Something about Lighthouses.Lighthouses were in use with the ancients. The towers of Sestos and Abydos, the Colossus of Rhodes, and the well-known tower in the island of Pharos, off Alexandria, are examples. Suetonius also mentions a lofty tower at Ostia, and another on the coast of Batavia, erected for the purpose of guiding the mariners by night. In lighting a great extent of coast, it becomes necessary to provide for the distribution of lighthouses in such a manner, that they may be readily distinguished from each other, and, at the same time, so disposed, as not to leave vessels without some point by which to direct their course.One of the most extraordinary lighthouses on our iron-bound coast, stands on a reef of rocks called the Eddystone, in the English Channel, about ten miles from the Land’s End, in Cornwall. It was erected by Mr. Smeaton, in 1759, and still remains a lasting monument of his scientific skill. It consists of four rooms, surmounted by a gallery and lanthorn. The floors are of stone, flat on the surface, but concave beneath, and are kept from pressing against the sides of the building, by means of a chain which is let into the walls. The entire edifice is about eighty feet in height, and yet, such is the immense power of the wind in the neighbourhood of therocks, that the waves are seen to ascend like a cupola, considerably above the lanthorn at the top. The appearance of this is truly wonderful and sublime.The Eddystone LighthouseAnother celebrated lighthouse is called the Bell Rock Lighthouse, which stands on the coast of Scotland, near Arbroath, in Forfarshire. These rocks have always been particularly dangerous for shipping, and when the commerce of Scotland was very much less than at the time of the erection of the lighthouse, it is said that the monks of the Abbey of Arbroath erected a bell on the rock, which was rung by machinery during the flowing and ebbing of the tide. About the year 1807, the present noble specimen of what man can accomplish, was commenced. The work was completed in 1811, under the direction of Mr. Stevenson, and reflects thehighest honor upon his professional skill. The difficulties that had to be overcome were of the most embarassing description. At the commencement of the work, in consequence of the short time the rock was not covered with water, two or three hours were considered a good tide’s work, and, frequently after a portion of the foundation had been completed, a sudden storm would render it necessary to perform the same labour twice over, and even oftener. On one occasion, Mr. Stevenson and the men who were with him at work were exposed to great danger, in consequence of the vessel that used to carry them from the rock having broken from her moorings, and the tide at the same time commencing its rise. They were, fortunately however, saved by a small boat, which happened to bring Mr. Stevenson some papers relating to the lighthouse at the time.The form of the lighthouse is that of an immense pillar; the lower courses of stones are trenailed and wedged together with oak timber, to the height of upwards of forty feet, or throughout the solid part of the building. At the stone staircase leading from the door to the first floor, the walls are seven feet thick, and from this it gradually decreases upwards. The stones of the walls of the several apartments are connected at the ends with dove-tailed joints. The floors are formed of long stones radiating from the centre, and set in such a manner that the pressure of the floors upon the walls is perpendicular. In the stranger’s room or library, the roof takes an arched form, but the centre is cut only upon the interior end of the stones of the cornice, the several stones of which it is composed being all laid upon level beds.In order to give a slight idea of the force this lighthouse has to withstand, we may quote the following remarks from Mr. Stevenson. He says:—“It is awfully grand, at the time of high water, to observe the spray rising on the building, and even to be on the rock at low water, when the waves are about to break. Being, in a manner, only a few yards distant, they approach as if they were about to overwhelm us altogether. But, now that we are accustomed to such scenes, we think little of it. You will, perhaps, form a better idea of the force of these gales, when I relate to you that, on the 15th of February, the large piece of lead which was used as a tack weight of the balance crane, weighing nearly five hundred pounds, was fairly lifted by the sea and carried to the distance of six feet from the hole in which it had laid since the month of August. It was found turned round, with the ring-bolt downwards, and it was with great difficulty that four of us could muster strength enough to move it.”There are many other lighthouses upon our coast. That at the Land’s End is a very fine one, as is that at Orford and Yarmouth Sound. Of late years a new mode of building lighthouses has been in operation, and of this I shall say a few words.Perhaps no class of persons are exposed to greater dangers than seamen. They have to contend, not only against the elements, when all around them is a barren waste of waters, but, no sooner are they gladdened by the