“Great I must call them, for they conquered me!”
The erection of the North Unst tower, completed in 1854, offered no difficulties comparable to those which tested the skill and perseverance of the builder of the Bell Rock; yet, not the less, it is interesting as one of the most important results obtained by our English engineers. As our illustration shows, it stands rooted on an isolated reef, near the Shetland Isles, whose elevation above the sea is estimated at 200 feet.
Its northern front is almost perpendicular, and exposed to the most violent assaults of Ocean; on the south the declivity is less abrupt, but scarcely easier of access; and its summit is only of breadth sufficient to receive the foundation of the tower. This is 50 feet in height, and contains, besides the light-room, a sleeping chamber, a kitchen, and a store-room. At its base is built an additional store-room for the supplies of oil, charcoal, and fresh water. It is only accessible in fine weather.
The North Unst lighthouse is provided with a staff of four keepers, whose habitations are situated on the island of Unst (one of the Shetland group), about four miles distant.
It has justly been said that one of the strangest operations recorded in the history of lighthouses is, undoubtedly, the work undertaken and successfully accomplished at Sunderland in 1841. Some important improvements had been effected in its harbour; and a jetty had been constructed which rendered useless the old pier, and the lighthouse built upon it. Consequently, preparations were made for the demolition of the latter. An engineer, of the name of Murray, however, conceived the idea of transporting the monument, in one piece, to the intended site of the new lighthouse, a distance of about 475 feet. His proposal was favourably received; for the removal of great masses of masonry, in Europe at least, is an enterprise which always excites a very general curiosity. In the United States, that “go-ahead” land of bold projects and daring inventions, such enterprises are more frequent, and the process has been several times applied to houses (as recently at Chicago) and factories, for which it was desirable to secure a more convenient or a securer site. In such cases a series of openings is made in the walls, and through these openings beams are introduced, united together by cross beams so as to form a kind of flooring; then the lowest part of the base of the walls is destroyed, leaving the building to rest upon the timber platform, which is afterwards set in motion by a system of grooves.