Chapter 3

The Empress of India is built throughout of mild steel, the stem and stern post, together with the shaft brackets, being of cast steel. Steel faced armor, having a maximum thickness of 18 in., extends along the sides for 250 ft. amidships, the lower edge of the belt being 5 ft. 6 in. below the normal water line. The belt is terminated at the fore and after ends by transverse armored bulkheads, over which is built a 3 in. protective steel deck extending to the ends of the vessel and terminating forward at the point of the ram. Above the belt the broadside is protected by 5 in. armor, the central battery being inclosed by screen bulkheads of the same thickness. The barbettes, which are formed of armor 17 in. thick, rise from the protective deck at the fore and after ends of the main belt. The principal armor throughout is backed by teak, varying in thickness from 18 in. to 20 in., behind which is an inner skin of steel 2 in. thick. The engines are being constructed by Messrs. Humphreys, Tennant & Co, London, and are of the vertical triple expansion type, capable of developing a maximum horse power of 13,000 with forced draught and 9,000 horse power under natural draught, the estimated speeds being 16 and 17½ knots respectively at the normal displacement. The regular coal supply is 900 tons, which will enable the ship to cover a distance of 5,000 knots at a reduced speed of ten knots and about 1,600 knots at her maximum speed. The main armament of the Empress will consist of four 67 ton breechloading guns mounted in pairs _en barbette_. The secondary armament includes ten 6 in. 100 pounder quick firing guns, four being mounted on the main deck and six in the sponsons on the upper deck, sixteen 6 pounder and nine 3 pounder quick-firing guns, in addition to a large number of machine guns.

The largest guns at present mounted in any British warship are the 110 ton guns mounted in the Benbow class, and the difference between these weapons and those to be carried by the Empress of India is very marked.

The projectile fired from either of the Benbow's heavy gun weighs 1,800 lb., and is capable of penetrating 35 in. of unbacked wrought iron at a distance of 1,000 yards. The projectile fired from the 67 ton guns of the Empress of India will have much less penetrating power, being only equal to 27 in. of wrought iron with a full charge of 520 lb. of prismatic brown powder, the missile weighing 1,250 lb. or about one-half less than the weight of the shot used with the 110 ton gun. It will thus be seen that the ordnance of the Benbow can penetrate armor that would defy the attack of the guns of the Empress. It should be said, however, that the heavy artillery of the latter vessel is capable of penetrating any armor at present afloat, and is carried at a much greater height above the designed load water line than in any existing battle ship, either in the British or foreign navies. The armor being of less weight, too, enables the new ship, and others of her class, to carry an auxiliary armament of unprecedented weight and power.

The Empress will be lighted throughout by electricity, the installation comprising some 600 lights, and will be provided with four 25,000 candle power search lights, each of which will be worked by a separate dynamo. The ship has been built from the designs of Mr. W.H. White, C.B., Director of Naval Construction, and will be fitted out for the use of an admiral, and when commissioned her complement of officers and men will number 700.--_Industries._

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THE "IRON GATES" OF THE DANUBE.

The work of blowing up the masses of rock which form the dangerous rapids known as the Iron Gates, on the Danube, was inaugurated on September 15, 1890, when the Greben Rock was partially blown up by a blast of sixty kilogrammes of dynamite, in the presence of Count Szapary, the Hungarian premier; M. Baross, Hungarian minister of commerce; Count Bacquehem, Austrian minister of commerce; M. Gruitch, the Servian premier; M. Jossimovich, Servian minister of public works; M. De Szogyenyi, chief secretary in the Austro-Hungarian ministry of foreign affairs; and other Hungarian and Servian authorities. Large numbers of the inhabitants had collected on both banks of the Danube to witness the ceremony, and the first explosion was greeted with enthusiastic cheers. The history of this great scheme was told at the time the Hungarian Parliament passed the bill on the subject two years ago. It is known that the Roman Emperor Trajan, seventeen centuries ago, commenced works, of which traces are still to be seen, for the construction of a navigable canal to avoid the Iron Gates.

For the remedy of the obstruction in the Danube, much discussed of late years, there were two rival systems--the French, which proposed to make locks, and the English and American, which was practically the same as that of Trajan, namely, blasting the minor rocks and cutting canals and erecting dams where the rocks were too crowded. The latter plan was in principle adopted, and the details were worked out, in 1883, by the Hungarian engineer Willandt. The longest canal will be that on the Servian bank, with a length of over two kilometers and a width of eighty meters. It will be left for a later period to make the canal wider and deeper, as was done with the Suez Canal. For the present it is considered sufficient that moderate sized steamers shall be able to pass through without hindrance, and thus facilitate the exchange of goods between the west of Europe and the east.

