tents may remain for a certain depth as a stratum for perhaps one minute; but it will disappear in a much shorter time than those will think who have not tried it. I have taken an immense vessel of carbonic acid, emptied it into a room, and in five minutes I could not detect the slightest trace of it, all had gone. The most injurious of all gas given out in this neighbourhood, is the sulphuretted hydrogen gas; it would kill an animal in a very short time, though much diluted; it is poisonous, and though much diluted, will readily kill a rat or any small animal immersed in it. The carbonic acid gas is one of the least injurious of all; any animal placed in it is destroyed as if plunged in water, from mere want of atmospheric air: it is not a poisonous gas. The evolution of those gasses would account for all or most of the circumstances described here, and exclusively charged on the muriatic acid gas. A moist atmosphere is the great ruster. The process of rusting is this :-moisture attaches to the iron, and carbonic acid to the moisture, and both together begin to to corrode the iron, and, whenever that process begins, it goes on with great rapidity. I don't think that any gas, unless very long applied, would have a deleterious action on meat. Muriatic acid gas produces no effect on meat at all; it washes off; it does not destroy meat; it wants that character altogether; some gases will destroy meat; acetic acid, for instance, will dissolve it-dissolve it into a jelly. Muriatic acid gas would dissolve the leaves of vegetables, cauliflowers or cabbages. Some trees are destroyed by the sea air; the beech is one, and the sycamore is another; their leaves become covered with black spots. After a long and lucid summing up by the judge the jury consulted together for upwards of an hour, and brought in a verdict of Guilty. LIST OF ENGLISH PATENTS GRANTED BETWEEN THE 22D MARCH, AND THE 25TH OF APRIL, 1838. James Lowe, of King-street, Old Kent-road. mechanic, for improvements in propelling vessels, March 24; six months to specify. Michael Wheelright Ivison, of Hailes-street, Edinburgh, silk-spinner, for an improved method of preparing and spinning silk, waste wool, flax and other fibrous substances, and for discharging the gum from silks raw and manufactured. March 26; six months. Julius Oliver, of Queen-street, Golden-square, gent., for a certain improvement in the filtres employed in sugar refining. March 26; six months. Auguste Coulon, of Token-house Yard, London, merchant, for improvements applicable to blockprinting, being partly a communication from a foreigner residing abroad. March 26; six months. Thomas Oram, of 27 East-street, Red Lionsquare, gent., for improvements in the manufacture of fluel. March 26: six months. Charles Hullmandel, of Great Marlborough-street, Westminster, lithographic printer, for a new mode of preparing certain surfaces for being corroded with acids, in order to produce patterns and designs for the purpose of certain kinds of printing and transparencies. March 26; six months. Charles William Grant, captain, bombay engineers, St. Alban's-place, Westminster, for certain improved modes of exhibiting signals for the purpose of communicating intelligence, either at sea or on shore. March 26; six months. Julius Jeffreys, of Kensington, esq., for improvements in stoves, grates, and furnaces. March 26; six months. John Clark, of Mile-end, Glasgow, cotton-spinner, for improved machinery for turning, some part or parts of which may be made applicable to other useful purposes. April 4; six months. William Angus Robertson, of Peterborough-court, Fleet-street, London, patent agent, for certain improvements in the manufacture of hosiery, shawls, carpets, rugs, blankets, and other fabrics, being a communication from a foreigner residing abroad. April 4; six months. George Barnett, of 49 Jewin-street, London, tailor, for an improved button, for protecting the thread or shank from friction and wear. April 7; two months. Joseph Rock Cooper, of Birmingham, gun-maker, for improvements in fire arms. April 10; six months. Thomas Watson, of Addle-hill, Doctor's Commons, mechanic, for improvements in stoves. April 10; six months. David Redmund, of Wellington Foundry, Charlesstreet, City-road, engineer, for certain improvements in the construction and apparatus of steam-boats or vessels, used for war or commercial purposes. April 10; six months. Edward Cobbold, of Long Metford, Suffolk, and Peter Richold the younger, of the same place, coachmaker, for improvements in the manufacture of certain pigments or paints, or such like substances, April 10; six months. William Fothergill Cooke, of Breeds-place, Hastings, esq., for improvements in giving signals and sounding alarms at distant places, by means of elastic currents transmitted through metallic circuits. April 18; six months. William Barnett, of Brighton, ironfounder, for certain improvements in the production of motive power. April 18; six months. Thomas MurrayGladstone, of Boottle-cum-Linacre, near Liverpool, chain cable and anchor manufacturer, for certain improvements in ships windlasses, which improvements are applicable to other purposes. April 21; six months. Edward Cooper, of Haverton, Wilts, clothier, for an improvement in the making or manufacturing of soap. April 21; six months. James Timmins Chance, of Birmingham, glass manufacturer, for improvements in the manufacture of glass. April 21; six months. James