Currents of the Tide.
Tides at the Bell Rock.
The tides at the Bell Rock, are observed to follow the same laws as on the opposite shores of the Firth of Forth. The currents alongthe coast take their direction from the figure of the land, and, in their course, they are therefore occasionally deflected from, and inclined towards it. At the Bell Rock the flood-tide sets south-west, and the ebb-tide north-east, being nearly in the direction of the shores of Forfar and Kincardine. The velocity of the water in spring-tides, or when the sun and moon are in conjunction, and in opposition, is about three milesperhour, but in neap-tides, or at the quadratures of the moon, the current is only at the rate of about one mileperhour. On the days of new and full moon it is high-wateruponthe Bell Rock at half past one o’clock, being about the same periodic time as at the harbour of Arbroath, or nearest point of the mainland. In the ordinary state of the weather, the perpendicular rise and fall of the sea at the Bell Rock, in spring-tides, is 15 feet, and in neap-tides, 8 feet; but so much depends upon the direction of a prevailing tract of winds, that the tides are often found to vary from 1 to 3 feet above and below these numbers. This irregularity in the tides of the German Ocean and its subsidiary friths or inland seas will be easily accounted for, by considering the effect of westerly winds passing for a length of time over the Atlantic, which must naturally force an undue quantity of water from thence into the entrance of the North Sea, between the coasts of Scotland and Norway; while the Strait of Dover, to the southward, from the same cause, is gorged by the surplus waters of the British Channel flowing in an opposite direction, and checking the tide of the German Ocean. When the winds blow from southerly and easterly directions, the reverse of this happens, and the waters are then proportionally low.
In and Off shore Currents.
A curious anomaly connected with the flowing and ebbing of the sea, in the early part of each tide, is observable in the contrary currents which take place along the shore, and at a distance from it. For example, the flood-tide begins to flow in many situations two or even three hours sooner on the shore than at the distance of from one mile to four miles in the offing. The same thing also happens with regard to the ebb-tide, which begins to fall and run in a contrary direction to the flood-tide, two or three hours sooner on the shore than at a distance. These effects are very different from the state of things three or four leagues from the land, or in the open sea, where the lateral motion of the tide-waters is scarcely sensible. That an extensive tract of coast should produce changes on the current of the tides, is perhaps what we should expect; but it is somewhat curious to find the same appearances connected with small islets, and, as in the case of the Bell Rock, even with an insulated reef, situate at the distance of 12 milesfrom the land, and sunk to the depth of from 2 to 3 fathoms under the surface of high-water. So strikingly observable is this, that the tide begins to ebb about two hours sooner on the Bell Rock than at the short distance of one mile from it. In the course of the light-house operations this was rendered sufficiently obvious, by the swinging round of the several vessels at their moorings according to the flood and ebb tides. For example, the Floating Light-ship was moored about three miles in a north-west direction from the Bell Rock, and the moorings of the Tender and two Stone Lighters, were respectively laid down at the distance of ¾ and ½ mile from it, as will be seen fromPlate V.Now, these vessels were all found to swing to the tide at periods proportional to their distance from the rock. Although it may, therefore, seem strange, that this comparatively small object should affect the tides in its vicinity in a manner similar to the shores of an extensive coast; yet, as the rock shelves outwards, with an extensive base, especially on the northern side, it must impede the under current of the tide, and indeed forcibly proves the existence of such under currents.
Not accounted for by Writers on the subject.
To account for these in and off shore tides, or central and marginal streams, would be interesting. But to what cause shall we ascribe them? Sir Isaac Newton, and the other eminent philosophers who have followed that great man in considering the theory of the tides, confine their attention chiefly to an explanation of the influences of the sun and moon, and the laws of gravitation, in affecting the waters of the ocean, leaving it to the result of experience and observation to account for such anomalies as those to which we now allude. It is noticed by Adair, Mackenzie, and other nautical surveyors, that the tides run longer upon the shore than in the offing, and the advantage of working a ship within and off shore tides, is familiar to every mariner. The existence of these opposite currents was also known to the author, prior to the commencement of the Bell Rock works, but they had not struck him so forcibly till that period. For here, even after the flood-tide had overflowed the rock, and put a stop to the operations, the boats in carrying the artificers on board of the Tender, had still to row against the current of a strong ebb-tide.
Currents along Shore considered as Eddy-tides.