The first portion of the rocks to be removed, and of the channels to be cut, runs through Hungarian territory; the second portion is in Servia. The new waterway will, it is anticipated, be finished by the end of 1895, and then, for the first time in history, Black Sea steamers will be seen at the quays of Pesth and Vienna, having, of course, previously touched at Belgrade. The benefit to Servian trade will then be quite on a par with that of Austria-Hungary. Even Germany will derive benefit from this extension of trade to the east. These, however, are by no means the only countries which will be benefited by the opening of the great river to commerce. Turkey, Southern Russia, Roumania, and Bulgaria, not to speak of the states of the west of Europe, will reap advantage from this new departure. England, as the chief carrier of the world, is sure to feel the beneficial effects of the Danube being at length navigable from its mouth right up to the very center of Europe.

The removal of the Iron Gates has always been considered a matter of European importance. The treaty of Paris stipulated for freedom of navigation on the Danube. The London treaty of 1871 again authorized the levying of tolls to defray the cost of the Danube regulation; and article 57 of the treaty of Berlin intrusted Austria-Hungary with the task of carrying out the work. By these international compacts the European character of the great undertaking is sufficiently attested.

The work of blasting the rocks will be undertaken by contractors in the employ of the Hungarian government, as the official invitation for tenders brought no offers from any quarter. The construction of the dams, however, and the cutting of several channels to compass the most difficult rocks and rapids, will be carried out by an association of Pesth and other firms. The cost, estimated altogether at nine million florins, will be borne by the Hungarian exchequer, to which will fall the tolls to be levied on all vessels passing through the Gates until the original outlay is repaid.

Very few persons know, says the _American Architect_, what an enormous work has been undertaken at the Iron Gates of the Danube, where operations are rapidly progressing, mainly in accordance with a plan devised many years ago by our distinguished countryman, Mr. McAlpine. The total length of that part of the river to be regulated is about two hundred and fifty miles, so that the enterprise ranks with the cutting of the Panama and Suez canals as one of the greatest engineering feats ever attempted. Work has been begun simultaneously at three points: at Greben, where there are reefs to be taken care of; at the cataract, near Jucz, and at the Iron Gate proper, below Orsova. At Greben, where the stream is shallow, but swift, a channel two hundred feet wide is to be blasted out of the rock, and below it a stone embankment wall is to be built more than four miles long. From a reef which projects into the river a piece is to be blasted away, measuring five hundred feet in length, and about nine feet in depth. The difficulties of working in this part of the river are very great. Not only is the current extremely rapid, but in certain places ridges of rock barely covered at low water alternate with pools a hundred and forty feet deep, which give rise, in the rapid current, to frightful whirlpools and eddies. These deep pools are to be filled at the same time that the reefs are cut away, and it is estimated that nearly three million cubic feet of loose stonework will be needed for this purpose alone. In addition to the excavation, artificial banks and breakwaters, for modifying the course of the stream, are to be built; so that it is estimated that the masonry to be executed in this section will amount to about five and one-half million cubic feet.

In the cataract section, at Jucz, a channel two hundred feet wide, and more than half a mile long, is to be blasted out of the rock, and a breakwater built, to moderate the suddenness of the fall. This breakwater is to be about two miles long, and ten feet thick at the top, increasing in thickness toward the bottom. The rock in which the channel must be cut at this point is partly serpentine greenstone, partly chrome iron ore, and is intensely hard. In the section of the Iron Gate, the work to be done consists in "canalizing" the river for a distance of a mile and a half, by building a wall on each side, and excavating the bed of the river between. The channel between the walls will be two hundred and fifty feet wide. It is estimated that nearly three million cubic feet of rock will have to be excavated here, all of which will be used to fill in behind the embankment walls. Of course, the greater part of the rock will be removed by means of blasting with high explosives, but some of it is to be attacked with a novel instrument, which was first tried, on a small scale, on the Panama Canal, and is to be used for serious work here. This instrument, as it is to be employed on the Danube, consists of an enormous steel drill, thirty-three feet long, and weighing ten tons. By means of a machine like a pile driver, this monstrous tool is raised to a height of about fifty feet, and allowed to drop, point first. So heavy a mass of metal, falling from a considerable height, meets with comparatively little resistance from the water, and the point shatters and grinds up the rock on which it strikes. Fifty or sixty blows per minute can be struck with a tool of this kind, and ten thousand blows in all can be inflicted before the tool is so worn as to be past service. Several of these drills will be at work at the same time, and to remove the fragments of rock which they break off, a huge dredge of three hundred and fifty horse power is to be employed. For excavating by means of explosives, arrangements have been made for drilling the holes for the cartridges with the greatest possible rapidity, as on this depends the celerity with which the work can be pushed forward. Much of the work will be done by means of diamond drills, which are mounted on boats. Five of these boats have been provided, each with seven diamond drills, arranged so as to work perfectly in twenty feet of water. Other boats are fitted with pneumatic drills, which are operated by means of air, compressed to a tension of seven hundred and fifty pounds to the square inch. The pressure of the compressed air is transmitted by means of water to the drills, which act by percussion, and work very rapidly. These drills are curiously automatic in their operation. After boring the holes to the allotted depth, the machine automatically sets in each a tube, washes out the dust, inserts a dynamite cartridge, withdraws the tube, and connects the wire of the electric fuse in the cartridge with the battery wire in the boat. The cartridges are charged with a pound of dynamite to each. In hard rock only one charge is fired at a time, but in softer material four are fired at once. If the water over the work is deep, the boat is not moved from its position, but in shallow water it is towed a few yards away from the spot where the explosion is to take place. The drill holes are about six feet deep, and are spaced at the rate of about one to every three square feet, something, of course, depending upon the character of the rock. The whole work is now under contract, the mechanical engineering firm of Luther, of Brunswick, having undertaken to complete it in five years, for a payment of less than four million dollars.

