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bine, that no animal above the fize of a cat could penetrate; especially when it is of fuch a depth as I have recommended.

The first hint I got for a fence of this kind, was from a small thicket of brush-wood that I had planted for ornament, pretty much in the manner above described; which, in a fhort time, became fo much interwoven with the sweet briar, that it was impoffible to find any access into it.

But, as all kinds of trees and fhrubs, if

planted very clofe upon one another, become naked at the root when they arrive at any confiderable fize, care fhould be taken to prevent it from ever coming to that state, by cutting it down whenever it is in danger of being open at the root.

And, as it would be improper ever to leave the field entirely defenceless, it is a great advantage to have the belt as broad as it conveniently may be, fo that the one half of it may be a fufficient fence

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by which means, we will have it in our power to cut down the infide and the outfide of this belt alternately, fo as still to keep the thicket young, and never to want, at any time, a fufficient fence. The brush-wood that this would afford at each cutting, would, in almost every fituation, yield fuch a revenue as might do much more than indemnify the proprietor for the rent of the ground that was occupied by the fence. And, if the field was in fuch a situation as required fhelter, fome trees might be allowed to grow to their full fize about the middle, without any inconvenience, if the belt were of a fufficient breadth.

§ XXVIII.

§ XXVIII.

Of fecuring the Banks of Rivers, fo as to prevent the Earth from being washed away by the Violence of the Stream.

There is yet another fpecies of fencing, as ufeful as any of thefe already mentioned, which is in general much lefs understood, and more difficult to execute properly, that deferves here to be taken notice of; viz. the method of fecuring the banks of rivers from being washed away by the violence of the ftream, and of preventing the damages that may otherwise be occafioned by the fwelling of the waters.

It frequently happens that, when a river runs in a bed of rich vegetable mold, the least accident that may chance to divert the

ftream

ftream towards any particular part of the bank, causes it to fweep away large tracts of fine ground, to the very great detriment of the proprietor, as well as the public; as this fine mold is ufually carried to the sea, and the place that the water leaves to occupy the new bed that it thus forms for itself, is generally of a much worse quality, consisting chiefly of ftones, fand, and gravel.

In fome cafes, where the whole force of the current is quite close to the bank, and the materials neceffary for fencing it are not to be found, it may perhaps be impoffible, or very difficult, totally to prevent this evil; but, for the most part, it admits of a cure that can be obtained at a pretty moderate expence.

If you carefully obferve the banks of rivers, you will readily remark, that these ravages are always moft confiderable at those places where the bank rifes perpendicularly to a pretty confiderable height above the

ordinary furface of the water, and never at thofe places where the banks fhelve down gradually towards the water's edge. For, when the river is fwelled to a great height by rains, and runs with a force and rapidity greater than usual, it ftrikes violently against these perpendicular banks that directly oppofe its course; and, as these are com→ pofed of earth quite bare and uncovered, they are easily foftened by the water, and quickly washed away; fo that the upper part of the bank being thus undermined, falls by its own weight into the river, and is carried off in prodigious quantities. But, when the river rifes to any confiderable height, it gently glides along the surface of those parts of the bank that shelve gradually downwards to the water's edge; which, being defended by the matted roots of the grafs with which it is covered, scarcely fuftains any damage at all; and is nearly the fame after the water

has

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