It would be foreign to this work to enter into the theory of the tides generally; all, therefore, that is here proposed, is to endeavour to account for these in and off shore currents. In doing this, however, it will be necessary to observe, that thegreat waveor “theoretical tide,” as it has been termed by the late eminent Professor Robison, is producedby the united attraction of the sun and moon, which, between the Tropics, has been calculated by philosophers to raise the water from 8 to 14 feet perpendicularly. It is observable, that the attractions of these heavenly bodies elevate the parts of the ocean to which they are vertical, without having any direct tendency to progressive or lateral motion. The currents along our coasts, may therefore be considered merely as Eddy-tides, occasioned by the interposition of the land, which obstructs the undulating motion incident to the rise or fall of a fluid. In this manner the land may be said to displace a portion of the tidal waters which have been elevated above the medium level of the sea; and were it not for such obstruction, the great waves of the tide might be supposed to undulate indefinitely over the expanse of the ocean. To compare small things with great, these effects may be conceived as in some degree exemplified, by the disturbing effect of a vessel passing along a navigable canal, or the undulations which are observable in thewakeof a ship or wheels of a steam-boat in motion on a smooth sea.
Progress of the Great Waves of the Tides.
The great wave which supplies theBritish tides, appears to be propagated between the coast of Labrador and Greenland, on the one hand, and the European shores on the other; and this great wave seems to be divided into two lesser waves. One of these flows between Ireland and the coast of France, into the British and St George’s Channels; while the other enters by the North Sea into the German Ocean; and in its course from north to south, supplies all the friths, rivers, and bays connected with it, invariably in the form ofIn and Off shore tides, which are every where observable along the margin of this great basin. This northern wave is found to occupy about 12 hours in flowing southward from the 58th to the 52d degree of latitude, or from the Orkney Islands to the numerous Sand-banks which pervade and encumber the apex of the German Ocean, where the currents become extremely desultory and irregular. The coast of the British Isles, accordingly, may be said to, displace a portion of this northern wave, and thus to produce the irregularities which we are endeavouring to account for.
Progressive periods of High-Water in the Firth of Forth.
At present, we shall confine our attention to the tides of the Firth of Forth. Here, as on other parts of the coast, the tidal waters have a tendency to flow towards the shores and higher parts of the Forth, till the instant of high-water upon the shore, when the tide begins to ebb, and run in a contrary direction. A central stream, however, continues to run with unabated force, as flood-tide, during two or even threehours longer, as before noticed, according to the situation and local circumstances of the coast. It appears, from a comparison of the several periods of high-water on the shores of the Firth of Forth, as nearly as some of them could be ascertained, that the precise time of high-water becomes later and later in the same tide, as we proceed westward; at the Bell Rock, for example, it is high-water on the days of new and full moon, as before noticed, at ½ past 1 o’clock; at the Carr Rock, at ¾ past 1; at Elie, still further up the Firth , at 2; Kinghornness, at ¼ past 2; Queensferry, at ¾ past 2; and at Alloa, at ¾ past 3 o’clock. The off-shore stream of the tide continues to flow proportionally longer till it has supplied the higher parts of this estuary with its portion of tidal waters; and in like manner, the central stream of ebb-tide continues its course till these waters are again run off.
Currents at the Mouth of the Dee and other Rivers.
In many points, it is found, that the operation of the tidal waters of extensive arms of the sea, bears a close resemblance to what is observable upon the small scale in the currents of rivers, especially at their junction with the ocean. An interesting example of this occurs on the river Dee, which falls rapidly into the harbour of Aberdeen. Here the author having occasion to make some observations on the tides in the summer of 1812, stationed several assistants at low-water mark, between the entrance of the harbour and the bridge, about two miles up the river. The waters of the Dee, even at the entrance of the harbour, have almost a constant current seaward, notwithstanding the opposite direction of the flood-tide of the Ocean. On the occasion alluded to, one of his assistants, a very intelligent shipmaster, continued at his post while the water flowed up to his middle; and, when accosted about his situation, he significantly observed, “That it was rather extraordinary, as the stream had never ceased to indicate the continuance of an ebb-tide, while the water was still rising upon his body.”
Water salt at bottom and fresh at top.
In connection with these observations on the tides, some experiments were also made with an instrument adapted for lifting water from considerable depths, without the possibility of its intermingling with the surface water. By means of this instrument, the water at the bottom of the Dee, at Aberdeen, was found to be salt, while that at the surface was quite fresh. These streams of fresh and salt water run in distinct currents, and in contrary directions, the salt water, from its greater specific gravity, flowing at the bottom of the river, and fluctuating with thelevel of the ocean, while the fresh water is actually lifted upwards, and continues all the while to flow seaward on the surface of the salt water. Towards the point of high-water, however, the flood-tide gains strength on the margin of the basin of the harbour, where the water becomes salt, and forms an eddy-tide in a contrary direction to the central stream, which is observed still to run toward the sea. Having made similar observations on the waters of the Thames, the Garonne, and other rivers, with nearly the same results, after making allowance for the more level state of the country, in the track of these great streams,—it is concluded, that the currents at the embouchure of rivers bear a strong resemblance to the operation of the in and off shore tides of the ocean.
