and interesting, the writer offers the following description of the process by which this object was successfully accomplished under his directions. The factory which required one row of cast-iron columns in each story to be cut out and removed to a distance of 2 feet 8 inches, is a fireproof building, eight stories high. It extends for 160 feet along Union Street, Manchester, fronting the Rochdale Canal, and runs parallel with it as far as Murray Street, where it terminates with an angular wing to a further distance of 80 feet. The width of the mill is 45 feet, divided by two rows of columns of three equal spans of 15 feet each, as seen in the annexed sectional diagram, which shows the position of the columns, those cut out being represented by the dotted line a (fig. 1), and those which replaced them by the black line b. The columns indicated by the line c were not disturbed. The figures d, e, f, g represent the position of the mule spinning-machinery, for the admission of which the original columns in the position of the dotted line had to be removed. The other mules next the side walls had quite sufficient room with the addition of the passage o, which extended along the side wall for the whole length of the mill. In carrying out the process by which these alterations were effected the first consideration was, how to support the ends of the middle beams and arches during the process of removing the columns from under them; and also how to support the middle beam permanently after the columns had been removed. This could not be done simultaneously throughout the mill when at work, as it would have involved a very heavy expense to support the ends of all the middle beams at once, with a superincumbent weight on each of 90 tons of brick arches, and machinery. Moreover it was essential that only one pair of the old mules in each room should be stopped at one time, and that only during the operation of fixing the new columns and cutting out the old ones. The first thing to be done was therefore to prepare the new columns with projecting brackets (as shown in sketch), of sufficient length to reach beyond the ends of the wall beam b (fig. 2), so as to support the ends of the middle one after the old columns were removed. As it was impossible, however, to remove that part of the column which went through the beams, it was necessary first to fix the new columns under the wall beams in the line d, and subsequently to cut out the old ones at c progressively, as the work advanced from one end of the room to the other. The brackets on the new columns were made to project to about the same extent on both sides; but as they could not be extended the whole length on the side next the original columns, until the latter had been cut out and removed, the bracket intended for supporting the end of the middle beam at c was left 12 inches short, so as to leave sufficient space for attaching the apparatus for cutting out the old column; and a loose end was afterwards bolted to the bracket, and made to fit the stump end of the old column after it had been neatly cut off and removed, as shown in sketch at c. The carrying out of this work was ably accomplished by the contractor, Mr. Andrew Ker; and in order to save time and labour, an apparatus was devised by him to take advantage of the shafts in motion, and thus to cut out the columns with great rapidity and success. The apparatus itself consists of two cast-iron clips embracing the column, and forming a table for supporting a spur-wheel, which revolves round the column and carries a steel cutter. The wheel is driven by a worm-shaft and pulley, which received motion from one of the driving-shafts in each room. The shank of the cutter is screwed to receive the rachet, and by means of a finger or peg the cutter receives the required advance, equivalent to the thickness of the cut every time the rachet passes the finger. By this means the old columns were quickly cut out and removed, and the loose end of the bracket having been inserted, with two strong bolts, the end of the middle beam was thus supported with the same security as if the original columns had never been disturbed. Improvement in Pontoon Trains. By G. FAwcus, North Shields. A complete pontoon train has been arranged to go either way or turn on its centre, with all the detailed fittings made reversible and interchangeable. This is a combination of a light and strong waggon-frame, with traversing frames between the wheels, where the beams and planks for forming the platform of a bridge are packed in separate compartments for simultaneous handling, and are secured there by a novel system of bolting, the load thus strengthening the carriage and increasing its stability. Above these frames the required number of inverted boats are packed.-See British Association Report of Transactions of Sections,' 1863, pp. 172, 173, article "Waggons and Boats" (Newcastle). In forming a bridge, the rowlocks on both gunwales form a double support for the beams, which are scarphed and keyed together with bolts and forelocks. The bolts are of an elliptical section, and fit into oblong holes and plates forming a rigid jointing. On Locomotive Engines and Carriages on the Central Rail System for working Steep Gradients and Sharp Curves, as employed on the Mont Cenis. By J. B. FELL. It appeared that this work is proceeding most satisfactorily, and that it will probably be completed by the end of the year, and will be opened about May next. When this is done, the line of rail will be unbroken between Paris and Brindisi, on the Adriatic, from which port the Italian Government are running a line of steamers to Alexandria. Should our Government adopt this route for our Indian mails, as it is expected will be the case, instead of that of Marseilles, a saving of something like forty hours will be effected in their transmission between London and Alexandria. The works at Mont Cenis could be executed for £1000 per mile for the railway, and £250 per mile for permanent way; the stations would amount to another £1000 per mile, the rolling stock amounting to £750 per mile, the total cost being £300,000. The tolls were high, being double those charged on an ordinary railway. Locomotive power for conveying passengers and