PRESERVATION OF IRON.
At a more recent period Mr. Stevenson experimented at the Bell Rock Lighthouse in the same way on twenty-five different kinds of malleable iron, with the result that all of them were soon affected, and that galvanised specimens resisted oxidation from three to four years, after which the chemical action went on as quickly as in the others.
CHAPTER X.
BRIDGES.
1811–1833.
Marykirk, Annan, Stirling, and Hutcheson stone bridges—High-level bridge for Newcastle—Timber bridge of built planks—Winch Chain Bridge—American bridges of suspension—Runcorn Bridge—Menai Chain Bridge—New form of suspension bridge.
Mr. Stevenson’s stone bridges over the North Esk at Marykirk, and the Nith at Annan ([Plate VI.]), are good specimens of road bridges of moderate extent; and his bridge over the Forth at Stirling, and Hutcheson Bridge over the Clyde at Glasgow ([Plate VII.]), are structures of a larger class.
Of the latter, Mr. Fenwick, of the Royal Military Academy, Woolwich, in the preface to his work on the Mechanics of Construction, published in 1861, says,—“The London and Waterloo Bridges, in the metropolis, which rank among the finest structures of the elliptical arch, and Stevenson’s Hutcheson Bridge at Glasgow, which is one of the best specimens of the segmental arch, together with many others, have supplied me with a variety of problems for illustration.”
PLATE VI.
ANNAN BRIDGE
1824.
MARYKIRK BRIDGE
1811.
W. & A. K. Johnston, Edinburgh.
PLATE VII.
HUTCHESON BRIDGE, GLASGOW.
1828.
STIRLING BRIDGE.
1829.
W. & A. K. Johnston, Edinburgh.
PLATE VIII.
DESIGN FOR HIGH LEVEL ROAD BRIDGE
AT NEWCASTLE ON TYNE.
1828.
TRANSVERSE SECTION.
W. & A. K. Johnston, Edinburgh.
The Hutcheson Bridge was completed in 1832. The masonry of the piers was laid at the level of seven feet below the bed of the Clyde, on a platform of timber, on piles eighteen feet in length. I found by a section made in 1845, after a lapse of thirteen years, that the level of the river had been lowered, in consequence of the deepening of the river Clyde by the Navigation Trustees, no less than eleven feet, and even with that amount of scour the bridge was, and might long have remained, a safe structure. But immediately above its site there is a weir which dams up the Clyde and forms a lake, or almost still pool, in the river’s bed for several miles. It was determined, in the interests of navigation, to take powers to remove the weir, and on its removal the bridge could, no longer be pronounced safe; it was also resolved to take powers to replace the Hutcheson by the new Albert Bridge, designed by Messrs. Bell and Miller.
* * * * *
Mr. Stevenson has also left behind him some traces of originality of design in bridge-building.
In 1826 he gave a design to the Corporation of Newcastle for raising on the existing bridge another roadway, on a high level, to communicate with the higher parts of the town, as shown in [Plate VIII.], being the idea since so successfully carried out on a large scale by the late Mr. Robert Stephenson in his justly celebrated “high-level railway viaduct.” Mr. Stevenson’s design, as will be seen, consists of piers of masonry raised on the piers of the old bridge supporting a roadway of cast iron. The upper bridge being continued across the quays on either side of the river, and joining the roadways leading towards the south and north by easy gradients, avoided the circuitous and dangerous route of the old post road through Newcastle.
For timber bridges Mr. Stevenson also proposed, in 1831, a new form of arch of a beautiful and simple construction ([Fig. 16]), in which what may be called the “ring-courses” of the arch are formed of layers of thin planks bent into the circular form and stiffened by kingpost pieces, on which the level roadway rests. This form of bridge was afterwards very generally employed for railway bridges before the discovery had been made that for such works, structures of iron were, in the end, more economical than timber.
Fig. 16.
In 1820, he proposed to the Cramond District of Road Trustees, with a view mainly to lessening the cost of the work, a form of suspension bridge applicable to spans of moderate width, in which the roadway passes above the chains, and the necessity for tall piers is avoided. The suspension bridge over the Rhone at Geneva, and other bridges, have since been constructed on this principle.
In 1821 Mr. Stevenson wrote an article on Suspension Bridges for the Edinburgh Philosophical Journal; and as it contains a description of this new form of construction, as well as some historical information relative to bridges on the suspension principle, a few extracts from the paper may not be without interest:—
“Winch Chain Bridge.—The earliest bridges of suspension of which we have any account are those of China, said to be of great extent; Major Rennell also describes a bridge of this kind over the Sampoo in Hindostan, of about 600 feet in length. But the first chain bridge in our own country is believed to have been that of Winch Bridge over the river Tees, forming a communication between the counties of Durham and York. This bridge is noticed and an elevation of it given in the third volume of Hutchison’s Antiquities of Durham, printed at Carlisle in 1794. As this volume is extremely scarce, owing to the greater part of the impression having been accidentally destroyed by fire, the writer of this article applied for a sight of it from the library of his friend, Mr. Isaac Cookson of Newcastle-upon-Tyne. The following account is given by Hutchison at p. 279:—‘The environs of the river (Tees) abound with the most picturesque and romantic scenes; beautiful falls of water, rocks and grotesque caverns. About two miles above Middleton, where the river falls in repeated cascades, a bridge suspended on iron chains is stretched from rock to rock over a chasm nearly sixty feet deep, for the passage of travellers, but particularly of miners; the bridge is seventy feet in length, and little more than two feet broad, with a hand-rail on one side, and planked in such a manner that the traveller experiences all the tremulous motion of the chain, and sees himself suspended over a roaring gulf, on an agitated and restless gangway, to which few strangers dare trust themselves.’ We regret that we have not been able to learn the precise date of the erection of this bridge, but from good authority we have ascertained that it was erected about the year 1741.