sight of land, than their perils are increased to a much greater extent. In the former case, the wind was, perhaps, the only danger they might have to provide against, but approaching land theymust take care to avoid sunken rocks and sand-banks, which might be the cause of their destruction. Upon rocks and the solid coasts, lighthouses have been erected with comparative ease (as we have already stated), but, upon sands, the erection of them is very difficult; and was, till within these few years, considered to be almost insurmountable. Floating lights, which are large lanthorns suspended in the rigging of a vessel, or built up in the hull, are frequently used to illuminate a sandy coast, full of shoals and sand-banks—but these are subject to many inconveniences, by the pitching and rolling of the vessel—for every now and then she is partially submerged in the trough of the sea, covered with spray and drift; or, what is most to be dreaded, she is liable to be blown away from her moorings—an accident productive of the most disastrous consequences to life and property; for should such a catastrophe happen, the ships sailing along a coast having nothing to warn them of their danger, run upon the shoals or sand-banks, and are frequently totally wrecked, and all traces of them lost, in the course of a very few hours.Such being the case, the attention of Engineers has for some time been directed to the best means for overcoming this difficulty. The building of a house upon a rock has ever been considered the proof of wisdom, whilst the erection of it on the sands has been held the proof of folly. But the advances of science prove that a house may be built even upon the sands, when proper care is taken in its construction—and the erection of lighthouses on this foundation is held to be a triumph in engineering.This remarkable result has been accomplished chiefly bymeans of Mitchell’s screw mooring, which consists of an immense screw, very similar to that of the corkscrew, with flat cutting spirals. It is a spiral or screw round a cast-iron spindle, having a square head, upon which a large key is placed (like the key of a watch), and the screw is turned by enormous leverage, and it is then forced into the ground, and can be carried to a great depth. This instrument was thought to be applicable to the establishment of Lighthouses upon sands; and, accordingly, a series of experiments was undertaken, and a lighthouse was speedily erected on the verge of the Maplin Sand, situated at the mouth of the Thames, about twenty miles below the Nore. The foundation was formed of seven screw piles, six occupying the six angles of a hexagon, and the seventh being placed in the centre. From each screw proceeded a pile fifteen feet in length, at the upper end of which was another screw for securing a wooden column. These columns were prepared of Baltic timber: the one in the centre was fifty-six feet, and each of the remainder forty-six feet in length, firmly bound together with iron hoops, and coated with pitch.The platform upon which the house stands is firmly secured round the centre column, and to the heads of the outer columns by means of hollow cast-iron capitals let down on the heads of the columns, and secured with screw bolts. To give lateral strength to the building, round iron angle traces were applied, by which means a resisting power, equal to at least three-hundred-and-fifty tons is presented in every direction.The platform upon which the house stands is twenty-seven feet in diameter and nine feet high; it has an outsidedoor and three windows, and is divided into two apartments—one having a fire-place. The floor is tiled, and the walls are ceiled, lathed, and stuccoed; access to the platform is secured by means of a Jacob’s ladder to one of the columns. From the summit of the house rises the lanthorn: it is twelve sided, and is ten feet in feet in diameter and eight feet high. The light is elevated about forty-six feet above low water level, and is bright, steady, and uniform—ranging over an horizon of eight miles and visible at the distance of ten miles from a coaster’s deck. During foggy weather a bell is tolled by machinery. Tide time for vessels of twelve feet draught is also denoted by signals.This admirable and useful structure was erected in two of the shortest day months of the year, during which time daylight did not occur at any low water period; the workmen, therefore, had to depend upon torches and moonlight; and what is quite as extraordinary, it can be taken down and erected on another site in a month, should circumstances render it necessary.Lighthouse
Lighthouses were in use with the ancients. The towers of Sestos and Abydos, the Colossus of Rhodes, and the well-known tower in the island of Pharos, off Alexandria, are examples. Suetonius also mentions a lofty tower at Ostia, and another on the coast of Batavia, erected for the purpose of guiding the mariners by night. In lighting a great extent of coast, it becomes necessary to provide for the distribution of lighthouses in such a manner, that they may be readily distinguished from each other, and, at the same time, so disposed, as not to leave vessels without some point by which to direct their course.
