The spect a vessel fitted for an African station. Avon is fitted with Captain Smith's paddle-box boats, and on the sides of the paddle boxes, numerous cabins have been constructed for sleeping on deck. A platform has been constructed nearly 10 feet above the deck, joining the two paddle-boxes to each other, and of the dimensions of 21 feet by 20 feet. The platform is immediately over the engine room, and by the protection it affords to the engines, to preserve them from wet, the use of glass windows has been obviated, and wire gratings, about 2 inches and a half square, have been substituted, giving ample room for the circulation of air at all times. In the centre of the platform a window has been made, to add to the light of the deck underneath, and the whole has been joined, at Commander Denham's request, with marine glue. Commander Denham has also suggested that the cabin windows, and, indeed, every place for sleeping, should be supplied with extra frames, fitted with wire gauze, which permits the egress of the heated air of the rooms, while it checks the effects of the rays of the sun when the windows are open; and Mr. Lang, master shipwright, and Mr. Read, assistant to the master shipwright, have expressed their opinion that the application of the wire gauze, as recommended by Commander Denham, is one of the best plans of ventilation and protectors from extreme heat in tropical climates that could have been adopted. The Avon has been fitted with an invention by Churcher, for guiding the chain attached to the wheel when directing the helm; it appears to be very simple in its operation, prevents the chain getting foul, and is the first of the kind introduced into Her Majesty's service. Alleghany Suspension Bridge.-This bridge is the work of a mechanic of Alleghany city. The suspension ropes which extend from pier to pier, in the form of an inverted arch, are to consist of seven strands of wire, each strand being about three inches in diameter. Four of these strands are already finished across the entire length of the structure, and the fifth will be completed to-day. The ropes will then be wrapped in annealed wire, (No. 14,) which will render it one solid mass; and as each individual wire is varnished before it is put across, and as the whole will be painted when finished and wrapped, it will be impervious to water, and consequently not liable to be weakened or impaired by the weather. On these two immense wire ropes the structure is to be suspended. But this is is not the only reliance for strength. The trunk is to be constructed from pier to pier; the sides being of solid lattice-work; that is, strong beams placed in this form-XXX. The beams are to be placed contiguous to each other for greater strength, so that when finished the trunk alone, without the wire-ropes, will be a firm and strong structure, capable not only of sustaining its own weight, but also of bearing up as much additional work as a lattice-work bridge would do. In effect, the trunk is a lattice-work bridge without arches. The ropes, being suspended across strong stone towers placed upon the piers, are, in fact, inverted arches, capable of sustaining more than double the additional weight which the letting-in of the water would place upon the trunk; the trunk its.lf is an independent, strong, and immovable structure, so that when finished, the aqueduct will not be liable to be moved either from the swell of water or the effect of storms. The wires are carried across the river, from one pier to another, by a wheel which traverses the whole distance upon ropes, unbinding the wire from the reel as it goes. The ropes are moved by horse-power. The splices of the wire are made by placing the two ends together and winding them with fine annealed wire; and it is done so strongly that sufficient force will break the wire, but will not affect the splice.-Pittsburgh Chronicle. Machine for taking Soundings.-A very ingenious contrivance for taking soundings at sea has lately been discovered by a Mr. Richard Wing. It is the application of electro-magnetism to this purpose. The instrument must be seen to be fairly appreciated. It is not cumbrous or expensive, being made of wooden bars about two feet long, in which the apparatus is placed. It is to be used in conjunction with a sustaining galvanic battery and an electromagnetic bell. There are conducting wires, &c. The instrument is to be suspended by a strong line over the side of the vessel at any required depth, say 30 fathoms. The moment the instrument touches the bottom sufficiently to cause it to incline to an angle of about 22 degrees, indication is given by the ringing of a bell in any part of the ship most eligible for placing it. The great difficulty of ascertaining depths by the sounding lead in great depths of water and in strong currents would, it is asserted, be remedied by this invention, for the moment the machine from being perpendicular in the water fell horizontally, indication would be given.-Times. Day and Night.