Chapter XXXIII: Appendix: No. I (6)

Fig. 1. Plate XIII., is the first entire course, which measures 42 feet in diameter. The dove-tailed method of connecting the solid part of the Light-house here delineated, extends to the height of the entrance-door, as will be further understood by examining the section in Plate XVI. The outward stones of this course are of a lighter shade, being intended to represent the granite blocks, while the central part of a darker shade, represents the sandstone. The thirteen small square or cubical stones in the Plan of this course, shew the upper sides of the joggles, sunk half into the one course, and penetrating half into the superincumbent one, acting as so many steady-pins, calculated to guard against any force tending to affect the fabric horizontally. By tracing the bounding-lines of the stones, from the centre to the circumference, it will be observed, that the whole are connected by means of a system of attachments technically termed Dove-tailing, by which the stones may be said to hook laterally into one another, forming a vertical bond of connection; but it is on _the gravity of the materials_ that the chief dependence is placed for the stability of the fabric. The small circular dots, of which there are four in the centre-stone, and two in each of the others, shew the position of the oaken trenails, measuring 1¾ inch in diameter, and varying in length from 16 to 26 inches, so as to pass through the upper or last laid course, and penetrate 6 inches into the course immediately below. Besides these circular holes, others of an oblong form were cut in the joints, as will also be observed from the Figure. These last were for the reception of wooden wedges, driven in pairs perpendicularly into the joints of the stones, with a view to bring the dove-tailed parts to a uniform bearing, before the joints were grouted with mortar; the bond throughout the building being carefully preserved, by placing the perpendicular joints over the middle of the stones immediately below, being what is technically termed “Breaking-band,”--a system universally attended to in good masonry.

Fig. 2. represents the upper side of the 27th course, or first of the Stair-case, which measures 6 feet 4 inches in diameter within walls, and 19 feet 8 inches over walls. This course is elevated 32 feet 8 inches above the Rock at the foundation of the first stone, as will be seen in the section of Plate XVI. Here the granite casing is discontinued, and sandstone only is in future used. It will be observed, that the same system of dove-tailing is attended to in the stair-case as in the solid: this unavoidably occasioned the working of the stones into very awkward forms, and required the utmost precaution in landing them on the Rock with safety.

The parts of this course which are not shaded, shew the plan of the entrance-door, passage, and circular void of the stair, crossed by the radiating lines of the steps, as also the form of some of the stones of the top of the solid. _a a_ represent the base of a column of cast-iron, which renders the drop-hole for the machinery continuous from the floor of the oil-store down to the level of the passage, and so through the centre of the solid, as shewn in the section Plate XVI.; _b_ is a small stove placed in the stair-case; _c_ is the position of the Inner door, of brass, as shewn in Fig. 2. Plate XIX., the upper part of which is glazed with plate-glass, to preserve the light of the stair-case; _d_ is the position of the entrance-door, which is fashioned agreeably to the circular form of the building, and is strongly bound with the brass-hinges, as also shewn in Figs. 1. and 2. of Plate XIX.

Fig. 3. is the 39th course of the building, and first of the provision-store, and is 45 feet 11 inches above the foundation. This apartment measures 11 feet 9 inches in diameter within walls, and 18 feet over walls. From the floor to the roof the height is 8 feet 7 inches. Here the dove-tailed system, excepting at the end joints, and in the centre stones of the floors, was laid aside. At this level another system of connecting the courses was adopted, by means of a zone or belt, which was raised or worked upon the upper bed of the stones, and fitted to a corresponding groove in the course laid immediately above, as may be seen by tracing the diagrams representing the habitable parts of the house. This zone or belt, together with the horizontal plan of the floors, form the chief distinctive differences between the Designs of the Edystone and Bell Rock.

Fig. 3. The parts in this Figure which are not shaded represent the two windows of this apartment with the landing at the top of the stone stair-case. _a a_ represent the storm-shutters, which will be more fully seen in Plate XIX. _b b_ are the outer glazed windows; _c c_ the inner glazed windows; _d_ the open trap-ladder, with its brass hand-rail, leading to the light-room-store; _e e_ the cast-iron coal magazine; _f f f f_ the water-cisterns, of cast-iron, lined with a mixture of pitch and sand, and containing each 150 gallons; _g g g g_ the four cast-iron magazines, for containing the provision casks, and various implements; _h h_ the machinery, placed on a level with the top of the water-cisterns, for raising the stores from the entrance-door of the building to the Light-house; _i i_ is the hole perforated through the wall for the passage of the chain for lifting the stores, the operation of which will be better understood by examining Plate XVI.; _k_ the cast-iron stage upon which the light-keepers stand when they work the machinery for taking up the stores; _l l_ the cast-iron steps leading to the stage _k_.

Fig. 4. is a plan of the floor of the light-room store, being the 48th course, which is 55 feet 10 inches above the foundation. This apartment, within walls, measures 11 feet 10 inches, over walls 16 feet 10 inches, and its height is 8 feet 7 inches. The shaded part of the floor marked _a a a a a a a_, represents the copper oil-cisterns, coated with tin, calculated to contain one whole year’s stock of oil, or about 1100 gallons. This apartment being chiefly occupied with these cisterns, there is only one window in it; _b_ is the trap-ladder, and shews also the manhole, measuring 3 feet in its greatest length and 2 feet in breadth; _c_ the store-room door; _d d_ the position of the oaken pannelled partitions, which separate and inclose the store-room from the stair.

