BOX GROYNES
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capital outlay. The area behind the corresponding English coast-line, relatively of greater value, is left without systematic defence against the inroads of the sea.
   The principal types of groynes on the English coast, other than those already described, may be summarized as follows:—
   Type No. / consists of piles about 12 inches square, driven from 8 to 10 feet apart, planked on one side, and with a single waling on the other, and held down by land ties secured by rows of short piles to right and left. The planking has to be carried a few feet below the lowest beach level, and the piles are sometimes stiffened by having short strips of railway metal bolted to them.
   In Type No. 2 the vertical timbers of the groyne proper are carried by transverse sole pieces attached to two rows of piling, the uprights being in pairs and the planking placed between them, with rakers as in the last instance. This is an undesirable type of construction.
   Type No. j is similar to Type No. 1, but instead of timber piles old railway metals in pairs, with planking between, are used, and the ties are also of iron. This type is not to be commended, as it is difficult of adjustment, the iron corrodes, and after a heavy gale is apt to become twisted out of shape.
   Another system is a modification of the Case groyne, already described, its essence being to embed the uprights of the piles in concrete pockets. The lower half of the uprights of the groynes in St. Margaret’s Bay are so embedded, the upper half of the piling being driven in the ordinary way. Sometimes raking timbers are only fixed on one side of groynes of this character. Some years ago the patent Dowson groyne was exploited, and a few such groynes were erected. The principle of this is to substitute for planking a steel mesh between the piles, the theory being that the shingle would be caught on the mesh and the weight of the water allowed to pass through the groyne. These groynes, though highly ingenious in design, have not commended themselves in practice.
   A distinct form of groyne is the box groyne, which consists of two rows of piling, both being planked, and the intervening space filled either with beach or rock. This type is doubly