Phenomena of in and off shore Tides accounted for.
We further observe, that the great wave of the German Ocean produces its tides in regular succession, and at stated periods, as it moves from north to south; but the tides of the more inland seas are subject to many irregularities, both in their periodic times, and in the direction of their currents. Let us suppose, then, that we have arrived at the instant of high-water on the shores at the entrance of the Firth of Forth, and that the tidal waters are then moving in a body, and with a certain pressure, towards the higher parts of the Firth , and even affecting the river above the bridge of Stirling. We find, that at the entrance of this estuary, on the days of new and full moon, it is high-water at a quarter past one o’clock; but at Alloa, situate 70 miles above the Bell Rock, it is not high-water till about two hours and a half later. The in-shore tidal waters having to encounter the shelving shores, islands, sunken rocks, and projecting points of land, which lie in their course up the Firth , acquire lateral as well as perpendicular motion, and being thus checked in their progress, are brought sooner to a maximum state than the off-shore stream, which flows in deeper water, and comparatively free of obstruction, till it reaches its ultimate limits; though it gradually diminishes in breadth, till the stream of thenew tidegaining strength becomes general; and the central current, formerly running in a contrary direction, at length disappears, and takes the course of the new tide.
We would, therefore, be understood to ascribe this anomaly in the flowing and ebbing of the sea, to the obstruction which the current of its waters meets not only at the surface or margin, but at the bottom, which, from the variety of the soundings of the depths, appears to be as various as the face of the land. A striking proof of this isafforded at the Bell Rock: on the northern side of which there are 11 fathoms, at the distance of about three quarters of a mile; while, on the southern side, and at a similar distance, the water deepens to 35 fathoms; so that a perpendicular section of this rock under water forms a precipitous declivity, such as we are quite accustomed to see on the land. Now, if we apply this irregular conformation of the bottom of the sea, to the production of the in and off shore tides, and conceive that the tidal currents extend their motion to the bottom, it must be evident, that this obstruction presented to the stream will bring the tides to a maximum state sooner on the northern side of the rock, where the water is so much shallower, than on the southern side. This is also agreeable to observation; for, the tidesupon the Bell Rockbegin to flow and ebb one hour sooner than at the distance of about three quarters of a mile from it on the northern side, and about two hours and a half sooner than at the same distance on the southern side. The marginal current is thus checked by the shallowness of the water, and the projecting points of land; while the central stream, flowing comparatively without obstruction, continues to run till the most inland creeks are supplied with tidal water; andvice versâ, it continues its stream outwards, till these waters are again run off.
Progressive times of high-water.
The progressive times of high-water, at intermediate points between the Bell Rock and the port of Alloa in the Firth of Forth, appear to follow the same general law, as the great wave of the German Ocean in its progress from the Orkneys southward. These observations on the tides of the Forth apply equally to the Firth and River of Tay, and indeed to all the tributary streams and arms of the sea which communicate with the German Ocean, according to their local situations and magnitudes.
Tides of the Mediterranean and Baltic Seas.
If due allowance be made for the peculiar situation and circumstances of the Mediterranean and Baltic seas, it is apprehended, from all that we have been able to learn of the operation of the currents at the Strait of Gibraltar, and Sound of the Cattigate, that these seas are supplied and discharged by in and off shore tides or currents, under certain modifications, and making due allowance for local circumstances, in the same manner as on all other parts of the coast.
I have been thus particular relative to the in-shore and off-shore tides, because they appear in a very puzzling form to the mariner, while writers on the theory of the tides are almost silent on this subject.
DANGEROUS POSITION OF THE BELL ROCK.—SIR ALEXANDER COCHRANE’s LETTER TO THE LIGHT-HOUSE BOARD.—DESIGNS FOR THE BELL ROCK LIGHT-HOUSE.—BILL BY LORD ADVOCATE HOPE IN 1803.—REPORT OF TRADERS OF LEITH.—RESOLUTION OF THE LIGHT-HOUSE BOARD TO APPLY AGAIN TO PARLIAMENT.—MEMORIAL TO THE BOARD OF TRADE.—BILL BY LORD ADVOCATE ERSKINE.—REPORT OF THE COMMITTEE OF THE HOUSE OF COMMONS.—THE BILL PASSED.
