This awkward circumstance induced the Harbour Board, in 1770, to call Mr. Smeaton to their councils. After a careful examination, he ascertained that no fewer than 268,700 cubic yards of sand and mud had already silted up, every tide bringing in a fresh quantity and depositing it in the tranquil water of the harbour, which possessed no natural scour to carry it away. In order to create such a scour, Smeaton proposed the construction of an adequate number of sluices, fed by an artificial backwater. He showed that Ramsgate harbour, having a sound bottom of chalk, was excellently adapted to insure the success of such a scheme; and pointed out that if the silt could thus be set in motion, the tide, running diagonally upon the harbour mouth, would easily carry it away. The proposition of our engineer, in detail, was as follows:-- To enclose two spaces of four acres each, provided with nine draw-gates: namely, four upon the westernmost, and five upon the easternmost basin, the whole pointing in three different directions; two towards the curve of the west pier, four towards the harbour mouth, and three towards the curve in the east pier. To give the sluices all possible effect, he recommended the construction of a caisson, shaped somewhat like the pier of a bridge, which, being floated to its place, and then sunk, might serve to direct the current right or left, according to circumstances. After some discussion, the trustees resolved to adopt Smeaton's plan; but as it was not carried out in strict accordance with his intentions, another failure occurred, necessitating a recourse for the second time to his advice. Among the improvements which he now recommended was the construction of a new dock, the first stone of which was laid in July 1784. In the course of the excavations numerous springs were tapped, and these breaking through the pavement with which the dock had been laid, Portland stone was substituted, in blocks of considerable size. These, too, proved of no avail, and Smeaton was again sent for, with the result that the execution of all further works connected with the harbour was put into his hands. The dock was rebuilt; a timber floor was laid throughout in the most complete manner possible; an additional thickness was given to the walls; the east pier was rebuilt of stone, and carried out into deep water to a further extent of 350 feet. In constructing this extension, Smeaton first employed the diving-bell in building the foundations, employing a square iron chest, weighing about half a ton. It measured four feet six inches in height and length, and three feet in width. Two men could work together in its interior, and these were supplied with a constant current of fresh air by means of a forcing-pump placed in a boat which floated above them. [Sidenote: Works at Ramsgate.]