-Nothing made so deep an impression upon our senses as the change from alternate day and night, to which we have been habituated from our infancy, to the continued daylight to which we were subjected as soon as we crossed the Arctic Circle. The novelty, it must be admitted, was very agreeable; and the advantage of constant daylight, in an unexplored and naturally boisterous sea, was too great to allow us even to wish for a return of the alternations above alluded to; but the reluctance we felt to quit the deck when the sun was shining bright upon our sails, and to retire to our cabins to sleep, often deprived us of many hours of necessary rest; and when we returned to the deck to keep our night watch, if it may be so called, and still found the sun gilding the sky, it seemed as though the day would never finish. What, therefore, at first promised to be so gratifying, soon threatened to become extremely irksome, and would, indeed, have been a serious inconvenience, had we not followed the example of the feathery tribe, which we daily observed winging their way to roost, with a clock-work regularity, and retired to our cabin at the proper hour, where shutting out the rays of the sun, we obtained that repose which the exercise of our duties required. At first sight it will no doubt appear to many persons that constant daylight must be a valuable acquisition in every country; but a little reflection will, I think, be sufficient to show that the reverse is really the case, and to satisfy a thinking mind that we cannot overrate the blessing we derive from the wholesome alternation of labour and rest, which is in a manner forced upon us by the succession of day and night. It is impossible, by removing to a high latitude, to witness the difficulty there is in the regulation of time-the proneness that is felt by the indefatigable and zealous to rivet themselves to their occupations, and by the indolent and procrastinating to postpone their duties, without being truly thankful for that allwise and merciful provision with which Nature has endowed the more habitable portions of the globe. -Beecher's Voyage of Discovery towards the North Pole. INTENDING PATENTEES may be supplied gratis with Instructions, by application (post-paid) to Messrs. Robertson and Co. 166, Fleet-street, by whom is kept the only COMPLETE REGISTRY OF PATENTS. LONDON: Printed and Published by James Bounsall, at the Mechanics' Magazine Office, GORDON'S PATENT FUMIFIC IMPELLER. [Patent dated March 3; Specification enrolled, September 3, 1845.] THE inventor of this impeller is Mr. Alex. Gordon, the author of the wellknown "Treatise on Elemental Locomotion." The present invention is stated to have been the result of a successful course of experiments upon the action of the hot products of combustion when brought by rapid delivery into immediate contact with water;" and the general considerations which led Mr. Gordon to institute these experiments are fully explained in a pamphlet which he has just published. We select from this pamphlet a few of its most striking passages: In the steam-engine, water exists in every stage of its history or operation. The heat from the fire separates the ultimate molecules of the water, overcoming their mutual attraction, and endowing each of them with a force of repulsion in proportion to the amount of heat. Heat, then, is the source of that power. All solids, liquids, and aëriform bodies, may be heated and cooled, expanded and contracted; very few of them, however, can be applied as an elemental power, and still fewer of them can be employed as a power for locomotion or navigation. Some of the solids are used where power without speed is required, as in the case of iron bolts, rivets, ties, wedges. Some liquids, as for instance, spirits of wine, ether, ammoniacal liquor, liquid carbonic acid, have been proposed and experimented upon, with the view of being employed as means for an available motive power, by the alternate application and abstraction of heat; but water has hitherto been found the most convenient and economical means for obtaining power from the chemical action of heat; and to this is due the general adoption of the steam-engine. Many attempts have been made to employ air as the means for obtaining power from the chemical action of heat. Some inventors have followed the manner in which water is treated in the steam-engine-by keeping the air altogether distinct from the fire, and transmitting the heat of the furnace through the materials of a tight chamber (like a boiler). Of these the most successful have been the productions of Mr. Erics son and Mr. Stirling.* Others have used the products of combustion by bringing them (without the intervention of any heating chambers like a boiler) at once to act in the piston-cylinder. This latter process was introduced in Sweden,† and more, recently has been carried into experimental operation by Sir George Cayley under a patent. But, prior to either the Swedish engine or that of Sir George Cayley, Mr. Robert Stein, of Edinburgh, had, in August, 1821, obtained a patent for improvements in steamengines, and his improvements consisted principally in directing the actual products of combustion in combination with the steam, at once into the piston cylinder. Sometimes Mr. Stein dispensed with a boiler and water, and used only the products of combustion from the close furnace. All of these, and all other inventors of hot-air