SPECIFICATIONS OF RECENT ENGLISH PATENTS. specification, three retorts or ovens are shown, as heated by the fire of one furnace; each of the chambers is covered by an arch, over which the furnace flue is led, so that the heat may be transmitted downward, through the arches, to the materials placed within the chambers. In each chamber there is a trough of stone, such as is used for the condensers and flues of alkali works; or the troughs may be made of fire-clay, moulded into the required shape. One side of each chamber is furnished with a leaden door, and at the opposite side there is a pipe of lead, or earthenware, for the escape of the chlorine. The fire being kindled, and the chambers sufficiently heated, lumps of manganese are placed in the troughs, and the doors closed; muriatic acid is then introduced through glass tubes, conveniently placed for that purpose, and the chlorine is given off. The muriate of manganese is drawn off from the troughs, on the completion of the process, by means of syphons. The claim is, 1. To the mode of manufacturing chlorine by the use of retorts or ovens, so arranged as to have the heat required for the process transmitted downward, through the covering or arch of the retort; 2. To the mode of constructing the troughs or bottoms of ovens or chambers for evolving chlorine when fire heat is used below, or at the sides, or tops, each of one piece of stone, or moulded fire-clay, as described. JOHN SEAWARD AND SAMUEL SEAWARD, OF THE CANAL IRON-WORKS, POPLAR, ENGINEERS, for certain improvements in steamengines. Enrolment Office, February 10, 1842. The The improvements comprehended under this patent are divided into four branches. The first comprehends various new modes of connecting and disconnecting the paddleshafts of marine steam-engines. The second consists of an addition to the ordinary airpump bucket of steam-vessels of a sort of false bottom, which, by excluding the water that now ordinarily collects at the bottom of the pump, facilitates the escape of the uncondensed vapour and gases, and thus helps to produce a more perfect vacuum. third branch embraces several modes of discharging, at regular intervals, and in duly proportioned quantities, the brine, or saturated or foul water, from marine steamengine boilers. And the fourth consists of a condensing and distilling apparatus, (superseding entirely the ordinary condenser,) by which the spent steam of the working cylinder is, previous to its condensation, made to assist in obtaining by distillation a constant supply of fresh water. By adopting the distilling part only of this apparatus, it may be used in connection with a condenser of the common form. 143 SAMUEL BROWN, OF GRAVEL - LANE, SOUTHWARK, ENGINEER, for improvements in the manufacture of metallic casks or vessels, and in tinning or zincing metal for such and other purposes. Enrolment Office, February 11, 1842. The improvement "in the manufacture" consists in a mode of fixing the heads and ends of metal casks and other vessels by means of tinning or soldering. The metal of which the cask is made having been previously tinned, the head is slightly forced into its place, and having been dipped into powdered rosin, is held by a suitable apparatus, and lowered into a shallow vessel containing melted tin, in which it is kept immersed for five or ten minutes. In some cases a hoop is driven on to the end of the cask, and fixed by the tinning process at the same time as the head. The improvement "in tinning, or zincing" sheets of metal consists in the employment of a hot plate on which the coated metal is laid after tinning or zincing (which is conducted in the usual manner,) while the superfluous metal is wiped off its surface. The claim is-1, To the mode of fixing the heads or ends of casks or other vessels, by immersing the ends of such vessels in a bath of suitable melted metal, as above described. 2. To the mode of keeping sheets of metal heated (in order to the superfluous coating metal being removed) by the application of a hot plate, as described. WILLIAM HALE, ENGINEER, AND EDWARD DELL, MERCHANT, both of Woolwich, for improvements in cases and magazines for gunpowder. Enrolment Office, February 12, 1842. These improvements consist in the construction of covered cases and magazines for gunpowder of cast or wrought tin, whereby cases containing gunpowder will not be chemically-injuriously acted on by the powder. The These cases are made six-sided, so as to possess considerable strength, and at the same time, to allow of a number of them being packed closely together. On the top there is a cylindrical neck, on which a male screw is cut or formed, blanks or spaces being cut in three equidistant parts, to admit corresponding projections on the inside