One of the most extraordinary lighthouses on our iron-bound coast, stands on a reef of rocks called the Eddystone, in the English Channel, about ten miles from the Land’s End, in Cornwall. It was erected by Mr. Smeaton, in 1759, and still remains a lasting monument of his scientific skill. It consists of four rooms, surmounted by a gallery and lanthorn. The floors are of stone, flat on the surface, but concave beneath, and are kept from pressing against the sides of the building, by means of a chain which is let into the walls. The entire edifice is about eighty feet in height, and yet, such is the immense power of the wind in the neighbourhood of therocks, that the waves are seen to ascend like a cupola, considerably above the lanthorn at the top. The appearance of this is truly wonderful and sublime.
The Eddystone Lighthouse
Another celebrated lighthouse is called the Bell Rock Lighthouse, which stands on the coast of Scotland, near Arbroath, in Forfarshire. These rocks have always been particularly dangerous for shipping, and when the commerce of Scotland was very much less than at the time of the erection of the lighthouse, it is said that the monks of the Abbey of Arbroath erected a bell on the rock, which was rung by machinery during the flowing and ebbing of the tide. About the year 1807, the present noble specimen of what man can accomplish, was commenced. The work was completed in 1811, under the direction of Mr. Stevenson, and reflects thehighest honor upon his professional skill. The difficulties that had to be overcome were of the most embarassing description. At the commencement of the work, in consequence of the short time the rock was not covered with water, two or three hours were considered a good tide’s work, and, frequently after a portion of the foundation had been completed, a sudden storm would render it necessary to perform the same labour twice over, and even oftener. On one occasion, Mr. Stevenson and the men who were with him at work were exposed to great danger, in consequence of the vessel that used to carry them from the rock having broken from her moorings, and the tide at the same time commencing its rise. They were, fortunately however, saved by a small boat, which happened to bring Mr. Stevenson some papers relating to the lighthouse at the time.
The form of the lighthouse is that of an immense pillar; the lower courses of stones are trenailed and wedged together with oak timber, to the height of upwards of forty feet, or throughout the solid part of the building. At the stone staircase leading from the door to the first floor, the walls are seven feet thick, and from this it gradually decreases upwards. The stones of the walls of the several apartments are connected at the ends with dove-tailed joints. The floors are formed of long stones radiating from the centre, and set in such a manner that the pressure of the floors upon the walls is perpendicular. In the stranger’s room or library, the roof takes an arched form, but the centre is cut only upon the interior end of the stones of the cornice, the several stones of which it is composed being all laid upon level beds.
In order to give a slight idea of the force this lighthouse has to withstand, we may quote the following remarks from Mr. Stevenson. He says:—“It is awfully grand, at the time of high water, to observe the spray rising on the building, and even to be on the rock at low water, when the waves are about to break. Being, in a manner, only a few yards distant, they approach as if they were about to overwhelm us altogether. But, now that we are accustomed to such scenes, we think little of it. You will, perhaps, form a better idea of the force of these gales, when I relate to you that, on the 15th of February, the large piece of lead which was used as a tack weight of the balance crane, weighing nearly five hundred pounds, was fairly lifted by the sea and carried to the distance of six feet from the hole in which it had laid since the month of August. It was found turned round, with the ring-bolt downwards, and it was with great difficulty that four of us could muster strength enough to move it.”
There are many other lighthouses upon our coast. That at the Land’s End is a very fine one, as is that at Orford and Yarmouth Sound. Of late years a new mode of building lighthouses has been in operation, and of this I shall say a few words.