engines, have taken the steam-engine piston and cylinder as their models; and, although several of them proved clearly that air is more economically heated to the required temperature than water, and, although Sir George Cayley proved this economy of fuel in an extensive practice, and Mr. Stirling has shown the economy to be immense, no one has yet contrived how to maintain the durability, and, by consequence, the current economy of a hot air or caloric engine, when a piston and cylinder are operated upon at once by the products of combustion. And of Mr. Stirling's engine it may be said, it bids fair to rival the steamengine for manufacturing purposes, such as the impulsion of mill-machinery. It is not necessary to enter into a tedious narrative of the hot-air or caloric engines just referred to, nor to enumerate the various attempts to make hot aëriform bodies actuate a piston in a cylinder. It may be asserted that hot aëriform bodies have not been successfully employed hitherto as the agents, because the great sensible heat has speedily destroyed some part of the machine; and because water has been preferred as the material, on account A full description of this elegant engine, with illustrative drawings, was presented to the Institution of Civil Engineers by Mr. Stirling, of Dundee, and a long discussion, on its construction, action, and economy, took place, to which I beg to refer. It will be seen that great difficulty was experienced by members in understanding the action of Mr. Stirling's air-engine. It appears to have been difficult of comprehension, principally because the steamengine is naturally taken by engineers as the standard of perfection. + See description by Mr. Ericsson, in a paper existing in the Institution of Civil Engineers. of the ease with which it can be procured, replaced, and managed. It has been said before, and cannot be too often repeated here, that heat is the source of power. And it would be absurd to suppose that any intelligent person considered that the machinery, or any part of it, from the paddle-floats of a steam-boat, back to the boiler, really augments the power which proceeds through the boiler, and along the steam-pipe. The power, i. e. the combined mechanical agency of elasticity and momentum of which the steam consists, is within the steam-pipe. The engine, machinery, and paddles only offer the means of bringing that power to operate upon the water, and urge the ship in her course. The proposers of hot-air engines have taken the steam-engine, subsequent to the discoveries of Newcomen, as their model, whilst they should have reverted at once to the engines of Savery and of Papin. They should be referred to the Marquis of Worcester's scantlings, and even to the smokejack of Hieronymus Cardan. The Marquis of Worcester employed the pressure of steam to act at once and directly upon the water which he desired to put into motion. Savery, also, used steam in direct connexion with the water. Denis Papin improved on these by interposing a loose floating piston between the steam and the water to be moved. Now, had any one of these latter used, instead of steam, the hot products of combustion from a close furnace, the steamengine would not now be the only available inanimate artificial power in use for such purposes as raising water, and for locomotion and navigation. * * * My invention and its value are embodied in three simple axiomatic propositions, which interested or ignorant opposition may challenge, but I defy it to overthrow. 1st. That heat is the source of power in all our artificial motive agents. 2nd. That machinery does not increase the power of any machine, but only transforms or transfers the motion. 3rd. That the expansion arising from a given amount of heat applied to gaseous bodies is much greater than from the same amount of heat when applied to liquid bodies. The first two propositions will be admitted as correct by any tyro. We need not stop to examine them. Our discussion of the third proposition shall be as nearly as possible in the words of the best chemical authorities. "It may be laid down as a general rule, to which there is no known exception, that every addition or abstraction of caloric makes a corresponding change in the bulk of the body, which has been subjected to the alteration in the quantity of its heat."* From the experiments of Dalton, Gay Lussac, and others, it is well established that all gaseous bodies whatever, similarly circumstanced, undergo the same expansion by the same increments of heat; and Dr. Ure adds his testimony that "Expansions of aëriform bodies are proportionate to the augmentation of temperature ;" and in the words of Dr. Thomson, the expansion and contraction differ exceedingly in different bodies. "In general, the expansion of gaseous bodies is greatest of all." We proceed now to give the description of the Fumific Impeller, as it is contained in Mr. Gordon's specification : Fig. 1 is a sectional elevation of such an 276 GORDON'S PATENT FUMIFIC IMPELLER. apparatus, as will explain the nature and action of the Fumific Impeller. A, is a fire-grate inclosed in a strong close furnace B B. There is on the top of this close-chamber B, a bonnet-valve C; and at the bottom there is another bonnet-valve C'.