of the sea, which being easily moved, may attain a corresponding motion, and assist in perpetrating a permanent stream. Is there any thing unreasonable in this? The question may, indeed, be started as an objection; that such stream ought to be less saline, than the sea-water, on either side; true, but has any one tried the experiment? Capt. Manderson says, the Florida stream is fresher than the ocean water; and Humboldt, that it is salter. Who is right? It is probable, however, that to a certain distance only, the water of the stream would be much less salt, than that of the ocean, through which it presses, the particles of the fluid, from their mobility, acquiring an impulse, according to the power of the initial velocity. Another objection may be, that, the Amazon, Orinoko, Congo, and other great rivers, pursue their courses, comparatively, but to a very limited extent in the ocean. Capt. Sabine has dispelled some of the mist which has hitherto involved this very question; but, who has traced those streams to the ne plus ultra, into the wide ocean! They have been crossed at two or three hundred miles from their respective places of discharge, but what navigator has followed their course from the land, to solve the interesting question? Who knows but that these rivers, and others of magnitude, by pressing the waters of the ocean onward into a stream, may after all, be the origin of some of the many currents which navigators report "far far at sea. Besides, may there not be sub-marine mountains, which by guiding and restraining the deep-seated current, perpetuate its flowing to a great extent? If, sir, we could possibly rise artificial mounds round the globe, a gigantic aqueduct, is there a single engineer, that would be bold enough to gainsay that, such a stream as the Amazon, would not flow throughout the whole distance? Fresh-water founts in the sea, are common in the vicinity of the Florida Channel; one we have seen; and subterranean rivers are well known to exist; we ourselves have heard more than one roaring and dashing their foaming and hidden waters over the impediments to their free course, whilst hastening in their descent to the ocean. We can, sir, only judge from the wonderful phenomena, which are known to exist in various parts of the world, but principally from those which take place in the Pacific, what is passing in the bed of the ocean. Let us reflect only, for an instant, on the vast scale upon which nature in her hidden laboratories carries on her works, to accomplish ends, the design of which, the capacity of man is unequal to account, and we shall no longer consider it chemerical, that subterranean rivers may produce super-currents of the ocean: if by fire and water she is capable of rising hundreds of miles of the bed of the ocean, may she not in her unlimited power of action, produce a rush of water from inland reservoirs, that, shall form a stream hundreds of miles in extent? Shall the mere mortal presume to fix limits to her operations? To conclude this long yarn, Mr. Editor, one could almost wish to possess for a "wee time," the gill-lungs of the mermaid, fanciful or not, to take a plunge into the deep recesses of Nuptune's domain, and peep at the wonders below. One could then, sir, promise you (saving tintereros, huge polipi, and such aquatic rovers,) a rich harvest for the "Nautical!" What a fidget the quadrupled eyed antiquarians would be in;-"bless my day-lights (as Jack lips it in vulgo-nautic,) how the knowing ones would stare, and well they might: For, there," sans doute" Are sights, Horatio, to take the shine CONDUIT. SIR. IMPROVEMENTS IN THE CONSTRUCTION OF LIGHTHOuses. (From the Shipping and Mercantile Gazette.) As the columns of your journal are, at all times, open to suggestions in any way calculated to promote the general interests of this great country, and to protect the lives and properties of persons employed in navigation, I beg to hand you a description of an improved method of constructing lighthouses, which I trust may be deemed worthy the attention of your readers, especially as the subject on which it treats so greatly tends to the promotion of our national wealth, and so closely connected, or, rather, forms the main link of the great chain of civilization. While it is obvious that every means should be used to facilitate the workings of the great branches of industry referred to, the numerous and fearful shipwrecks, which are continually occurring on our coast, are sufficiently cogent to assure us, that our coast is not sufficiently lighted to warn the enterprising mariner of his danger in time to prevent accident. The vast amount of shipping to and from our ports, and the yearly increase of the British commerce, both by sea and land, calls upon the legislation of the British empire for a more improved system of lighthouses. From the efficient state of our steam ships, we are no longer dependent on the winds and tides for an intercourse with our colonies, and other nations; but access to all parts of the globe is now perfectly easy. Much remains to be done at home, to render the approaches to our ports more distinct; but so long as the Goodwin Sands, and other such places, remain unlighted, life and property must be considered in danger. Sir, with your permission, I shall call the attention of your scientific readers, and, more especially, the elder brethren of the Trinity House, to the means by which a substantial foundation, for lighthouses, on all such dangerous places, might be effected at a moderate expense, and without any risk. The system I propose is by no means of a novel description, but has been long in extensive use for sinking operations, in mining districts, to effect a passage through running sands. It is well known that, in shaft sinking, running sands of the most formidable nature have presented themselves to the miner, who, on making the discovery, immediately resorts to what he terms a sinking tube-the NO. 1.