female screw of the cover to enter. cover is held to the case by a quadrant-shaped bolt or pin, which prevents its being detached when the case is opened. On the inside of the cover is placed a leather or other washer, so that on placing the cover in its place, and turning it partly round, a close joint is made. These cases may be cast in moulds of either sand or metal, or they may be made of wrought tin soldered up. By this means, say the patentees, a covered case or magazine of any required size may be made, which, from the peculiar character of the metal, will retain gunpowder with great safety, and without the metal of which it is composed being prejudicially acted upon by the chemical properties of the gunpowder. The patentees state that they do not confine themselves to the form, or to the mode of fixing the cover, both of which may be varied, nor do they confine themselves to the exclusive use of tin. But they consider tin, in an unalloyed state, to be best adapted for this purpose. NOTES AND NOTICES. Pearl Fisheries of Ceylon.-The principal pearl fishery in Ceylon is that off Aripo, where the oysters lie in from five and a half to seven fathoms water, protected on the west and south-west by a ridge of sand and coral; this ridge is considered by the natives to be a submerged island, but it is generally believed to be a rising bank of coral and sand. The age of the oyster, at its separation from the rock, is stated by an intelligent diver to be six years and a half; the pearls are found in all parts of the fish; as many as sixty-seven have been found in one oyster; they are not generally found in those oysters that would be considered the finest for eating, which favours the idea that pearls are produced by disease in the fish. A single diver will generally bring up in a day from 1000 to 4000 oysters; the fishing takes place in March. Gold-Dust.-The St. Petersburgh papers state that an important discovery has been made by the expedition sent in search of deposits of sand containing gold. It consists of a bed of sand, near the source of the Nadejoni, not far from the washing station called Pesaskoi Tersinski; it is estimated to contain 100,000 lbs. of sand, and, to produce 3 pouds 9 punds 16 zols of gold. In the essays already made 4 punds 60 zols of metal, rich in quality have been extracted. The poud is rather more than 40lbs. English. Progress of Rust.-M. Montgolfier, jun., having learned that a grating of iron wire from the church of St. Martin's, at Paris, was about being taken down, after having remained forty years without any repair, had the curiosity to prove these wires, after having carefully ascertained their number, and he was convinced that they had lost but one fifth of their entire strength. The increase of oxidation is not as rapid as might be supposed, for the first layer of rust which covers the surface of a bar of iron, instead of favouring this oxidation, proves a coating which is an obstacle to it. Steam Navigation of the Indus.-A correspondent, on whom we can rely, has favoured us with some interesting information as to the navigation of the Indus, and the British craft now on it. Sir Alexander Burnes had thought that a vessel of four feet water might always ascend it in safety; but it is found, by experience, that one drawing more than three feet water is useless, from the perpetual shifting of the river's bed and channel, and the peculiar formation of its bars. Vessels of that draught have ascended to Loodieana on the Sutledge, and could reach Kalabagh on the Attock branch: the Rava branch is navigable to Lahore; and the Cheenab is believed to be navigable to a considerable distance from its junction with the main stream near Moul taun. There are at present only three steam-vessels, all of iron, on the Indus-the Comet, Planet, and Satellite; the first of forty-horse, the others of sixtyhorse power. They draw thirty-six inches of water. A smaller vessel, the Meteor, is under repair at Bombay. Two of the Euphrates steamers, of fifty and forty-horse power, have been ordered to Bombay, most probably for the Indus. The communication between Bombay and Kunatchee is kept open by the Indus steamer; but it draws too much water for the river.-Spectator. India-rubber Welted Hose.