Fig. 1. Fig. 2. Fig. 3. Fig. 4. Fig. 5.

Published by A. Constable & Co. 1819. adjust themselves, either by the gravity of the material alone, or jointly with the loosening and spreading operation of the water.

The noblest attempt of this sort ever made in Britain was that of W. A. Madocks, Esq. M. P., to unite the counties of Merioneth and Cardigan by a mound across an estuary and embouchure of the Glasslyn two miles wide. Mr Madocks had, in 1802, succeeded in protecting from spring tides, by a wall or bank of the first species, 1800 acres of good alluvial soil, which he let at from 30s. to 50s. per acre; and his enterprising spirit induced him to contemplate the idea of gaining the whole bay or mouth of the stream, extending to nearly 4000 acres of alluvial and sandy earth, overflowed in great part by every tide. Besides the mere gaining of the land, this patriotic improver had another object in view; that of uniting two maritime points in two counties which at that time were separated by a day's journey; and, by effecting this, he would, at the same time, have rendered practicable a new line of road from Worcester along the top of this embankment, through a creation of his own, called the town of Tre Madoc, to the newly-formed harbour of Porthdynllcyn; by which 40 miles would have been saved to the public between Dublin and London, and 50 between Dublin and Bath, &c.

After consulting various engineers, the first operation was begun in 1807, and consisted in forming an immense bridge of flood-gates in the solid rock of the shore; as such a bridge and gates could not be formed in any part of the mound. The use of this was to admit the exit of the river. This done, the mound was commenced from both shores, and rocky, sandy, and clayey materials thrown down in the direction of the mound, and left to take their own slope. The greater part of these materials were argillaceous rock broken into small pieces, which being mixed with clay the mound would have been of the strongest texture. As the work proceeded, an iron rail-road was laid along the top of it, and extended to the quarries and excavations, by which means much labour was saved. In the course of three years the work was brought within fifty yards of meeting in the middle, but was found extremely difficult to close from the rapidity of the influx and reflux of the tide. This difficulty, however, would have been overcome, and the proposed improvement effected at little more than the estimated cost, L. 20,000, had not the various and extensive projects in which the proprietor was at that time engaged, led him into pecuniary difficulties which put an end to the undertaking, and, as is usual in such cases, called forth popular clamour against the plan. It is but justice, however, to those concerned to state, that the very plan now put in execution was contemplated above a century ago by Sir Hugh Middleton, who then wrote to a friend, that, if he were not so deeply engaged in the scheme of bringing water to London, he should certainly engage in it.

Very little has been written on the subject of embankments, as a separate branch of art, by British authors. Dugdale's work is entirely historical and topographical. But the writings of Smeaton, Young, Gregory, &c. contain the general principles on which is founded the art of embanking, and every other operation connected with water.

(A.A.A.)