DANGEROUS POSITION OF THE BELL ROCK.—SIR ALEXANDER COCHRANE’s LETTER TO THE LIGHT-HOUSE BOARD.—DESIGNS FOR THE BELL ROCK LIGHT-HOUSE.—BILL BY LORD ADVOCATE HOPE IN 1803.—REPORT OF TRADERS OF LEITH.—RESOLUTION OF THE LIGHT-HOUSE BOARD TO APPLY AGAIN TO PARLIAMENT.—MEMORIAL TO THE BOARD OF TRADE.—BILL BY LORD ADVOCATE ERSKINE.—REPORT OF THE COMMITTEE OF THE HOUSE OF COMMONS.—THE BILL PASSED.
Dangerous Position of the Bell Rock.
Whatever may have been the early state of the Inch Cape or Bell Rock, as an Island, its present character is strictly that of a sunken rock; and, as such, its relative situation on the eastern shores of Great Britain has long rendered it one of the chief impediments to the free navigation of that coast. It is almost unnecessary to remark, that there are only three great inlets or estuaries upon this coast, to which the mariner steers, when overtaken by easterly storms in the North Sea or German Ocean. These are the Humber, and the Friths of Forth and Moray; of which the Firth of Forth is the principal rendezvous. The mouth of the River Thames, excepting in certain narrow and intricate channels, has not a sufficient depth of water, and is so much encumbered with sand-banks, that no vessel can enter it under night, or approach it in bad weather. On the coast and shores in the neighbourhood of the Humber, the land is flat, and defective in those bold and characteristic features which are essential to the situation of an anchorage for ships in bad weather when they cannot keep at sea. The entrance of the Humber is also considerably obstructed with sand-banks, of which the mariner is, if possible, more afraid than of rocks, because more liable to uncertainty, by the shifting of their position, and thereby changing the direction of the accustomed channels. The great places of resort for ships, therefore, in the North Sea, are the Roads of Leith and Cromarty, lying in the Friths of Forth and Moray, as will be seenfromPlate III., in both of which we find the natural advantages of an ample entrance, and a coast so strongly marked as to be easily recognised by the mariner. But from the dangerous position of the Bell Rock, his approach to the shores of this coast, prior to the erection of the Light-house there, was liable to the greatest peril and uncertainty.
Great storm in December 1799.
A memorable example of this occurred during a storm from the south-east, in the month of December 1799. This storm having continued with little intermission for three days; a number of vessels were driven from their moorings in the Downs and Yarmouth Roads; and these, together with all vessels navigating the German Ocean at this time, were drifted upon the coast of Scotland. Many found shelter, both in Leith and Cromarty Roads, which, from the state of the winds, lay quite open for their reception. But still, from the dread of the Bell Rock, in the one case, and the danger of mistaking the entrance to the Firth of Dornoch for that of Moray, by taking the northern instead of the southern side of Tarbetness, in the other, a great number of vessels were lost, or much hardship was sustained by the mariner in seeking safety in higher latitudes. It has even been reckoned, that seventy sail of ships were either stranded or lost upon the eastern coast of Scotland during that gale, when many of their crews perished.
At the Bullers of Buchan, near Peterhead, alone, on the first night of this storm, the wrecks of seven vessels were found in a small cove, without one survivor of the crews, to give an account of their disaster. As a remarkable instance of escape on this occasion, it may be mentioned, that a coal-ship, in ballast, returning from London to Newcastle, was carried completely round the coast of Great Britain and Ireland, the first land made by this vessel, after leaving Flamborough Head in Yorkshire, being the Land’s End of Cornwall. Having put into Falmouth to refit the ship and refresh the exhausted crew, she continued her voyage up the British Channel to the Straits of Dover, and so to Newcastle, thus making a complete circuit of the British shores. In the summer of 1800, the writer saw the wrecks of two fine vessels on the Orkney Islands; one of which, on her way to Gibraltar, had been as far as Ushant on the coast of France, when, by contrary winds, she had been driven back to the Downs, and, in the month of December 1799, she was ultimately stranded on the Island of Sanday, along with the other vessel, which in that gale had been driven from Yarmouth Roads.
From the situation and circumstances attending the Bell Rock, it may well be supposed, that this dangerous sunken reef was found to be either the direct or ultimate cause, in many cases of shipwreck upon the eastern coast of Great Britain, and as such, every scheme which had for its object the fixing of some distinguishing mark upon it, was regarded as a matter of public interest, claiming a degree of attention proportionate to its apparent practicability and usefulness. The traditionary story of the Bell said to have been erected by the Abbots of Aberbrothock upon this rock may, perhaps, have given rise to many plans of this nature. But, on account of the limited advantages which must have attended any erection merely in the form of a beacon, without a light, upon a sunken rock, at so great a distance from land,—none of the many proposals of this kind which were from time to time suggested, ever met with the serious attention of the public. It was evident, that nothing but a light-house could not be essentially useful, and that all temporary erections in a situation of this kind were to be avoided.