“American Bridges of Suspension.—It appears from a treatise on Bridges by Mr. Thomas Pope, architect, of New York, published in that city in the year 1811, that eight chain bridges have been erected upon the catenarian principle, in different parts of America. It here deserves our particular notice, however, in any claim for priority of invention with our transatlantic friends, that the chain bridge over the Tees was known in America, as Pope quotes Hutchison’s vol. iii., and gives a description of Winch Bridge. It further appears from this work that a patent was granted by the American Government for the erection of bridges of suspension in the year 1808. Our American author also describes a bridge of this construction, which seems to have been erected about the year 1809, over the river Merrimack in the State of Massachusetts, consisting of a catenarian arch of 244 feet span. The roadway of this bridge is suspended between two abutments or towers of masonry, thirty seven feet in height, on which piers of carpentry are erected which are thirty five feet in height. Over these ten chains are suspended, each measuring 516 feet in length, their ends being sunk into deep pits on both sides of the river, where they are secured by large stones. The bridge over the Merrimack has two carriage-ways, each of fifteen feet in breadth. It is also described as having three chains which range along the sides, and four in the middle, or between the two roadways. The whole expense of this American work is estimated to have been 20,000 dollars.
“Proposed Bridge at Runcorn.—Perhaps the most precarious and difficult problem ever presented to the consideration of the British engineer was the suggestion of some highly patriotic gentlemen of Liverpool, for constructing a bridge over the estuary of the Mersey at Runcorn Gap, about twenty miles from Liverpool. The specifications for this work provided that the span of the bridge should measure at least 1000 feet, and that its height above the surface of the water should not be less than sixty feet, so as to admit of the free navigation of this great commercial river. The idea of a bridge at Runcorn, we believe, was first conceived about the year 1813, when the demand for labour was extremely low, and a vast number of the working classes of Lancashire were thrown out of employment. A variety of designs for this bridge were procured by a select committee of the gentlemen who took an interest in this great undertaking. The plan most approved of, however, was the design of a bridge of suspension; and Mr. Telford the engineer, and Captain Brown of the Royal Navy, are understood pretty nearly to have concurred in opinion as to the practicability of such a work. Mr. Telford has reported fully on the subject, and has estimated the expense of his design at from £63,000 to £85,000, according to different modes of execution. Though as yet little advancement has been made in carrying this enterprising design into execution, yet the novelty and magnitude of an arch of 1000 feet span is a subject of so much interest that we have thought it proper in this place to mention these circumstances.
“Menai Chain Bridge.—The Straits of Menai, which separate the island of Anglesea from Caernarvonshire, have long formed a troublesome obstruction upon the great road from London to Dublin by Holyhead, by which the troublesome ferry of Bangor might be avoided. Many plans for the execution of this undertaking have also been agitated, chiefly in cast iron, including a range of estimate from about £128,000 to £268,000; but that which is now acted upon is a bridge of suspension upon the catenarian principle, the extent of which between the piers or points of suspension is to be 560 feet, the estimate for which is only about £70,000. This by many has been considered a work of great uncertainty; but the Union Bridge on this plan has already been executed on the Tweed, to the extent of 361 feet.”
Mr. Stevenson then goes on to mention several wire and chain bridges erected in Scotland, and gives the following description of his design for Cramond Bridge:—
Fig. 17.
“[Fig. 17] is a section and plan designed for crossing the river Almond on the great north road between Edinburgh and Queensferry. The extent of the span between the points of suspension is laid down at 150 feet. The chief circumstances which particularise this design are a mode of fixing the chains to the abutments of suspension on each side of the river, by which the main chains can be distributed equally under the roadway. The main chains are likewise made to collapse or turn round the abutments of masonry, as will be seen from the section, in which the parts of the work are so contrived that access can be had to the chains by an arched way on each side. In this design the two ends of the chains are formed into great nails or bolts, with countersunk or conical heads made to fit into corresponding hollow tubes of cast iron built into the masonry of the abutments.
“From this description the reader will readily form an idea of the simplicity and effect of this mode of fixing the chains, being such, also, that any particular chain may be withdrawn and replaced without deranging the fabric of the bridge. The roadway, instead of being suspended from the main chains, is made up to the proper level upon the chains by a framework of cast iron, prepared for the reception of a stratum of broken stones for the road.
