Chapter XXIX: Appendix: No. I (2)

The Bell Rock, as appears by the best charts of the coast, is situated at the mouth of the Firth of Forth, in west longitude 2° 22´, and north latitude 56° 29´. It lies nearly fifteen miles from the Island of May, in a north-eastern direction _per_ compass, and twelve miles south-west from the Red-head in Angusshire, which it resembles, being a free-stone of a reddish colour, though of a much harder body, and closer grit. Besides its natural asperities, the surface in general is thickly coated with sea-weed, and, on the higher parts, the barnacle, white buckie or whelk, and limpets, abound, and altogether it presents a very rugged appearance, owing to the sloping of the strata from south, where highest, to north, at an angle of about 30 degrees. The material part of the rock, which lies north-east and south-west, measures, on an average, about 300 feet in length, and 240 feet in breadth. The highest part above the surface of the sea, does not exceed seven feet at low-water of spring-tides; which part, at high-water of same tides, is from nine to ten feet under water. The reporter also found, that the medium height of the foundation of any building erected upon it, will not exceed two or three feet above the surface of the sea at low-water of spring-tides. The above dimensions may be termed the material part of the rock; but, south-west of this, there runs a reef or shoal, of considerable extent, which is only visible in very low tides.

The short time which the Bell Rock is seen above water, and the irregularity of the soundings in its vicinity, are the cause of many wrecks upon it. Indeed, after the water has flowed, in ordinary tides, but a very short time, the most skilful mariner cannot point out its place, without its proper meaths or land-marks in sight, which lie from twelve to twenty miles distant. Under these circumstances, the Bell Rock will be found more dangerous to vessels coming near it, than perhaps any of those reefs upon which Light-houses have as yet been erected.

The Edystone Rock, for example, is about eleven miles from land, situate at the entrance of Plymouth Sound. Before the rock was reduced for the foundation of the Light-house, it was about three feet above high-water of spring-tides. The Longships Rock, situate three miles off the Lands-End, is about forty feet above high-water mark, though barely large enough for the foundation of the Light-house. The Smalls lie fourteen miles off St David’s Head; and the rock on which the light-house is built, is about five feet above high-water of spring-tides. The South Rock, lying three miles off the land, between Loch Strangford and Donaghadee, is about four feet under the surface at high-water of spring-tides. The Tour de Corduan, upon the coast of France, is built upon a sunken rock at the entrance of the Garonne, and is said to be about eight feet under the surface of the sea at high-water of spring-tides. And, lastly, the Bell Rock, the subject of this report, lying upwards of eleven miles from land, is from nine to ten feet under water, as before stated.

Ever since the reporter had an opportunity to know the danger and inconvenience that must attend the navigation of the Firth of Forth, while the Bell Rock remains without some signal upon it, to forewarn seamen, he has been much employed in considering what kind of building would be most applicable to its situation; and he has, therefore, endeavoured to obtain as much information as possible about works of this kind. The first light-house erected upon an insulated rock on the coast of Great Britain or Ireland, appears to have been that of the Edystone, which was begun in 1696, and was scarcely finished, when a dreadful storm carried it completely away. This erection was constructed of timber, and was designed and executed by Mr William Winstanly, who, with his artificers and the light-keepers, unfortunately perished in its ruins. The next light-house that was built upon the Edystone Rocks, consisting partly of stone and partly of wood, it was finished in 1709, and was the work of Mr John Rudyard, who, carefully avoiding the errors of his predecessor, lopped off all superfluous ornaments, and produced a plain building; which, after withstanding the fury of the waves for forty-nine years, had the misfortune to be destroyed by fire. The present Edystone Light-house was begun in 1756, and finished in 1759. It has now stood forty-four years, a memorial of the ingenuity and indefatigable labours of Mr John Smeaton, who, guarding against the defects of the two former buildings, constructed the whole of stone; the blocks of the solid part are curiously dove-tailed into each other; and every thing unnecessarily tending to give resistance to the water is carefully avoided, while the whole is completely fire-proof. The next light-house erected upon a situation of this kind, was the Smalls, which is placed upon eight beams of oak, arranged round a centre one. The latest light-house built on an insulated situation, is that upon the South Rock on the coast of Ireland. The reporter made three successive journeys to this light-house, during its progress: First in 1796, when it was only 12 feet in height; again in 1797, when it was nearly finished; and a third time in the month of August 1800. This light-house is built of granite, quarried in the mountains of Morne. The method of dove-tailing or joggling the stones, and attaching the courses to each other, is different from that of the Edystone; throughout the solid part of the masonry, and eighteen inches within the circumference of the building, six great bars of malleable iron are carried up, each four inches square; and upon the top of every alternate course, a circular plate of iron is let into the stone, and fixed by spear-bolts to the upright bars. The building is of a conical figure, and was built in the course of three years from a design by Mr John Rodgers of Dublin.

