A tower or other lofty building erected upon some headland or rock of the sea-coast, the upper part of which is brilliantly illuminated during the night-time to guide ships in their course, or warn them of contiguous danger. The fire-beacons or towers used for this purpose by the ancients were dedicated to the gods, and sacrifices were regularly offered up to implore safety to the mariners. As a knowledge of the sciences increased, they became establishments for the instruction of youth in navigation and astronomy. We have only very imperfect accounts of the construction of these buildings, but they appear to have consisted of a large tower of masonry, sometimes of a circular form, but more commonly square, finished on the top with a battlement, and containing various apartments. The fire was kept in a large and peculiar kind of chafing dish. To the early navigators the frequent recurrence of these buildings was absolutely needful, as they were destitute of the compass or any other guide, and were under the necessity of keeping near the shore, and were consequently in great danger from rocks and shoals.
These towers also formed a considerable part of the fortifications of the early ages, and before the invention of making distant signals, the watchmen were furnished with large sea-conchs, which they sounded from the battlements to warn the mariners, or to alarm the country in the case of an enemy. These fire-towers, which were once thickly scattered along the shores of the Mediterranean and the Red Seas, became, in time, scenes of the most horrid outrages; thus perverted from their original beneficial uses to the most baneful purposes, they were more dreaded than the dangers of the navigation; consequently they fell into disuse and decay, and gradually disappeared.
The most extraordinary of ancient structures of this kind was the Pharos of Alexandria, built on a small island at the mouth of the Nile, whence the word pharos has since been considered as synonymous with lighthouse. It was erected by Sostrates with such great magnificence, that it is said to have cost Ptolemy Philadelphius eight hundred talents of gold. It had several stories raised one above another, adorned with columns, ballustrades, and galleries, of the finest marble and workmanship. On the top a fire was kept constantly burning, which, according to Josephus, was seen at the distance of 300 stadia, or about 42 English miles. The famous Colossus of Rhodes served also as a pharos. The buildings which have in modern times replaced these ancient structures on the shores of the Mediterranean, etc, are far inferior to those of our own country; and as our limits will not allow of an extended view of the latter, we shall confine our account to the three most remarkable lighthouses on the British and Irish coasts; namely, that on the Eddystone, that on the Bell, and that on the South rocks.
The Eddystone lighthouse is situated at the entrance of Plymouth Sound, upon an extensive reef of rocks well known to mariners as the Eddy-stone (a name sufficiently significant of its dangers), lying at the distance of 9 1/2 miles from the Ram-head or nearest point of land. The many fatal accidents which happened on these rocks, rendered it very desirable to erect a lighthouse on the spot, but the numerous and apparently insurmountable difficulties of such an undertaking prevented the attempt till the year 1696, when Mr. Winstanley undertook and accomplished this important object, though it was the work of four years. A violent storm, however, in 1703, destroyed every vestige of it, except some irons that were fastened in the rock. It was rebuilt in an improved form by John Rudyerd, a linen draper of Ludgate Hill, London. This building was of wood, in form the frustrum of a cone; it was formed of 71 upright beams, united together by being bolted to circular kirbs of wood placed within side, and upon which the floors were framed. Mr. Rudyerd made his building quite plain, without the least projection or ornament on which the water could act when dashing against it.
The building was fitted up quite solid for 19 feet from the lowest point of the rock, and, excepting the well for the stair-case, was solid to the height of 37 feet The solid was formed of three beds of moor-stone, with strong floorings of timber between each bed, to unite them with the external uprights. The whole erection, in addition to the weight of this stone, (which was about 280 tons,) was secured to the rock by 36 iron cramps. In the centre of the building a strong mast was erected, secured by 2 cramps to the rock at the bottom, and rising above the solid to the height of 48 feet, being united to the framing of each floor it passed through, and thus forming a central axis to strengthen the whole. This building had some repairs of its timbers in 1723, and again in 1744; but it showed itself, during the buffetings of the sea, for 49 years, to be of a very excellent construction. It was destroyed by fire in 1755. In 1756 Mr. Smeaton was employed to rebuild it. From the great uncertainty of the weather, every stone was so contrived that it was of itself in a condition to resist the wash of the sea, even when it was immediately laid.
