Progress of the Bell Rock Works.
Drawn by J. Slight.
Engd. by W. Miller.
PLATE IX.
Pl. IX.
Fig. 1. shews the state of the works about the close of the second season, or year 1808, with two of the moveable beam-cranes, with their guy tackles and working gear, which will be more particularly described under [Plate XIV.] These are placed upon the top or fourth course of the building. In the fore-ground, part of the unfinished railways are seen, with waggons and artificers at work; and on the right the beacon is partly traced in faint lines.
Fig. 2. represents the state of the works in the month of August 1809, at the close of the third season’s work, when only one of the cranes was set upon the building; the other, as the work increased in height, and became less in diameter, was placed upon a temporary stool or prop of masonry, marked a a a a. This prop was found extremely useful, as, by elevating one of the cranes upon the top of it, the lift of the materials was divided, and brought more conveniently within reach of the higher crane, which at this period was about 30 feet above the Rock. In the fore-ground of this diagram, part of the circular track of railway round the building is seen. On the right, a part of the Beacon-house appears with the rope-ladder of communication, extending from the top of the solid of the Light-house to the mortar-gallery. On the rope-ladder a figure is represented walking from the Beacon to the Light-house, and a tackle, with its travelling pulley, is also stretched, for conveying the mortar-bucket, to the builders.
Fig. 3. represents a section of the void or habitable part of the Light-house as it appeared in the month of August 1810, when the masonry was nearly completed. On the right is an elevation of part of the Beacon-house, but instead of the rope-ladder of communication, a bridge of timber is constructed. Letters a a represent the top of the solid, or level of the entrance-door of the building, from which the stair-case ascends to the several apartments. Resting on the sill of the door at b, is seen one of the beams for supporting the road-way of the bridge, and below this, at the point c, is the step of one of the diagonal braces of the bridge, where it is inserted about 6 inches into one of the courses of the solid masonry. Regarding the frame-work of the bridge, it may only further be noticed, that the road-way was chiefly suspended from the king-posts d d.
Letter e represents a block of stone, in the act of being raised from the rail-way on the Rock, to the level of the bridge, by means of the crab or winch-machine marked f, with wheel and pinion apparatus; the pully of the working chain is suspended from the cross beam g, which rests or is supported upon the top of the king-posts. One of the figures on the bridge at h, is in the act of pushing forward a truck cart or waggon i, to receive the stone e; when raised through the aperture in the road-way, it is then lowered upon this waggon, and removed towards the building within the sphere of the several purchases or machines, by which it is transported to the hands of the builders.
Letter k refers to a life-buoy, and a coil of rope, kept in readiness upon the bridge, in case of accident by the fall of any of the people from the building or beacon while the Rock was covered by the tide. l l represent two of the fire-buckets, which were hung round the beacon, under the projection immediately above the cook-room. The stone marked e, in the second stage of its progress towards the top of the building, is now seen immediately above the lintel of the entrance-door, the purchase chain, by which it is suspended, passes over a pulley at m, attached to the beam n n, which is projected from one of the windows of the Light-room store, where it is supported upon a block of timber, so as to admit of the chain passing under it. The further end of this beam, being within the Light-house, was bolted to an upright post marked o o, and the whole apparatus was worked by means of the crab or winch-machine at p, similar to that upon the bridge marked f f. The stone e is next supposed to have gained the height of the floor of the bed-room, where another apparatus, similar to those at f and p, is placed. Here a figure is represented at q, with a rod in his hand, in the act of hooking the chain of the balance-crane into the Lewis-batt, fixed in the stone e, still in its progress to the top of the building. r r r represent the strong oaken beams placed on the floor of the library, on which the foot of the cast-iron balance-crane is supported. s s two of the four diagonal braces of oak timber, bolted into a collar-piece of cast-iron, clasping the upright shaft of the crane at t t, and butting against the upright stretchers at u u; intended as a security to the walls, in case the balance-crane should at any time get out of equilibrium. The two figures marked v v, are represented as working the balance-crane, and are supposed to be standing upon a moveable platform x x, suspended from the body of the crane by rods of iron y y. This platform or stage, with the artificers upon it, being moveable with the body of the crane, gave great facility and conveniency to those who wrought it. z is the balance-weight, moveable by the machinery along the balance-beam of the crane, to keep the whole in a state of equilibrium, according to the varied load suspended from the working or opposite beam; accented á represents the moveable block or cross-head of malleable iron, with two eyes, into which the chains of the crane were hooked, when the body (comprehending the machinery and beams) was to be elevated upon the shaft in the progress of building. But the cross-head, together with the other apparatus of this machine, will be better understood by examining [Plate XVII.], with its letter-press description. b´ b´ b´ represent the form and position of the Light-room in dotted lines; c´ the mortar-bucket made to traverse upon the guide-rope d´ d´, stretched between the building and the mortar-gallery of the Beacon; the end of the rope attached to the building being fixed to the stanchion é, inserted into one of the Lewis batt-holes, on the balcony of the Light-room.