-VOL. XVII. Ꭰ size of the shaft, including the brickwork. The tube, or cylinder, is, in most cases, made of wood; and, when placed in the required position, is weighted with brickwork, and so forced through the sand; and, by these means, the brickwork casing is effected. But as this system is so practically understood among your practical readers generally, a detailed account of the operation would be useless. It is evident that, if by means of a cylinder, a passage can be effected through the running sands in a shaft, the same means could be used on the Goodwin Sands, and other dangerous spots, with the same success. From the many inquiries I have made respecting the depth of the Goodwin Sands, I believe they are not more than 30 feet thick-at the bottom of which is the chalk formation. If we can by any means get to the chalk, we have at once a foundation for the lighthouse, which would resist every storm, I should propose to construct a wrought-iron cylinder (say) three-eights of an inch boiler (plate-iron) of 30 ft. diameter, which would give a sufficient base for a lighthouse of 120 feet above high-water mark. Such a light would be seen at a suitable distance. The cylinder should be made into sections of 4 feet in length, and should be fitted up on shore with the greatest care. A stage could be made on piles driven into the sand, and the whole well braced together. Having adjusted the preliminary arrangements, 16 feet of the cylinder could be put together, suspended between four lighters; and then by the aid of a small steamer could be towed into its intended position, and there lowered into the sand. Having fixed and secured the first portion of the cylinder to low-water mark, the remaining sections could be floated in the same manner. joints being previously prepared, each section could be screwed together, and sunk to the required depth, in a short time. In case it was found that the cylinder had not sunk to the required depth, I should resort to Dr. Pott's atmospheric pile-driving system, by which means the cylinder could be forced down to the required depth. The next plan of operation would be to drive the external piles, as shown in the annexed dia gram. The The piles should also be driven by Dr. Pott's system, and the whole well braced together. When the pile-driving is completed, the sand between the cylinder and the piles, A, A, should be taken out as deep as possible with the bag and spoon apparatus; the space thus excavated should be immediately refilled with the best concrete, which would entirely protect the foundation against every storm. The cylinder being so far perfectly secured, a few ship's pumps could be fixed inside to pump out the water; and in order then to secure the cylinder against the external pressure, a process of timbering should be resorted to, as shown in diagram. After having pumped out the water, and well secured the cylinder against the external pressure, the sand inside the cylinder could be taken out, and the same process of timbering repeated every five feet, until the whole of the sand is excavated to the chalk formation. The sand being excavated, the concrete foundation for the lighthouse should be put in without delay, as shown at A, Fig. 1, the concrete being set in one mass, the stone-work, C, could be commenced; and, as the stone-work rises inside the cylinder, the timber could be taken out. The stone-work should be of the strongest construction, and every block well bound together. All works of this nature should be commenced in the early part of the spring. While the apparatus lies in readiness on shore, the cylinder could be quickly sunk into its position, and perfectly secured by the piles and concrete in a few months. In case of storm, or bad weather, it would be only requisite to let the water into the cylinder, to counterbalance the external pressure of the waves, and which could be easily removed when the storm had abated. This plan of effecting a firm foundation for lighthouses, is not only applicable to the Goodwin Sands, but can be extended to all bars of rivers and places where a light is required to warn the mariner of danGEORGE SHEPHERD, C E. ger. Fleet Street, London, Nov. 29. TIDAL HARBOURS COMMISSION. THE following important paragraphs conclude the second appendix to the second report of the Tidal Harbours Commission-The volume contains the evidence taken at all the Scottish ports, together with the engineers, and other reports, and is accompanied by plans, sections and an index. Shipwrecks." Among other general points which have come before us in the course of our inquiries, there is one too intimately connected with the state of our harbours and coasts to be passed over without notice, I mean the frequency of shipwreck around the shores of the United Kingdom. The Appendix to this Report contains long lists of wrecks off Dunbar, Peterhead, and elsewhere, along the east coast of Scotland, and a reference to Lloyd's list will show a loss of about 600 British ships every year, and including foreigners trading to this country, vessels not registered at Lloyd's, and wrecks unrecorded, we shall not err greatly in assuming the loss at two vessels a-day throughout the year, with life and property to a great extent. Many causes, probably, combine to produce these casualties, as stress of weather and want of good harbours, rapid tides, shoals, want of lights, buoys, and beacons (although this last cause is much diminished of late), bad charts, unseaworthiness of vessels, being ill-found with anchors and cables, incompetency and neglect of masters, and drunkenness. The recent regulation by which masters may be examined will do some good, but as the examination is not compulsory, much cannot be expected from it. As the case stands at present, it is difficult to say to which of these several causes wrecks are to be chiefly attributed, and we are thus, in some measure, liable to legislate in the dark. I would submit, then, that a public Court of Inquiry be held on the spot in every case of wreck along the coasts of the United Kingdom, whether attended with loss of life or not: it could be as easily managed as an inquest, the machinery for the purpose being already organised; the Inspecting Commander of the coast-guard of the of the district, the Collector, or chief officer of Customs, and Lloyd's Agents, are to be found everywhere, and they would form a tribunal, well acquainted with nautical affairs, in which all merchants and shipowners would have confidence; and were such a body, with the assistance of the nearest magistrate, authorised to inquire into and report on every case, there is a little doubt but that in a very few years the list of wrecks on our own coasts would be diminished one-half." Ballast." Another point to which it is again necessary to revert, is the throwing over of ballast in our harbours, and rivers, and roadsteads. It will have been seen in the course of this Report that there are many complaints of this practice, at Kirkwall, at Stromness, at Lochindeal, and even in the Firth of Forth. Nor is the pernicious custom confined to Scotland only, the inquiries of this Commission have proved that ballast is commonly thrown overboard in, or on the passage to, all coal ports, as Shields, Sunderland, Hartlepool, and Stockton; in all mining ports, as at Swansea, Neath, Milford Haven, Fowey, and Fal |