Before being properly certified as to the possibility of getting a foundation for a building of any kind upon the Bell Rock, the reporter thought of a Floating-light, like those moored off the Dudgeon-shoal, and other sand-banks on the coast of England. But the foulness of the ground about the Bell Rock, the great depth of water near it, together with the unsteadiness of a light of this description,--and above all, the perplexing uncertainty which must ever attend such a light in a storm, cannot fail to unhinge the confidence of the mariner, and thereby prevent him from making free with his course; and when, from an error in it, or in the distance run, he is disappointed in seeing the light, wrong conclusions are apt to be formed: he supposes that the Floating-light has drifted, and by changing his course, perhaps turns upon the very point of danger. These were considerations from which much relief was felt, upon learning that the rock was large enough to form the foundation of a permanent building; but, till the moment he landed upon it, he was uncertain if a building of stone was applicable; and foreseeing the difficulties which would be avoided, if, instead of carrying up the lower part solid, it could be formed of pillars, after the manner of the Smalls Light-house; reflecting also upon that elegant and useful application lately made of cast-iron, in the construction of bridges, choice was made of this metal, in his first model for the Bell Rock, as being more substantial than timber, and also less liable to corrosion from the action of the atmosphere than malleable-iron. This light-house (see Plate VII.), was to consist of six hollow tubes or pillars, built each to the height of ninety feet, measuring two feet in diameter at the base, and diminishing to six inches at the top, ranged round a common centre so as to form a diameter of thirty-five feet at the base, and eight feet at the top, immediately under the light-room. The pillars were to be cast in lengths or pieces of ten feet each; and at every joint horizontal bars were made to grasp the pillars, and the whole was also connected diagonally with various cross braces. Under the light-room, the building was to be laid out into four heights of apartments for the light-keepers and stores, formed within the range of the pillars, which occupying 45 feet of their height, the part below being of similar height, was left free for the passage of the sea, thus presenting the least possible resistance to the waves. These apartments were to be formed and covered in with strong copper, which, to prevent its acting upon the iron, was to be coated with tin. The lower part, or floor nearest to the sea, was to form an inverted cone, presenting a surface calculated to disperse the seas which might strike against it. In order still more to increase the common base, and strengthen this fabric, Professor Robison advised that a diagonal bar should be attached to the exterior side of each of the pillars.

In this first design, provision was made chiefly against the impulse of the sea, without taking into account the possibility of a vessel or wreck getting near it; but he found, after landing upon the rock, that it was possible for a vessel at high-water to come, without interruption, against the pillars. To guard against misfortune from this quarter, the reporter first thought of defending the pillars in various ways, particularly by throwing a kind of _Chevaux de Frise_ round them, with beams of oak. He, however, found it difficult to suppose any set of pillars of adequate strength to resist the force of a loaded vessel, violently agitated in a winter storm, which must render the pillar-formed construction very uncertain, even after every precaution should be taken to guard against such accidents. Nor ought the danger to which such a mass of metal, constantly exposed to the effects of the marine-acid, to be wholly overlooked, in giving a preference to a circular building of stone, which being a compact figure of solid matter, would resist any force that might be brought against it. The reporter has estimated the Pillar-formed Light-house at L. 15,000; and, although that for the Tower of masonry amounts to L. 42,636, 8s., yet, as it is treading a beaten path, which leads to certainty, it is surely to be preferred in a work of this kind: the foundation-course of stone must be more tedious than that of so many pillars, yet, in this there is nothing impracticable; and when the difficulties of the first courses are surmounted, the superiority of a fabric of stone over one of iron will readily be admitted.

In the model for a building of stone, made since the reporter first landed upon the Bell Rock, he has retained nearly the same elevation as that of the Edystone Light-house, which presents less resistance, and preserves a greater base than perhaps any other figure that could have been thought of. In this design he has also followed Mr Smeaton in the use of oak-trenails to keep the stones in their places, while the work is in progress; but has differed in the mode of diminishing the interior-walls, as the building rises in height. Instead, also, of Mr Smeaton’s plan of dove-tailing the stones, and connecting the floors, various other modes are resorted to, for effecting this perpendicularly as well as laterally, with the view of introducing larger materials, and keeping the stones in a more entire state. One of these is by an iron-bat, which is inserted into the joints of the lower courses, while the void or upper courses are to be indented, or let perpendicularly into one another. Upon inspection of the models and drawings of this design, it will perhaps be found to render the construction more simple, to divide the strength of the walls more equally, and, upon the whole, to give that stability which the situation of the Bell Rock seems so peculiarly to require. (See Plate VII.)

Upon comparing the pillar-formed Light-house, with the circular tower of masonry, it is matter of surprise that ever the Smalls Light-house should have been erected upon that plan, unless it were to avoid the additional expence of a stone building. There is, however, one circumstance which materially favours the pillar-formed construction at the Smalls, the want of which becomes a principal objection to its application at the Bell Rock; namely, that the Smalls Rock being five feet above high-water of spring-tides, the pillars are more obviously defended from injury in the event of a vessel or wreck coming against them, and also from the violence of the sea, whereas the Bell Rock, at certain periods of the tide, is from nine to ten feet under water.

