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.