"The general size of our building stones being thus determined upon at a ton-weight, those would have been far too heavy to be expeditiously transferred and managed, even in the work-yard, unless our machinery rendered that easy, which would otherwise be difficult, without too great an expense of labour : and as the moving and transferring the pieces of stone in the work-yard would be greatly increased in quantity, by the very mode of attaining a certainty in putting the work together upon the rock ; this consideration made it still the more necessary to be able to load upon a carriage, and move the different pieces from one part of the yard to the other, with as much facility (comparatively speak ing) as if they had been so many bricks: for, that we might arrive at perfect certainty in putting the work ultimately together in its place upon the rock, it did not appear to be enough, that the stones should all be hewn as exactly as pos. sible to moulds that fitted each other; but it was farther necessary, that the stones in every course should be tried together in their real situation in respect to each other, and so exactly marked, that every stone, after the course was taken asunder, could be replaced in the identical position in which it lay upon the platform, within the fortieth part of an inch. Nor was this alone sufficient; for every course must not only be tried singly together upon the platform, and marked, but it must have the course next above it put upon it, and marked in the same manner, that every two conti guous courses might tit each other on the outside, and prevent an irregularity in the outline : and this indeed, in cact, amounted to the plattbrming of every course twice: so that, in this way of working, every stone must be no less than six times upon the carriage :-1st. When brought into the yard from the ship, to carry it to the place of deposition, till wanted to be worked-2ndly. When taken up and carried to the shed to he worked.—:3rdly. After being wrought. to be returned to its place of deposition.-4thly. When taken up to be carried to the platform.-5thly. When finished on the platfin•m. to he returned to its place of deposithm.—(ithly. When taken up to be carried to the jetty, to be loaded on board a vessel to go to sea.
It might, at first sight, appear superfluous to try the courses together upon each other, as the under and upper sides of all the courses were planes : and, in ease the work could have been put together upon the rock in the same way that common masonry generally is done, it would have been so : that is, if we could have begun our eonrses by setting the outside pieces first, then it would have been very practi cable to have regulated the inside pieces thereto ; but as our hope of expedition depended upon certainty in every part of our progress, this required its to be in a condition to resist a storm at every step : the outside stones therefore, uncon nected with the inner ones, would have scarce any fastening besides their own weight, and would be subject to the most immediate and greatest shock of the sea ; and, after com pleting the outward circle. the inner space would be liable to become a receptacle for water : the necessity therefore of fix ing the centre stone first, as least exposed to the stroke of the sea, and of having sure means of attaching all the rest to it, and to one another, rendered it indispensable that the whole of the two courses should be tried together; that if any defect appeared at the outside, by an accumulation of errors from the centre, it might be rectified upon the plat form.
"The moor-stone, though very hard with respect to its component parts, yet being of a friable nature, is extremely difficult to work to an anis (or sharp corner,) or even to be preserved, when so wrought by great labour and patience: that is, with sharp tools, and small blows; it therefore soon appeared to me, that we should make very rough and coarse work of it, if the finishing of the pieces were left to the workmen of the country where produced : for, though care fully wrought there in their place, yet in loading and unload ing from their carriages, and again putting on board, and unloading from the vessels, the arrises would be very subject to damage. Therefore, to have as much done in the country as possible, and to save weight in carriage (leaving the finish ing part to be done at home) rough moulds were sent for each size and species of stone, which were to be worked by them to a given parallel thickness, and with length and breadth enough, when so bedded, (as it is called) to be cut round all the sides to the true figure of the finishing mould : but they were to reduce them as near the size as they could safely do it by the hammer; and, that they might not leave an unne cessary waste, they were to be paid no more for either stone or carriage, than what the mould measured upon the thick ness given ; and if they were wanting of substance sufficient to make the figure complete, it should be at our option to reject them when they Caine home." Our author next proceeds to detail his experiments on cements ; but as they constitute no part of the building pro cess, the reader is referred to the articles CEMENT and Moit TAR, where the subject is duly considered.
On the 5th of June, 1757, the operations on the rock were recommenced, and by the 10th all the preliminary matters were settled ; so that " on Saturday, the llth of June, the first course of stone was put on board the Eddystone boat, (see Plate III. Figure 1,) with all the necessary stores, tools, and utensils. We landed at eight on Sunday morning, the 12th of June, and before noon had got the first stone into its place, being that upon which the date of the year 1757 is inscribed, in deep characters ; and the tide coming upon us, we secured it with chains to the old stanchions, and then quitted the rock till the evening tide, when it was fitted, bedded in mortar, trenailed down, and completely fixed ; and all the outward joints coated over with plaster-of-paris, to prevent the immediate wash of the sea upon the mortar. This stone, according to its dimensions, weighed two tons and a quarter. The weather serving at intervals, it was in the evening of Monday, the 13th, that the first course, consisting of four stones, was finished ; and which, as they all presented some part of their faces to the sea, were all of moor-stone.