When Mr John Rennie, civil engineer, obligingly favoured the reporter by examining his models, he gave a decided preference to the structure of stone, as did Professors Robison and Playfair. And Captain Huddart also, upon seeing the pillar-formed model, mentioned that the Trinity-House did not approve of iron pillars which, in the instance of the Smalls, were considered not so proper as beams of oak. The chief motives which induced the reporter to model a light-house upon the plan of the Smalls, were the uncertainty of procuring a foundation for a stone building; the small resistance which the pillars present to the force of the waves, and the first cost being very considerably less. But although this is true, with regard to the resistance, it must also be remembered, that the pillars come prodigiously short of the weight of a tower of masonry, of the dimensions of the one modelled, containing upwards of 2000 tons; whereas the iron pillars, even in their most improved state, do not exceed 200 tons. When, therefore, the stone light-house is compared with the iron one, all idea of the greater resistance of the former is lost in its solid contents, and in the uniformity of its figure.

In alluding to the great utility of an erection on the Bell Rock, it may, in general, be observed, that it is in the same degree of latitude with the Town of Holstebro in Denmark, and that the Naze of Norway, or entrance to the Baltic, lies north of Holstebro 1° 30´. It therefore follows, that all vessels bound to the Baltic, from, any port south of the River Tweed, must cross the latitude of the Bell Rock, while the degree of east or west longitude, in which such vessels pass, must depend upon the direction of the winds and other circumstances. In order to avoid the enemy in the time of war, it is common for shipping in this track, first to make the land about Buchanness in Aberdeenshire, and from thence take their departure either over seas, or along shore to their respective ports. With regard to ships bound for Archangel and Greenland, they, at all times, make the Islands of Shetland, and from thence take their departure. If, therefore, lines be drawn from Buchanness and Girdleness in Aberdeenshire, to Flamborough Head in Yorkshire, and the mouth of the Tyne in Northumberland, the Bell Rock will only be found to lie from six to ten leagues distant from these courses or lines. So that vessels crossing the mouth of the Firth of Forth, from Buchanness to the Humber and Thames, &c., may not only come in sight of a light upon this rock, but be materially benefited by it, according to the state of the weather, while those upon the course of the nearest line bound for Newcastle and Sunderland, &c. must, in every voyage which carries them north of the Tweed, be essentially served by a light upon the Bell Rock.

It further deserves notice in this place, that the principal estuaries on the eastern coast of Great Britain, are those of the Friths of Moray and Forth, and the Rivers Humber, and Thames. The most material general purpose which would be answered by a Light upon the Bell Rock, is the opening of the Firth of Forth as a place of safety, in storms from south-east, east, and north-east. When mariners at sea are overtaken with a gale under such circumstances, they make for the most contiguous of these four inlets; but are often known to avoid the Forth, on account of this Rock, which, like another Cerberus, guards its entrance. Of this, a melancholy example occurred (which will long be remembered with that regret which never fails to accompany the forlorn case of the widow and fatherless), in that heavy gale at south-east, which happened in the winter of 1799, and drove many vessels from their moorings in Yarmouth Roads, put them past the Humber, and the crews being afraid to make free with the Firth of Forth, even though the wind was fair, were, with others, driven ashore between the Redhead in Forfarshire, and Kinnaird Head in Aberdeenshire, to the number of about thirty sail. Nor were they all saved that weathered Kinnaird Head; several were wrecked in Orkney and Shetland; and the whole loss occasioned by this gale has been stated as high as seventy sail, with many of their crews! amongst which are reckoned two that were known to have been lost upon the Bell Rock. This fatal catastrophe, of which the history of our coast affords few examples, is the more to be lamented, when it is considered that a light upon the Bell Rock, by opening the way to a place of safety, would infallibly have been the means of preventing much calamity, to those who sought safety, with various fortune, in more northern latitudes. In conclusion, it may be observed, that until this improvement of the coast comes from the Commissioners of the Northern Light-houses, it is much to be feared that the cause continuing, the sad effects will not cease.

(Signed) ROBERT STEVENSON.

To the Honourable the COMMISSIONERS } of the Northern Light-houses. }

REPORT by Mr RENNIE.