goods over the mountain cost 1s. 4d. per passenger, and 4s. 8d. for each ton of goods. The total revenue was estimated to amount to £100,000 per annum. Assuming the traffic to increase at the rate of 10 per cent., the whole of the capital would be repaid within four years. The cost of this line would be only one-third that of a tunnel line. The working expenses would amount to 2 per cent. of the ordinary expenses. There would be no probability that the line would be choked with snow. About eight or nine miles of the line would be constructed in galleries some of masonry and some of wood. An Invention for the Purpose of attaining greater Adhesion between the driving-wheel and the Rail. By W. D. GAINSFORD. The proposed plan consists merely in adding a second flange to the drivingwheel. The two flanges being closer together at the base than the middle of the rail, thus causing the weight of the wheels to be carried by the flanges pressing upon the sides of the rail instead of the face of the tire. The tractive power obtained by this means is 1 to 1 times the imposed weight. As the flange is flat, and the rail, an ordinary double headed one, is round in section at the point where the tire touches it, the contact is little more than a point, and consequently there is no grinding between the flange and the rail, both becoming as bright and smooth as the face of an ordinary rail. In passing round curves, the inner rail is laid with a narrower head, so that it falls to the bottom of the groove in the wheel, rendering the latter of a smaller diameter, and allowing it, if necessary, to slip, as in the ordinary railway wheel. A locomotive was constructed upon this principle to rum upon a colliery railway. Its weight was 20 cwt. loaded; 12 cwt. were borne by the driving-wheels, and 8 by the leading wheels. The gradients experimented upon were 1 in 14 and 1 in 7. Less a gradient of 1 in 14 the engine drew a load, including wagons of 5 tons, at a speed of 3 miles per hour. Less the gradient of 1 in 7 the engine drew a load of 35 cwt. at about the same speed. The dimensions of the engine were: cylinder 3 inches diameter, 10 inches stroke; driving-wheels 12 inches diameter; highest steam pressure 120 lbs. to the inch. Description of a Newly-invented System of Ordnance. By W. D. GAINSFORD. The projectile thrown by the proposed gun is a sharp-edged disk, formed by the junction, at the basis of the frusta, of two equal and similar cones. Each frustum is half the height of the original cone, and each cone is one-third its base diameter in height. Consequently, the major is three times the minor axis. The disk is fixed in an upright direction, and the rotation is upon the minor axis. To propel this projectile a gun is used, which internally consists of two parts, a chamber for the powder and the barrel or receptacle for the shot. The barrel is very short, so that when loaded the front of the disk is level with the mouth of the gun. Direction is given by the close fitting of the sides of the barrel to the disk, rotation by a pin passed through the barrel in a horizontal direction, in its lower part, so as to take hold in a notch cut in the edge of the disk. It is thus evident that the disk, on leaving the gun, will acquire a rotation equal in speed at the mouth to the speed of the disk itself where it last touches the catch. By putting the catch nearly under the centre of the disk, a speed of rotation of the periphery nearly equal to the initial velocity of the projectile would be obtained. As, however, much less than this will suffice to keep the axis of the disk at right angles to its line of motion, the catch is placed further back, and offers but little resistance to the exit of the projectile. Thus an efficient rotation is obtained without friction; and from the absence of friction great initial velocity is obtained; and the recoil being small, from the same reason, large charges of powder may be used. A long maintenance of the velocity is ensured by the shape and rotation of the disk, which is more adapted for retaining its velocity than a conical or bolt shaped shot. The recoil is small from the absence of friction, which in rifled guns amounts to from one-third to one-half the power employed. In the proposed gun the only recoil is that due to the simple propulsion of the shot. An experimental gun has been made on this principle, throwing a shot of 4 lb. 2 oz. The charged used was one-eleventh, or 6 oz. of powder. The first shot was fired from H.M.S. 'Cambridge,' the gunnery ship at Devonport, at the target in the creek, a distance of 1000 yards. The rotation was perfect, and the direction excellent. The gun was again fired from Boviesand, Devonport, and gave a range of 2000 yards first graze with the same charge. Had the construction of the gun allowed a heavier charge of powder, no doubt a much greater range would have been obtained. Further experiments were prevented by the cracking of the gun at the muzzle. On the Chalmers Target. By Captain DOUGLAS GALTON, F.R.S., F.G.S. The target may be understood by looking upon it as a beam, in which the top flange is the front plate, the bottom flange a thinner plate behind, these two flanges being kept apart by means of a web of plates at right angles to the flanges. These intermediate plates are supported laterally by layers of wood to prevent their breaking. The author stated that the results of the experiments made by the Iron Plate Committee had been most successful, and showed that the princíple was correct. On the Electrical and Mechanical Properties of Hooper's India-rubber Insulated Wire for Submarine Cables. By WILLIAM HOOPER. The author described the method by which he secures the durability of his rubber. Its high degree of insulation was pointed out, and its durability under very trying conditions, over long periods of time, confirmed by experiments conducted by Sir Charles Bright, Capt. Mallock, and others. It was stated that Mr. Latimer Clark had found it unnecessary to ship Mr. Hooper's cables in watertanks; and the Ceylon cable, now on its way out, is coiled dry. The inductive capacity of Mr. Hooper's wire remains practically the same at all temperatures, while that of gutta percha increases considerably at 100° Fahr. Diagrams, representing