The cables to be submerged in the Black Sea are, by this time, completed, and in a few weeks will be on their way to their submarine destination. In order to avoid the mountainous range of the Caucasus, the Indo-European Telegraph Company (the progress of whose works we lately alluded to), determined to lay a cable from the Crimea to a point on the Asiatic shores of the Black Sea, considering that the difficulties of the submarine would be far less than those of the mountainous route, the probability of interruption in the former being much less. The original cable route was not adhered to, but a shorter route finally settled upon, the length of cable being 100 miles, starting from a point near Djulfa, on the Black Sea, and landing at Suchum Ea-16. The second section of cable is that for the Straits of Kertch, a three-wire cable of heavy proportions. The insulated core of the Black Sea cable is similar to that of the cables that are generally known----a stranded conductor surrounded by coats of 'gutta-percha. The insulated con ductors in this cable are three, each of them weighing 273 lbs.pernauticalmile (copper, 107 lbs. per mile; gutta-percha, 166 lbs. per mile). It is in the materials specially used for strengthening and preserving the core that this cable so essentially differs from all others. Its construction is sim-,. ilar in every respect to some small cables mado by Messrs Siemens Brothers, for the French Government, some few years ago, and laid in the Mediterranean, on the place designed and specially advocated. by Mr. C. W. Siemens. The present cable has been manufactured at the works at Charlton. In the ordinary system of cable making', the core is protected with a serving of hemp, and sheathed externally for extra protection, and for strength, with a helical covering of iron wires; the number and size of which depending upon the size of the core and the locality for which the cable is intended. In Siemens' cable, however, the main strength rests in a large serving of best Italian hemp, giving it the character of a rope; this serving is protected (adding, at the same time, some strength to the cable) by a sheathing, laid helically, of strips of fiat copper of about fin. in diameter. The copper selected is of the best quality, and arrives in the shape of long broad sheets. These sheets aro first passed through the shearing machine, where, by means of knives placed above and below, the entire sheet, as it passes through, is divided throughout its breadth into equal narrow strips of the breadth required for sheathing the cable. On comiEg away from the shearing machine the strips are wound on small bobbins. If a strip of metal or anything be attempted to be wound around a long cylinder, it will infallibly bulge up and tend toward the trumpet form, and in order to prevent such a result happening to the copper strip in the cable, it undergoes a process termed " rabitting." Each strip, before going to the sheathing machine, passes through this operation, which consists in slightly bending its edge and grooving its centre. The bobbins, of prepared copper, are then taken to the closing machine, for the final process, but wo must first describe the ordinary covering with hemp. The three insulated wires of the Black Sea cW are served 402 together and wormed, the worming consisting of a number of strands of best Italian hemp. In compound cables some difficulty is experienced (unless special marking be adopted), of knowing one wire from another. In the present cable, Mr. Siemens adopts the simple but excellent plan of passing along with one of the hemp wormings, a white tape, which serves as a zero line. After being twisted together and wormed, the core receives its strengthening protection by being served with two servings of best Italian hemp. Each serving consists of about twenty compound strands of hemp, served under tension, and with a very short lay. The second serving is in the reverse direction to the first. After this serving, the cable receives its external protection of copper sheathing, which consists of four strips ot the prepared copper, laid helically, one strip overlapping the other for one half its breadth. In consequence of the strip being previously prepared, the cable comes out nice and smooth, and coils most readily, being exceedingly flexible and easily managed. The strips of copper are soldered into continuous lengths, care being taken that no two joints be allowed within a certain distance of each other. In the manufacture of these cables, the whole process goes on at the same time, and really in the same machine. By the application of the same power, the wires are stranded and wormed, served, and finally sheathed in one continuous machine. Usually, these operations are separate and distinct; the core is commonly stranded, wormed, and served in one machine, and afterward finally sheated. At Charlton, these several operations are conducted on the same machine (or, rather, combination of machines), at the same time. Where space is an object, this plan is, undoubtedly, advantageous; but otherwise, where there is plenty of room, we cannot but think that time must be lost. Anything required to be done to any one part, necessitates a stoppage of the whole. The jointing of the gutta-percha wire, the replacing a hemp bobbin, or the jointing of an external wire, each must stop the whole machine; whereas, in separate machines, only one