-The making of this description of hose is rapidly extending in France; from some astonishing cause, the few attempts made in Nottingham have not succeeded. We believe the causes are-first, that the English web is deficient in the number of warp-threads; secondly, that the web is stretched too far on the needles; thirdly, that the weavers do not turn the welt down over the stocking, which increases the comfort to the wearer; and, lastly, that the hose and half-hose are not made that extra length to allow for such turning down. We speak for ourselves when we say that, having worn stockings with India-rubber welts, nothing can excel their comfort, as they act as an elastic garter, without the trouble of buckling and unbuckling, and wholly prevent that most unpleasant circumstance-the stockings coming down about the heels of the wearer. The India-rubber will wash, but it is rather injured by long boiling. Always anxious for the good of the English hosier, we advise them that French India-rubber welted hose have made their appearance in London; we saw large quantities in Paris, in September last.Nottingham Journal. Sheathing Steam-boilers with Lead.-A correspondent of the Mining Journal states that, at a manufactory in Newcastle-on-Tyne, the boilers have been cased with sheet-lead, one-eighteenth of an inch in thickness, and weighing four pounds to the foot; and that the amount of the radiated heat is thus so much diminished, as to be equal to a saving of 17 per cent. in fuel. "The average consumption of coal, by these boilers, previous to the adoption of this plan, was 60 cwt. per day, but now 50 cwt. is found to be amply sufficient; therefore a positive advantage is obtained of 10 cwt. per day, which is one-sixth, or 17 per cent." Iron Wire Rigging.-A vessel, "the Marshall of Grimsby," is now in the river off Hermitage Stairs, the rigging of which is all of wire, (Smith's patent wire rope). It has been nearly six years thus fitted up, and the rigging is stated to be nearly as good as new.-Taking a 3-inch wire rope, and comparing its size, weight, and cost with hempen rope, or chain, of equal strength, the results are found to beA 3-inch patent wire rope, weight 64 lbs. per fathom; hemp rope, of 8 inches, 144 lbs. ; and chain, 36 lbs.-equal to a strain of 16 tons. The comparative cost being-3 inch wire rope, 3s. 8d. per fathom; 8 inch hempen rope, 6s. 3d.; and chain, 7s. 6d. per fathom. Intending Patentees may be supplied gratis with Instructions, containing every particular necessary for their safe guidance, by application (post-paid) to Messrs. J. C. Robertson and Co., 166, Fleet-street, by whom is kept the only COMPLETE REGISTRY OF PATENTS EXTANT, (from 1617 to the present time.) Patents, both British and Foreign, solicited. Specifications prepared or revised, and all other Patent business transacted. LONDON: Edited, Printed, and Published by J. C. Robertson, at the Mechanics' Magazine Office, DESCRIPTION OF THE HADDINGTON MARINE STEAM-ENGINE. BY THE INVENTOR. The marine steam-engine about to be described was modelled for the first time at the request of Mr. George Rennie, and examined by Mr. Lloyd, at Woolwich, by order of the Admiralty, in May, 1841. At that time, the method of connecting two engines on the principle shown by the model was not explained, and Mr. Lloyd considered an intermediate shaft would be necessary, with a greater length of hatchway across the deck of the vessel than he approved of, or than was, perhaps, convenient. Since then, however, I have devised connecting the engines by a single link, which is simple, and, from its accommodating nature, well suited to marine engines having foundations, at best deficient of rigidity. This mode of connection is shown by the accompanying drawings, and its action was clearly defined by a second model that was submitted to the notice of the Admiralty. Mr. Lloyd also objected to the apparent inconvenience there might be in keeping the packing tight round the piston-rod, from the stuffing-box being below the cylinder, and the screws which compress the packing less accessible than when placed above the cylinder in the ordinary way. This defect has also been removed by substituting a weight and lever for the screws, making, in fact, the stuffing-box self-adjusting, and thereby avoiding the trouble of screwing it up. The piston-rod is lubricated from an external chamber by an induction-pipe, and the same method is used to lubricaté the piston-rod of the slide-valve. By my arrangement for marine engines, the crank-shaft is placed upon the top of the cylinder, which is inverted, and requires to be removed when the cylinder cover is taken off. To some individuals this has appeared a serious matter; with me it has little or no weight. Having placed a man-hole in the cover, the trouble of removing either the cover or crank-shaft will be avoided, unless the piston or piston-rod should want a thorough repair. By the present mode of managing marine engines, there is no such convenience, and the cylinder cover is always removed when the engineer thinks it necessary to have a peep at the inside. When Mr. Lloyd inspected the model that was made at Messrs. Rennie's, he informed me it would be considered with reference to the most