Fig. 5. being the kitchen floor, forms the 57th course, which is elevated 65 feet 8 inches above the foundation. This apartment measures 11 feet 11 inches in diameter, over all 16 feet, and its walls are 8 feet 9 inches in height. This room, in the position of its windows, manhole, and trap-ladder, is similar to what has already been described in reference to Figs. 3. and 4. In Fig. 5, _a_ is the door leading to the apartment below; _b_ the door leading to the trap-ladder of the apartment above; _c c_ the oaken partitions, formed into lockers, which shut off the stair from the apartment; _d_ is the cast-iron kitchen range or fire-place, which stands free and unconnected with the walls, forming a connected piece of pannelled work, extending from the floor to the ceiling; _e_ is a strong cast-iron fender, and also a receptacle for the ashes; _f f_ copper coal-boxes, formed into seats, on each side of the fire-place; _g_ the cook’s table and locker; _h_ the handle of the pump, by which water is raised from the provision-store or the second floor below; _i i_ other lockers, also formed into seats.

Fig. 6. is the bed-room floor, or 66th course of the building, and is elevated 75 feet 8 inches above the foundation; it measures 11 feet 11½ inches in diameter, and over all 15 feet 6 inches; the walls are 9 feet in height. The windows, manhole, trap-ladder, doors, and oaken partition are similar to what have already been described in the floors below; _a_ shews the position of the aperture for the cast-iron funnel leading from the kitchen-chimney through the several apartments to the cupola of the Light-house; _b b_ the bed-frames, forming two bed-places in breadth, which are three tiers in height, reaching from the floor to the roof, and capable of accommodating six persons; _c c_ lockers on each side of the beds, for the use of the four light-keepers.

Fig. 7. the next in order is the floor of the Strangers’-room or Library, being the 75th course of the building, which is 85 feet 11 inches above the foundation. The diameter of this floor is 12 feet, it measures 15 feet over walls, and the height of the roof, at the centre, is 11 feet 1 inch. The walls, windows, and other particulars of this apartment are nearly similar to those formerly described; _a_ is the cast-iron funnel leading from the kitchen-chimney; _b b_ the oaken framed book-case; _c_ the tube through which the machinery-rope is conducted by the side of the walls of the several apartments, to the ceiling of the Provision-store.

Fig. 8. is the Light-room floor, or 86th course of the building, which is elevated 97 feet 9 inches above the foundation; within walls the floor measures 11 feet in diameter, over walls 13 feet 6 inches. The stones of the floor of this apartment, as will be observed, extend from the centre stone to the circumference of the balcony, varying from 7 feet to 7 feet 6 inches in length. The parapet-wall of the light-room, as will be seen from the Plate, has its outward face of an octagon form, but is worked circular within. In the several courses of the parapet, the principle of the zone or belt in the beds of the stones is still continued, and also the dove-tail of the end joints. The Light-room measures from the floor to the top of the stone work, or sole of the glazed sash-frames, 6 feet. _a_ is the circular aperture for the cast-iron smoke-tube leading from the kitchen-chimney; _b b_ is the manhole of this floor, having its landing towards the centre of the apartment, instead of being close to the wall, as in the several floors below. To have formed the length-way of the man-hole of this floor along the wall, would have occasioned the cutting of the stones in the dome-roof of the Library, in a manner hurtful to the strength of the building, which was conveniently avoided by introducing a platt in the ladder, instead of ascending more directly as by the trap-ladders of the floors below; _c c_ is the case of the revolving-machinery, which gives motion to the Lights; _d d_ is the drum or barrel, with its connecting wheels, on which the rope is coiled, from which the weight is suspended; _e_ the position of the upright shaft for supporting the chandelier on which the reflectors are ranged, which is put in motion by its connecting train of machinery. The dotted lines marked _f f_ shew the direction of the grooves cut in the floor for the horizontal shafts, which derive their motion from the machinery, and work the hammers of the two alarm-bells placed on the balcony; _g g_ the bell-hammers with their cases; _h h_ the bells, weighing each 5 cwt., which are tolled during the continuance of foggy or snowy weather; _i i_, &c. are the screwed batts of brass, forming the fixtures of the balcony-rail; _k_ the Light-room door communicating with the balcony, which measures in the clear 5 feet in height, and 1 foot 10 inches in breadth.

Fig. 9. is a plan of the Lantern, showing the position of the trimming-path, and reflector-frame. The height from the foundation to the sill of the sash-frame is 102 feet 6 inches, and from thence to the lining of the cupola 13 feet four inches. _a_ is the smoke-tube leading from the kitchen to the cupola; _b b b b_ the cast-iron grated trimming-path, on which the light-keepers stand when they trim the lamps; _c c_ the reflector-frame or chandelier, on which three tiers of reflectors are ranged; _d_ the upright shaft; _f f_, &c. the position of the fountains for the reflector-burners, _g g_ the position of the shades of red-coloured glass, by which the light is distinguished; _h_ the iron trap-ladder communicating with the trimming-path.

PLATE XIV.

MOVEABLE BEAM CRANE.

_MOVEABLE BEAM CRANE &c._

_Drawn by A. Slight_

_Eng^d. by A. Wilson_

_PLATE XIV._]

[Sidenote: Pl. XIV.]

Fig. 1. is an Elevation of the Crane. In cranes of the common construction, the beam is a fixture, and is placed at right angles to the upright-shaft; but in the machine represented in this Plate, its attachment is at the lower extremity of the crane, where it is moveable up and down upon a journal or bolt. This crane is therefore termed a Moveable-beam-crane. The moveable property of the beam, in so far as the writer knows, is new, and possesses the advantage of laying any stone within its range perpendicularly on its site. This, from the dove-tailed form of the stones at the Bell Rock, rendered it essentially useful to this work, to which a crane of the ordinary construction could hardly be said to be applicable. At the Edystone Light-house this operation was performed by means of Triangular-sheers; but, from the greater extent of the Bell Rock works, and their greater depth in the water, such means must have rendered the process of building extremely tedious.