“The making up of the roadway of this bridge, however, and the enlarged angle of its suspension, may be considered as limiting the span or extent of bridges of this construction to about 200 feet. The structure represented by [Fig. 17] appears to possess many advantages for bridges of that modified extent, and the manner of fixing the chains is applicable to all bridges of suspension; it is likewise new, so far as we know.”
In the close of his paper Mr. Stevenson says:—
“To what extent suspension bridges may be carried is very uncertain, and he who has the temerity to advance sceptical or circumscribed views on this subject would do well to reflect upon the history of the steam-engine. When the Marquis of Worcester first proposed, by the boiling of water, to produce an effective force, no one could have conceived the incalculable advantages which have since followed its improvement by our illustrious countryman, Watt.”
A prophetic announcement, which has had its full realisation in the Suspension Railway Bridge of 821 feet span at Niagara Falls, and in the still bolder design now in execution for connecting New York and Brooklyn by a steel wire suspension bridge, having a clear opening between the piers of no less than 1600 feet.
CHAPTER XI.
WOLF ROCK LIGHTHOUSE.
About the year 1812, Mr. Stevenson having, as adviser of the Commissioners of Northern Lighthouses, attained the position of being the most eminent Lighthouse Engineer of his day, was requested by the Admiralty to report on the practicability of erecting a lighthouse on the Wolf Rock, lying about eight miles off the Land’s End in Cornwall.
I give, from Mr. Stevenson’s “Journal,” the following curious account of the first visit he made to the rock; and it may perhaps be as well to say that all quotations made from what I have called his “Journal” are records of what he roughly noted down at the time in the form of a Diary, and are on that account perhaps all the more interesting, at least to non-professional readers.
“14th Sept. 1813.—Waited upon Sir Robert Calder, Admiral of the port of Plymouth, on the 13th, in consequence of letters from Lord Melville relative to a vessel to carry me to the Wolf Rock.
“The Admiral accordingly appointed the ‘Orestes,’ Captain Smith, to proceed with me to the Wolf, and after landing me there, and having made my observations, Captain Smith was directed to land me at any port most convenient for me, according to the state of the weather. Captain Smith, in consequence of this order, and to suit my convenience, got the ‘Orestes’ in readiness two days sooner than he otherwise intended, and I embarked on the 14th at 2 P.M. agreeably to appointment.
“The Captain took me by the hand and welcomed me on board His Majesty’s ship, and introduced me to his first lieutenant, Mr. Fallick. He then proceeded to give orders for casting off, which was done in an instant after the word was given. The ‘Orestes’ is properly a gun brig, but rigged as a ship, has 28 guns and 100 men. Kept plying to windward, and in the evening had the Eddystone light in view, still upon our lee quarter, distant eight or ten miles.
“15th.—Kept working along the shore all day, and at 7 P.M. a pilot from Mousehole by Penzance came on board. Upon consulting the pilot, he recommended that the ship should be brought to an anchor in Mounts Bay, or rather Newland Road, all night, as it would answer no good purpose to go round the land so soon after a fresh gale of wind, with the view of landing on the Wolf, which he represented as being only practicable in the finest of summer weather. This was poor heartening. The Captain submitted to me whether it were not more advisable to come to an anchor, in which, with all submission to him, I consented. The ship, accordingly, was brought to an anchor in twelve fathoms, clean sand.
“On board of the ‘Orestes’ two of the people were punished,—one for threatening to knock down the serjeant of marines, while on duty, received three dozen; another who offered an insult to a lieutenant, received one dozen.
“I was sitting below, the time this was going forward, when all hands were piped on deck, and the Captain began to read the Articles of War. He had previously said to me that two men were in irons, whom he meant to punish and liberate. I went upon deck to learn the cause of all being so quiet, and discovering what was intended, I went below and waited in great suspense till the men began to call out for mercy. I took the liberty of sending a note to the Captain—the circumstances were so painful to me—to see if he could remit any part of the punishment, to which I afterwards understood he had listened, as he did not give them so many lashes as was intended. Captain Smith had by no means the character of a severe commander, as I understood from some of the officers he had been two years in the ship, and had only punished twice.
“About 9 P.M., while the Captain and myself were at supper, we heard a conversation between the pilot and Mr. Fallick, the first lieutenant, about a vessel being on fire. The former was of opinion that it was a pilchard boat, the crew of which were roasting pilchards, while Mr. Fallick insisted that it was a vessel on fire. In a short time the vessel or boat appeared to be in flames, and with all sail set she approached the ‘Orestes.’ On shore the people of Penzance and Mousehole were afraid of the ‘Orestes’ taking fire and discharging a broadside upon the town. In the meantime the vessel on fire approached the ‘Orestes’ so directly that Captain Smith gave orders to veer out all the cable, stand by to cut or bend on more rope, according to circumstances.
“The weather became moderate, and we had little or no wind, and the vessel on fire (which turned out to be a sloop of 80 or 90 tons, bound for St. Sebastian with bottled porter and bale goods) passed ahead of the ‘Orestes’ about half a cable’s length. Her hull was then completely on fire, but the rigging and sails had not then caught fire, and she kept an undeviating course till she grounded on the shore.