Sir Alex. Cochrane’s Letter.
The following letter from Sir Alexander Cochrane, while stationed on the eastern coast in the year 1793, is particularly deserving of a place in this work, as well from being the first official application made to the Commissioners on the subject of the Bell Rock, as on account of that officer’s great experience in nautical affairs, and the clear and decided manner in which the advantages which would result from the erection of a light-house there, are pointed out.
“On board his Majesty’s ship Hind, Leith Roads, January 7. 1793.Gentlemen, I think it a duty I owe to the public, to call your attention, as Trustees for the Northern Lights, to the great hazard and peril that the trade of the east of Scotland is subject to, from the want of a light-house being erected on the Bell or Cape Rock, the only dangerous one upon this coast, from the Staples to Duncansbay-head, except the Carr, which lies so close to Fifeness and the Isle of May as to render it comparatively of less consequence.
“The situation of the Cape being about 12 miles from the nearest shore, bearing off the Redhead, by compass, S. ¾ W.—Taybar, SE. by E. ¼ E.—Fifeness, NE. by E.—Isle of May Light, NE. 17 miles, (consequently, too distant to be useful to shipping during the night); this rock is therefore placed in the most dangerous situation possible, for thetrade of the Friths of Forth and Tay; the more so, from the prevailing winds on the coast, being from the W.NW. to SW., which occasion vessels bound inwards, to stretch across from shore to shore, that is, from the south to the north, or the opposite, according to their situations. This they can do in the day time; but at night, the danger of falling in with the Cape Rock, prevents them from standing to the northward of the Firth of Forth, and they are thereby prevented from taking the advantage of working up under the land in St Andrew’s Bay, by which they would get into smooth water, and avoid the heavy swell and gusts of wind that are always met with in the opening of this Firth .
“Ships from the Baltic, which have not made the land, are often driven off the coast, from the caution they are obliged to take, in consequence of their not knowing what their situation is respecting this rock; which, from being covered early in the tide, and having little or no sea or breakers on it in moderate weather, the wind being off the shore, the soundings are no guide whatever; for, within one mile of the south-east side, the depth of water is 32 fathoms, (the general soundings on the coast); from all which circumstances, a ship standing in for the shore, perhaps without having had an observation of the sun for some days, runs the utmost danger of being wrecked. From the experience I have, in consequence of cruizing on this coast, I give it as my most decided opinion, that the greatest good consequence would arise to the trade of Scotland, were a light-house erected on it; but, in the event of its being so, a distinction must be made between it and the light of May, such as is adopted at Scilly and the Caskets, the light on which revolves, I believe, once in a minute, so as to be obscured and visible alternately.”
Expence of a Light-house on the Bell Rock, as estimated by the Public.
Although the subject of this letter had occasionally occupied the attention of the Commissioners of the Northern Light-houses, yet the Bell Rock, as the site of a light-house, was then for the first time brought formally under the notice of the Board; and some erection there, was considered a primary object, whenever the funds should be in a state to meet the expence of such a work. But, the estimates for such an undertaking admitted of an almost unlimited range of amount, both from the nature of the buildings which were proposed, and on account of works of this kind being subject to unavoidable risk in all their stages, from the commencement till the completion. In conversation, it was common to compare the situation of the Bell Rock with the rocks of the Eddystone off Plymouth Sound, and Corduan at the mouth of the Garonne.Designs for the Bell Rock Light-house.The expence of erecting a light-houseon the Eddystone, though understood to have been about L. 20,000, has never been communicated to the public by the lessees of the light-house duties, from the consideration, perhaps, of their being obliged, by their agreement with the Trinity Board of London, to erect and uphold the building, and also from claims which they afterwards made, for having the value of the light-house reimbursed to them at the end of their lease; but it was well known that the present building is no less than the third erection which the lessees had made upon the Eddystone, between 1696 and 1759, or in the space of 63 years. It was therefore natural to conclude that a building on the Bell Rock, situate under a greater depth of water, being nearly on a level with low-water mark, would be a work of greater difficulty and expence, than the Eddystone light-house, where the top of the rock is on a level with high-water mark. We are also left in the dark in forming any opinion on the important point of expence with regard to the French work at Corduan, but we know that it met with repeated misfortunes while in progress, and that it occupied from 1584 till 1610, or 26 years in building. The main rock here is about a mile in length, and half a mile in breadth, and, in its position as a sunken reef, it resembles the Bell Rock more than the Eddystone. From the difficulties which attended the erection of these two celebrated light-houses,—both of which the writer has visited,—the erection of a light-house upon the Bell Rock, in comparison with these, was estimated by the public at so wide a range as from L. 20,000 even to L. 100,000.
