No. XCVI.
A way to make a sea-bank so firm and geometrically strong, that a stream can have no power over it; excellent likewise to save the pillar of a bridge, being far cheaper and stronger than stone walls.
NOTE.
The break-water erected by Mr. Rennie at Plymouth is, in its results, precisely what the noble author has here described. The plan of its construction is this: a mass of stone in blocks, of about three feet in diameter, is thrown promiscuously into the sea, and left to find their own base, the extremity of which is generally about seventy yards. This sea-wall has been carried about eight hundred fathoms in length, and the total expense attendant on its erection is estimated at £1,150,000. In 1766, Mr. Smeaton also applied loose stones to strengthen the middle piers of London bridge, which was the means of preserving that venerable structure from the almost certain ruin which threatened it.
But the most economical sea-bank yet constructed was executed at Rye, in 1804, under the superintendence of the Rev. Daniel Pape, curate of that place.
The dam or bank was formed in its lower part in two parallel ridges close to each other, like the double roof of a house, which were covered over, first with straw, and then with hazel faggots about thirteen feet long; and the whole was then pinned down with piles, which were united to each other at their heads by pieces put across the direction of the faggots. When this bank was completed, Mr. Pape formed another bank, on the top of the preceding, by filling up the interval between the two ridges, and covering the whole in the manner above described. All this was accomplished in one tide, and when completed it fully answered the purpose for which it was intended.