His predecessors had lost much valuable time from the difficulty of landing on the rock, and of working on it continuously for any considerable period. To obviate this, Smeaton decided on mooring a vessel within a quarter of a mile of it, which should accommodate the workmen and their tools, and enable them to seize every favourable opportunity of putting out their boat and carrying their materials to the Eddystone, instead of making a long voyage from Plymouth on each occasion.
With respect to the form of his intended erection, he resolved to adopt Rudyerd’s idea of a cone, but to enlarge the diameter considerably, and, on the whole, to keep before him as a model the trunk of a stately oak tree.[27]
The first actual work done on the rock was in August 1756, but the autumn was mainly occupied in the transportation and preparation of the granite and other materials, and in excavating the steps or stages for the reception of the foundation.
Early in June 1757 Smeaton resumed his task with great energy and decision. On the 12th, the first stone was laid, weighing two tons and a quarter. On the next day the first course was finished, consisting of four stones. These were ingeniously dove-tailed together, and into the rock, so as to form a compact mass, from which it was impossible to separate any particular stone. The sloping form of the rock, remarks Mr. Smiles,[28] to which the foundation of the building was adapted, required but this small number of stones for the first course; the diameter of the building increasing until it reached the level of the rock. Then the second course, completed on the 30th of June, consisted of thirteen stones; the third, completed on the 11th of July, of twenty-five pieces; the fourth, on the 31st, of thirty-three. The sixth course was finished on the 11th of August, and rose above the general wash of the tide, so that Smeaton might fairly consider he had surmounted the greatest difficulties of his task.
Up to this level, the highest point of the rock, all the courses had been begun by the stones that were securely dove-tailed into the rock, and also made fast by oak wedges and cement. To receive these wedges, a couple of grooves were cut in the waist of each stone, from the top to the bottom of the course, an inch deep and three inches wide. We borrow from Smeaton’s own narrative his description of the manner in which each stone was laid:—
“The stone to be set being hung in the tackle, and its bed of mortar spread, was then lowered into its place, and beaten with a heavy wooden mall, and levelled with a spirit-level; and the stone being accurately brought to its marks, it was then considered as set in its place. The business now was to retain it exactly in that position, notwithstanding the utmost violence of the sea might come upon it before the mortar was hard enough to resist it. The carpenter now dropped into each groove two of the oaken wedges, one upon its head, the other with its point downwards, so that the two wedges in each groove would lie heads and points. With a bar of iron about two inches and a half broad, a quarter of an inch thick, and two feet and a half long, the ends being square, he could easily (as with a rammer) drive down one wedge upon the other; very gently at first, so that the opposite pairs of wedges, being equally tightened, they would equally resist each other, and the stone would therefore keep place. A couple of wedges were also, in like manner, pitched at the top of each groove; the dormant wedge, or that with the point upward, being held in the hand, while the drift-wedge, or that with its point downward, was driven with a hammer. The whole of what remained above the upper surface of the stone was then cut off with a saw or chisel; and, generally, a couple of thin wedges were driven very moderately at the butt-end of the stone; whose tendency being to force it out of its dove-tail, they would, by moderate driving, only tend to preserve the whole mass steady together, in opposition to the violent agitation that might arise from the sea.”
When the stone was firmly secured, the next step was to liquefy a certain portion of mortar; and the joints having been carefully pointed, up to the upper surface, this mortar or cement was poured in with iron ladles so as to occupy every empty space. The more consistent parts of the cement naturally fell to the bottom, and the watery were absorbed by the stone; the vacancy thus left at the top was repeatedly refilled, until all remained solid; then the top was pointed, and, where necessary, defended by a layer of plaster.
The whole of the foundation having thus been elevated to a proper level, some other means was required to obtain a similar amount of security for the substructure.