"The whole of the building was, indeed, a piece of ship wrightry : for it is plain, from the preceding account, that the interposed beds of moor-stone had nothing to do with the frame of the building, it being entire and complete ex clusive thereof : the beds of moor-stone could therefore only be considered in the nature of ballast, and amounted, from what has been before stated, in the whole, to the weight of above two hundred and seventy tons.
"All the windows, shutters, and doors, were composed of double plank, cross and cross, and clinked together ; which f fling into a rebate when shut, their outside formed a part of the general surface, like the port-holes in a ship's side ; without making any unevenness or projection in the surface. There were, however, two projecting parts terminating this frustrum ; one at the top, and the other at the joining with the rock ; the utility of which seems to render them indis pensable. They had each a projection of about 9 inches. The top projection, which is in the nature of a cornice, con sisted of a simple bevel, and the use of it was very great ; for in times of storms and hard gales of wind, when, accord ing to the accounts of Mr. Winstanley's building, the broken sea rises to a far greater height than the whole structure, it would be likely to break the windows of the lantern, unless there was something to throw it off, as their use does not admit of any defence by shutters. Therefore Mr. Rudyerd applied this simple cornice, judging it sufficient to have the effect of throwing off the sea in times of storms ; and yet not so much projection as that the sea, at the height of 71 feet above the foot of the building, could have power enough to derange it.
"The bottom projection, which has been called the kart, and which fills up the angle formed between the uprights and the sloping surface of the rock, so as to guard the foot of the uprights from that violence of action which the waves naturally exert when driven into a corner, was certainly a very useful application ; but I am inclined to think it was not there upon the first completion.
" Upon the flat room of the main column, as a platform, Mr. Rudyerd fixed his lantern, which was an octagon of 10 feet fi inches diameter externally. The mean height of the window-frames of the lantern above the balcony floor, was nearly 9 feet ; so that the elevation of the centre of the light above the highest side of the base was 70 feet ; that is, lower than the centre of Mr. Winstanley's second lantern
by 7 feet ; but higher than that of his first by 24 feet. The width of Rudyerd's lantern was, however, nearly the same as that of Mr. Winstanley's second ; but, instead of the towering ornaments of iron work, and a vane that rose above the top of the cupola no less than 21 feet, Mr. Rud yerd judiciously contented himself with finishing his building with a round ball, of 2 feet 3 inches diameter, which termi nated at 3 feet above the top of his cupola. The whole height of Mr. Rudyerd's lantern, including the ball, was no more than 21 feet above his balcony floor ; whereas that of Mr. Winstanley's including the iron ornaments, was above 40.
"The whole height, then, of Mr. Rudyerd's light-house, from the lowest side to the top of the ball, was 92 feet, upon a base of 23 feet 4 inches, taken at a medium between the highest and lowest part of the rock that it covered.
1 have endeavoured to describe this building with all possible minuteness, because it aflbrds a great and very useful lesson to future engineers. We are sure that a building such as Mr. Winstanley's was not capable of resisting the utmost fury of the sea, because, in four years after its completion, it was totally demolished thereby : but Mr. lIudyerd's building having sustained the repeated attacks of that element, in all its fury, for upwards of forty-six years after its completion ; and then being destroyed, not by water, but by tire ; we must conclude, it was of a construction capable of withstand ing the greatest violence of the sea in that situation. And by withstanding it there, this light-house proves the prac ticability of a similar erection in any like exposure in the known world.
"I have seen a paper in the hands of one of the present proprietors, upon which were put down the quantities of materials said to have been expended in the construction of this building : viz., 500 tons of stone, 1,200 tons of timber, SO tons of iron, and 35 tons of lead ; and of trenails, screws, and rack-bolts, 2,500 each." Mr. Smeaton then proceeds to detail the means by which the erection of the new lighthouse fell into his hands, his several interviews with the proprietors, and various other pre liminary occurrences, among which the following remarks on the difference in structure of stone and wood, and on the bond of the stones to the rock and to each other, are particularly worthy of notice.