The large masses were first lowered, and then smaller stones, quarry rubbish, &c., to fill up the interstices. The structure was completed in 1841, with the use of 3,670,444 tons of stone(62) and at a cost of something like a million and a half of money. A distinguished French engineer, M. Dupin, who visited the works during their progress, describes in glowing terms the admirable arrangements, the order and regularity visible in all the proceedings. “Those enormous masses of stone,” he remarks, “which the quarrymen strike with heavy strokes of their hammers; and those aerial roads of flying bridges, which serve for the removal of the superstratum of earth; those lines of cranes, all at work at the same moment; the trucks, all in motion; the arrival, the loading, and the departure of the vessels, all this forms one of the most imposing sights that can strike a friend to the great works of art. At fixed hours the sound of a bell is heard, in order to announce the blasting of the quarry. The operations instantly cease on all sides; all becomes silence and solitude. This universal silence renders still more imposing the noise of the explosion, the splitting of the rocks, their ponderous fall, and the prolonged sound of the echoes.” “The waves,” said Rennie, “were the best workmen” in the construction of a breakwater of rough stones, and on the whole his belief was confirmed, for the storms by which his great work was assailed rather helped than hindered it, by showing the most desirable slope on the sea-side, while comparatively little damage was done. The slope of the stone barrier was, however, by their force changed very greatly. An inclination of three to one was altered to about five to one, and Rennie had recommended that the authorities should take a lesson from nature and finish the breakwater according to her teachings. “It would appear,” says Mr. Smiles,(63) “that Mr. Whidbey, the resident engineer, contrived to finish most of the exterior face at a slope of only three to one, as before; and that it stood without any material interruption until several years after Mr. Rennie’s death. By that time nearly the whole of the intended rubble, amounting to 2,381,321 tons, had been deposited, and the main arm, with 200 yards of the west arm, making 1,241 yards in length, had been raised to the required level. The work had arrived at that stage when it had to experience the full force of another terrific storm, which took place on the 23rd of November, 1824. It blew at first from the south-south-east and then veered round to the south-west, and the effect of this concurrence of winds was to heap together the waters of the Channel between Bolt Head and Lizard Point, and drive them, with terrific force, into the narrow inlet of Plymouth Sound. This storm was not only greatly more violent, but of much longer duration than that of 1817. When the breakwater could be examined it was found that out of the 1,241 yards of the upper part, which