" Figure 11. The upright of the capstan-roll, axis, and middle pm-t of the bar to the same scale. At I, 2, is shown the capstan in full, to the scale of the yard ; and 3, 4. and 5, mark the direction of the rope, which, from a snatch-block at 5, ascends to the upper block of the main tackle, sus pended from the top of the shears, as per Figure 6, wherein the in-hauler guy-tackle is marked 7, being a runner and tackle ; and the out-hauler, marked S, are simple blocks. The guy-rope, 7, 0, was attached to a ring-bolt, passing through a large rough stone, rammed into the ground ; its place being shown at 6, (Figure 2,) the out-hauler guy 8, 9, being secured in the same manner.
"The marble rocks, marked 10, go round the point of the bay.
" Figure 12. The elevation of the upper part of the jetty-head in front, with the shears upon it, to an enlarged scale ; more particularly to show the smaller parts.
B. The front pair of piles, to which the cross-beam c D is bolted, and, in like manner, to each pair of piles.
" E, E. The ends of the longitudinal half balks.
" F F. The cross joists.
"a, G. The ends of the flat rails that the wheels of the carriage run upon.
" n I1. A single cross timber, serving as a stop to the car riage at the end.
" a. The snatch-block.
"IV. B. The scantlings are marked, because this jetty or scaffold, erected as slight as possible for a temporary purpose, sustained the whole tonnage of the Eddystone matter, in and out, without derangement.
" The detached Figure 13, gives a part of the top of one of the shear legs, showing how they were plated on each side to support the bolt of the anchor from betiding, and thereby from splitting the poles.
"Figure 14. The enlarged figure of the runner and tackle (marked 7, in Figure 6.) " K. The runner-block of one large single pulley.
"L am. The tackle-blocks, of three pulleys each, making a purchase of twelve, equivalent to the great blocks.
"Figure 15. An upright diagonal view of the main-tackle blocks; having six pulleys each upon two pins ; the larger tier being ten, and the lesser eight inches diameter. This figure distinctly shows the method of salvagee strapping; being double, that the pins being readily knocked out, they could be frequently greased without trouble.
" X. B. The shears, blocks, and tackles, used at Bay, were mmly the same as at the rock ; and one pair of main tackle blocks at each place, with the same pulleys, went through the whole service ; but the pins were renewed each season, and sometimes oftener, being of wood, on account of the salt-water ; but were frequently greased. The main
tackle-fill at each place was no larger a rope than of three inches circumference ; being a white rope, remarkably soft laid, hauser-fashion; and which is of material consequence.
" Plate V II I.—Descriptions of supplemental matters, having reference to the Eddystone huihling.
" Figure 1. An upright font view of the great tackle, or purchase-blocks of twenty sheaves, or pulleys.
" Figure 2. A side view of the same blocks, referring to Figure I. The advantage of, this construction is, that the tackle-141h or ruuning-rope, may be reeved through the twenty sheave-1, without it Cross or interference ; so that the standing part, or beginning, may be in the middle of the upper block : and the ending, hauling part, or fan, upon the middle pulley of the same block. The weight therefore being suspended by twenty ropes instead of six, as in common triidc-blo•ks, the tackle-tidl, as relative to a given weight, may be lesser or of fewer yarns in the same proportion ; which renders the whole much more flexible and pliant, and which, together with the advantage derived from the mode of Icevirag, occasions their rising and falling nearly upon a parallel. Beginning in the middle, the greater sheaves are reeved as fir as can he on them ; from thence going to the first of the smaller sheaves, and reeving the whole of them throughout, you then go to the first of the greater sheaves, before lett unreeved, ending upon the middle sheave of the upper block ; and thus arises a diminution of the friction from the more equal distribution thereof " Figure :1. An upright section of the store-room, to an enlarged scale ; in it is shown the centre whereon the upper store-room floor was turned ; and in like manner the rest.
" Figure 4. The plan relative thereto, the letters being common to both.
" o b, c d. Two of the sixteen ribs, formed to the circle of the vaults of the floors. These ribs are connected at their ends by two wooden rings, e g le I k; the former supported by fim• posts, three of which are shown in their places, and the latter by eight ; of which only one is shown on the right hand, and one on the left, to avoid confusion. The rings are each made to take asunder, that after striking the centre they might be got out of the room.