“Captain Smith then despatched officers and men in three boats to endeavour to save as much as possible, but a report having gone abroad that she had gunpowder on board no person ventured near the vessel on fire till it was too late to be of any service, and in the morning when Captain Smith and I went on shore nothing remained but the keel and a few of the ‘futtocks’ half burned, and the mast over by the deck, the lower part having been consumed by the flames. The vessel was just getting under weigh when the accident occurred, through the carelessness of a boy, who set a lighted candle into a crate of straw in which bottles were packed. The crew soon afterwards appear to have carelessly deserted the vessel and landed at Mounts Bay, three miles from Mousehole, and appear not to have been very active in doing what was in their power. The loss of ship and cargo was estimated at £14,000.
“16th.—Got under weigh at 6 P.M., and left Mousehole Bay with an intention to go round the land; but the weather fell calm, and after shutting in the Lizard lights came to an anchor in Mounts Bay till next morning. The Lizard lights appeared to very great advantage.
“17th.—Got under weigh at 6 A.M., wind shifting from southwest to east with a fine breeze, and at 11 A.M. got up with the Wolf Rock. At 12 noon two boats were manned—one commanded by a midshipman, and the other by Lieutenant Fallick, into which I went, and after pulling round and round the rock with both boats, sounding all the while, we made preparations for landing. Mr. Fallick arranged his boat’s crew, and let go a grapling over the stern, then veered away upon this stern rope watching a smooth, and when the boat was near enough the young man (the same who had two days before got one dozen of lashes) appointed to land with a bow rope to make fast, leaped upon the rock, and upon these two ropes the boat was hauled off and on with great ease and facility. In this manner Lieutenant Fallick landed next, then I landed, but not without much difficulty, and watching an opportunity to get on the rock with a smooth between the seas.
“Upon leaving the ship, about a quarter of a mile from the rock, I began to sound, and at from two to three cables’ length off the rock have 41, 40, and 38 fathoms water, with shell sand of a fair colour. At about one cable’s length have 13 fathoms, same bottom. Within this distance have 10, 8, 5, 3½, and 2 fathoms, chiefly rocky bottom.
“The rock is steep in all directions; the south-west if anything draws to a point with rather less water near it than in other directions.
“At low water of a neap tide the rock appeared to be about twelve or fourteen feet in perpendicular height above the surface of the water. Its surface is very irregular, jutting up in masses of from six to ten feet in height. These inequalities all presented marked and angular outlines, terminating in well-defined points and edges. The central part of the rock is formed pretty much into a hollow, where there have been some quarrying operations in fixing the beacon which was erected upon it. The margin of the rock is upon the whole pretty regular, as it appears jutting out of the water. On the eastern side it is not so regularly formed at the water’s edge as on the western side. It slopes outwards, and seems to form a large stool in every direction. At some places there are guts or slips in the rock, but none of these are large enough to be useful for a boat landing at. The best and perhaps the only landing place is at the north-east side, where the rock is most precipitous.
“Taking the dimensions in the largest directions with the lead-line, in fathoms, it measured twenty-two fathoms in a north-east and south-west direction, and sixteen fathoms in a north-west and south-east direction.
“Upon the surface in the middle, at the hollow place, I found a hole of six inches in depth, and about nine inches square, and connected with it, at six feet distant, three holes for bats, which I presume to have been the step of the beacon, and the iron bats were still to be seen which had been used as guys. This fragile affair appears to have wanted base and every requisite suited to such an exposed situation and important purpose, and accordingly the beacon, with a wolf of metallic work, erected by a Lieutenant Smith, who erected the Longships Lighthouse, is said not to have remained longer than a few days, and was carried away in the first storm.
“Besides these holes and bats, which last seem not to have exceeded 1½ inch iron in strength, I found several eye bolts in different parts of the rock, particularly at the landing place, which had been put in to make fast boats, etc., while the beacon was being erected.
“The surface of the rock is extremely rugged, and running in every direction into sharp angular points. The rock seems to run in beds from an inch to a foot in thickness. It has much the appearance of limestone, but upon a narrow inspection it turns out to be porphyry. It is covered with the barnacle, many limpets of a very large size—say two inches diameter,—and mussels. These were the only animal productions that were found upon it. Of the marine fuci there were two or three varieties.
“That it would be practicable to erect a building upon this rock I have no doubt, but from its shape and figure, and the great depth of water in all directions round it, together with the smallness of its dimensions, it would be a work of great difficulty, and be attended with much expense and great hazard.
“I am therefore of opinion that it might cost from £80,000 to £90,000 to erect a lighthouse at the Wolf, with all the requisite buildings and appointments, like the Bell Rock Lighthouse.
“In a conversation on this subject with Lieutenant Smith in 1806 (who had erected the beacon on the Wolf), he pronounced it as an impracticable work. But his opinion, from the work he had performed at the Longships, and other circumstances, made very little impression upon my mind, at the time, in regard to the Bell Rock, and since seeing the Wolf Rock I think his arguments were ill founded, and I am perfectly decided in opinion that the work is a practicable one.
