cubic feet of mud going down the Ganges per diem. Assuming the specific gravity of mud to be half that of granite, the matter would equal 4,320,550,000 feet of granite. Now about twelve and a half cubic feet of granite weigh one ton; and it is computed that the Great Pyramid of Egypt, if it were a solid mass of granite, would weigh about 6,000,000 of tons." There is some reason to doubt the accuracy of Rennell respecting the quantity of earthy matter in the water of the Ganges, though it is generally agreed to be the most turbid river upon the face of the globe, owing to the lightness of the soil of the Bengal plains favouring its transportation by the current, and the great violence of the tropical rains. Supposing it therefore to hold but th part of mud in suspension, instead of an estimate given with reference to the Rhine when most flooded,—the result will still be, that the river discharges in two days a mass of matter equal in bulk and weight to the Great Pyramid. A considerable portion of this goes to form new land along the coast at the mouth of the Ganges, but a large quantity is swept onwards into the Bay of Bengal, and contributes to lay upon its floor a carpet of soil in course of perpetual renewal.

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The Sea of Azov, well-known to the Greeks and Romans under the name of Mæotis, was believed in the time of Aristotle to be filling up by the earthy matter conducted into it by its rivers. Its excessive shallowness now has no doubt been produced by the alluvium principally discharged by the Don, the average depth of the main body of the sea being only between six and seven fathoms. The Yellow Sea, an arm of the Chinese Ocean, so called from its waters being coloured by an intermixture of particles of yellow mud, supplies a similar example of the accumulation of debris in its bed. It receives the rapid Hoang Ho, one of the largest rivers of China, which carries along with it an immense quantity of earthy material in a state of solution in its waters. Sir George Staunton calculated that this powerful stream brought down in a single hour two million feet of earth, or forty millions daily; so if the Yellow Sea be taken to be 120 feet deep, the river will convert an English square mile into firm land in seventy days. Currents carry far away into the ocean much of the sediment it receives, but the immediate deposition of the major part produces gradually increasing shoals and shallows, which interfere with the navigation. Captain Hall in the Lyra, sailed across this sea in 1816 on his voyage to Loo Choo, and had occasion to apprehend fairly sticking in the mud several times in the passage. When no land could be perceived from the mast-head, the ship was in less than five fathoms of water, and upon the ebb of the tide, its bottom was within three feet of the ground. It was discovered, at one time, that the Lyra was actually sailing along with her keel in the mud, indicated sufficiently by a long yellow train in her wake. There was more apparent than real danger in this extreme shallowness, as it was found, by forcing long poles into the ground, that for many fathoms below the surface on which the sounding lead rested, and from which level the depth of water is estimated, the bottom consisted of nothing but mud formed of an impalpable powder, without the least particle of sand or gravel. The fact unquestionably is, that the bottom of the Yellow Sea is gradually rising, from the deposits of innumerable streams flowing into it from China and Tartary, and in process of time, this arm of the ocean, which has probably an extent of 125,000 square miles, will become terra firma, exhibiting a horizontal plain like the great deltas of the Nile and the Ganges.

While, by the action of rivers, soil is transported from far inland situations, and brought into the sea, it is borne by the currents of the ocean, which sweep along the coasts, to a