In reference to this Figure, _a a a_ is the upright shaft of the crane; _b b_ the cast-iron foot into which the lower journal of the shaft was stepped; _c_ the cap into which the upper journal works, and into which two of the hooks _d d_ of the four guy-ropes _x x x x_ were entered, for commanding the top of the upright-shaft. From the immersed state of these cranes, while the building was low in the water, a guard-plate was introduced, and bolted to the cap, which laid hold of a collar raised round the journal, to prevent the cap from being unshipped by the waves; _e e_ is the moveable beam, formed and built of two strong pieces of oak timber, connected in the centre by a serpentine row of bolts. This beam was mounted at the upper and lower extremities with strong cast-iron plates; _f_ marks the cast-iron sheers or cheeks, fixed to the bottom of the upright shaft, into which the moveable beam works upon the journal or bolt _g_.

In order to direct the strain of the main purchase-chain _h h h h h h_ passing over the cheek pulley _i_ fixed upon the shaft, and to prevent its effect from bringing home the moveable beam _e e_ to the upright shaft, a martingale or tail-block _l_ is introduced and made fast to the shaft at _m_. When the purchase-chain is not in action, the block _l_ is suspended from the small chain at _n_, which prevents it from falling too low, and thereby deranging the position of the purchase-chain. That the beam may be made applicable to laying the stone marked _k_, at the foot of the crane, or at the utmost reach of the beam, a chain or purchase marked _o o o_, is introduced, which also passes over a cheek-pulley _i_ on the opposite side of the shaft. By this additional apparatus the beam is capable of being elevated or depressed at pleasure. The handle marked _p p_, with its pinion and connecting wheel _q q_, and larger wheel _r r_, together with its intermediate pinion, form the main purchase, and exert a force calculated at the rate of about 98 to 1. When a smaller weight was to be lifted, and greater speed wanted, the handle was transferred to the axle _s_, whose pinion being always in gear with the wheel _r r_, produced an accelerated motion, with a power in the ratio of 20 to 1; at the same time, the handle _t t_, with its pinion in action with the wheel _u u_, worked the beam _e e_, so as to lay a stone perpendicularly with the greatest facility within any part of its range.

Fig. 2. is the cast-iron tripod, used as a prop to the moveable beam, when applied as a lever, for lifting the crane; _a a a_ mark the foot, _b_ the cross head, having a stud which works into a circular hole perforated in the top of the tripod. By this simple apparatus, the crane could be moved and shifted either perpendicularly or horizontally, with a facility which added greatly to the conveniency of the operations. When the tripod was applied to use, it was placed under the heel-plate of the moveable beam marked _v_, and when rested upon it, the beam became a lever of great power.

Fig. 3. is an Elevation of the Working-gear of the Moveable Beam-Crane. _a a a_ is the upright-shaft, as in Fig. 2.; _b b_ the cast-iron foot; _c_ the cap with its guard-plate; _d d_ guy-hooks for commanding the top of the shaft; _f f_ the edges of the sheers or cheeks, for the heel of the moveable beam; _g_ the bolt or journal on which the beam is moveable; _h h_ the purchase-chain; _i i_ the cheek pulleys; _o o_ the moveable beam-chain; _p p_ the two main purchase-handles; _q q_ the smaller wheel of the main purchase; _r_ the greater wheel, with the intermediate pinion _w_, connected with the axle _s_ of the wheel _q q_. The handles and pinion _t t_ are connected with the wheel _u u_, for working the moveable beam-purchase; _x_ is the drum or barrel for the main purchase-chain; _y_ the barrel of the purchase-chain of the moveable beam.

Fig. 4. is a Section, shewing the connection of the purchases for working the beam, and lifting the weight: the axle _s_, of the lesser wheel _q_, with its intermediate pinion _x_ of the main-purchase, work through the eye or centre of the wheel _u u_, and barrel _y_ of the beam-purchase. _x_ and _r_ refer to the corresponding letters in Fig. 3.

Fig. 5. is an Elevation of the Winch-machine. The machines, used for the various purposes of landing the materials and raising them to the top of the building, were framed or made of cast and malleable iron. _a a a a_ are the cheek plates or frames in which the axles of the machinery work. Those employed upon the Rock were fixed down by means of spear-bolts, to four bats, as shewn at _b b_; but in other situations they were fixed by straps of iron to beams of timber. The cheeks _a a a a_ were connected by means of three strong bolts passing through hollow tubes, which butted against the inner sides of the cheeks and kept them in their places. The large wheel marked _c c_ measures 3 feet 3 inches in diameter, and the smaller wheel _d d_ is 2 feet 6 inches: these, with their respective pinions, of 6 inches in diameter, exerted powers respectively of 20 to 1, and 98 to 1, being of a size similar to the cranes; as one set of wheel and pinion patterns were made to answer the several machines employed at the work. Letter _e_ is one of the handles connected with its axle and pinions, which, at pleasure, is made to work with a double or single purchase, by simply slipping the axle out and into gear with the larger and smaller wheels.

Fig. 6. is a Plan of the Winch-machine. _a a a a_ is the sole of the frame, shewing the bat-holes for fixing it down; _c_ is the large, and _d_ the small wheel, with its axle; _e e_ the handles, with their axle and pinions _f f f_; letter _g_ is the barrel attached to the axle of the large wheel, with part of the purchase-chain; _h h_ is the axle of the small wheel and intermediate pinion; and _i i_ one of the hollow pipes through which the bolts pass for connecting the two cheeks or frame of the machine together.