Designs for the Bell Rock Light-house.
Funds for the Light-house Board inadequate.
In the year 1793, when Admiral Cochrane addressed his letter to the Light-house Board, its surplus funds amounted only to a few hundred pounds; a sum so inadequate to meet the necessary expenditure of such a work, that the Commissioners judged it better for the interests of navigation, to go forward with the less expensive improvements on other parts of the coast, aware that nothing essential could be undertaken at the Bell Rock without the effectual aid of Government.
In this state, matters were allowed to rest till the great storm in December 1799, already noticed, which roused the public mind to fresh speculations about the necessity of some erection being made upon the Bell Rock; not merely as a local improvement, but as one essentially calculated to benefit the ships navigating the German Ocean, by opening the Firth of Forth more effectually as a place of safety in easterly storms, sothat the Bell Rock, in place of being the dread of mariners, might in future become a point from which they would take their departure, and for which they might steer in sailing for the coast. Nautical and commercial men, especially, were interested, and felt this state of things in its fullest extent. Remarks were accordingly made in several of the periodical publications of the day, calling the attention of the public to the erection of a light-house there, as a subject of national importance.
In order to advance this object, the Corporation of the Trinity-House of Leith, made public advertisements, calling on persons likely to produce some practical plan that might lead to the means of making the erection in question. This, of course, produced various propositions on the subject.
Designs by Captain Brodie and Mr Couper.
The late Captain Joseph Brodie of the Royal Navy, prepared and brought forward a model of a cast-iron light-house, supported upon four pillars, to be built and connected together in a very strong manner. This model was made by Mr Joseph Couper, Iron-Founder in Leith, who, in conjunction with Captain Brodie, proposed to erect a light-house on this plan on the Bell Rock, on being authorised to draw certain duties from shipping for their mutual remuneration. With this view, they sent their model, and made certain propositions to the different commercial towns on the coast, as Newcastle, Dundee, and Aberdeen. After having been at considerable trouble and expence with this scheme, as a private adventure, these gentlemen applied to the Commissioners of the Northern Light-houses, requesting their inspection of this model. The design, however, was not altogether approved of by the Light-house Board, in the form in which it had been modelled; yet such was the confidence of its projectors, that at different times, in pursuance of their plan, they erected two temporary beacons, constructed with spars of fir-timber; these unfortunately were almost immediately washed down. The Merchants of Leith, applauding the great perseverance of these gentlemen, aided their exertions by a subscription of about L. 150, when they erected a third beacon on the Bell Rock on a more extended scale. It consisted of four spars of fir-timber, each about 40 feet in length, strengthened by flat bars of iron, laid the lengthway of the spars, which were kept in their places by rings or hoops of iron, firmly wedged overthem. These spars, when erected upon the rock, formed a common diameter of about 20 feet at the base, and crossed each other about 6 feet from the top. They were let into holes made in the rock, of about ten inches in depth, and were fixed by straps of iron, forming bats of about two inches square, and about six inches in length, which were also let into the rock, and run up with melted lead. At the place of junction, near the top, the spars were bolted together with iron, and above this, they were connected with small pieces of timber, nailed to the principal spars. After much labour and difficulty, with the assistance of a number of workmen, this temporary erection was fixed on the Bell Rock, in the month of July 1803. In the month of August the writer landed on the rock and examined it; but when the gales of winter set in, this erection also disappeared, having never been seen after the 20th of December. Nothing further was attempted to be done upon the Bell Rock till the author commenced the Light-house operations in the year 1807, by direction of the Commissioners of the Northern Light-houses.
Make further proposals to the Light-house Board.
Not discouraged, however, by the failure of these trifling works, Captain Brodie and Mr Couper addressed a letter to the Light-house Board, in which an offer was made to erect a cast-iron light-house, in the space of two years, agreeably to the model already alluded to, and on the following terms, viz. L. 6000 to be paid over to them during the first year of the work, together with the produce of a certain Duty for the erection, to be exacted from shipping, as a Northern Light, until the original cost of the work should be paid off. But this description of building having been considered objectionable, Captain Brodie proposed to construct a new model, upon an improved plan, by which the base of the building, instead of being raised on pillars, was to be continuous, with small interstices or holes in its circumference, or outer casing, to admit the water into the interior void, with a view to lessen the weight and expence of metal, and check the force of the sea. But this also appeared to the Commissioners to be defective, when compared with an erection of stone, like the Eddystone and Tour de Corduan Light-houses.
Captain Brodie’s remuneration.