Macnee, coachmaker, George-street, Edinburgh, for an improvement or improvements in carriages. April 21; two months. Moses Poole, of Lincoln's-Inn, Middlesex, gent., for improvements in manufacturing of carpets, rugs, and other napped fabrics, being a communication from abroad. April 21; six months. Christopher Nickels, of York-road, Lambeth, manufacturer, for improvements in machinery for recovering fibres, applicable to the manufacture of braid and other fabrics. April 21; six months. Robert Finlayson, of Regent-street, Cheltenham, Gloucester, M. D., for improvements in harrows. April 21; six months. Francis Pope, of Wolverhampton, Stafford, fancy iron worker, for certain improvements in machinery for making or manufacturing pins, bolts, nails, and rivets, applicable to various useful purposes. April 24; six months. Thomas Vaux, of Woodford Bridge, Essex, land surveyor, for improvements in tilling and fertilizing land. April 24; six months. Samuel Wagstaff Smith, of Leamington Priors, Warwick, iron founder, for improvements in regulating the heat of furnaces for smelting iron, which improvements may also be applicable to retorts for generating gas. April 24; six months. Alexandre Happey, of Basing-lane, London, gent., for a new composition applicable to paving roads, streets, terraces and other places, which improvements are also applicable to the different purposes of building; and also in the apparatus for making the said composition, being a communication from a foreigner residing abroad. April 25; six months. Richard Goodwin, of Saint Paul's Terrace, Camden Town, coal merchant, for an improved prepared fuel. April 26; six monts. AND THE LIST OF SCOTCH PATENTS GRANTED BETWEEN THE 22D MARCH, 22D APRIL, 1838. Henry Bessemer, of City-terrace, City-road, Middlesex, engineer, for certain improvements in machinery or apparatus for casting printing types, spaces and quadrats, and the means of breaking off and counting the same. Sealed 23rd March, 1838: four months to specify. Richard Tappin Claridge, of 8 Regent-street, gent., in consequence of a communication from abroad, for a mastic or cement or composition applicable to paving and road-making, covering buildings and the various purposes to which cement, mastic, lead, zinc, or composition are employed. March 27. Jeremiah Bynner, of Birmingham, Warwick, lampmaker, for improvements on lamps. March 30. Auguste Coulon, of Token-house Yard, London, merchant, partly in consequence of a communication by a foreigner residing abroad, and partly by invention of his own, for improvements applicable to block-printing. March 30. Joshua John Lloyd Margary, of Wellington-road, Saint John's Wood, Middlesex, esq., for a new mode of preserving animal and vegetable substances from decay. March 30. Julius Oliver, of Queen-street, Golden-square, Middlesex, gent., in consequence of a communication from a foreign residing abroad, for a certain improvement in the filtres employed in sugar refining. April 6. Charles Wye Williams of Liverpool, Lancaster, gent., for certain improvements in the means of preparing the vegetable material of peat moss or bog, so as to render it applicable to several useful purposes and particularly for fuel. April 6. Alexandre Happey, of Basing-lane, London, gent., in consequence of a communication from a foreigner residing abroad; for a new composition applicable to paving roads streets, terraces and other places which improvements are also applicable to the different purposes of building, and also in the apparatus for making the said composition. April 9. John Stewart, of Glasgow, for improvements in machinery for manufacturing ropes, lines, twines, and yarns, from hemp, flax, or tow. April 12. Marie Claudine Veronise Lenoble, of Leicestersquare, Middlesex, for certain bituminous mastics or cements, capable of receiving various colours which compositions are applicable to various usefu purposes. April 17. Michael Wheelwright Ivison, silk-spinner, residing in Hailes-street, Edinburgh, for an improved method of consuming lime in furnaces and other places where fire is used, and for economising fuel, and also for supplying air heated or cold to blasting or smelting furnaces. 19th April. LIST OF IRISH PATENTS GRANTED IN MARCH, 1838. William Watson, of Temple-street, Dublin, for an improved boat or vessel to be used on canal and other inland navigation. Moses Poole, of Lincoln's Inn, for improvements in looms for weaving figured and ornamental fabrics. Henry Quintin Tenneson, late of Paris, but now of Leicester-square, Middlesex, for an improved construction of the portable vessels used for containing portable gas, and of the apparatus or machanism for regulating the issue or supply of gas, either from a portable vessel, or from a fixed pipe communicating with an ordinary gasometer. Thomas Joyce, of Camberwell New-road, gardener, for an improved apparatus for heating churches, warehouses, shops, factories, hothouses, carriages, and other places requiring artificial heat, and improved fuel to be used therewith. Richard Burch of Haywood, Lancaster, engineer, for certain improvements in manufacturing gas from coal. John George Bodmer, of Bolton-le-Moor, Lancaster, civil engineer, for certain improvement in machinery for spinning and doubling cotton, wool, silk, flax, and other fibrous material. NOTES AND NOTICES. "In America the trade of a chimney-sweeper is unknown. There are whole states, including some of the greatest towns, where such a creature was never heard of. To supply this defect every man sets fire to the soot in his chimney by way of clearing-a practice often productive of serious conflagrations."