Fig. 7. refers to a machine fixed to the walls of the Provision-store, for raising the stores from the railways to the entrance-door, as pointed out in Plate XVI. _a a a a_ a section of part of the walls of the Provision-store, in which a hole _x x_ is perforated, and lined with a copper tube, for the passage of the purchase-chain; _b_ is the pulley, with its case, over which it works; _c c c_ is the frame of the machine; and _d_ the handle, with its bevelled pinion. The distinctive feature of this apparatus is the vertical motion of the barrel, by which it receives and discharges the chain always at the same point; the direction also of the chain may thus be altered almost close to the barrel, which in this case was the chief desideratum. To effect this purpose, the barrel is made to move vertically upon the axle _f_, by means of a screw _y_, upon its lower end, which works into a corresponding screw-rack _g_; in its operation, the wheel _h h_ is worked by the cylindrical upright-pinion of brass, marked _i_. The two pairs of bevelled wheels, supported upon the small intermediate frame _l_, are introduced, for applying a double or single purchase, according to the load to be raised.

PLATE XV.

FOUNDATION-PIT, OR EXCAVATED SITE OF THE LIGHT-HOUSE.

_FOUNDATION PIT OF THE LIGHTHOUSE._

_Drawn by J. Slight._

_Eng^d. by W. H. Lizars_

_PLATE XV._]

[Sidenote: Pl. XV.]

Fig. 1. is a Plan of the site of the Light-house, and of the ground or _imperfect course_, in readiness for receiving the first _entire course_ of the building, represented in Plate XIII. Fig. 1. The dark shaded figures delineated upon the Plan in Plate XV. represent the stones of the ground-course, consisting of 18 detached pieces, which vary in their forms according to certain irregular holes in the Rock. From the same cause, the stones of this imperfect course vary in thickness from 6 to 18 inches. The situation of the Foundation-stone will be seen from its having the year of our Lord 1808 cut upon it, as noticed at page 237. The four exterior stones, which are cut somewhat of a dove-tail form, are of a lighter shade being granite, while the 14 interior pieces, being of sandstone, are of a darker shade. The dark shading on the northern side of the Plan represents merely the shadow of the higher parts of the Rock round the excavated site of the Light-house.

Fig. 2. is a Section of the Foundation-pit, upon the line A B, varying in depth from 18 inches to 5 feet, representing also the dip or inclination of the strata; while the dotted lines above show the form of the lower part of the Light-house.

PLATE XVI.

ELEVATION AND SECTION OF THE LIGHT-HOUSE.

_ELEVATION AND SECTION OF THE BELL ROCK LIGHT HOUSE._

_Drawn by D. Logan_

_Eng^d. by W. H. Lizars_

_PLATE XVI._]

[Sidenote: Plate XVI.]

Fig. 1. is an Elevation of the Light-house, with the brazen-ladder leading up to the entrance-door. Part of the Rock and railways are seen, on which several figures are at work, landing stones from a boat, as at low-water of spring-tides. The small aperture bored through the outward wall between the door and the window of the Light-room-store, is for the passage of the chain for raising the stores, as described in Fig. 7. Plate XIV. The two leaves of the entrance-door are shewn folded back upon the walls. The first window above the door seen in this view of the building, is that of the Light-room store; the second is one of the bed-room windows; and the third is in the Library; immediately over this are the cornice and balcony-rail, through which last is seen the Light-room door, with the alarm bells on each side. Through the glazed sashes, the reflectors are seen arranged upon the chandelier, connected with the revolving apparatus. On a level with the lower part of the cupola is the signal-ball. On the ensign-staff a flag is hoisted, with a light-house in the field, used as a complimentary signal in the service of the Northern Light-houses.

Fig. 2. is a Section of the Light-house, shewing parts of the Rock and ground-course. _a a_ show part of the railways; _b_ the brazen ladder leading to the entrance-door, which is marked _c_. In the central part of the solid of the building is shewn the cylindrical drop-hole _d d_, which passes through the centre-stones of each course, and forms part of the range of the machinery-weight. On each side of the drop-hole, throughout the solid, and walls of the stair-case, are seen the stone-joggles _e e_, &c. as they occur in the several courses, and were noticed in the description of Plate XIII. Figs. 1. and 2. At the entrance-door a figure is represented receiving stores into the house. Immediately behind him, one of the leaves of the inner door, of brass, appears folded back into its recess in the wall, the upper part being glazed with plate-glass, for the admission of light to the stair-case. In continuation of the range of the machinery-weight above alluded to, and extending between the solid and the ceiling of the provision-store, a column of cast-iron, marked _x x_, passes up through the well-hole of the stair. The provision store, with which the stone stair communicates, is formed by a scarsement of the walls at the level of letter _f_, on which the water-cisterns, lockers for provisions, and coal magazine, are ranged. Over these a stage or platform of cast iron is erected, on which a figure is seen at work at the machinery for raising the stores from the railways to the entrance-door of the house. The purchase-chain of this machine passes over the pully at _g_, as described in Plate XIV. Fig. 7.