Captain Brodie having, however, shewn a most laudable zeal in this work, and considering that he must have expended a sum of money beyond what had been subscribed for the erection of the Spar Beacon, the Commissioners proposed to make him a liberal allowance for the last model, to the preparation of which they had given their countenance. He was accordingly requested to state the expence of this model, with a view to his reimbursement. But, under an erroneous impression, he brought forward an account, containing an enumeration of charges connected with the Bell Rock, from the year 1792; and by applying these items to the imaginary profits of trade, the sum amounted to several thousand pounds. This appeared so contrary to the views of the Commissioners, that the account was returned, with an offer of L. 400 in full of all claims. This sum, however, was refused, and another proposition made, that the Board should apply to Government to have his services publicly rewarded. But it was finally intimated, that L. 400 were at his disposal; and here the matter rested till after Captain Brodie’s decease, when that sum, with interest, was, in 1816, paid to his widow.
The Author’s early designs for the Bell Rock Light-house.
In noticing the progress of the designs of the Bell Rock Light-house, it will here be necessary to give some detail of the writer’s own exertions in the preliminary stages of this measure, in his capacity of Engineer for the Light-house Board. In the summer of 1794, when on a voyage to the Northern Light-houses, in passing the Bell Rock, he directed the vessel to be brought near it, when he had an opportunity of observing the sea breaking heavily upon it. From this period, the difficulties which must attend the erection of a habitation on this rock, appeared in a stronger point of view than they had hitherto done. He, nevertheless, was resolved to embrace every opportunity of forwarding this great object. In the year 1796, he visited the operations of the Kilwarlin light-house, then erecting on the South Rock, a sunken reef, situate three miles off the coast of Downshire in Ireland, as a work resembling that which was in contemplation for the Bell Rock.
His pillar-formed Light-house.
The disastrous shipwrecks which occasionally happened at the entrance of the Friths of Forth and Tay, deeply impressed every one conversant in nautical affairs, with the most convincing proofs of the necessity for some distinguishing mark being erected upon the Bell Rock. As yet, the writer had not landed upon the rock; though he had begun to prepare a model of a pillar-formed light-house, to be supported upon six columns of cast-iron, under the impression that this description of building was alone suitable to its situation. The general features of this model may be understood, by examiningPlate VII., which represents the author’s original designs for the Bell Rock Light-house.
In the summer of the year 1800, this model was presented to the Light-house Board, when an official application was made to the Commissioners of his Majesty’s Customs, for the use of the Osnaburgh cutter, then lying in the harbour of Elie, on the coast of Fife, to carry the writer to the Bell Rock, that, by landing there, he might be enabled to judge of the applicability of his pillar-formed design to the situation of the rock. Upon reaching Elie, the Osnaburgh was found to be under repair, and could not possibly go to sea for several days, by which time the spring-tides would be over. On consulting with the commander, as to the most advisable course to be followed, in order to avoid losing these tides, it was resolved to go to St Andrew’s in quest of a boat; but being there also disappointed, the journey was continued along the coast to West Haven, on the northern side of the Firth of Tay, where a large boat was procured, and manned with fishermen who were in the habit of visiting the rock to search for articles of shipwreck.
His first visit to the Bell Rock, with Mr Haldane, architect.
On this first visit to the Bell Rock, the writer was accompanied by his friend Mr James Haldane, architect, formerly principal assistant to the late eminent Mr John Baxter. The crew being unwilling to risk their boat into any of the creeks in the rock, very properly observing that the lives of all depended upon her safety, and as we could only remain upon the rock for two or three hours at most, we landed upon a shelving part on the south side of the rock, at the spot marked “First Landing” onPlate VI.Having been extremely fortunate both as to the state of the weather and tides, an opportunity was afforded of making a sketch of the rock at low water: meantime, the boatmen were busily employed in searching all the holes and crevices in quest of articles of shipwreck, and by the time that the tide overflowed the rock, they had collected upwards of 2 cwt. of old metal, consisting of such things as are used on shipboard. A few of these were kept by the writer, such as a hinge and lock of a door, a ship’s marking-iron, a piece of a ship’s coboose (orkambuis, cover of the cooking-place), a soldier’s bayonet, a canon ball, several pieces of money, a shoe-buckle, &c.; while the heavier and more bulky articles, as a piece of a kedge-anchor, cabin-stove, crowbars, &c. were left with the crew, who were, however, disposed to make very light of their booty, when it was urged in extenuation of an extravagant demand which they made for the boat’s freight, being at the rate of one guineaperman, and one guinea for the use of the boat, besides expences, amounting altogether to about eleven guineas.
He concludes that a building of stone is most suitable for the Bell Rock.