-Painter's Church of England Gazette. In several parts of England a similar practice prevails, and is often attended with the same fatal consequences. In Edinburgh and many provincial towns a check is put upon this practice by the infliction of a pecuniary fine; in London a similar fine is incurred in the shape of fees to the enginekeepers who may attend such fires. Spontaneous Combustion.-Among the numerous bubble companies of the day, is a "Self-producing and Self-consuming Coal Company." A sort of fuel which should produce itself would certainly be an acquisition, were its good quality not counterbalanced by the very bad one of self-consumption! It is to be feared that the parties who venture to deal with so fiery a material will only burn their fingers for their pains. Mechanics' Magazine, Complete sets. The proprietor of the Mechanics' Magazine has now effected the repurchase of the earlier portions of the stock of this journal from the parties who were possessed of the same in the right of his first publishers; and he is now able to supply several complete sets of the work. Price, twenty-seven volumes, half-cloth, 11 78. British and Foreign Patents taken out with economy and despatch; Specifications, Disclaimers, and Amendments, prepared or revised; Caveats entered; and generally every Branch of Patent Business promptly transacted. A complete list of Patents from the earliest period (15 Car. II. 1675,) to the present time may be examined. Fee 2s. 6d.; Clients, gratis. LONDON: Printed and Published for the Proprietor, by W. A. Robertson, at the Mechanics Magazine Office, No. 6, Peterborough-court between 135 and 136, Fleet-street.-Sold by A. & W. Galignani, Rue Vivienne, Paris. PLAN FOR KEEPING THE BOILERS OF HIGH PRESSURE STEAM ENGINES ALWAYS FILLED WITH WATER UP TO THE REQUIRED LEVEL, BOTH WHEN THE ENGINES ARE WORKING AND WHEN THEY ARE NOT AT WORK; TOGETHER WITH DIRECTIONS HOW THE PLAN MAY BE APPLIED TO THE BOILERS OF CONDENSING STEAM-ENGINES. Sir,-a a a in the figure (see front page) shows a section of one end of a high pressure boiler, and the dotted line bb is drawn near to the place at which the water in it should stand. The feed pump e is wrought by means of a small steam-engine, the cylinder, nosles, and steam pipe of which are marked by d, e, and ff, respectively. gg is a casing fixed upon this boiler, h and i are holes which allow the water always to stand at the same level in the casing as in the boiler, and these holes diminish the agitation which the water in the casing would have if the whole of one of its sides was open into the boiler. Inside of the casing a chest k is fixed, having a space left round its sides and top for the steam and water to get past it freely. The chest k has two openings, or ports in one of its sides, with one of the valves marked l, working upon each in such a manner as that the inside of the chest has no communication with the casing g g, during the time the piston of the feed pump is working upwards; but when the piston of this pump is working towards the cylinder d, then there is always a communication with the chest k and the casing. A pulley upon the crank pin of the little engine works into a horizontal slit in a frame fixed upon the top of the piston rod, and the bottom end of the rod of the feed pump is attached to the top side of the same frame in this way the crank shaft as well as the feed pump are set in motion. The eccentric m, which works the valves 77 is fixed upon the crank. Both of the valves marked are attached to the same rod, and in order that the eccentric m may stand right under them, the steam cylinder d and the feed pump are placed a little towards one side of the boiler, while the casing g g, and the chest k, stand towards the other side. The fly wheel is on the second motion, and its shaft is driven by means of the spur wheel n and the pinion o, so as to make double the number of revolutions as the crank shaft. As the fly weel makes two revolutions for one of the crank shaft, its heavy side p will always be next the end of the boiler, and in a line level with its own shaft every time the piston is at the top or bottom end of its stroke; by this arrangement (if the parts work in the direction of the arrows, and if the fly wheel has the position on its shaft, as per the figure,) the engine can never stand on its centres, however slow its motions, as the heavy side of the fly wheel will always be in a position to carry it past them. The slide valves 17, must be fitted upon the chest k in such a manner that they will not be forced away from their faces when the pressure inside of the chest is greater than the pressure in the boiler. When the piston of the feed pump arrives at the top end of its stroke, as then a pump full of water has passed into the chest k, the steam in the top part of the chest will be compressed, and on this account it will have a greater pressure than the steam in the boiler; and if the space in k, which lies above the surface of the water in the boiler is twice as large as the contents of the pump-barrel, then when a full of the pump is sent into k, the steam in it will be of twice the density of the steam in the boiler. If the space in k, which lies above the dotted line b b, is double that of the