“The wind being nearly easterly, and consequently unfavourable for returning with dispatch to Plymouth, the captain gravely proposed that we should stand towards ‘the Bay’ for a few days, when it might shift. Not being fully aware of what was meant by the Bay, I put the question, when to my surprise he meant the Bay of Biscay, and said we should see St. Sebastian, which had just fallen; but to this I replied, that I should much rather be landed at the Land’s End. He was constantly on the outlook for prizes, and as I came not to fight I wanted much to be on shore, that I might pursue my way to Bath, where I knew Mr. Rae, the Sheriff of Edinburgh, would be waiting my return to proceed upon the visit to the Prisons on our return to Scotland.
“The ship was therefore directed to steer for the Land’s End, and the pilot took the ship within the Longships Lighthouse, and he and I landed at Sennan on the same evening.
“Having procured horses for myself and luggage, I set off immediately for Penzance, which I reached about 10 o’clock at night, the 17th September, much pleased with my trip upon the whole.
“18th.—Leave Penzance, and reach Falmouth by the fly.
“19th.—Leave Falmouth, and that same night, or early next morning, reach Exeter.
“20th.—At 6 A.M. leave Exeter, and 8 P.M. reach Bath.
“From Plymouth to the Wolf, and returning to Bath, only eight days.”
Mr. Stevenson at a subsequent date made another visit to the Wolf, accompanied by an assistant, when a careful survey was made, followed by a well-considered design, which is shown in [Plate IX.], and is described by him as follows:—
PLATE IX.
DESIGN FOR WOLF ROCK LIGHT HOUSE.
W. & A. K. Johnston, Edinburgh.
“[Plate IX]. is the section of a design formed by the revolution of the parabola round the axis of a building, as its asymptote, whose base measures fifty-six feet in diameter, and parallel at the top of the solid is thirty-six feet; and height to the entrance door, thirty-five feet. The contents of this figure between these parallels is calculated at 45,000 cubic feet; but the whole of the masonry of the design is estimated at 70,624 cubic feet. Its general features may be stated as similar to those of the Eddystone and Bell Rock Lighthouses, the parts being only enlarged, and the parabolic instead of the logarithmic curve adopted for its outline. In this design, the parabolic curve is continued from the basement to the copestone of the light room, exclusively of the projection for the cornice and balcony. The masonry is intended to be 120 feet in height, estimating from the medium level of the sea, of which the solid, or from the foundation to the entrance door, forms thirty-five feet, the staircase twenty-five feet, and the remaining sixty feet of its height is occupied with six apartments, and the walls of the light room. In the staircase a recess is formed for containing the machinery for raising the stores to the height of the entrance door; here a small hole is perforated through the building for the admission of the purchase chain. The thickness of the walls immediately above the solid is twelve feet; at the top of the stone staircase they are eight feet, and where the walls are thinnest, immediately under the cornice, they measure two feet. A drop hole formed in the courses of the staircase and solid, provides for the range of the weight of a revolving light. The ascent to this building, as at the Bell Rock, is intended to be by an exterior stair or ladder of brass, and the interior communication between the several apartments by means of flights of circular oaken steps.”
The only estimate Mr. Stevenson ever made of the work was that already stated in his Journal, at a cost of £80,000 to £90,000 for the tower and requisite dwellings for the lightkeepers and crew of attending vessel ashore.
Mr. Stevenson’s original visit was, as we have seen, made in 1813, and in 1870, after a lapse of fifty-seven years, the present tower on the Wolf Rock, the joint work of the late Mr. James Walker and of Mr. James N. Douglass, was successfully accomplished under the auspices of the Trinity House. The cost of the tower, exclusively of the shore establishment, which it was unnecessary to provide, was £62,726, being not very different from the estimate of Mr. Stevenson (from £80,000 to £90,000), which included a shore establishment.
CHAPTER XII.
CARR ROCK BEACON.
1810–1821.
The Carr Rock is a tide-covered reef extending about 1¾ mile from the shore of Fifeness, and forming a turning point in the navigation of the northern-bound shipping of the Firth of Forth, and on Mr. Stevenson’s recommendation the Commissioners of Northern Lighthouses resolved to erect a beacon of masonry to mark the danger.
It may seem to be unnecessary, after describing the Bell Rock Lighthouse, to notice so apparently small a work as this; but in such matters it is unsafe to generalise; each case must be considered on its own merits, and great difficulties were encountered in accomplishing the work. The formation of the Carr Rock rendered it impracticable to secure a base for a building of greater diameter than eighteen feet, and as part of that base had to be founded under the level of the lowest tides by cofferdams which were removed and taken ashore after each tide’s work, even the Engineer of the Bell Rock Lighthouse found all his resources taxed to a considerable extent, and he was in the end foiled in carrying out his design for the building. But irrespectively of these physical difficulties, the Carr Rock is a work of great interest to the lighthouse engineer, inasmuch as Mr. Stevenson at that early date conceived the idea of calling to his aid the power given by the rise of tide on the building to move a train of clock work to sound a warning bell; and again, when the destruction of the upper portion of his beacon by the sea obliged him to relinquish this plan, unwilling to be beaten, he suggested that the same tidal action might be made to sound a whistle; and failing that, he proposed to exhibit a phosphorescent light from the top of the building. All of these ideas suggested by Mr. Stevenson’s inventive mind have been from time to time revived by modern inventors.