The immediate result of this visit on the mind of the writer and of Mr Haldane, was a firm conviction of the practicability of erecting a building of stone upon the Bell Rock; and from that moment the idea of a pillar-formed light-house was rejected, as unsuitable to the situation. This opinion was chiefly founded upon the area or extent of the part which dried, or was exposed to view in the spring-tides, being found to measure about 280 by 300 feet, and consequently affording a sufficient space for a foundation, and even a degree of shelter from the force of the waves, for the lower courses of a building.
Pillar-formed building compared with one of stone.
The depth at high-water upon the Bell Rock was much against the design of a building with pillars, as a vessel drawing 12 feet water, and loaded with 100 or even 200 tons, may come with full sail against any erection made there. Were such a circumstance to happen to a pillar-formed building, and a ship to get thus entangled among the openings of the under part of the light-house, there is little doubt that the event would prove fatal to a building of that construction, however strongly framed. On the contrary, supposing a vessel to strike a building of stone, under these circumstances, it is not at all likely, that she could have any effect upon a mass of matter extending to 2000 or 3000 tons, so as to injure such a fabric.
Author’s designs and models of a stone-building.
Under these impressions, the writer, after his first visit to the Bell Rock, in the year 1800, made a variety of drawings, and constructed new models for a building of stone, shewing various methods of connecting the stones, by dove-tailing them laterally, like those of the Eddystone light-house, and also course to course into one another perpendicularly. Other methods were likewise modelled, for connecting the whole building in a more simple manner, by means of joggles, or square blocks of stone, and also by dove-tailed bats of iron cased in lead, as delineated in the various designs ofPlate VII.These plans and models were duly submitted to the Light-house Board, accompanied with estimates of the expence, amounting to the maximum sum of L. 42,685, 8s.
Mr Telford requested to visit the Bell Rock.
Sir William Pulteney having taken an interest in forwarding a bill for this measure in Parliament in the year 1803, gave Mr Thomas Telford, engineer, instructions to inquire into the circumstances of the Bell Rock, in the course of his journey to the Works of the Caledonian Canal. Mr Telford had accordingly taken some preparatory steps for making a Design; and, with this view, he had engaged Mr Murdoch Downie,author of several Marine Surveys, to accompany him to the Bell Rock. But the weather proved unfavourable at the time for effecting a landing upon the rock; and, the bill then in progress having been withdrawn before another opportunity occurred, Mr Telford’s visit was not resumed.
Mr Downie’s pillar-formed Light-house of Stone.
Mr Downie, however, who had previously been upon the rock, when making his Nautical Survey of the Eastern Coast of Scotland, prepared a drawing and an estimate of the expence of erecting a light-house upon it, which he stated at about L. 29,000. His light-house was to have consisted of eight columns of stone, of an elliptical or egg form, as he expressed it, ranged round a common centre, having the longer axis and smaller end towards a circular column in the centre of the plan. These columns were to support a circular building of stone for the habitation of the light-keepers and the site of the light room. By this plan it was meant to give less resistance to the waves. But it did not seem to be well adapted for the situation, as it wanted that solidity and unity of parts which are so essential to the stability of a building upon a sunken rock. Such a work would have been of difficult execution. It would have required similar apparatus with the solid masonry for its construction, and while in progress, it would have been in greater danger of being destroyed than a solid fabric. There seemed, therefore, upon the whole, to be but two opinions as to the proper description of a light-house for this situation, viz. either that it should be constructed of iron, as was maintained by Captain Brodie, or of solid masonry, as proposed by the writer.
Bell Rock Light-house proposed at a Meeting of the Royal Burghs.
The erection of a light-house upon the Bell Rock had been occasionally alluded to at the Convention of the Royal Burghs of Scotland, which meets annually at Edinburgh; and, in consequence of recent losses on that reef, the Convention of 1802 was moved, by Provost Duncan of Arbroath, to take this subject under its serious consideration. It was accordingly resolved, That the Lord Advocate Hope, one of the Commissioners of the Northern Light-houses, and Member of Parliament for the City of Edinburgh, should be requested to use his influence in forwarding this desirable object. His Lordship being present, readily engaged to undertake the measure, and declared that he would not allow it to rest until something satisfactory should be done.
The Commissioners of the Light-houses having afterwards furnished the particulars, the heads of a bill were arranged, which, in the session of 1803, was brought forward by his Lordship and the late Sir William Pulteney, who took a great interest in the Scotch business before the House of Commons. This bill had for its object to empower the Commissioners to borrow L. 30,000, and to exact the Northern Light-duty of 1½d.perton upon British shipping, and 3d.perton upon Foreigners, from all vessels bound to or from any port on the eastern coast of Great Britain, that should cross the latitude of the Bell Rock.