_London, 30th December 1805._

GENTLEMEN,

In consequence of your directions, I set out in a vessel called the Pharos, from Leith, on the 15th of August last, early in the morning, in company with ROBERT HAMILTON, Esq. one of your Commissioners, and Mr STEVENSON, your Engineer, to view the Bell or Cape Rock, for the purpose of considering the practicability of building a Light-house thereon. But, owing to the want of wind, we did not get near the Rock till dusk, _i. e._ about half-past seven, which was near half ebb; but although we were not above a mile distant, we could discover but little of the rock itself. Its situation, however, was sufficiently apparent, by the breakers upon it, which, although the sea was very little agitated where we were, yet the waves were very high on the Rock itself, breaking over it with considerable violence. We approached within less than half a mile of it, and took soundings; but it becoming dark, we judged it advisable to sail further off, and anchored about a mile from the Rock all the night, in expectation we should be able to land on it next morning, which, from the serene appearance of the sky, we doubted not we should be able to effect. We had not dropped the anchor long, when the little wind there was during the day ceased, and it became a dead calm, but, notwithstanding this, there was a heavy swell, and the vessel rolled much. Frequently, during the night, I viewed the place where the Rock lies, and saw the heavy breakers which played about it, till near three quarters flood, when they nearly ceased, and no appearance of such a place was to be observed. They commenced again about quarter ebb, and continued increasing for some time; but, by nine in the morning, the sea became more smooth, and about half-past nine, the rock appearing several feet above water, we left the Pharos in a small boat, and had the satisfaction of landing on it about half-past ten, a little before low water. The spring-tides, however, were rather past their height, being five days after the full moon. We landed on the north-east side of the Rock, in a little bay or inlet, through some breakers, but these were just on the verge of the Rock, for when we got in, the water was quite smooth.

The Rock lies in a direction nearly south-west and north-east, magnetic bearing. That part which was dry, saving some small inlets, I found to be about 280 feet long, and 220 feet wide. Its general surface was about 4 feet above the level of low water, though some places were about 6 feet high. The Rock, however, extends for some distance all round that part which was dry, and dips downward. It extends under the surface for about 400 feet on the south-west side, about 100 feet on the north-east side, and about 50 on the south-east and north-west sides; and on those parts the water is shallow. At about 300 feet south-west, I found about 13 feet water, but, on account of the breakers, could not sound on the low parts of the Rock, or either of the other sides. At the extremities of the main Rock above mentioned, the dip is sudden; the bottom, however, is rocky for a considerable extent round its bed, but the water is deep.

The Rock itself is a hard red freestone, in beds dipping to the south-east, about one in five; these beds are various in their thickness, some being much greater than others; but, generally, well connected together. Such parts as are not immediately exposed to the violent wash of the waves, are coated with a hard crust, and covered with limpets; and, indeed, when it is exposed to the full fury of the sea, there seems to be little appearance of decay, so that I have no doubt, were a Light-house constructed here, no fears need be entertained for the durability of the Rock, as it seems to me well calculated to resist the effects of the waves.

We remained on the Rock for about an hour and a half, when the tide began to flow rather quickly, and having got all the necessary measurements as to height and size, we left it, and returned to our vessel, having been much gratified with the ample view we had of it, and soon after our getting on board the vessel, we weighed anchor at one, and the wind suiting, we arrived at Arbroath about four o’clock.

The Inch Cape, or Bell Rock, lies in West longitude 2° 22´; North latitude 56° 29´, as stated by Mr STEVENSON. It is about eleven miles distant from the harbour of Arbroath, about ten miles from the Bluff Point of the Sands of Barry, at the northern side of the entrance to the River Tay, and about eleven miles from the Red Head, which lies between Arbroath and Montrose; so that in fact it is about the same distance from the shore as the Edystone Rock, on which Mr SMEATON completed a stone light-house in the year 1759. The soundings on the south-west side, and near to this Rock, as taken at low water, were about 7 fathoms, within half a mile of it; and, in the same direction, about 15 fathoms, bottom rock. About three-fourths of a mile, 19 to 20 fathoms, bottom gravel. At the north-east side, and near to the Rock, the soundings were 6 fathoms. About three-fourths of a mile north-west of the Rock 15 fathoms, and about a mile and a quarter in the same direction 18 fathoms. We did not take the soundings on any other side of the Rock, or at a greater distance; but I was informed they were full as much as those we had taken.

Such being the situation of the Cape or Bell Rock, lying nearly in the direction which vessels generally take in sailing into the Firth of Forth, from northerly directions, or out of it, in sailing to the north or east, it is no wonder that many accidents should arise in hazy weather or dark nights, there being no means of discovering its situation correctly, unless when the land-marks are to be seen, for the deep water lying so close all round the Rock, nothing can be ascertained from soundings, until too near to enable vessels to get out of the way. Breakers, no doubt, frequently point out its situation, but these, in dark nights, and hazy weather, often are not sufficient, and at high-water, even in good nights, are not always discernible; for want of other means, many vessels have been wrecked thereon, and numberless valuable lives and much property lost.

Vessels trading from the Humber, and northwards to the Baltic, to Norway, Greenland, &c. are often, by stress of weather, driven towards the coast, and even those from more southerly ports often share the unfortunate fate of coasting vessels. It is therefore of the utmost importance that something should be done to mark out the situation of this dangerous and frightful Rock.