is stopped at a time. The specific gravity of tlie copper sheathed cable in 1'6; its weight a little over 2 tuns; and, although apparently showing but slight signs of strength, its breaking strain is considerably more than would be imagined, amounting to nearly 5 tuns.' The shore ends are of heavy iron wires, and of the usual construction. The Kerich cable is also an iron covered cable, but the core consists of three wires insulated with Hooper's material. The iron wires are protected externally with a serving of tarred hemp, and the whole weighs about 12 tuns to the mile. The steamer Hull has been engaged for the work, and fitted up with the necessary watertight iron tanks, which are three in number. They are placed in the fore and main holds, the forward containing the Kertch cable; the main, the Black Sea (copper sheathed) cable. Over the fore tank, when the cable is in, will be placed a second tank to receive the shore ends of the Black Sea cable. The paying out and piling up machinery, with engines, have been constructed by Messrs. Easton Amos, and are placed at the stem of the vessel, the paying-out machine being used, if required, for picking up. This machine is so arranged that at any moment it can be stopped and the engine attached to it, in order that the cable may be drawn in to any distance. The engine is supplied with steam either from the main boiler or the donkey. There are some special features of interest relative to the friction brake and the dynamometer, which call for attention, but we regret that want of space compels us to postpone our notice of them to a future occasion. It ia expected that the vessel will leave at the end of this month or the beginning of the next. Mr. C. W. Siemens goes out with the vessel, and' will superintend the operations in connection with laying the cable; and we trust that the expedition will meet with all successcompleting successfully an important section in the system of the Indo-European Telegraph.Mechanic's Magazine. Threatened Extinction of Patent Rights To the brainworkers of England we appeal for support in resisting the attempt now commencing in the House of Coni-mons to deprive them of all prospects of reward for their labors. The assault is to be made in the basest spirit of ingratitude by one of our commercial men, who himself has al-already profited, as have all his class, by the efforts of inventors. To those of our legislators who profess to regard as of the highest moment, the interests and welfare of the working classes, we need scarcely urge that here is a crucial test for their sincerity. To both, we say, rally round your flag and do not permit this suicidal folly to be perpetrated,even though a few narrow-minded manufacturers may be found so devoid of common sense-as not to perceive that they would but un-edgethe tools with which alone they can hope to work effectively, and maintain the supremacy of this country in the mechanical and chemical arts, it' indeed they have failed to (Vcover that competition with our foreign rivals cannot be vc i except by cheapened productions. Yet cheapened production can only be effected by inventive genius, which merely asks for and is entitled to its fair reward, and no manufacturer has any right to demand exceptional legislation in order to rob others that he may be profited. Were the blow simply aimed at the existing patent laws, so that a more sensible procedure, a more complete protection, and cheapened charges, might be exchanged for the perverted system we have so long and persistently condemned, the change would have commanded our heartiest support, as it has now our firmest opposition. But such is not the object of Mr. Macfie, M.P., who has long been known as the ringleader of those who expect inventors, without fee or reward from them, to work for their benefit. He is also one of the ablest exponents of a theory, fallacious in its assumptions, savoring of the wildest socialism and the most despicable selfishness, a theory which, if put in practice, would bring ruin and destruction upon all our industries. Now, if ever, is the time for all who have at heart the interests of invention, of science, of industrial progress, and who desire to maintain for this country that proud position which it has acquired among the nations as the initiator of the steam engine, the railway, and the electric telegraph, to join, as one man, not only in converting this audacious attack into a triumphant vindication of popular right and justice, but to stand forth as the liberators of the inventive genius of England from its final shackles, by obtaining for the poorest inventor a property in the fruits of his labor as simple and perfect as that which the law already confers on books or works of art. Had an M. P.a publisher for instancegiven notice that ho would move in the House of Commons a similar resolution affecting the existence of the law of copyright, there is not a thinker or writer in the land who would not join heart and hand in denouncing so revolutionary and infamous a proposition. On our part, no effort shall be wanting to show Mr. Macfie that he shall not with impunity enter upon his course of spoliation; and we cannot more appropriately conclude this appeal than by quoting the soul-stirring words of the immortal Nelson" England expects every man to do his duty." Scientific Review.
This article was originally published with the title "Sea Cables"