the effects of pressure and immersion, were shown, from which it was seen that pressure improves the insulation of his wire in the same way as is observed with gutta percha. The result of carefully conducted experiments, extending over three years, proves that the absorption of water is so small that the most refined electrical tests failed to discover it. On Rotary Engines, with special reference to one invented by W. Hall. On recent Improvements in the Application of Concrete to Fireproof Constructions. By FREDERICK INGLE. The author pointed out what he considered a radical defect of concrete formed of lime, as ordinarily used, viz. that by the action of fire it becomes reconverted into lime, which, when the water from the engines is brought to bear upon it, expands greatly, and forces out the walls to the destruction of the building. He advocated the use of a concrete formed from gypsum, which is not liable to this defect. The gypsum, which is of a coarse and inexpensive character, is formed into plaster of Paris by roasting, and mixed with a peculiar kind of clay found in connexion with the beds of gypsum. On a New Arrangement for picking up Submarine Cables. By FLEEMING JENKIN, F.R.S. This machinery was intended to limit and regulate the strain which could possibly be brought on a submarine cable or rope attached to it while being hauled on board by the ordinary drum driven by a steam-engine. During this operation it had hitherto been necessary to watch the cable carefully, regulating the speed of the engine so as to keep the strain, as shown by the dynamometer, below that 1866. 10 which was considered safe. It was further necessary to be ready, at an instant's warning, to stop the engine in case the cable fouled any part of the ship; and the author had seen a cable broken owing to the impossibilty of stopping the engine soon enough. Moreover, even when the above precautions were taken, it was impossible to avoid a considerable variation of strain, due to the pitching of the ship, which alternately slackened and lengthened the cable as it hung vertically; and in most cases in the author's experience cables, while being picked up in great depths, had broken from this cause. All these dangers were avoided by the machinery invented by the author, of which two models were shown. These two forms were identical in principle. A spur-wheel, fast on a main shaft, driven by the engine, geared into another spur-wheel centered in the periphery of a brakedrum, loose on the main shaft, and restrained from turning by an Appold's brake; the second spur-wheel in one form geared directly into an internal-toothed wheel bolted on the picking-up drum, which was also loose on the main shaft above mentioned. When the brake-drum was stationary, the engine simply drove the brake-drum through the spur-wheels in the ordinary manner; but when the strain on the cable reached the amount corresponding to that given by the weight restraining the brake-drum, the picking-up drum ceased to revolve, because the brake-drum turned instead, carrying round the second or intermediate spur-wheel, which rolled inside the internal-toothed wheel, instead of driving it; the centre on which this intermediate spur-wheel worked might be looked on as a fulcrum, and the wheel itself as a lever, by which the engine pushed round the picking-up drum: if the fulcrum yielded, the weight could not be lifted. The second form of model was exactly similar in principle. A second intermediate wheel, of different diameter, fast on the same shaft as the first, geared into an external-toothed spur-wheel connected with the picking-up drum. The action was identical with that already described. If the strain increased beyond that required to stop the picking-up drum, it would turn in the other direction, and the cable would be paid out instead of picked up, although the engine would continue to run in the same direction as before, and exerted the same power. In practice, as was shown by the models, the engine might be driven at any speed; the cable would only be subject to the strain chosen, which might be increased or diminished at will; it would come up quicker or slower as the ship fell or rose; it would stop wholly if the cable fouled; it would be paid out if, from inattention, the ship drifted out of position, or from any other cause the strain increased on the cable. More than this, the cable might actually be paid out as the ship rose, and picked up as it fell, and the whole would take place with perfect smoothness and constancy of strain. The Appold brake gave a constant restraining power to the brake-drum, whatever the coefficient of friction might be. The gear exhibited formed at once a payingout and picking-up machine. It might be termed an accurate slip-coupling, and could be applied to many purposes-as, for instance, to the measurement of steam power let out. With one of these couplings on the transmitting shaft, it would be impossible to overload the shaft. Similarly, the coupling would serve to prevent a break-down in cases where the machinery was liable to sudden starts or stoppages. It would prevent undue strains on the ropes of collieries and lifts, and other applications would readily occur to mechanical men. On Zine Sheathing for Ships. By SAMUEL J. MACKIE, F.G.S. Iron ships are subjected to a great amount of corrosion, and are so liable to foul, that sailing-ships of iron cannot be sent on long voyages. Copper sheathing, or Muntz's metal, cannot be applied to iron ships as it is to wooden ones, because the iron being positive to copper, electrical action would be set up, by which the iron would be destroyed at a greatly increased rate. If, then, a metal were found which should be positive to iron, when the two metals were in contact in seawater, the conditions of the voltaic battery formed by the iron ship and its sheathing would be reversed, and the sheathing would be destroyed while the iron would be preserved. A further condition was required to be satisfied, namely, that the metal forming the sheathing should not be destroyed too quickly, but only sufficiently to prevent the growth of animal and vegetable parasites by the slow but constant scaling of the surface. Such a metal was zinc, the cost of which |