much greater distance from its original site. At not less than three hundred miles from the mouth of the Amazon, Captain Sabine found the sea discoloured by the waters of the river, where they were still running with considerable rapidity; but the stream does not deposit its load of earthy material off its own estuary, for the great tropical oceanic current westward crosses its course, takes up a part of its burden, bears it towards the Caribbean Sea, and may even strew it over the bed of the Gulf of Mexico. In like manner, the sedimentary matter which the mighty Mississippi discharges, and the rivers. of the United States east of the Alleghanies, is taken up by the majestic current of the Gulf stream, and distributed over the floor of the North Atlantic. The greater part of our own eastern coast is annually deprived of a large mass of material by the stormy action of the German Ocean. It undermines and sweeps away the granite, gneiss, trap rocks, and sandstone of Shetland, and removes the gravel and loam of the cliffs of Holderness, Norfolk, and Suffolk, which are between fifty and two hundred feet in height, and which waste at the rate of from one to six yards annually. It bears away the strata of London clay on the coast of Essex and Sheppy-consumes the chalk with its flints for many miles continuously on the shores of Kent and Sussex-commits annual ravages on the fresh-water beds, capped by a thick covering of chalk flints in Hampshire, and continually saps the foundations of the Portland limestone. It receives, besides, during the rainy months, large supplies of pebbles, sand, and mud, which numerous streams from the Grampians, Cheviots, and other chains send down to the sea. To what regions is all this matter consigned? This question is no doubt answered in part by those immense banks which are found along the coasts of England, Holland, and Denmark, and penetrate to the central regions of the German Ocean, equal to about of its whole area, or of the whole extent of Great Britain. There are thus formations proceeding upon a gigantic scale, elevating and variously shaping the bed of the ocean, the result of the deposition there of the solid materials abraded from the land by the agency of rivers and sea-currents.

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It is easy to perceive, that should any upheaving cause expose to the gaze of man the bottom of the existing seas, precisely similar phenomena would be exhibited to those which the continents now present. Vast spaces of regular strata would appear, bearing clear marks of having been formed by aqueous deposition, slowly and horizontally, however inclined and fractured by the power of the elevating agent.

In addition to the soil transported from inland regions into the heart of the ocean, the plants and trees which fall into the river-channels through the undermining of their banks, or which are uprooted by their agency in floods, undergo a similar transference, and are finally imbedded in the sediment accumulating below the waters of the deep. When we reflect upon the combined influence and constant action of innumerable streams in this respect, we shall readily admit that, in the course of a few ages, a prodigious quantity of animal and vegetable remains, derived from the existing continents, receives a subaqueous deposition. Similar remains of marine species contribute largely to augment and diversify the formations in process at the bottom of the seas. We have referred to huge fragments of rock borne by icebergs from the shores into the central parts of the ocean, and there submerged upon the dissolution of their frozen vehicles; and this single operation must, in a century or two, work great changes, scattering isolated blocks upon the sandy slopes and plains over which the North Atlantic rolls its waves, or piling them upon each other in every variety of form. Shakespeare, in describing the dream of Clarence, draws a vivid picture of other contributions which the occurrence of disaster annually submerges, involving many of the human race, with the monuments of their industry, and the signs of their opulence.

Methought that I had broken from the Tower,
And was embarked to cross to Burgundy;
And, in my company, my brother Gloster:
Who from my cabin tempted me to walk

Upon the hatches; thence we look'd toward England,
And cited up a thousand heavy times,

During the wars of York and Lancaster,

That had befallen us. As we paced along

Upon the giddy footing of the hatches,

Methought that Gloster stumbled: and in falling,
Struck me, that thought to stay him, overboard,
Into the trembling billows of the main.

O Lord! methought what pain it was to drown!
What dreadful noise of water in mine ears!
What sights of ugly death within mine eyes!
Methought I saw a thousand fearful wrecks;
A thousand men, that fishes gnawed upon,
Wedges of gold, great anchors, heaps of pearl,
Inestimable stores, unvalued jewels,

All scattered in the bottom of the sca.

Some lay in dead men's skulls; and in those holes

Where eyes did once inhabit, there were crept,

(As if in scorn of eyes) reflecting gems,

That woo'd the slimy bottom of the deep,

And mock'd the dead bones that lay scattered by."

During the modern wars of this country, the navies of the continental powers, Spain, France, and Denmark, were almost annihilated, and our own losses amounted to an enormous aggregate, a large number of stately vessels being battered to pieces, and consigned to the bottom of the deep. "In every one of these ships were batteries of cannon, constructed of iron or brass, whereof a great number had the dates and places of their manufacture inscribed upon them in letters cast in metal. In each there were coins of copper, silver, and often many of gold, capable of serving as valuable historical monuments; in each were an infinite variety of instruments of the arts of war and peace, many formed of materials, such as glass and earthenware, capable of lasting for indefinite ages, when once removed from the mechanical action of the waves, and buried under a mass of matter which may exclude the corroding action of sea-water. But the reader

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