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THE NEW GERMAN SHIP CANAL.

The gates which admit the water into the new canal which is to connect the Baltic with the North Sea have been recently opened by the Emperor William. This canal is being constructed by the German government principally for the purpose of strengthening the naval resources of Germany, by giving safer and more direct communication for the ships of the navy to the North German ports. The depth of water will be sufficient for the largest ships of the German navy. The canal will also prove of very great advantage to the numerous timber and other vessels trading between St. Petersburg, Stockholm, Dantzic, Riga, and all the North German ports in the Baltic and this country. The passage by the Kattegat and Skager Rack is exceedingly intricate and very dangerous, the yearly loss of shipping being estimated at half a million of money. In addition to the avoidance of this dangerous course, the saving in distance will be very considerable. Thus, for vessels trading to the Thames the saving will be 250 miles, for those going to Lynn or Boston 220, to Hull 200, to Newcastle or Leith 100. This means a saving of three days for a sailing vessel going to Boston docks, the port lying in the most direct line from the timber ports of the Baltic to all the center of England. The direction of the canal is shown by the thick line in the accompanying sketch map of the North Sea and Baltic. Considering that between 30,000 and 40,000 ships now pass through the Sound annually, the advantage to the Baltic trade is very apparent.

The new canal starts at Holtenau, on the north side of the Kiel Bay, and joins the Elbe fifteen miles above the mouth. From Kiel Bay to Rendsborg, at the junction with the Eider, the new canal follows the Schleswig and Holstein Canal, which was made about one hundred years ago, and is adapted for boats drawing about eight feet; thence it follows the course of the Eider to near Willenbergen, when it leaves that river and turns southward to join the Elbe at Brunsbuttel, about forty miles below Hamburg. The canal is 61 miles long, 200 ft. wide at the surface, and 85 ft. at the bottom, the depth of water being 28 ft. The surface of the water in the two seas being level, no locks are required; sluices or floodgates only being provided where it enters the Eider and at its termination. The country being generally level there are no engineering difficulties to contend with, except a boggy portion near the Elbe; the ground to be removed is chiefly sandy loam. Four railways cross the canal and two main roads, and these will be carried across on swing bridges. The cost is estimated at £8,000,000. About six thousand men are employed on the works, principally Italians and Swiss.--_The Engineer._

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THE KIOTO-FU CANAL, IN JAPAN.

Japan is already traversed by a system of railways, and its population is entering more and more into the footsteps of western civilization. This movement, a consequence of the revolution of 1868, is extending to the public works of every kind, for while the first railway lines were being continued, there was in the course of excavation (among other canals) a navigable canal designed to connect Lake Biwa and the Bay of Osaka, upon which is situated Kioto, the ancient capital of Japan.

The work, which was begun in 1885, was finished last year, and one of our readers has been kind enough to send us, along with some photographs which we herewith reproduce, a description written by Mr. S. Tanabe, engineer in chief of the work.

The object of the Kioto-Fu Canal is not only to provide a navigable watercourse, putting the interior of the country in connection with the sea, but also to furnish waterfalls for supplying the water works of the city of Kioto with the water necessary for the irrigation of the rice plantations, and that employed for city distribution. It starts from the southwest extremity of Lake Biwa, the largest lake in Japan, and the area of which is 800 square kilometers. This lake, which is situated at 84 meters above the level of the sea, is 56 kilometers from the Bay of Osaka. As this bay is already in communication with Kioto by a canal, the Kioto-Fu forms a junction with the latter after a stretch of 11 kilometers and a difference of level of 45 meters between its extremities.