improved engines in Her Majesty's service, namely, the Gorgon engines, and those of Messrs. Maudslay and Field's invention, and not the oid engines with side levers. As respects Messrs. Maudslay and Field's engines, the comparison would be quite fair; they have the advantage of a long stroke and long connecting-rod, and are contained in much less space than engines having side levers, which are the very advantages aimed at in my design; whereas, in the Gorgon engines, neither the one nor the other is considered. In effecting this improvement, Messrs. Maudslay and Field have been compelled to divide the cylinder into two parts; and by placing one of them a little distance from the other, space is afforded for the connecting-rod to vibrate between them, by means of a T-formed cross head. The top connects the piston-rods of the separated halves, (as a matter of course,) formed into cylinders, and the leg drops between them, and gives motion to the connecting-rod from a joint at the end. The plan is highly ingenious, but whether separated pistons, working in separated cylinders, connected by a cross head of the above form, is not more liable to derangement than the single cylinder, in the position I have placed it, remains to be proved. What the space which Messrs. Maudslay and Field's engines occupy, and their cost, may be, in comparison with mine, there is nothing to show, but I think the advantage would be on my side. From the arrangement of a Gorgon engine, as it is termed, the stroke of the engine and connecting-rod is unavoidably short. The stroke of every engine being double the length of the lever or crank which it turns, it follows that the paddle-wheels of these engines must be driven by a reduced leverage power. To make good this defect, the cylinder of the engine is enlarged, and the velocity of the piston is impeded, to economise the steam. To obtain adequate results from such an arrangement, the force of the steam power must be increased in proportion to the diminished length of the crank this is easily effected, but its evil consequences are, perhaps, not so easily avoided. If two engines were placed in the same DESCRIPTION OF THE HADDINGTON MARINE STEAM-ENGINE. vessel, but not connected, so that each might drive its own paddle-wheel, and one of them were 100 horses power, with a 6 feet stroke, and the piston travelling at the rate of 200 feet per minute, while the other had a stroke of 4 feet, with the piston travelling at the rate of 133 feet per minute, the latter must exert a force on the crank-pin equal to that of 150 horses power engine to be a match for the former. Both paddle-wheels would then make the same number of revolutions; but the immense difference between the forces employed to effect this adds greatly to the strain on the crankpin of the short-stroked engine, and to the friction on the brasses of the connect b 147 ing-rod, and the bearings of the crank shaft. The circumstance of impeding the velocity of the piston only serves to economise the steam, but in no respect lessens the strain on any of the moving parts of the engine which are employed in conveying the motive power to the crank shaft. Neither can it lessen the strain on the framing of the engine, or ship, but substitutes, as it were, an engine of 150 horses power to perform the labour which can be done by another of 100 horses power, the piston of the former travelling at the rate of 133 feet per minute, and that of the latter at 200 feet. Fig. 3. The usual way to determine what should be the length of a connecting-rod of an engine, is by the length of the crank it turns. With land engines it is generally made six times the length of the crank; in the case of marine engines with side levers, somewhat less than five; and with the short-stroked Gorgon engines, only three. A connecting-rod only three times the length of the crank lies in a very oblique direction when the crank is in the position of communicating its greatest power to turn the paddle-wheels; consequently, acting with more friction and less effect at that important portion of the crank's revolution when the paddle-wheels h feel the force that propels them in the highest degree. As the crank moves round from its extreme leverage, the length of the connecting-rod may be said to be virtually increasing, but the proportion of 3 to 1, in my opinion is much too short when the crank is at right angles to the piston-rod, and in the position described as respects its effect on the paddle-wheels. From this view of the subject two evils are combined in the arrangement of the Gorgon engines. One is, the introduction of a much greater mechanical force to propel the paddlewheels than is necessary; and the other, losing the full advantage of the crank's |