The original design of the Carr Rock Beacon was made in 1810, and the work was commenced in 1813. After portions of the masonry had repeatedly been carried away by the sea, the original design for surmounting the building by a bell to be rung by the rise and fall of the tide was abandoned, and the beacon was completed in 1821, by raising an iron structure, as shown in [Plate X]. [Fig. X-2], on the foundation that had escaped the fury of the sea, and that structure is still in perfect preservation. So great, indeed, was the difficulty that Mr. Stevenson, in 1818, contemplated using blocks of cast iron instead of stone to insure greater specific gravity—a proposal which is believed to have been then made for the first time.
The following is Mr. Stevenson’s own description of this interesting work:—
“The form and construction of the Carr Rock Beacon, as originally designed and ultimately executed, will be better understood by referring to [Plate X]. The motion originally intended to be given to the bell-apparatus, or tide machine, [Fig. X-1], was to be effected by admitting the sea through a small aperture of three inches in diameter, perforated in the solid masonry, communicating with a cylindrical chamber in the centre of the building, measuring two feet in diameter, in which a float or metallic air tank was to rise and fall with the tide. During the period of flood tide, the air vessel, in its elevation by the pressure of the water, was to give motion to machinery for tolling the bell and winding up a weight, which last, in its descent, during ebb tide, was to continue the motion of the machine, until the flood tide again returned to perform the joint operation of tolling the bell and raising the weight. A working model of a machine upon this principle having been constructed, it was kept in motion for a period equal to several months; this was effected by water run through a succession of tanks raised by a pump from the lower one to the higher, thus producing the effect of flood and ebb tides. The time during which this apparatus was in action having been ascertained by an index, a constant attendance upon the machine during this protracted experiment became unnecessary.
PLATE X.
CARR ROCK BEACON AS DESIGNED
IN THE YEAR 1810
CARR ROCK BEACON AS EXECUTED
IN THE YEAR 1821
“The upper termination of the beacon, in its present form, as shown in [Fig. X-2], does not admit of the application of the tide machine with the bell apparatus. Experiments as applicable to this have, however, been tried with a wind instrument, to be sounded by the pressure of the sea water, but it has not succeeded to the extent that seems necessary for a purpose of this kind. We have, indeed, thought that the application of pressure as a power, communicated by the waters of the ocean, in mechanical operations, might be carried to almost any extent by simply providing a chamber or dock large enough for the reception of a float or vessel, of dimensions equivalent to the force required. This description of machinery is more particularly applicable in situations where the tides have a great rise, as in the Solway Firth, Bristol Channel, and other parts of the British seas; and at St. Malo on the coast of France.
“A beacon of any form, unprovided with a light, must always be considered an imperfect landmark, and therefore various modes have been contemplated for more completely pointing out the position of the Carr Rock. It has been proposed that phosphoric lights should be exhibited from the top of the building. This object, however, would be more certainly accomplished by the erection of leading lights upon the island of May and mainland of Fife. But these, with other plans, which have been under the writer’s consideration, would necessarily be attended with a great additional expense, which, in the present instance, it is not thought advisable to incur.”
CHAPTER XIII.
CRANES.
It appears that Mr. Stevenson was much perplexed as to what sort of cranes he should use in building the Bell Rock Lighthouse. His difficulties were twofold:—
First, In consequence of the dovetailed form of the stones he required a crane that would drop them as nearly as possible on the beds on which they were permanently to rest.
Second, Supposing he devised a guy crane that overcame this difficulty, what was to be done as the building rose in height, and the guys became too nearly perpendicular to admit of such a crane being used?
In his private notes Mr. Stevenson regrets that he could get no advice from anybody he consulted, all of whom recommended him to employ common sheer poles, such as had been used by Smeaton at the Eddystone; and he adds, “I may say, morning, noon, and night, these difficulties have haunted me.” But thrown back on his own resources, and appreciating the difficulty as no one else could so well do, he found, as is often the case, that he was his own best counsellor, and he succeeded in solving the problem that had given him so much concern, by inventing what he called the “moveable beam crane,” and also the “balance crane,” which are shown in [Plate XI]. The former, as modified to suit particular cases, is now in universal use for building purposes, and the latter has been employed in rearing most of our Rock Lighthouses, so that I think professional readers will not object to my giving Mr. Stevenson’s description of these cranes, as designed by him at the beginning of this century. He says:—
“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 the [Plate (Fig. XI-1)], 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 dovetailed form of the stones at the Bell Rock, rendered it particularly fitted for this work, to which a crane of the ordinary construction could hardly be said to be applicable. At the Eddystone Lighthouse 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. These cranes were necessarily immersed at high water, and were retained in their places by four guys fixed at the top of the upright shaft, and the moveable jib or beam being lowered down, was secured to an eyebolt batted into the rock.”
PLATE XI.
MOVEABLE JIB and BALANCE CRANES.
