horse," as it was popularly called, with three wheels; it was a costly experimental affair, and the builder being over 18 stone weight, his family were in a constant state of alarm at his enterprise-which ended in failure.

PENETRATION OF ARMOUR-PLATES WITH LONG SHELLS.

MR. (now Sir Joseph) WHITWORTH, has read to the British Association "On the Penetration of Armour-Plates with Long Shells containing Large Bursting-Charges fired obliquely."

At the meeting of the British Association, 1868, he contributed a paper to the Mechanical Section "On the Proper Form of Projectiles for penetrating through Water." The paper was illustrated by diagrams, showing the effect produced on an iron plate, immersed in a tank of water, by projectiles with flat hemispherical and pointed heads. In that paper he claimed for the flat-pointed form of projectile, made of his metal, these points of superiority over the ogival-pointed projectiles adopted in the service: 1. Its power of penetrating armour-plates even when striking at extreme angles; 2. Its large internal capacity for bursting-charge when constructed as a shell; 3. Its capability of passing undeflected through water, and of penetrating iron armour below the water-line. The latter feature was, he thought, satisfactorily proved by the experiments described in 1868, and the author desired to draw the attention of the Section to the experiments made for illustrating the penetrative power of long projectiles with the flat front, fired at extreme angles against iron plates. These experiments were illustrated by the projectiles actually fired and the plates they penetrated, which were laid on the table, and also by diagrams.

WHITWORTH METAL.

SIR JOSEPH WHITWORTH, after a long course of experiment, has succeeded in producing iron and steel, which, as he states, will resist any amount of shock or strain that may be put upon them. This "Whitworth Metal," as it is called, is, while in a molten state, subjected to enormous pressure, by which all the air-bubbles those sources of weakness- are got rid of, and the metal is rendered perfectly homogeneous. If Sir J. Whitworth be right in his conclusions, our iron trade is about to undergo another revolution. Besides guns of the largest size, which will send their bolt through anything and everything, and never burst, we shall have wheels for railway-carriages that will never crack, boilers that will never blow up, and wire for submarine cables that will not break in the laying.

An interesting account of the application of the Whitworth metal to ordnance, written by an officer of the Royal Artillery, has appeared in the Times. As this would occupy more space than we can devote to it, we quote its conclusion, which

clearly states the question: "Whitworth's system of artillery consists essentially in small-bore guns with long projectiles. The twist of the rifling must be rapid, because otherwise the long projectiles would turn over. All this involves a great strain upon the interior of the gun. Until now he has not succeeded in making heavy guns to stand this strain, except in small numbers at a prohibitory price. He now asserts that he has found the material he has so long sought; but there is as yet no heavy gun in existence made of this material. We say, let him make one and let it be tried. Then there is that other question of his shells, which has nothing to do with the gun question, and may be settled by firing some projectiles out of the costly pieces now in the possession of Government. If the shells succeed, it will be interesting to know whether Sir Joseph Whitworth can really make guns at a reasonable price capable of firing them. Then will come the last question, perhaps more difficult still to answer, where can such guns be placed without involving such a complication of ammunition and stores as would be detrimental to the public service? We hold that Sir Joseph Whitworth has made out a case for experiment."

GREAT GUNS AND GUN-COTTON.

AMONG the incidents with which M. Dumas was entertained during his recent visit to London for the Faraday Lecture, was a trip to Woolwich, where, under the guidance of Mr. Abel, he saw the making of big Guns in the Arsenal, and experiments with Gun-cotton which must have surprised him. A palisade was built of oak timbers a foot thick, firmly fixed in the ground, and supported in the rear by strong trusses. Discs of guncotton were placed along the face of the palisade about a foot above the ground, and were fired by a battery in the usual way. The effect may be described as wonderful. The palisade was literally blown away amidst a deafening report, as if the massive timbers offered no more resistance on one side of the gun-cotton than the atmosphere on the other. The discs require no fixing; merely laying them on is sufficient. Solid blocks of iron and stone can be shivered into fragments by firing a disc laid on the top. In future sieges, if some desperate fellow can but get to the gate or a thin part of the walls, and hang on a few discs of gun-cotton, a breach can be made by firing with a galvanic current from a long distance. Henceforth Indian stockades and New Zealand pahs will be but vain defences; and if a hole can be blown in the side of a ship, what will be the use of building vessels of war? After all, cotton may prove to be king in the shape of gun-cotton.-Athenæum.