The next apartment in ascending the oaken trap-ladders leading through the several apartment, is the Light-room-store, marked _h_, occupied chiefly with 7 copper oil-cisterns, which are strengthened with polished brass bars forming the front into pannels. This, and the several apartments above are partitioned off from the stair with a pannelled framing of oak. The kitchen _i_, over the store-room, is chiefly occupied with the fire-place, (though not seen in this section), which, with its cast-iron pipe or chimney ascending through the different rooms to the cupola, stand free, or are not embedded in the walls of the house. On the right-hand side of the kitchen a figure is seen at the cook’s table and lockers; and on the left are seen the oaken trap-ladder set close to the wall, and the lockers, by which it is partitioned off from the apartments. A similar arrangement takes place in the bed-room marked _h_, occupied chiefly with the oaken bed frames, described in Fig. 6. Plate XIII. The apartment marked _l_ is the Strangers’-room or Library, which contains a small collection of books. The furniture is of oak timber, executed in Mr Trotter of Edinburgh’s best style. The walls were painted by Mr Macdonald of Arbroath, in handsomely decorated pannel-work; and from the dome an antique bronze lamp is suspended. The upper apartment _m_ forms the Light-room and Lantern, rendered fire-proof, as every thing is of stone or metal, excepting a small oaken table and chair for the use of the light-keeper on watch; accented _m´_ is the copper-ball, shown as hoisted for the signal “All is Well.” The reflecting apparatus and revolving machinery with which the Light-room is occupied, will fall to be described under Plate XX.

PLATE XVII.

BALANCE-CRANE.

_BALANCE-CRANE._

_Drawn by J. Slight_

_Eng^d. by A. Wilson_

_PLATE XVII._]

[Sidenote: Pl. XVII.]

Fig. 1. is an elevation of the Balance-Crane, constructed for building the upper part of the Bell Rock Light-house, when the guy-ropes of the Moveable Beam-crane, became “too taunt,” as sailors express it, or were too near the perpendicular, thereby rendering the machine unstable. To remedy this, the crane alluded to was kept in equilibrium by a back-weight of cast-iron, so adapted as to counteract the varying load upon the working arm or beam. The elevation here represented is the same in principle with that used at the Bell Rock, but differs somewhat in form, agreeably to more recent improvements made in order to adapt it to the erection of the Carr Rock Beacon. _a a_ is the cast-iron foot or socket, into which the upright central column _b b_ is stepped, being a tube of cast-iron put together in convenient lengths, with flush joints, after the manner of spiggot and faucet, fitted by turning and boring. The centre column of this machine might have been carried to any suitable or convenient height, by adding length to length, as the building advanced, without once moving the foot; but at the Bell Rock, not more than three lengths of from 6 to 9 feet were generally in use. _c c_ represent a malleable iron cross-head, which was stepped into the void of the central shaft or column, when the body of the crane was to be elevated. This operation was accomplished simply by hooking the main-purchase and traveller-chains into the eyes _c c_, when the machinery of the crane was employed with great facility as a locomotive power for lifting itself; _d_ is a stone supposed to be suspended in the purchase-chain; and _e_ is the back-weight or counterpoise, which, at pleasure, was moved horizontally along the balance-beam marked _f_, consisting of two plates or bars of malleable iron; _g_ is the working-beam, of similar construction; _h-h_, _h-h_, _h_, _h_, are four of the eight main and secondary suspending ties of malleable iron, applied from above, in order to leave the lower part of the crane unobstructed. This afforded great conveniencey particularly at the Carr Rock, and also at the erection of the Melville Monument of Edinburgh, where the space for the workmen was extremely circumscribed, the shaft of the column not being more than 10 feet 6 inches in diameter towards the top. The main ties _h-h_, _h-h_, at the lower extremity, were made fast by the same bolt which passes through the pulleys _f_ and _g_, while the upper ends were bolted into a collar, which is seen clasping the central column at _i i_. This collar is fitted with four friction-rollers, one of which is seen at _k_. _l l_ shew two of the four principal rods or bars of malleable iron for connecting the Crane, and answering the purpose of a king-post to the ties _h-h_, _h-h_, of the frame-work; _m m_ mark two of the four braces forming a connection between the main ties and arms or beams of the crane. The cheeks _n n n_, which contain the train or series of wheels of the crane, are of cast-iron. In the formation of these cheeks they present as little obstruction to the workmen as possible, while, at the same time, they embrace the various journals or axles of the machinery. The upper part is connected by a square framed collar of malleable iron, seen at Fig. 5. fitted with friction rollers, and, like the collar above alluded to, works round the central column. This lower collar is connected with the cheeks of the crane by studs passing through them, and fixed by means of screw-nuts. The lower part of the frame is in like manner connected with the upright shaft, by a collar, which is moveable upon friction-balls of cast-iron, contained in a circular race or chamber _o o_, a plan of which, shewing the balls, is given at Fig. 3. The whole machine thus fitted, is supported upon the central shaft by means of the cutter or spear-bolt _p_. The winch handle marked _q_, is that with which the main-purchase chain _r_, passing over the pulley _s_, is worked, from which the stone _d_ is suspended. Connected with the main-purchase, a wheel, marked _w_, of 30 inches diameter, is worked by a pinion of 5 inches, mounted upon the axle of the handle _q_, producing a power or force in the ratio of 18 to 1; this power may at pleasure be increased by throwing another pinion on the same axle into gear with the wheel marked _n´_, of 16 inches diameter.

The handle _u u_ is connected with the main-traveller _s_, balance-chain _v v v_, and their traveller _x_, to which the back-weight _e_ is appended. The main-traveller wheel _y_ measuring 36 inches in diameter, with its pinion of 5 inches marked _u_, exerting a power in the ratio of 21 to 1, serves to work the main-traveller. On the same axle with the pinion _u_, is another pinion, working two wheels, as seen in Fig. 4, which gives motion to the balance-traveller. These two combinations of wheels are so arranged, that, by working the small levers _m_ and _z_, they can with facility be thrown in and out of gear, so as to work the traveller either together or separately. The whole weight of the Balance-crane, here represented as resting upon the oaken beams A A B, on one of the floors, weighed about three tons; but the balance and working beams having latterly been made of malleable iron, and the other parts of the machine considerably lightened, it did not exceed more than two tons in weight when used at the Carr Rock.