W. & A. K. Johnston, Edinburgh.
“The ‘balance crane’ ([Fig. XI-2]) was constructed on a new principle for building the upper part of the Bell Rock Lighthouse, when the guy ropes of the moveable beam crane became ‘too taut,’ as sailors express it, or were too near the perpendicular, thereby rendering the beam cranes unstable. To remedy this, the balance crane was so arranged as to be 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 improvements made in order to adapt it to the erection of the Carr Rock Beacon. The upright central column is a tube of cast iron put together in convenient lengths with flush joints, after the manner of spigot 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 on which it rested, but at the Bell Rock not more than three lengths of from six to nine feet were generally in use. A malleable iron cross head 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 of the crosshead, when the machinery of the crane was employed with great facility as a locomotive power for lifting itself as each new length of central column was added. The weight of this crane as used at the Carr Rock did not exceed two tons.”
CHAPTER XIV.
FISHERIES.
Mr. Stevenson was ever an intelligent and anxious observer of the habits and industry of the people of those remote and isolated parts of the country which he so often visited. He was specially interested in the fisheries from which they mainly derive their support, as testified by frequent allusions to them in his journals and notes.
The following notice regarding the state of the Scottish fisheries, made in 1819, to the editor of the Edinburgh Philosophical Journal,[11] will be read with interest:—
“Having been for many years conversant with the navigation of the Scottish seas, I have, prior to the war with Holland, seen fleets of Dutch ‘busses’ engaged in the herring fishery off the northern parts of our coast. For a long time past, however, those industrious fishermen had not ventured to approach these shores; and they are now only beginning to reappear.
“In the early part of August last, while sailing along the shores of Kincardineshire, about ten miles off Dunnottar Castle, the watch upon deck, at midnight, called out ‘Lights ahead.’ Upon a nearer approach these lights were found to belong to a small fleet of Dutch fishermen employed in the deep sea fishing, each vessel having a lantern at her mast head. What success these plodding people had met with our crew had no opportunity of inquiring; but upon arriving the next morning at Fraserburgh,—the great fishing station on the coast of Aberdeen—we found that about 120 boats, containing five men each, had commenced the fishing season here six weeks before, and had that night caught no fewer than about 1500 barrels of herrings, which in a general way, when there is a demand for fish, may be valued at £1 sterling per barrel to the fishermen, and may be regarded as adding to the wealth of the country perhaps not less than £3000. In coasting along between Fraserburgh and the Orkney Islands, another fleet of Dutch fishermen was seen at a distance. The harbour and bay of Wick were crowded with fishing boats and busses of all descriptions, collected from the Firth of Forth and southward even as far as Yarmouth and Lowestoft. The Caithness fishing was said to have been pretty successful, though not equal to what it has been in former years.
“In the Orkney and Shetland Islands one would naturally look for extensive fishing establishments, both in herrings, and what are termed white fish (cod, ling, and tusk); but it is a curious fact, that while the Dutch have long come from their own coast to these islands to fish herrings, it is only within a very few years that the people of Orkney, chiefly by the spirited and praiseworthy exertions of Samuel Laing, Esq., have given any attention to this important source of wealth. It has long been a practice with the great fishmongers of London to send their welled smacks to fish for cod, and to purchase lobsters, around the Orkney Islands; and both are carried alive to the London market. This trade has done much good to these islands, and has brought a great deal of money to them; but still it is of a more circumscribed nature, and is less calculated to swell the national wealth, than the herring and white fishery in general.
“Hitherto the industry of the Orcadians has been chiefly directed to farming pursuits; while the Shetlanders have been almost exclusively occupied in the cod, ling, and tusk fishing. It is doubtful, indeed, if, up to this period, there be a single boat belonging to the Shetland Isles which is completely equipped for the herring fishery. But on reaching Shetland another fleet of Dutch doggers was seen collecting in numbers off these islands—a coast which is considered a rich harvest in Holland.
“So systematically do the Dutch pursue the fishing business upon our coasts, that their fleet of busses is accompanied by an hospital ship. This vessel we now found at anchor in Lerwick roads, and were informed that she paid weekly visits to the fleet, to supply medicines, and to receive any of the people falling sick, or meeting with any accident.
“Though Shetland is certainly not so much an agricultural country as Orkney, yet it may be hoped that the encouragement judiciously held out by the Highland Society, for the production of green crops in Shetland, may eventually have the effect of teaching these insular farmers the practicability of providing fodder for their cattle in the spring of the year. This has long been a great desideratum. The command of a month or six weeks’ fodder would enable the proprietors of that country to stock many of their fine verdant isles with cattle, and to employ their hardy tenantry more exclusively in the different branches of the fishery.
“It is well known, that, next to the Newfoundland Banks, those of Shetland are the most productive in ling, cod, tusk, and other white fish; and by the recent discovery of a bank, trending many leagues to the south-westward, the British merchants have made a vast accession to their fishing grounds. The fishermen who reside in the small picturesque bay of Scalloway, and in some of the other bays and voes on the western side of the mainland of Shetland, have pursued with much success the fishing upon this new bank, which I humbly presume to term the Regent Fishing Bank—a name at once calculated to mark the period of its discovery, and pay a proper compliment to the Prince. Here small sloops, of from fifteen to twenty-five tons burden, and manned with eight persons, have been employed. In the beginning of August they had this summer fished for twelve weeks, generally returning home with their fish once a week. On an average, these vessels had caught 1000 fine cod fish a week, of which about 600 in a dried state go to the ton, and these they would have gladly sold at about £15 per ton. So numerous are the fish upon the Regent Fishing Bank, that a French vessel, belonging, it is believed, to St. Malo, had sailed with her second cargo of fish this season; and though the fishermen did not mention this under any apprehension, as though there were danger of the fish becoming scarce, yet they seemed to regret the circumstance, on account of their market being thus preoccupied.