A Beacon has been proposed, but this would but ill answer the purpose. Nothing, in my opinion, would do it effectually, except a Light-house; and the question is, whether a Light-house could be built on this Rock, and, if so, of what materials it should be composed, and which, in point of strength and durability, are most likely to become a lasting work, without which the mariner can never make free with his course.

Of all the works which could be erected here, perhaps a wooden Light-house would be the cheapest. But were a wooden Light-house to be constructed, I apprehend a solid base of stone must first be constructed, similar to that built on the Edystone by Mr RUDYARD; but wood is liable to decay; it would require constant repairs, and would also be liable to be destroyed by fire, as that of Mr RUDYARD’S was. A Light-house of cast-iron might also be constructed here, and I will allow that it might have a coating of lead, or other metallic substance, so as for a long time at least to resist the effects of the marine acid. But to make a Light-house that would last of such materials, would be nearly, if not wholly, as expensive as one of stone, which I believe, I need scarcely say, no human ingenuity could render as durable; and as the durability of such a work as this is of the utmost consequence, I apprehend a moderate sum of extra expence ought not to be looked on as an object of material consideration, when put in competition with the advantages of durability. But, besides these objections to a work constructed of wood or iron, vessels being apt to be driven against it at high-water, there being at spring-tides from nine to ten feet deep on the top of the Rock, and should the vessel be a large one, and acted on by a heavy sea, it would not be difficult to foretell the consequences.

The durability and efficacy of a stone Light-house has been proved in the most satisfactory manner at the Tour de Corduan, near the mouth of the River Garonne, on the coast of France; at the Edystone, off the mouth of Plymouth Harbour, and in other situations. Why, therefore, with such incontestible proofs before our eyes, should recourse be had to a material new in itself for such purposes, and untried? a material which, if fitted and joined together as it ought to be, would consume nearly as much time in getting the lower part laid, as the laying of three or four courses at the bottom of a stone Light-house, and when the stone-work is got to the height of five or six feet above the Rock, the greatest part of the difficulty may be said to be over; and besides, such a solid mass of materials would resist any violent shock of a vessel which might be brought against it by the sea. I have, therefore, no hesitation in giving a decided opinion in favour of a stone Light-house.

As to the practicability of erecting such a work on the Bell Rock, I think no doubt can be entertained, with such examples before us as the Tour de Corduan and Edystone before mentioned.--In the 4th volume of the _Architecture Hydraulique_ of BELIDER, an account is given of the Tour de Corduan. It is built on a low rocky island, dry at low water, and whose surface is nearly level; it is covered at high-water, as near as I can ascertain from his draughts and description, about 8 or 9 feet. It is exposed to a very heavy swell of the sea, lying quite open to the Bay of Biscay, from whence it is well known very heavy swells come, and beat against it with great fury; yet this Light-house has resisted the fury of the waves for above 250 years.

The Edystone Light-house is built even in a more exposed situation than that of the Tour de Corduan, and upon a rock whose surface is little larger than the base of the Light-house itself. The top of this rock is shelving, and was seldom covered by ordinary spring-tides before Mr SMEATON began his foundation; the lower part, however, was always covered over at the top of neap-tides. At the lowest place, when he began his work, the rock was dry about six hours each tide, although there the Edystone Rock is less in size than the Cape Rock, yet the advantage of being so long dry, is greatly in favour of building a Light-house; the most difficult and tedious part of the work being the establishment of the four or five lower courses of the foundation.

The higher parts of the Cape Rock, as I have before stated, are little more than six feet above the low water of an ordinary spring-tide. But I apprehend, when a place sufficiently large for the foundation is levelled, its surface will be little more than three and a half feet above the low water of an ordinary spring-tide. I do not think that above three hours’ time for work can be expected, which is about half of what was got at the Edystone. The depth of the water all round it, and its exposure to the German Ocean, renders it as difficult a situation to construct a durable work upon as that of the Edystone, if not more so. I doubt, therefore, more time will be required for the work; but this depends so much on the state of the weather, that no certain calculation can be made. It is better, therefore, to reckon on a sufficient time, and this I would beg leave to state at four years; and if it can be done in less time so much the better. The Rock upon which the Edystone Light-house stands is certainly harder than the Cape Rock, and of course required more time to work; but, on the other hand, the Cape Rock lying in a more northerly latitude, and where the weather is more variable, it is likely that greater interruption will be given to the proceedings than in the other; so that, all circumstances considered, the time I have mentioned, I doubt, will be little enough.

Mr STEVENSON, to whose merit I am happy to bear ample testimony, has been indefatigable in obtaining information respecting this Rock, and he has made a model of a stone Light-house, nearly resembling that of the Edystone, in which he has proposed various ingenious methods of constructing the work, by way of facilitating the operations. I own, however, after considering these in the fullest manner I have been able, and comparing them with the construction of Mr SMEATON’S, I mean in the building, and also that there is undoubted proofs of the stability of the Edystone, I am inclined to give it the preference. No doubt some methods different from the Edystone will require to be put in practice for the foundation; but its general construction, in my opinion, renders it as strong as can well be conceived,--in fact, it may be looked upon as a solid mass of rock. Viewing the matter, therefore, in this light, it will be unnecessary for me to accompany this Report with the design of a Light-house. It will be time enough to make such a design, when the Commissioners shall be in a situation to give orders for the erection, and then I have no doubt Mr STEVENSON will furnish much valuable matter towards the perfecting of it.