Perhaps no class of persons are exposed to greater dangers than seamen. They have to contend, not only against the elements, when all around them is a barren waste of waters, but, no sooner are they gladdened by the sight of land, than their perils are increased to a much greater extent. In the former case, the wind was, perhaps, the only danger they might have to provide against, but approaching land theymust take care to avoid sunken rocks and sand-banks, which might be the cause of their destruction. Upon rocks and the solid coasts, lighthouses have been erected with comparative ease (as we have already stated), but, upon sands, the erection of them is very difficult; and was, till within these few years, considered to be almost insurmountable. Floating lights, which are large lanthorns suspended in the rigging of a vessel, or built up in the hull, are frequently used to illuminate a sandy coast, full of shoals and sand-banks—but these are subject to many inconveniences, by the pitching and rolling of the vessel—for every now and then she is partially submerged in the trough of the sea, covered with spray and drift; or, what is most to be dreaded, she is liable to be blown away from her moorings—an accident productive of the most disastrous consequences to life and property; for should such a catastrophe happen, the ships sailing along a coast having nothing to warn them of their danger, run upon the shoals or sand-banks, and are frequently totally wrecked, and all traces of them lost, in the course of a very few hours.
Such being the case, the attention of Engineers has for some time been directed to the best means for overcoming this difficulty. The building of a house upon a rock has ever been considered the proof of wisdom, whilst the erection of it on the sands has been held the proof of folly. But the advances of science prove that a house may be built even upon the sands, when proper care is taken in its construction—and the erection of lighthouses on this foundation is held to be a triumph in engineering.
This remarkable result has been accomplished chiefly bymeans of Mitchell’s screw mooring, which consists of an immense screw, very similar to that of the corkscrew, with flat cutting spirals. It is a spiral or screw round a cast-iron spindle, having a square head, upon which a large key is placed (like the key of a watch), and the screw is turned by enormous leverage, and it is then forced into the ground, and can be carried to a great depth. This instrument was thought to be applicable to the establishment of Lighthouses upon sands; and, accordingly, a series of experiments was undertaken, and a lighthouse was speedily erected on the verge of the Maplin Sand, situated at the mouth of the Thames, about twenty miles below the Nore. The foundation was formed of seven screw piles, six occupying the six angles of a hexagon, and the seventh being placed in the centre. From each screw proceeded a pile fifteen feet in length, at the upper end of which was another screw for securing a wooden column. These columns were prepared of Baltic timber: the one in the centre was fifty-six feet, and each of the remainder forty-six feet in length, firmly bound together with iron hoops, and coated with pitch.
The platform upon which the house stands is firmly secured round the centre column, and to the heads of the outer columns by means of hollow cast-iron capitals let down on the heads of the columns, and secured with screw bolts. To give lateral strength to the building, round iron angle traces were applied, by which means a resisting power, equal to at least three-hundred-and-fifty tons is presented in every direction.
The platform upon which the house stands is twenty-seven feet in diameter and nine feet high; it has an outsidedoor and three windows, and is divided into two apartments—one having a fire-place. The floor is tiled, and the walls are ceiled, lathed, and stuccoed; access to the platform is secured by means of a Jacob’s ladder to one of the columns. From the summit of the house rises the lanthorn: it is twelve sided, and is ten feet in feet in diameter and eight feet high. The light is elevated about forty-six feet above low water level, and is bright, steady, and uniform—ranging over an horizon of eight miles and visible at the distance of ten miles from a coaster’s deck. During foggy weather a bell is tolled by machinery. Tide time for vessels of twelve feet draught is also denoted by signals.
This admirable and useful structure was erected in two of the shortest day months of the year, during which time daylight did not occur at any low water period; the workmen, therefore, had to depend upon torches and moonlight; and what is quite as extraordinary, it can be taken down and erected on another site in a month, should circumstances render it necessary.
Lighthouse