Fig. 2. The cast-iron foot of the Crane is necessarily very ponderous, and weighs about half a ton. The toes _a a a a_ extend about 5 feet; _b b b b_ are the bat-holes for fixing it down, in case of its at any time getting off the balance, but, in practice, these bats were seldom applied. When the crane was supported over the void or central holes left in the floors during the progress of the work, the toes were clasped to the oaken beams A A B, formerly noticed, represented as resting on one of the upper floors of the building, B, in Fig. 1., being a cross section of the lower beam, with its levelling-block; _c_, the socket for the central column, or upright shaft, is 10 inches in diameter at the upper side, and diminishes to 9 inches, that the column may become fixed into it by the pressure of the machine.

Fig. 3. _o o_, in reference to Fig. 1., represents the collar-chamber, filled with cast iron friction-balls, upon which the body of the machine rested, and traversed horizontally with the greatest facility.

Fig. 4. is a perpendicular section taken across the cheeks and wheels with a view to shew the train of the machine more fully. _a a_ is the foot; _b b_ two lengths of the central column, or hollow cylinder, with their spiggot and faucet joint in the middle, shewing also that the metal is about an inch and a quarter in thickness; _c c_ the cross-head, referred to in Fig. 1.; _i i_ the upper collar, shewing its connection _l l_ with the king-posts or main rods; _n n_ the cast-iron cheeks, with the lower collar, and the chamber for the friction-balls; _o_ the cutter or spear-bolt, which supports the whole machine; _u u_ the traveller handles, the main-purchase handles not being embraced in this section; _y y_ the wheels and pinion of the main traveller; accented _y´ y´_ the wheel and pinion of the balance-traveller _x x_. In the central part of this figure, the barrel or drum _x_ of the traveller-chains is seen, and also the middle collar _x_, with its friction rollers.

Fig. 5. is a plan of the body of the Crane, in reference to Fig. 1. _b_ is a cross section of the central column, seen in connection with the upper collar _d d_; with a stone suspended from the end of the main-beam; _e e_ the back weight suspended from the balance-beam: _f_ and _g_ the extremities of these two beams; _h´ h´ h´ h´_ four horizontal braces, extending from the cast-iron cheeks to the middle of the beam. Letters _n n n n_ the cast-iron cheeks of the body; _q q_ the main purchase-handles; _r_ the main-purchase chain; _s_ its traveller; _t t_ the traveller-chain; _u u_ the traveller handles; _v_ the balance traveller-chain; _x_ its traveller; _w w_ the main-purchase wheels; _y y_ the traveller wheels; _z_ the lever, for stopping the main traveller-wheel.

Fig. 6. is a plan of the frame work of this machine: _b_ is the upright column, with the upper malleable iron-collar, shewing its connection with the king-posts _l l_ of Fig. 1.; _f_ and _g_ are the extremities of the main-purchase and balance-beams; _m´ m´_ the horizontal rods connecting with the main-ties; _h h_, &c. the main ties; _h´ h´_, &c. the horizontal braces; _n n n n_ the cheeks or frame of the wheels and machinery, with the two great bolts marked _n´ n´_, by which the frame was principally connected; these bolts being passed also through the interior ends of the balance and working beams.

PLATE XVIII.

GENERAL VIEW OF THE WORKS.

[Sidenote: Pl. XVIII.]

This Plate gives a Perspective view of the Works at the Bell Rock, taken by Carse, at low-water of spring-tide, from on board the Light-house Yacht, in the month of July 1810, at the distance of about half a mile in a southern direction from the Rock, and is here reduced from a picture in the possession of the writer. In the fore-ground a boat is introduced, approaching the Rock with a party of strangers, and another is leaving it, supposed to be receiving orders from a figure on the Rock, who is pointing towards her. In the back-ground, the shipping belonging to the work is introduced, viz. the Tender, a Schooner, and the stone-vessels Smeaton and Patriot, with the Floating-light. In the distance, the hills of Fife and Forfar are seen, but the entrance to the Firth of Tay is intercepted by the beams of the Beacon-house. Between the Light-house and Beacon, or in the direction of the chain and stone suspended from the Wooden-bridge, the ruins of the Abbey of Aberbrothwick are seen. The operation of landing the stones with the sheer-crane at Duff’s Wharf, toward the right, is seen; and also one of the moveable beam-cranes, in a working position, at Pitmilly Wharf, on the left.

The principal lines of the railways, with waggons, and a variety of operations which are in progress, form a very busy scene upon the Rock. On the praam-boat’s deck, toward the left of the picture, Captain Wilson, the landing-master, is represented with a speaking-trumpet in his hand; and at the foot of the Beacon-house, Mr Francis Watt, foreman mill-wright, is supposed to be giving directions about some operations. On a level with the entrance-door of the Light-house, the bridge of communication is situate, and four blocks of stone are seen, in progress of being raised from the railways to the top of the building, viz. one is suspended from the winch-machine upon the bridge, another from the beam projecting out of the window of the Light-room store, a third from the bed-room, and a fourth from the Balance-crane, which last is about to be laid upon the parapet-wall of the Light-room. Here the operations are going forward under the direction of Mr Peter Logan, foreman builder. In the open gallery of the Beacon-house, Mr Dove, the foreman smith, is seen at work, with the smoke of the respective fires of the forge and cook-room. The tackle, distended in a diagonal direction, from the balcony of the Light-house, to the mortar-gallery of the Beacon, shews the mode of raising the mortar-buckets. The figure on the small scaffold suspended from the balcony, shews the method of pointing the walls with Roman cement.

PLATE XIX.

ENTRANCE-DOOR, WINDOWS, HINGES, AND THUNDER-ROD.