“Here, and at Orkney, we had the pleasure to see many ships arriving from the whale fishing, and parting with a certain proportion of their crews. To such an extent, indeed, are the crews of the whalers made up from these islands, that it is calculated that not less than £15,000 in cash are annually brought into the islands by this means. With propriety, therefore, may the whale fishery be regarded as one of the most productive sources of national wealth connected with the British Fisheries.
“From the Orkney and Shetland Islands our course was directed to the westward. A considerable salmon fishing seems to be carried on in the mouths of the rivers of Lord Reay’s Country in Sutherlandshire: the fish are carried from this to Aberdeen, and thence in regular trading smacks to London. We heard little more of any kind of fishing till we reached the Harris Isles. There, and throughout the numerous lochs and fishing stations on the mainland, in the districts of Gairloch, Applecross, Lochalsh, Glenelg, Moidart, Knoidart, Ardnamurchan, Mull, Lorn, and Kintyre, we understood that there was a general lamentation for the disappearance of herrings, which in former times used to crowd into lochs which they seem now to have in some measure deserted. This the fishermen suppose to be owing to the Schools being broken and divided about the Shetland and Orkney Islands; and they remark, that, by some unaccountable change in the habits of the fish, the greatest number now take the east coast of Great Britain. This is the more to be regretted, that in Skye, the Lewis, Harris, and Uist Islands, the inhabitants have of late years turned their attention much to the fishing. Indeed, this has followed as a matter of necessity, from the general practice of converting the numerous small arable farms, which were perhaps neither very useful to the tenants nor profitable to the laird, into great sheep walks; so that the inhabitants are now more generally assembled upon the coast. The large sums expended in the construction of the Caledonian Canal have, either directly or indirectly, become a source of wealth to these people: they have been enabled to furnish themselves with boats and fishing tackle, and for one fishing boat which was formerly seen in the Hebrides only twenty years ago, it may be safely affirmed that ten are to be met with now. If the same spirit shall continue to be manifested, in spite of all the objections which have been urged against the salt laws, and the depopulating effects of emigration, the British Fisheries in these islands, and along this coast, with a little encouragement, will be wonderfully extended, and we shall ere long see the Highlands and Islands of Scotland in that state to which they are peculiarly adapted, and in which alone their continued prosperity is to be looked for, viz., when their valleys, muirs, and mountains are covered with flocks, and the people are found in small villages on the shores.”
* * * * *
The following history of the origin of the Shetland herring fishery, communicated to Blackwood’s Magazine in 1821, is, I think, worthy of being recorded:—
“Few people, on examining the map of Scotland, would believe that the herring fishing has only within these few years been begun in Orkney, while the natives are almost strangers to the fishing of cod and ling.
“On the other hand, it is no less extraordinary that although the cod and ling fishery has been carried to so great an extent in Shetland as to enable them to export many cargoes to the Catholic countries on the Continent, not a herring net has been spread by the natives of Shetland till the present year (1821), when Mr. Mowat of Gardie, and a few other spirited proprietors of these islands, formed themselves into an association, and subscribed the necessary funds for purchasing boats and nets, to encourage the natives to follow the industrious example of the Dutch.
“The immediate management of this experimental fishery was undertaken in the most patriotic and disinterested manner by Mr. Duncan, the Sheriff-Substitute of Shetland. Having procured three boats, he afterwards visited Orkney, to ascertain the mode of conducting the business there, and having also got fishermen from the south, this little adventure commenced. Its nets were first wetted in the month of July, and it is believed its labours were concluded in the month of September, after obtaining what is considered pretty good success, having caught as follows, viz.:—
| The ‘Experiment,’ | 6-manned boat, | 212½ | crans. |
| The ‘Hope,’ | 5” | 119¾ | ” |
| The ‘Nancy,’ | 4” | 80 | ” |
| 412¼ | ” |
“The great object which the Shetland gentlemen have in view, in this infant establishment, is to give employment to their fishermen in the herring trade, after the cod and ling season is over, and by this means to enable them to partake of those bounties and encouragements so properly bestowed by Government on the fisheries; and thus abstract the attention of the lower orders of these islands from an illicit traffic in foreign spirits, tea, and tobacco, which has greatly increased of late years.
“The profit of the herring fishing at its commencement has, however, afforded more encouragement than could have been expected; for, besides paying the men a liberal allowance for their labour, a small sum has been applied towards defraying the expense of the boats and nets. But what is of far more consequence to this patriotic association is the spirit of enterprise which it is likely to create by bringing forward a number of additional boats in the way of private adventure, which must be attended with the best advantage to the Shetland Islands.”