The total height of the Edystone Light-house, from the lower course of stones on the rock to the top of the platform or balcony-floor, is about 70 feet; from thence to the bottom of the iron-frame of the lantern about 6 feet 9 inches; and the lantern itself is about 8 feet 3 inches; so that the total height to the eve of the cupola is about 84 feet 6 inches. Now, as the Bell Rock lies so much lower than that of the Edystone, I think the height of the shaft or tower of the Light-house should not be less than 80 feet, or, perhaps, a little more, say 85 feet; so that the cupola will, in this case, be about 100 feet above the surface of the rock. With such a height of Light-house as is here proposed, I would advise that the diameter of the base should be greater, and as it is less surrounded by such an extent of rock, it will give facility to the gradual diminution of the effects of the waves breaking upon it; will render the fabric more steady, and, as it will diminish quickly, no great additional surface will be presented to the sea.

The floor of the lower room, _i. e._ the height of the solid part of the Light-house, I would propose to be about 50 feet, and from thence to the top of the platform 35 feet, making a total height, from the rock to the platform or gallery, of 85 feet. As to the lantern itself, I need say little on that head, as lanterns for light-houses have, of late years, been greatly improved, as well as the lights. The substitution of lamps with reflectors, in place of coal or candle lights, has been found of the greatest advantage to the mariner; and it is not unlikely, from what I have been lately made acquainted with, that the substitution of the hydrogen gas in place of lamps, will not only prove a much cheaper, but a better light than even lamps. I am told that it will not cost above one-eighth of the price of oil. The kind of light to be used is also a matter of consideration, for unless lights are so constructed as to enable the mariner to distinguish between one and another, he may be apt to mistake his situation; but that also can be easily arranged, when this part of the subject comes to require consideration. The new light on the Skerries in Orkney is a revolving one; perhaps a similar one may also be judged advisable here, as, if the Light-house on the Island of May was to be fitted up with reflectors in the usual manner, it would not always be easy to distinguish this from the Cape Rock, unless one of them was to be made a revolving, or the lights to be placed in different situations of the house.

A Light-house has, of late years, been built on the South Rock, near the mouth of Loch Strangford, on the coast of Ireland. This Light-house was begun on the 11th of June 1795, and completed the 25th March 1797. It is 30 feet diameter at the base, and about 15½ feet just below the balcony floor. It is 56 feet high from the rock to the platform or balcony floor, and its shape is the frustum of a cone. It is built of granite from the Mountains of Morne; and the lantern, from the platform to the cupola, is about 12 feet high, and 10 feet wide. The light is a revolving one, and lighted by 10 lamps with reflectors, 3 in the upper course, 3 in the lower course, and 4 in the middle, and makes a revolution in five minutes. This distinguishes it from the Copland lights.

The rock on which this Light-house stands is about 400 yards long, and about 100 wide, and is covered about 18 inches deep at high-water, ordinary spring-tides. The rock is composed of beds of schistus, intermixed with beds of a kind of indurated clay, which are wearing fast away by the washing of the sea; and, unless some speedy and effectual means are taken to secure it, this Light-house will not be of long duration. It has cost about L. 22,000, and it is said that L. 7000 more will be required to secure the rock from washing away. I will not take upon me to say that this sum will be sufficient for the purpose; but it seems to me that it will not be a very difficult matter to secure the rock, if proper means are taken. The channel is here narrow, and the seas cannot be very heavy; indeed MACCULLOCH the Light-house keeper informed me, that they seldom rise above the first landing, which is only about 27 feet from the top of the rock.

In the construction of a Light-house at the Cape Rock, great care will be necessary in choosing stone of the most durable quality, fit to resist the effects of the waves. For this purpose, I examined the rocks lying along the shore nearest adjoining the Inch Cape Rock, but found none of a very durable quality; most of it is a red freestone, softer than the rock itself, which has been much worn away by the wash of the sea, and therefore by no means fit for the exterior work of such a building; and there does not appear to be any fit for that purpose nearer than Kingoodie, about three or four miles from Dundee. This stone is a hard millstone-grit, of an excellent quality; very hard to work, but can be raised in blocks of any size and thickness required. It therefore appears to me to be most fit for the exterior work of a Light-house to be built on the Cape Rock; but as the price the proprietor asks for it is very high, it becomes a question whether the solid part of the building may not be done with the stone from near Arbroath, which, although not fit for exterior work, is yet of a pretty strong quality, and might be used in the solid part of the building, not exposed to the weather or wash of the sea: Or, it may be a question, whether the saving that would arise from using the stone near Arbroath, is a consideration, when put in competition with the superior strength and specific gravity of the Kingoodie stone.