contents of the barrel of the feed pump, then the conical valve r must have its weight s so heavy as that it will allow the valve to open as soon as the pressure inside of the chest k is double of the force of the steam in the boiler. If the steam space in the chest k holds twice the full of the pump-barrel, and if the valve r is loaded to the extent now mentioned, a pump full of water will pass into the boiler after each stroke, as soon as the valves are opened, whenever the water in the boiler stands at or under the dotted line bb, as in this case the pressure inside of k will not have opened the valve r, and allowed part of the contents of the feed-pump to be discharged back into the hot-well of the large engine. But if the water in the boiler stands above the line bb then (as by this the steam space in k is diminished) the pressure inside of k will open the valve r before the pump has finished its stroke, and allow part of the water to escape through the communication, running betwixt the top of the pump and a part of the pipe g (behind its valve) leading to the hot well. So by this contrivance, whenever the water in the boiler stands so high as that the steam space in k is not double that of the contents of the pump barrel, then a portion of the water in the pump will be sent through the valve r back into the hotwell, and when the valves 77 are opened there will not be a barrel full of water in k to pass into the boiler. The more the steam space in k is diminished by the water rising in the boiler, a less quantity of the water from the feed pump will pass into k at each stroke, and on this account the boiler will always get less water from the feed-pump the higher the water stands in it above the line b b. If the water in the boiler stood as high as the top of the chest k, then no water would pass into it from the pump. When the water in the boiler is low, and on this account the steam space in k is made as great or greater than double the contents of the feed-pump, then a pump full of water will pass from the chest k into the boiler every time the valves 1 1 open. In this way, if the boiler is too full of water, it gets less feed than its average quantity at each stroke of the pump; and if there is not enough of water in it, it is supplied with more than the average quantity, and for this reason the water in it will keep always at the same level. It is to be understood, that the feedpump is double acting, and in its downward stroke the water is discharged through the pipe t, into a chest placed alongside of the chest k, and of the same dimensions. This chest is also to have valves working on it, like those marked 7. The small circle at the bottom of the feed-pump, shows the pipe which leads the water into it: the pipe at the bottom of the pump for this purpose should have been drawn running in the same direction as this one, if it had not been wanted to show the loaded valve r, &c. I have not shown the loaded valve at the bottom of the pump, as it, and the other parts are of the same construction as shown for the top end. It is not important that the space which is above the line b b in the chest k, is double of the contents of the feedpump, only if this space is made in any other proportion to the contents of the pump; the weight s must be made to correspond to it; I may here remark, that the additional pressure given to the steam in the chest k, by the water pumped into it, helps the water to pass from the chest into the boiler as soon as the valves ll open. By having the cylinder d and the nosles e, as well as the feed-pump pretty large, the small engine will not require more steam to work it than if these parts were made small, as in this case, it will work slow when it is forcing the water through the loaded valve r, if this valve is fitted so that it can only open a small distance. From the manner in which the fly wheel is applied to the engine, it cannot stop, although its motion is not a quick one. When two boilers are to be supplied with water by means of a small engine, with one feed-pump, then the chest k, and the other parts in connection with it, must be fixed upon one boiler, and the other chest of the same sort as k, and which is in connection with the bottom end of the feed-pump, must be fixed to the end of the other boiler. If four boilers are to be supplied with water by means of a small steam-engine and one feed pump, then a chest, as k, and its appendages must be fixed upon each boiler, two of them in connection with the top end of the pump, and the other two in connection with its bottom end. If two or more chests, like k, are connected to the same end of the pump, then a pipe passes from the pump to one of them, and a pipe as the one at r connects the others of the set. On the principle now explained, any number of boilers may be supplied with water by means of the same feeding ap paratus. Only one loaded valve to the top of the pump, and another to the bottom are required, whatever may be the number of boilers to be fed. The pump, for an apparatus, as now described, may be wrought by the large steam-engine in the ordinary way, if the loaded valve is very large, and if it is made to open sufficiently. In this case the pump may be single acting, and only one chest like k will be required. If the feed pump is wrought as now described, the boilers will get no water when the large engine is standing. When the feed pump is wrought by the large en |