Imágenes de página
PDF
ePub

Of small Lakes that are turned into dry Land we have several Instances, especially in Holland.

PROPOSITION VII. Streights are dried up and turned into Isthmus's, or

Parts of Continents.

THIS is caused by the continual gathering and fubsiding of the Mud and earthy Matter, which in Time choaks up the Streight, and stops the Intercourse of the Water.

THU S it seems very probable that the Ifthmus between Africa and Asia, which parts the Red-Sea from the Mediterranean, was formerly a Streight and joined them. The Depth of the Sea in several Streights is also found to grow less, and the Water to become shallower than it used to be, which is a certain Sign that such a Streight, fome Time or other, will be left bare, and be turned into dry Land. So that Bay in the Atlantic Sea which the Hollanders call the Zuider Sea, and the Streights of the Texel, will not now admit of loaded Ships of the first or second Rate, as they used to do formerly ; and as the Water evidently lessens and becomes shallower every Year, it is likely the Texel, will one Time or other, become dry Ground : and that Streight which they call Ulie will, very likely, have the same Fate.

| PROPOSITION VIII.

Bays may be in time dried up, and turned into firm

Ground. !

THIS may happen from a two-fold Cause: 1. . If the Streights which join the Bay to the Ocean become an Isthmus, or be choaked up with Sand

and

and Mud (that such a thing may happen, we shewed in the last Proposition); by this means the Bay is cut off from the Ocean, and becomes a Lake, which is turned into a Fen, or Bog, and then intodry Ground. . 2. If the Chanel of the Bay be heightened continually by the Sand and Gravel, brought down by the Rivers into it, it will in Time be higher than the Ocean, and receive no more Sea-Water. .

THUS the Mediterranean, Baltic, Red-Sea, Persian Gulph, &c. which are now Bays, may be changed, one Time or other, into dry Land; as we shall further prove in the next Proposition, i

. PROPOSITION IX.

The Ocean in some Places for sakes the Shores, so that

it becomes dry Land where it was formerly Sea.

THIS is caused by these Means : 1. If the force of the Waves dashing against the Shore, be broken by Cliffs, Shoals, or Rocks, scattered here and there, under Water, the earthy Matter contained in the Water, as Slime, Mud, &c. is made to subside, and increase the Height of the SandBanks, whereby the Violence of the Ocean is more and more resisted, which makes it yield more Sediment; so that at length the Sand-Banks, being raised to a great Height and Bulk, entirely exclude the Ocean and becomes dry Land. 2. It contributes much to heightning the Shores if they be sandy and rocky, for then the Sea dashing against them, and withdrawing, carries little or nothing away from them, but every Time it approaches them it brings Dregs and Sediment, whereby they are increased in 'the Manner aforesaid. 3. If some neighbouring Shore consist of light, mouldring, porous, Earth, which is easily VOL, I,

Dd

washed

washed away by the Flux of the Sea, it is mixed with the Water, and left upon some other adjacent Shore that is harder ; besides, when the Sea encroaches upon one Shore, it relinquishes another not far off. 4. Large Rivers bring down vaft Quantities of Sand and Gravel to their Mouths, (where they exonerate themselves into the Sea) and leave it there, partly because the Chanel is wider and shallower, and partly because the Sea resists their Motion ; but this is chiefly observed in Countries, whose Rivers annually overflow their Banks. 5. If frequent Winds blow f um the Sea to the Shore-wards, and the Shore itself be rocky or of tough Earth without Sand, it gathers Slime and Mud, and becomes higher. 6. If the Tide flow quick, and without great Force, but ebb flowly, it brings a great deal of Matter to the Shore, but carries none away. 7. If the Shore defcend obliquely into the Sea for a great Way, the Force of the Waves are broke and leffened by Degrees, and the Sea leaves it's Filth and Slime upon it.