A NEW STEAM STAMP-MILL.

A VERY efficient Stamp-mill has been introduced by the New York Steam-Engine Company, and those engineers who have adopted it express themselves thoroughly satisfied with its

operation. An excellent illustrated description of the machine has been published in a recent number of the American Journal of Mining, from which it appears that the stamps which are attached directly to steam piston rods are arranged in a group of four, and surrounded by a screen. The battery in which the stamps work is surrounded by a trough cast in the bedplate of the mill. The ore to be crushed is fed through a hopper directly into the centre of the group of stamps, and so distributed equally to all, and as fast as it is pulverised finely enough it is delivered on all sides through the screen into the trough. The stamping is done wet, and the very finest portion of the powder is washed over from the trough by the overflow of water through spouts into an outer surrounding gutter. There is a separate steam cylinder and piston for each stamp. The cylinders are all cast together with a surrounding exhaust steam jacket, and sole plate, and are supported on wrought-iron pillars erected upon the bedplate. All the cylinders can be adjusted simultaneously by means of nuts fitted to screw threads on pillars, for the purpose of adjusting the clearance between the piston and the top and bottom of the cylinder, and for maintaining a uniform clearance by lowering the cylinders as the stamps wear away and allow the pistons to descend lower. The steam acts above and below the pistons, so that it not only lifts the stamps, but the force of its downward pressure on the piston is added to that due to the weight and fall of the stamps. Each cylinder has an independent valve and automatic valve gear, so that each piston and stamp may work independently of all the others. The valves are short double-faced slides, working horizontally in the chests, and operated partly by the steam and partly by conical surfaces on the upper parts of the piston and stamp rods, which pass upward beyond the tops of the steam cylinders into closed central caps on the cylinder covers. The conical parts of the rod act upon the valves through levers and attached slides. This method of operating the valves permits the stamps and pistons to turn freely as required. The cylinders are 5 in. diameter, and the pistons have from 6 in. to 8 in. stroke, according to the depth of material in the battery. The machine is estimated at about 30horse power, and is stated to crush thirty tons of hard ore in twenty-four hours.-Mechanics' Magazine.

INDIAN INK.

THE manufacture of Chinese Ink, to give it its proper term, is carried on upon a very large scale at Shanghai, where a very superior description is prepared. The cause of the difference in quality between the various inks made in China results from the non-employment of a constant material for the production of the lamp-black. In order to impart an agreeable odour to the production, the Chinese add a small portion of musk and camphor, from the Isle of Borneo, two articles which are exceedingly dear in the celestial empire. Ordinary Chinese ink for home use is

not scented in any manner whatever. The gilded mystic letters that are so attractive to young pupils and students are first formed by the action of the mould. When the cake is dry, the letters are traced over with a solution of gelatine in water, and the gold or copper is laid on with a fine brush. Like their neighbours the Japanese manufacture Indian ink, but consider it of a quality inferior to that which they obtain from the mainland. Not having given so much attention to the matter as the Celestials, they are not so well versed in the manner of preparing the lamp-black, which is the real secret of the whole art.-Mechanics' Magazine.

CRAMPTON'S COAL-DUST FIRE.

