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قراءة كتاب Chambers's Journal of Popular Literature, Science, and Art, No. 720, October 13, 1877

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Chambers's Journal of Popular Literature, Science, and Art, No. 720, October 13, 1877

Chambers's Journal of Popular Literature, Science, and Art, No. 720, October 13, 1877

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دار النشر: Project Gutenberg
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our island, know the ancient church of Reculver—or the 'Reculvers' as it is now named—as a familiar landmark. Its two weather-beaten towers and the dismantled edifice are the best known objects amongst the views of the Kentish coast; and to both geologist and antiquary the 'Reculvers' present an object of engrossing interest. In the reign of Henry VIII. the church was one mile distant from the sea; and even in 1781 a very considerable space of ground intervened between the church and the coast-line—so considerable indeed, that several houses and a churchyard of tolerable size existed thereupon. In 1834 the sea had made such progress in the work of spoliation, that the intervening ground had disappeared, and the 'Reculvers' appeared to exist on the verge at once of the cliff and of destruction. An artificial breakwater has, however, saved the structure; but the sacred edifice has been dismantled, and its towers used as marine watch-houses. The surrounding strata are of singularly soft nature, and hence the rapidity with which the eroding action of the waves has proceeded.

An equally instructive case of the destructive action of the sea is afforded by the history of the parish of Eccles in the county of Norfolk. Prior to the accession of James VI. to the English crown the parish was a fairly populous one. At that date, however, the inhabitants petitioned the king for a reduction of taxes, basing their request on the ground that more than three hundred acres of their land had been swept away by the sea. The king's reply was short but characteristic. He dismissed the petition with the remark, that the people of Eccles should be thankful that the sea had been so merciful. Since the time of the niggardly sovereign just mentioned, Eccles has not been spared by the sea. Acres upon acres have been swallowed up by the insatiable waves, and as Sir Charles Lyell informs us, hills of blown sand—forming the characteristic sand-dunes of the geologist—occupy the place where the houses of King James's petitioners were situated. The spire of the parish church, in one drawing, is indeed depicted as projecting from amongst the surrounding sand-dunes, which the wind, as if in league with the ocean, has blown in upon this luckless coast.

The comparison of old maps of counties bordering on the sea with modern charts, affords a striking and clear idea of the rate and extent of this work of destruction. No better illustration can be cited of the ravages of the ocean than that exhibited in maps of the Yorkshire coast-lines, and particularly in the district lying between Flamborough Head and the mouth of the Humber. Whilst the district between the Wash in Lincolnshire and the estuary of the Thames shews an equally great amount of destructive change. Three feet per annum is said to be no uncommon rate for soft strata in these localities to be carried away; and the geologist may point to the famous Goodwin Sands—notorious alike in ancient and modern history—as another example of the results of sea-action, and of the wear and tear exercised by the mighty deep. The contemplation of such actions fits us in a singularly apt manner for the realisation of the full force and meaning of the Laureate's words:

There rolls the deep where grew the tree.
O Earth, what changes hast thou seen!

It is highly important, however, to note that the sea receives aid of no ordinary kind in its acts of spoliation by the operation of certain forces affecting the land itself. Land frequently disappears from sight beneath the surface of the sea by a process of subsidence or sinking. We must therefore clearly distinguish between the land which the sea literally takes by its own act, and that which becomes its property through this curious subsidence and sinking of the earth's crust. No doubt the result is practically the same in each case; the sea being in either instance the gainer, and the land the loser. But the sinking of land being a phenomenon less familiar to the ordinary reader, we venture to note a few of its more prominent aspects.

A primary consideration to which it is needful to direct attention consists in the due appreciation of the fact that the land and not the sea is to be here credited with the action under discussion. When a considerable part of a coast-line formerly existing above tide-marks is found to gradually sink below the sea-level, the observer is probably apt to assume that the sea has simply altered its level. The idea of the sea being a constantly changing body is so widely entertained, and that of the land being a solid and immovable portion of the constitution of the earth, is also so deeply rooted in the popular mind, that it may take some little thinking to throw on the land the burden of the change and alteration. It is nevertheless a fact that the great body of water we name the ocean in reality obeys the laws we see exemplified in the disposition of the water contained in a cup or bowl. The water of the sea thus maintains the same level, and is no more subject to violent and permanent alterations than is the water in the cup or bowl. Hence when part of a coast-line appears to become submerged, we must credit the land with being the seat of the change, seeing that the sea must be regarded as stable, unless indeed it could be shewn that the level of the sea had undergone a similar change on all the coasts it touches. Thus if the southern coast of England were found to have been depressed say to the extent of six feet, we must credit the land with the change, unless we could shew that the sea-level on the opposite or French coast had also changed. Now the alterations of land are mostly local or confined to limited areas, and are not seen in other lands bounded by the same sea or ocean as the altered portion. Hence that the land must be regarded as the unstable and the sea as the stable element, has come to be regarded as a fundamental axiom of geology.

When, therefore, the works of man—such as piers, harbours, and dwellings—become the spoil of the sea, the action has either been one effected by the force of the waves without any change of level of the land, or one in which land has simply subsided independently of the destructive action of the sea. In the extreme south of Sweden this action of land-subsidence is at present proceeding at a rate which has been determined by observations conducted for the past century and a half or more. The lower streets of many Swedish sea-port towns have thus been under water for many years, and even streets originally situated far above the water-level have been rendered up as prey to the sea by this mysterious sinking of land. Linnæus (as on a former occasion we remarked) in 1749 marked the exact site and position of a certain stone. In 1836 this stone was found to be nearer the water's edge by one hundred feet than when the great naturalist had observed it; the subsidence having proceeded at this rate and degree in eighty-seven years. The earliest Moravian missionaries in Greenland had frequently to shift the position of the poles to which they moored their boats, owing to the subsidence of land carrying their poles seawards, as it were, by the inflow of the sea over what was once dry land. On the coasts of Devon and Cornwall the observer may detect numerous stumps of trees—still fixed by their roots in the soil in which they grew—existing under water; the site being that of an old forest which was submerged by the sinking of the land, and which has become converted into the spoil and possession of the sea. Even the long arm of the sea—the 'loch' of the Scotch and the 'fjord' of Norway—which seen in the outline of a map, or in all its natural beauty, imparts a character of its own to the scenery of a country, exists to the eye of the geologist simply as a submerged valley, whose sides were once 'with verdure clad,' and on whose fertile slopes trees grew in luxuriant plenty. The subsidence

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