The lake terminates in a marshy plain (Fig. 1), in which the first excavation was made. This is protected by longitudinal dikes which lead back the water to it in case of freshets. At the end of this cutting, which is 100 meters in length, begins the canal properly so called, with a width of 5.7 meters, at the surface, and a depth of 1.5 meters, for a length of 540 meters. It then reaches the first tunnel for crossing the Nagara-yama chain. This tunnel is 2,500 meters in length, 4.8 in width and 4.2 in height. The water reaches a depth of 1.8 meters upon the floor. It was pierced through very varied materials, such as clay, schists, sandstone and porphyry, and is lined throughout with brick masonry. The construction was effected by means of a working shaft 45 meters in depth, sunk in the axis of the work, at a third of its length from the west side. At the upper extremity are established sluices that permit of securing to the canal a constant discharge of 8.5 cubic meters per second. Fig. 2 represents the head of this work.

Starting from the tunnel, the canal extends in the open air for a length of 4,500 meters. To reach the basin of Kioto, it traverses the Hino-oko-yama chain of hills, through two tunnels of the same section and construction as the one just mentioned, and of the respective lengths of 125 and 841 meters. Traction in the tunnels is to be effected by means of an immersed chain.

On leaving tunnel No. 3, at about 8,400 meters from its origin, the canal divides into two branches. The first of these, which is designed to serve as a navigable way, has a slope 0.066 per meter for a length of 540 meters. It is a true inclined plane, which the boats pass over by means of a cradle carried by trucks and drawn by a cable actuated by the fall furnished by the other branch. At the foot of the inclined plane, the canal widens out to 18 meters at the surface, with a depth of 1.5 meter, and, through a sluice, joins the Osaka Bay Canal, after a stretch of 2 kilometers.

The second branch traverses a small tunnel, crosses the valley of the emperors' tombs upon an aqueduct of 14 arches (Fig. 3), and reaches Kogawa, a faubourg north of Kioto, after a stretch of 8 kilometers. Its slope is greater than that of the main canal, from which it derives but 1.4 cubic meter. The 7 cubic meters remaining may be employed for the production of motive power under a fall of 56 meters. It is proposed to utilize a portion of it, at the point of bifurcation and at the top of the inclined plane, in a hydraulic installation that will drive electric machines. The total cost of the work was one million dollars, a third of which was furnished by the imperial treasury, a quarter by the central government, and the rest by various taxes.--_La Nature._

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HOW TO FIND THE CRACK.--Most mechanics know that by drilling a hole at the inner end of a crack in cast metal its extension can be prevented. But to find out the exact point where the crack ends, the _Revue Industrielle_ recommends moistening the cracked surface with petroleum, then, after wiping it, to immediately rub it with chalk. The oil that has penetrated into the crack will, by exudation, indicate the exact course and end of the crack.

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FAST AND FUGITIVE DYES.[1]

[Footnote 1: A paper recently read before the Society of Arts, London.]

By Prof. J.J. HUMMEL.

As it is with many other arts, the origin of dyeing is shrouded in the obscurity of the past; but no doubt it was with the desire to attract his fellow that man first began to imitate the variety of color he saw around him in nature, and colored his body or his dress.

Probably the first method of ornamenting textile fabrics was to stain them with the juices of fruits, or the flowers, leaves, stems, and roots of plants bruised with water, and we may reasonably assume that the primitive colors thus obtained would lack durability.

By and by, however, it was found possible to render some of the dyes more permanent, probably in the first instance by the application of certain kinds of earth or mud, as we know to be practiced by the Maori dyers of to-day, and in this way, as it appears to me, the early dyers learnt the efficacy of what we now call "mordants," which I may briefly describe as fixing agents for coloring matters.

At a very remote period therefore, I imagine, the subject of fast and fugitive dyes engaged the attention of textile colorists.

Our European knowledge of dyeing seems to have come to us from the East, and although at first indigenous dyestuffs were largely employed, with the discovery of new countries many of these fell slowly and gradually into disuse, giving way to the newly imported dyestuffs of other lands, which possessed some advantage, being either richer in coloring matter, yielding brighter or faster colors, or being capable of more easy application. Thus kermes gave way to cochineal, woad to indigo, and so on.

Down to about the year 1856, natural dyestuffs alone, with but one or two exceptions, were employed by dyers; but in that year a present distinguished member of this Society, Dr. Perkin, astonished the scientific and industrial world by his epoch-making discovery of the coal tar color mauve. From that time down to the present, the textile colorist has had placed before him an ever increasing number of coloring matters derived from the same source.

Specially worthy of notice are the discoveries of artificial alizarin, in 1868, by Graebe and Liebermann, and of indigotin, in 1878, by Adolf Baeyer, both coloring matters being identical with the respective dyes obtained from plants.

In view of the vast array of coal tar colors now at our disposal, and their almost universal application in the decoration of all manner of textile fabrics, threatening even the continued use of well known dyestuffs of vegetable origin, it becomes of the greatest importance to examine most thoroughly, and to compare the stability of both old and new coloring matters.