SOME time ago Mr. Crampton conceived the idea of utilising Coal Waste by grinding it to a fine powder and burning it by a blast jet suspended, as it were, in the air, much as one has seen lycopodium seed blown through a spirit lamp into a cloud of flame. By practical experiments it was soon seen that a large economy in the consumption of fuel, as well as a more uniform condition of heating in the furnace, was possible by this mode of combustion, and that ultimately it might be advantageous to employ fuel in this way instead of in the customary manner. Permission was recently granted Mr. Crampton, on the recommendation of General Balfour, for a trial of the process in one of the furnaces of the gun factory at the Woolwich Arsenal, and a practical exhibition was made in the presence of the War Office, Control, and Arsenal authorities, and many influential ironmasters and manufacturers. The trial was made in an ordinary heating furnace, fitted up in a temporary but sufficiently effective way for the immediate purpose of this experiment. The fuel operated with was the fine siftings of the Bebbside coal, and in the Arsenal works ground in an ordinary mill ("Peak" stones of 3 ft. 6 in. diameter) to a fine powder. This powder is put into a hopper, from the base of which it falls down a shoot or feeder, and meeting at the bottom with the strong draft of a horizontal blast pipe, there is blown forward a rolling cloud of mixed air and coal-dust, the current shooting downwards obliquely into the combustion chamber, the lighter dust firing instantly, and the heavier having time given it to consume before entering the utilising chamber, where piles of iron scrap were placed for heating. The work was carried on by the regular workmen of the factory by the "piece," the same as at the other furnaces; the piles coming out in about the same time as from the rest, but exhibiting a very fine heat indeed without any symptom of "cutting." Indeed the results obtained were satisfactory in the highest degree. The total of work carried on with this furnace on the day previous in one shift was 5 tons 4 cwt. 3 qrs. 13 lbs. by the consumption of 36 cwt. of coal-dust.-Standard.

87

Natural Philosophy.

THE FARADAY LECTURE.

THE first Faraday Lecture, delivered before the Chemical Society, at the Royal Institution, presented several remarkable features. The Council chose for this purpose a Frenchman, M. Dumas, the great chemist, who gave up his time to this duty, and whose address to a large English audience was given in his native tongue. Dr. Williamson, the President, thought it was a fitting commemoration of Faraday, that a most intimate friend and associate in the great world of science should represent the catholicity of his discoveries. It was in this spirit M. Dumas accepted it; and from that place, so often occupied by Dr. Thomas Young, Davy and Faraday, Dumas proceeded to deliver his discourse. What the nature of it was to be no one knew, nor from the beginning could any tell whether it was to be a formal éloge or how it was to shape itself. After a few remarks on the nature of the individual discoveries of Faraday, he proceeded to observe that these discoveries connected themselves with four great topics, the nature of inorganic matter, and the nature of the forces by which it is operated upon; the nature of organic matter, and the nature of the forces operating on this matter. These were problems which had occupied the ancient world, and particularly the great Greek philosophers; and he maintained that in substance our real and ultimate knowledge was in the same state as that of the Greeks, and went no further. In rendering a tribute to Aristotle and his fellows, he affirmed that Faraday had approached all those subjects in the spirit of a Greek philosopher. He described what Faraday, and more particularly Dalton and other Englishmen, had done to show the identity of matter; and he avoided all reference to foreign philosophers, except, as it were on compulsion, to Lavoisier. He went on to detail the means by which Faraday had proved the identity of forces, and their relation to that of gravitation; but he affirmed that of this ultimate force we know no more than Aristotle did, and that the knowledge of it rested with One above. By this time it was perceived that the oration of M. Dumas, delivered with the ease and grace almost of an improvisation, and assuredly with the gifts of a refined orator, was a vindication of natural science in the sense of immaterialism and in the spirit of Faraday. Proceeding to organic matter, he described the way in which modern chemistry had succeeded in multiplying the combination of its forms, and in imitating with inorganic elements organic substances. He referred to the influence of solar heat and light in the development of the organic world, and to the dispersion of the constituents of these into that infinite space, the elements of which we know to be the same as those of this globe.