Granite is also a stone that will resist the waves without wearing, and it is therefore a matter of consideration, whether granite stone might not be had from Peterhead or Aberdeen for this purpose. Granite, it is true, cannot conveniently be had in such large blocks as the Kingoodie stone, but it may be had in blocks sufficiently large to answer the purpose, and, if well dove-tailed, and properly cemented together, the whole may be made to act as one solid body of rock.

As to the expence of a Light-house in such a situation, it is not a very easy matter to form any thing like a correct calculation. So much depends on weather, on the untoward circumstances that may probably happen while the work is in hand, that they baffle even the most experienced artist to make the proper allowances. The price and quantity of materials is by no means difficult to ascertain; but the expence of putting them together must be more a matter of guess than of correct and well founded calculation. I have, however, computed the expence that such a work ought to cost, and have made every allowance for contingencies, from my own experience of works in the sea, and from what I have been able to collect from the experience of others, in which, I think, I have made a very full allowance for contingencies, and the cost amounts, by my estimate, to L. 41,844, but I will say L. 42,000, and, I trust, if ever the work is executed, and done with judgment, it will not exceed that sum.

I have gone on the supposition, that the outside is to be made of Kingoodie stone, and the hearting of stone from near Arbroath. I am, Gentlemen, your most humble servant,

(Signed) JOHN RENNIE.

To the Honourable the COMMISSIONERS} of the Northern Light-houses. }

REPORT by Mr STEVENSON.

_Edinburgh, 15th November 1806._

In the year 1800, when the Reporter laid before the Commissioners various models of a Light-house for the Bell Rock, the prospect of the undertaking was so distant, that it then appeared unnecessary to trouble the Board with any scheme for carrying the work into execution; but since the passing of the act of Parliament for this purpose, the case is materially altered. In preparing any method for carrying on a work, the most difficult in its nature, and one to which the common tests of experience can hardly be applied, he is aware, that it is impossible, by any previous arrangement, to determine what will answer in all respects. In so far as the operations on shore are considered, the ordinary rules of practice apply, but, in forming plans for the Rock itself, matters must be adjusted to the situation and circumstances of the case.

Certain measures, of a preliminary nature, are, however, indispensably necessary, while others may be of doubtful application; among the former, it appears to be essentially necessary to provide a vessel to be moored at the distance of from three quarters to one mile north-west of the Rock. She must, of course, be fitted up as a store-ship, with accommodation for the artificers, and ground-tackle for riding in from 17 to 20 fathoms water, on rather a hard bottom. This vessel, besides answering as a store-ship for water and provisions, may occasionally take on board lime, cement, and other materials from the small craft at the Rock, when lying at anchor with them on board may be found inconvenient. There is also another and most important service, which this vessel will fall to perform in terms of the act of Parliament, which is the carrying of a Light upon her mast, for the benefit of shipping, and to enable a duty to be collected, even before the commencement of the work, agreeably to the suggestion of Mr CUNINGHAM.

The Reporter, in order to inform himself more fully regarding the construction of such a vessel, while attending the progress of the Bill in London, visited the Floating-light ship at the Nore, under the command of Mr BENNET, who very politely described every particular connected with the business. He had also frequent communications with Captain HUDDART of the Trinity House, who takes a particular charge of the Floating-lights under the management of that Board, since which he has also corresponded with him upon the subject, who has obligingly stated his ideas relative to a vessel and moorings fitted for the Bell Rock. Upon the whole, the Reporter is of opinion, that a dogger, or Dutch-built vessel, is best calculated for this service. Such a vessel would require to be from 80 to 100 tons burden, moored with a mushroom-anchor, weighty iron mooring-irons, having likewise on board a hempen cable of 16 inches in circumference. The mushroom-anchor, which is but a late invention, is now in use at all the Floating-lights on the coast, and even in some of his Majesty’s store-ships. Its great property consists in its being hardly possible for a vessel to _foul her anchor_ with it; and the construction is such, that it may be made in part, or wholly, of cast-iron, agreeably to the accompanying model, from which an idea may more easily be formed of its application. (See Plate X.). This vessel must be furnished with such a light as to be readily distinguishable from the Coal-light on the Island of May; and although the Dudgeon Floating-light, off the Norfolk coast, which carries two lanterns, is at a great distance, yet, as it is the nearest Floating-light to the Bell Rock, it may be advisable to distinguish it from that also. As a vessel cannot be dispensed with for the accommodation of the artificers, it will be found to be a great saving to employ her as a store-ship. As this vessel is only meant to answer a temporary purpose, by purchasing one of the Dutch or Prussian prize-ships, now for sale in Leith, she might perhaps be fitted up for about L. 2000.