* The valves being open for the purpose of laying and lighting the fire, which may be of coal, wood, coke, charcoal, peat, or of any other fuel: and the fire having attained a good state of combustion, the valves C and C' are well luted and closed tightly on their respective openings. D is a blower, which supplies atmospheric air to support the combustion in the close furnace. The air being directed by means of the valve E, so that it shall pass through the pipe F or the pipe G; the former conducting it under or up through the fire, and the latter to the top and over the fire; thus the exact quantity to pass through or close to the fire may be regu lated for consuming a quantity of fuel sufficient for producing the hot products required for the fumific influence; and thus the speed and power of the Fumific Impeller may be increased or diminished. H is a pipe leading off from the top of the close furnace, by which the hot aëriform matters generated by the process of combustion are carried off to be applied in the manner which shall be explained more fully below; and these hot aëriform products of combustion are intermingled usually with some dust, ashes, and other solid matters, but which do not interrupt the dynamic action of the gaseous body. Air, it is well known, will, when heated by one degree of Fahrenheit, expand about 4th part, and continue to expand so as to have its expansive force or tendency increased in about the same proportion for every additional degree of temperature.* It B the inside of this close furnace is constructed of fire-clay, or fire-tile, and the external shell is formed of wrought-iron, of sufficient strength and sufficiently tight to resist the pressure from within. It might be made altogether of iron; but if the iron were not protected by some inner casing, it would not withstand for any great length of time the high temperature to which it must necessarily be exposed. C C', these valves are kept tight upon their seats by means of the usual springs or weights, and not only serve for closing their respective apertures, but they are arranged so that they can blow open as safetyvalves, when the pressure from within shall exceed the power of the springs or weights employed to keep them close. T is a pipe fitted in the close furnace, which, being provided with a talc-sight, enables the attendant to see the state of the fire." + Dalton determined that 100 parts of air being heated from 55° to 312°, expanded to 1325 parts; this gives us an expansion of parts for 1° Fahr. Gay Lussac determined the expansion to be; and although in Sir David Brewster's edition of follows that if the temperature of a permanently elastic aëriform body be augmented by about 480°, the bulk of that body will be doubled, or if it be retained within the space it originally occupied, its presure will be doubled. It is by availing myself of this well-known law of expansion by heat and the new arrangement of particles in the close furnace, that I can obtain a rush of power from the furnace along the pipe H, analogous to the rush of steam from a steamengine boiler along the steam-pipe to the engine,-equal to it in pressure, power and constancy, and, when required, at much greater velocity. The air driven into B for support of combustion must, of course, be driven in against the pressure due to the heat of the products of combustion; for, supposing the latter are at the temperature of about 500°, there will be an atmosphere of surplus pressure against the blower; and it will be found that the blower, to do its work, will require a power of half the power generated by the heat. The manner in which this blower is worked, and also the manner of starting the engine, are shown below. It has been before shown, that the power of a steam-engine is from the fire" through the boiler and along the steam-pipe; that the power-i. e. the combined mechanical agency of elasticity and momentum, of which the steam consists-is within the steam-pipe." Now, in the Fumific Impeller, the power-i.e. the combined mechanical agency of elasticity and momentum-is in the hot products of combustion themselves, which are in the pipe H. In a steam-engine, the power of heat is necessarily transmitted through a costly and elegant system of machinery to act upon the bodies, which it moves or which it moves upon; the steam being carefully prevented from contact with any body but its own engine. In the Fumific Impeller, the power of heat is brought without the aid of any transmitting machinery, to act directly and at once upon the body or bodies to be put in motion, or on the medium or media in, or on, or through which the ship, or machine, or carriage, is to be moved or impelled. A stream or streams of the hot products of combustion are discharged under water backwards, and the vessel moves forward, or they are discharged forward, and the ship is moved backward. It is a case of recoil analogous to that which takes place in a rocket occasioning its flight, but differing from that Robinson's philosophy, 24, or about 17 is stated, we find Dr. Ure, in his 'Dictionary of Arts' (artic.e Expansion,') states that all gases expand 4 for each degree of Fahrenheit. |