_ENTRANCE DOOR, WINDOWS, HINGES AND THUNDER ROD._

_Drawn by J. Slight_

_Engraved by R. Scott_

_PLATE XIX._]

[Sidenote: Pl. XIX.]

Fig. 1. represents part of the outward wall A A A A, and entrance-door, one leaf or half of which is open, and the other shut; _a_, one of the handles for opening and shutting it, connected with a thumb-latch; _b b_ the bolts for securing the door when shut; _c c c c_ the hinges; _d d d d_ the brass guard-plates at top and bottom of the door, for defending the timber. The door is framed of fir-wood, and measures 6 feet 4 inches in height in the clear, besides the brass-checks upon which it shuts at top and bottom, which are of 2 inches in depth, as shewn at _e_ in Fig. 1., and also by an end view in Fig. 2. The two leaves form a common breadth of 2 feet 10 inches in the clear. A cornice of brass is formed on the lintel of the door answerable to an eaves-drop, in which a friction roller _h_ is placed, for the chain of the crane, with which the stores are raised. The door, when shut, finishes flush with the building, and is therefore of a circular form, framed and double lined, the whole being put together with white-lead paint: each leaf measures 5 inches in thickness at the hinge side, and diminishes to 2½ inches at the meeting edges, as will be understood by examining the section in Fig 3. When the leaves of the door are thrown open, they are kept in their places by catch-hooks of brass, to prevent gusts of wind from shutting them suddenly; _f_ shews a moveable handle or piece of brass rail, within the passage, for laying hold of in stepping off the brazen ladder to enter the house; _g_ shews the upper extremity or highest step of the ladder, which terminates at the sill of the door.

Fig. 2. shews the relative position of the outer and inner entrance-doors, in which _a a a_ is an end view of the former; _b b b b_ a front view of one of the leaves of the inner brass door; _e e_ the outer door check, faced with plates of brass; _f_ the moveable handle or rail, for the greater conveniency of entering the threshold; _g_ the termination and upper step of the brazen-ladder, attached to the building, for communicating with the Rock. _h_, section of the cornice and friction-roller. The passage being only 2 feet 10 inches in breadth, the rails or moveable handles _f_, on each side, are made to slide into brass sockets _i i_, sunk into the walls, and, like the inner door, are flush with the wall when not at use. _k k_ the sockets for the centre-pin hinge of the inner-door.

Fig. 3. is a cross section of one of the leaves of the entrance-door, shewing the position of the brass-case of the hinge-bat, as it lies in the building. A A part of the walls, B B part of the side-walls of passage, C C part of the surface of the outward wall. _a a a a_ is the brass-case, containing the Lewis-bat-tails or palm of the hinge, (described in Plate XI. Fig. 3.); _b b b b_ the working-tails; _c c_ the outside lining; _d d_ the inside lining; _e e e_ the frame-work of the door, with the bolts and nails connecting the hinges; _f_ the joint of the hinge, shewing the journal pin-hole; _g_ the half-check joint of the door.

Fig. 4. represents a front view of the door-hinges, lettered in reference to Fig. 3. _a a a a_ is the brass box or case, which is built into the wall for containing the palm-end of the Lewis-hinge; _b b_ is the exterior or working tail, with its screw bolt and nail holes; _f f f_ the double-joint and slip-pin.

Fig. 5. is a cross section of the Lewis-box on the line A B of Fig. 4. with its dove-tail feathers; _a a a a_ shew the parts of the Lewis-bat _b c d_, as it lies in the box, which is built into the wall.

Fig. 6. represents a longitudinal section of the box and palm of the hinge, shewing its position, in reference to the cross section in Fig. 5. _a a a a_ is the brass box; _b_ and _d_ are the dove-tailed compartments of the palm; _c_ is the tongue or locking-piece; _e_ the pin hole, perforated in the locking-piece, for drawing the parts of the palm in the event of the joint wearing and requiring to be renewed; _f f_ is the slip pin-hole in the other two parts of the palm of the Lewis. The weight of one of the entire hinges of the door, with its Lewis-tail and brass-box was 56 lb., and consequently the four sets for the door weighed about 2 cwt.

Fig. 7. shews the elevation of one of the windows of the Light-house, with part of the exterior wall marked A A A A; one-half of one of the storm-shutters, marked _a a_, is closed, and the other marked _c c_, is open; _b_ is a bar of brass, which folds across the window when the shutters are closed, and is used as a stretcher, for preserving them in their places when opened. It will be observed by comparing the close shutter _a a_ with the open one _c c_, that they are double or cross boarded; they are also fastened with hammered copper nails; _d_ is the clasp used as a handle, which also locks the shutter; _e e e e_ the ends of the dove-tailed hinges as they appear projecting through the walls; _f f f f_ the working-tails of the hinge, forming at the same time the guard-plate of the shutters, as described in Fig. 1. Letter _g_, upon the open shutter, shews one of the brackets connected with the stretching-bar _b_, for keeping them open, as will be better understood by examining the following Figure.

Fig. 8. is a plan of one of the window-sills, and a section of one of the storm-shutters, with part of the walls A A, shewing the position of the Lewis-bat cases; _a_ and _c_, the storm-shutters in an open state; _b_ the stretching-bar in its place, when the shutters are open; _e e_ the exterior ends of the Lewis-bats, with their cases _é é é é_, which are built into the wall, and, together with the other parts of the hinge, weigh about 28 lb., or 1 cwt. for each set, being one-half of the weight of the door-hinges; _g g_ the brackets connected with the stretching-bar; _h h_ the check in the wall for receiving the shutters; _i i_ the stiles or framing of the outer-window, which opens in two leaves; _k k k_ the framing and case of the inner window, which slides up and down in one sash; _l l_ the balance-weight of the inner-window.