Although it would be perfectly impossible to do any thing with much effect at the Bell Rock, without a vessel stationed in the offing; yet as she must necessarily be moored at the distance of about a mile from it, to give a sufficient birth for swinging, according to the wind, and also to give sea-room to clear the Rock, in the event of her breaking adrift, the inconveniency and difficulty of the frequent passage between the Floating-light and the Rock must be very considerable. It therefore occurs to the Reporter, that the greatest advantages would arise from the erection of a temporary residence for the artificers upon the Rock during the working-months of summer, and also to answer as a store for some of the materials. The greatest difficulties which Mr SMEATON had to struggle with at the Edystone, arose from the smallness of the rock, which at once precluded any attempt of this kind from being undertaken, and subjected the work to all the disadvantages and trouble so particularly described as experienced in communicating on all occasions with the store-ship. But, from the extent of the Bell Rock, an opportunity may be had for erecting a temporary residence, for facilitating the work. It was under the conviction that such an accommodation might be constructed, that the clause was introduced into the act for allowing the collection of half-duties upon the erection of a Beacon. But, independently of these advantages, the Reporter conceives some erection of this kind necessary, to give confidence to the artificers, in the event of accident to the boats, of which they might lay hold, until assistance could be procured from the store-vessel. This temporary residence is provided for in his estimate for the Light-house, and having modelled it, he proposes that it should consist of beams of timber, not less than 50 feet in length, and of proportional strength; the beams are coupled together at the top, where they form a cabin for the workmen, and, at the same time, answer all the purposes of a Beacon.

The next material object to be considered, is a method which may prolong or extend the working hours at the Rock, especially in the first instance, to low water of neap, as well as spring tides. In this respect we also find, that Mr SMEATON had no alternative, having had barely extent for the foundation of the Light-house; but, in this respect, he had less occasion for such an apparatus, as the top of the Edystone Rock was rather above high-water, although, from its shelving form, the level of the ground-course was not more than nine feet above low water of spring-tides. The ground-course of the Bell Rock, however, will not be more than about two feet above low-water of such tides. It therefore becomes an object of great importance, to construct a water-tight fence round the site of the building, which might be the means of saving a whole season with the work, and securing the proper execution of the lower courses, by enabling the workmen to go on in a more deliberate manner with their operations. The Reporter has had several methods in view for raising a coffer-dam for this purpose to the height of about six feet or thereby, which would allow the work to proceed regularly in moderate weather at low water of neap as well as spring-tides. He has, accordingly, modelled a coffer-dam with this view, which he proposes to be three feet more in diameter than the base of the building, and, from its exposed situation, the greatest attention must be paid to the strength and fitness of the materials. At first he intended this to be of timber, but at length fixed upon cast-iron, strongly connected with iron-bolts, passing through flanges raised upon the joints, which are to be provided with a groove, for the conveniency of tightening them. The whole of this apparatus is estimated to weigh about 40 tons, and is so constructed, that when all the pieces are landed on the rock, and laid in their places, the foundation for them being prepared, they may be set up, and temporarily fixed, in the course of a good spring-tide.

There is no part of this critical work which will be attended with so much difficulty as the landing of heavy materials, nor is there any part of the business that has occupied so much of the Reporter’s attention. Mr SMEATON appears to have had a great deal of trouble upon this head; and in conversing with one of those having charge at the South Rock Light-house, on the coast of Downshire in Ireland, while it was building, it was stated, that there was more time lost in getting a regular supply of materials, and more vexation attending this department, than any other part of the operations, although this rock is exposed and dry at every tide, and only 3 miles from the shore, with a beach where vessels were laid to discharge their cargoes; whereas the Bell Rock is about 11 miles from land, forming neither a steep-face, like that of the Edystone, nor a sloping beach, like that of the South Rock, while it is so low in the water, that it can afford little or no shelter to vessels, if brought alongside of it. Under all these adverse circumstances, the landing of the materials becomes a consideration of the most perplexing nature. He has sometimes thought that the depth of water upon the rock might be turned to advantage in landing the stones at high-water; yet this mode has its disadvantages, and could not always be depended upon; others must, therefore, be resorted to, more certain in their application. Vessels of an easy draught of water, and not exceeding 20 tons burden, might in very moderate weather be brought close into some of the small creeks of the rock. Some of these will admit of improvement, where cranes might be fixed for unloading them. This may, perhaps, turn out to be the surest mode upon trial; but it may also be necessary to resort to others, such as having buoys moored in different directions, at a convenient distance from the rock; by making fast a hawser to the buoy best suited to the direction of the wind; the hawser may be veered out till the vessel with the materials gets so close to the Rock as to discharge. Some have even supposed, that the materials may be transported to the Rock under these circumstances by a float of cork or timber, and when the vessel is thus cleared of her cargo, she may be hauled off again, and so make sail. The stones, when landed, if not immediately built, may be stowed into the cast-iron coffer-dam, which, for this purpose, will be found of the greatest use, while the lower courses of the building are in progress; and as the work advances, other plans will present themselves.

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