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Thirdly, The benefits derived from warping, are many andgreat; they are described by Mr Brown in the same work»“ Warp, ” says he, “ consists of mud and salts. Letting infresh water, would not therefore be called warping, but simplyflooding. Though the latter may be useful, it is not equal towarping, as the sediment left by the latter operation, is not onlymore abundant in quantity, but richer in quality. In some situa-tions, an inch of sediment is sometimes deposited over the sur-face by a single tide. Cherry-cob sands were reclaimed by warp-ing; they are supposed to be at least four yards thick of warp;the fertility of such land is great. Sometimes they are ploughedand cropped 12, 14, or 16 years in succession, before they aresown down in grass. Indeed, it is proper to take at least sixcrops from warped land. When laid down in grass seeds, theland is not warped, for the salts and mud would destroy such acrop. Potatoes, however, have been often raised on warpedland, though in its original state of inferior quality. ”
Land that will thus admit of cropping for 6, 12, or even 16years in succession, must be rich indeed ; and when it is consider-ed, that this fertility is entirely owing to warping, there is noneed to say more to prove the vast advantages of that process.It cannot be doubted, however, that the warp of some riversmust be much more valuable than that of others. The valuemust depend on a variety of circumstances; on the quantity ofsalt contained in the mud—on the proportion of calcareous mat-ter washed up from the sea, or down the rivers—and on thenumber of common sewers from large cities, which enter intotheir course. Each of these ingredients must add value to thewaters of any river; and the greater the proportion of all ofthem which any river contains, the more valuable must the warpor sediment be which is deposited by it.
Lastly, The flotations and foils fuited for warping are limited!no land, but fuch as is on a level, or below that of fpring tides, canbe improved by this procefs : yet of this defcription of wafte andredeemable land, there are feveral hundred thoufand acres along theIhores of the Britilh empire. In almoft every firth in the three king-doms, fuch lands may be feen ; extenfive trafts of barren fands,which are overflown by fpring tides, are of this defcription ; how-ever barren they may be when firft redeemed from the fea by bank-ing, they might be reclaimed and rendered fertile by warping.
There is another kind of foil, of equal extent, that might be re-claimed in the fame way. Along the Britilh Ihores, many modeshave been overwhelmed by the deep; they are indeed now coveredwith fea fand, fleich and fhells.
No veftige of their original Hate now remains, excepting thetrunks of immense trees peeping through the furface of the fand.The fubfoil, however, is itill mofs, to the depth of 6, 8, or 10 feet ;m many cafes, there is only one, two, or three inches of fand on
VOL. II. C