Fig. 9. is a perpendicular section of one of the windows, shewing the triple mode of shutting them during stormy weather. A A a section of a part of the walls. _a a_, the storm-shutter; _h h_ the check in the building for its reception; _i i_ the frame of the outer-window; _k k_ the inner-window; _l_ the case into which the inner-window drops when not in use.

Fig. 10. A A is a section of part of the thunder-rod and outward wall. _a a_ shew part of the zones or bond-belts, noticed in Plate VII. Fig. 7., and Plate XVI. Fig. 2.; _b b_ the brass-bats let into the wall, for attaching the thunder-rod with the screws _c c_, which vary from 2 to 3½ feet apart; _d d_ the thunder-rod, made of the best gun-metal, and weighing at the rate of 7 lb. per lineal foot in the range of the sea, or from the Rock to the entrance-door, and from thence to the Light-room, at the rate of about 4 lb. per lineal foot; _e_ is the joint technically termed Half-checking, by which the pieces, of about 7 feet in length, are connected by two screws at each joint, as shewn in the section. This rod, which extends from the Light-room to the Railways, forms an exterior Conductor, while another, which is not seen here, is connected with the chimney, brazen ladder and railways, and completes the interior conducting process.

PLATE XX.

BALCONY AND LIGHT-ROOM.

_LIGHT-ROOM AND BALCONY._

_Drawn by W. Lorimer_

_Eng^d. by J. Moffat Edin^r._

_PLATE XX._]

[Sidenote: Pl. XX.]

Fig. 1. _a a_ represent the Balcony or walk round the exterior of the Light-room; _b b_, &c. the brass bats, made in the form of the paw of an animal, are used for supporting the balcony-rail; _c c_ the two Alarm-Bells; _d d_ the hammers by which they are tolled, during the continuance of foggy or stormy weather; _e e_ the case for defending the levers which work the hammers; _f f f_ the stone parapet-wall of the Light-room, of an octagon form on the outside, and circular within; _g g g_ the cast-iron sill of the lantern; _h h_, &c. the angular cast-iron pillars or mullions, formed by the junction of the contiguous parts of two of the sash-frames; _i i_, &c. the smaller upright bars, forming the astragals or principal divisions of the sash-frames; _k k_, &c. the grated cast-iron trimming-path; _l_ the smoke-tube, leading from the kitchen through the cupola or roof; _m_ the trap-ladder leading from the light-room-floor to the trimming-path; _n n_ the reflector frame or chandelier, on which are seen 8 of the reflectors marked _o o_, &c. with their oil-fountains _p p_, &c. the whole being framed or built upon the moveable upright-shaft _q_.

Fig. 2. is a section of the dome-roof of the library, the parapet-walls of the light-room, the lantern and its cupola. _a a_ is the balcony, shewing the position of the Alarm-Bells, and cast-iron rail; which last is made in the form of meshes, with a massive coping of brass; _f f_ the parapet-wall of the light-room; _g g_ the cast-iron sill of the lantern; _h h_, &c. the angular pillars or mullions; _i i_, &c. the astragals; _k k_ the grated trimming-path; _l l_ the smoke-tube passing through the cupola; _n n_, &c. the reflector frame, on which 20 reflectors, marked _o o_, &c. with their fountains _p p_, &c. are ranged; _q q_ the upright shaft upon which the reflector-frame is built, and which is connected with the revolving-machinery; _r r_, &c. the copper smoke-tubes from the respective reflectors; _s s_ the cross-bars supporting the upright shaft at _t t_; and _u u_ a copper receiver for any accidental drop from the upper or central ventilator marked _v´ v´ v´_, while the letters _v v v v_ mark the exterior line of the cupola; _w w_ the external cornice of the lantern, used as a gutter or eaves-drop, from which the rain-water is conducted off the roof in small pipes to the parapet-wall of the Light-room; _x x_ the handles which the light-keepers lay hold of; and _y y_ the exterior grated path on which they stand when cleaning the outside of the windows; _z z z_ the steps fixed to the parapet of the Light-room and lantern, by which they ascend to the cupola; _á á_ the copper-tube, used as a flag-staff; _b´_ the signal-ball, hoisted daily at the Light-house, between the hours of 9 and 10 o’clock in the morning, when “All is Well:” The ropes for raising this ball pass over two pulleys fixed in the top of the flag-staff, and are let down through the interior of it: _c´ c´_ part of the cornice of the building, shewing the mode of connecting the horizontal and perpendicular joints of the Library-roof; _d´ d´_, &c. shew the zone or bond-belt worked in the beds of the courses, as mentioned in the description of Plate VII. Fig. 7., Plate XVI. Fig. 2., and Plate XIX. Fig. 10.; _e´ e´_, &c. from the enlargement of the scale, shews more distinctly than any of the other diagrams, the mode in which the horizontal joggling of the joints of the Light-room and other floors of the building is accomplished; _f´_ the door leading from the Light-room to the balcony; _g´ g´ g´_ the case and machinery for causing the Reflecting-apparatus to revolve, so as to distinguish this Light from others upon the coast; _h´ h´_, &c. the connection-rods, with their various wheels of communication, for changing the direction, and giving motion to the Bell-hammers; _i´ i´_, &c. the brass tubes for supplying fresh air to the Light-room; _k´_ the Time-piece, set upon brackets fixed in the wall, for regulating the Revolving-machinery, and for the direction of the light-keepers in changing the day and night watches; _l´_ a bracket of cast-iron attached to the machinery-case, for supporting the foot on which the upright shaft works; _m´_ the bevelled wheels connected with the interior machinery and upright shaft, which can be thrown out and into gear at pleasure.