Each stone had one or two holes drilled through it before it left the work yard; and this hole being continued a few inches into the rock, or the stone beneath, a strong tree-nail was driven through it to pin it fast to its place: dovetails were also cut in the edges of each stone to connect them by oaken wedges, which secured the joinings whilst the mortar or cement was hardening; and as a further precaution against the latter being effected by the weather, all the outsides of them were coated with plaster of Paris. The work went rapidly on in this manner, and the second course was nearly set in a few days; but a gale sprang up, which obliged the operators to quit the work, leaving a few stones of the second course lowered down into their places, and chained strongly to the rock; and one of the most exposed was secured by laying upon it five cwt. of lead. A storm came on, and it was afterwards found that this weight had been lifted by the waves, so that the stone beneath it had escaped and was lost, as were four others; from which circumstance the force of the sea on the rock may be conceived.
The light-room was prepared in London; it consisted of eight cast-iron pillars for containing copper sash-frames for eighteen panes of glass each, with a cupola of wrought-iron and copper, terminating with a large gilded ball. The light consisted of twenty-four large tallow candles, suspended in a chandelier, and the first light was exhibted on the 16th of October, 1759, which has been continued ever since without any particular occurrence, or any accident produced by the many violent storms which have happened. In the year 1807 the chandeliers and the candles were removed, and in their place a reflector frame was fitted up with Argand burners and parabolic reflectors of silvered copper, to the great and essential improvement of the light. See Smeaton't Narrative, etc. of the Eddystone Lighthouse.
We now proceed to a brief account of the Bell-rock lighthouse, which, like its model, the Eddystone lighthouse, has figured in a thousand periodical publications, and will therefore not require the accompaniment of illustrations in our work. The Bell-rock is a dangerous reef, situated in the Firth of Forth, and the lighthouse upon it is of recent date. Various expedients have been resorted to at different times to warn the mariner of his approach to this rock, which is the more dangerous, as it is 12 feet below the surface at high-water. None of these, however, could be rendered durable; and though the necessity of a lighthouse was acknowledged on all hands, the difficulties and expenses attending such a work prevented the undertaking till the year 1806, when it was finally determined to erect a building of stone similar to that on the Eddy-stone rock. The work was begun in the year 1807 by erecting a building of timber as a temporary refuge for the workmen, which occupied the whole of the first season, as it was only for two or three hours each tide that the workmen could proceed. The winter was spent in preparing the stones ashore at Arbroath, and in the following summer four courses of stories were completed.
In 1809 the solid part of the lighthouse was finished, being about 30 feet high. By September in the next year, the building was raised to its height of 100 feet, and a light was exhibited in February, 1811. The building is a circular tower, measuring 42 feet in diameter at the base, and 13 feet in diameter at the top. The ascent from the rock to the top of the solid, or lowest 30 feet, is accomplished by a trap ladder; but strangers who cannot well ascend by such paths, are hoisted up in a chair by means of a crane. The light-room is 88 feet above the medium level of the tide, yet the sprays of the sea occasionally lash against the glass, so that it becomes necessary in gales of wind to shut the whole of the dead-lights to windward. The light-room is of an octagonal figure, 12 feet across, and 15 feet in height. The light is from oil, with Argand burners placed in the focus of silver-plated reflectors. Machinery is used for tolling two large bells night and day during the continuance of foggy weather. Four light-keepers are appointed, three of whom are always at the lighthouse, and one, in his turn, is ashore at liberty.
At Arbroath, a village on the coast about 12 miles distant from the Bell-rock, is a signal tower with an observatory, from which corresponding signals are kept up with the lighthouse.
The most remarkable lighthouse on the Irish coast is the Kilwarlin or South-rock lighthouse, lying off the coast of Downshire, and near the entrance of Loch Strangford, a station of great importance to the navigation of the Irish Channel. This lighthouse stands upon an extensive reef, lying about 3 mile: from the shore. Part of the rock is at all times above the perpendicular rise of the tide, but the foundation of the lighthouse is only about 4 or 5 feet above low water of spring tides. It was the work of the late Mr. Rogers, engineer to the Board of Customs: it was founded in 1795, and measures 31 feet diameter at the base, 17 feet diameter at the top, and its height about 70 feet.