"THERE are several Places of the Earth, which, it is certain were formerly covered by the Ocean. Where Egyp: is now, it was formerly Sea, as appears both from the Testimony of the Antients, and Experience ; for the Nile, flowing from the remote Regions of Ethiopia, when it overflows it's Banks, covers all Égypt for a Time, and then settling by Degrees, it leaves the Dregs, Mud, Dirt, and earthy Matter, which the fwift Course of the River had brought down; by this means Egypt becomes annually higher and higher. But before fuch a Quantity of Matter was brought down to the Nile, the Sea covered the Land of Egypt, tho' it be repulsed and hemmed in now by the Earth's ac. quired Altitude. Aristotle, among others, asserts this, and says: This Place, and the whole Coun

try

[ocr errors]

2

[ocr errors][ocr errors][merged small][ocr errors][ocr errors][ocr errors][ocr errors][ocr errors][ocr errors][ocr errors][ocr errors][ocr errors][ocr errors][ocr errors]

try (meaning Egypt) were formed by the pouring in of the Nile, and seems to gain Firmness every Year. But since the neighbouring Inhabitants, by Degrees, began to cultivate the Marshes and Bogs as they dried up, it is impossible to guess at the Time of this Mutation. However, it seems that all the Mouths of the Nile have been made by Hand, and not by the River, except that of Cao nopus. It is further evident, that all old Egypt consisted only of one Town, which they called Tbebes. Homer declares this, who flourished (I may say) not long after these Changes; for he mentions that place as if there were then no such City as Memphis, at least not so large. Seneca explains this better thus: Egypt (says he) arose wholly at first from Mud; and if we may credit Homer, the INand of Pharos was so far distant from the Continent, as a Ship, with all her Sails spread, could fail in a Day, but now it is joined to the Continent; for the Nile flowing muddy and troubled, and carrying down múch Slime and Dirt, leaves it about it's Mouths, whereby the Continent is annually enlarged, and Egypt is stretched further and further every Year. Hence comes the Fatness and Fertility of the Soil, and also it's Evenness and Solidity; for the Mud fettles and grows dry and hard, and the Ground becomes firm by what is laid upon it. · THE Ganges and Indus, both famous Rivers in India, do the same as the Nile, by their Inundations; also the Rio de la Plata in Brasil. And it is very probable that China was formed by this means, or at least enlarged; because the impetuous River, called the Hoambo, flowing out of Tartary into China, and frequently overflowing it's Banks, (thoʻ not annually) hath so much Sand and Gravel in it, as to make a third part of it's Waters,

Dd2 THESE

THESE Examples demonstrate the fourth Calse, qiz, that Rivers make the Sea forike the Score; but the Sea itself, in several Councies, is the Cause of it's own retiring, by brir.ging to the Shore, ard there leaving Seaiment and Matter erough to encrease the Altitude of the Coast; so that it suffers not the Sea to overflow it any longer, Thus Holland, Zeeland, and Gelderland, were formed; for the Sea covered these Countries formerly, as is known both from the antient Monuments mentioned in History, and the Quality of the Soil itself. In the Mountains of Gelderland, not far from Ni. maguen, there are found Sea-Shells, and at a great Depth in Holland are dug up Shrubs and ouzy matter; add to this, that the Sea itself is higher than these Countries, and would overflow and cover them, but that it is restrained by Banks and Dams. On the other hand, there are some that think Holland and Zeeland arose from the Mud and Sand brought down by the Rhine and the Maes ; nor is this unlikely. Prusia also and the adjacent Countries daily become larger by the Sea's retiring.

PROPOSITION X.
To explain the Origin or Rise of Sand-Banks.

BY Sand-Banks we understand large Collections or Cliffs of Sand in the Water, standing up above the Chanel of a River, to such a Height as to hinder the Passage of Ships. The Dutch Sailors call them een Droogte, een Banck, een Riss; the Portuguese, Abrothes, and Baixes. They differ not from Rocks, only that Rocks are hard, folid, and coherent in their parts ; whereas Sand-Banks consist of grains of Sand, that stick more loosely together. Tho these two are often confounded :

THESE

« AnteriorContinuar »