NEW METHOD OF ORNAMENTING FANCY CUTLERY. mand cannot be obtained by the old channel the ash-pit and bars-some other arrangement, and some other channel must be sought for. Two supplies are required, the one for the solid, and the other for the gaseous combustibleso also are two distinct orifices for admission called for; and as every introduction of new fuel creates a new and additional demand for air, which cannot be obtained through the more than ever obstructed bars, a new and separate channel of admission becomes indispensable. The self-evident remedy is providing two means of supply, giving to each an independent action, and keeping both, under all circumstances, open and undisturbed. By thus dividing the supply of air, we have made the first step towards regulation; for as the fresh charge of coal, had, as it were, shut the door against itself and its own demand-by giving a separate door, we prevent the recurrence of such mischievous influence or interference. Our next step is to inquire to what extent these separate supplies require adjustment. For this purpose we have to examine the combustible gases generated, and their order of succession from the beginning to the end of the charge, each succeeding charge being but a repetition of the same order of causes and effects. We shall thus have to inquire the results as to the temperature produced, and the most desirable or practicable management as regards the admission and action of the air in supporting combustion. The fresh charge being in action, the evolved gases will be, in the first instance, the carburetted and bi-carburetted hydrogen-the proportion of the latter being governed by the nature of the coal, and the intensity of the heat in the furnace, and, to no small extent, its depth and distribution in the bars. This will be confirmed by the appearance of the gas in combustion-the bi-carburetted being the most brilliant white, and giving the strongest light behind the bridge, though not so in the body of the furnace. For this purpose the furnace may be considered as a species of retort, with the double duty, first, of generating the gas, and then of heating it to the proper temperature for chemical action-but certainly, to a very small extent of effecting its combustion, and for the reason 261 already adduced, namely, the impossi- The 1. Carbonic oxide, before the charge. 2. Carburetted and bi-carburetted hydrogen. 3. Carburetted hydrogen alone. 4. Carburetted hydrogen and carbonic oxide. 5. Carbonic oxide alone. In my next I will give a tabular view of the quantities developed; their respective lengths and temperatures, and the relation they bear to the admission or exclusion of the air. I am Sir, yours, &c. Liverpool, March. C. W. WILLIAMS. NEW METHOD OF ORNAMENTING FANCY CUTLERY. Sir, I beg to communicate to you a description of a mode of ornamenting sword-blades and fancy cutlery, which is, to my knowledge, quite new; and you will oblige me by inserting it in the columns of your interesting and useful Magazine. The process is explained in a very few words. It consists in applying printed The impressions to the surface of the articles, I am, Sir, M. T. BRAZENDALE. March 21, 1842. METHOD OF PRODUCING EXCELLENT DAGUERREOTYPE PRINTS WITHOUT THE AID OF AN ENGRAVER. Sir, Every body who may have had an opportunity of seeing an impression from an electro-etched Daguerreotype plate will have perceived in it a generally poor effect, arising from the indent not being of sufficient depth to hold the molecules of the printing-ink in requisite quantity; this is at least the case if the minute details of the picture are left clear and well defined. On the other hand, should the plate be etched to the proper depth, all the exquisite and inimitable beauty of the finer parts is destroyed. The following method will produce an effect closely approximating to that observed in ordinary prints, and vastly superior to any of those heretofore executed simply by Mr. Grove's method. A Daguerreotype is first etched by the voltaic process invented by Mr. Grove,* when an impression is taken therefrom, on "transfer paper," using the kind of composition ink usually employed for transferring operations. This impres • Vide Proceedings of the London Electrical Society, vol. i. 1841, page 94. +That containing the smallest quantity of lampWe ought to be chosen. STEAM-BOILER EXPLOSIONS. Dear Sir,-Previously to reading the paper of M. Jobard upon this subject, I had made several experiments, with a view of ascertaining whether, after the hydrogen gas is formed in the boiler from the decomposition of the water by the heated plates, the explosive mixture might not be completed by the steam itself, independently of any atmospheric air, which might obtain access to the interior of the boiler from the feed-pumps, or otherwise. From several experiments, accurately and carefully made, I am induced to believe that such is the case; and that when once an evolution of hydrogen gas has taken place in the boiler, we need not look for the other ingredient of a dangerous and highly explosive mixture, such mixture being immediately formed by the steam. I have burst a small wrought-iron boiler under such circumstances, that no air could possibly have been mixed with the steam, having first carefully expelled it from the water which I used. I allowed the water to get very low in the boiler, and fired it by means of a platinum wire ignited by a galvanic battery. When once we have an explosive mixture formed in the boiler, I think no difficulty will be found in kindling it: a sudden rush of steam will lift the safety-valve, when imme THE LEEDS SMOKE NUISANCE REPORT. diately the electric spark will pass between it and the seat. Another theory, which I believe to be purely original, and certainly only the offspring of the moment, is this: may not a sudden evolution of steam or gas cause a sufficient degree of compression to produce ignition? We know that a piston, by being forcibly pushed down into a cylinder, causes sufficient heat to inflame amadon or German tinder-may not so powerful an agent as steam produce the same effect? However, this is but the idea of a moment; but every little helps to elicit truth. I am, Sir, Your most obedient servant, Eltham, March 25, 1842. WALKER'S HYDRAULIC ENGINE. Sir,-The description of Walker's Hydraulic Engine, by Mr. Baddeley, in your valuable magazine, did, I must confess, a little astonish me; but not so much as seeing it at work afterwards at the inventor's manufactory. The term "cylinder" which your correspondent uses, led me a little astray so far as regards the exact principle on which it depends for action. I thought there was something within the cylinder which was not explained, and I have no doubt others of the many readers of your magazine have been led away by the same idea. However, upon examining the apparatus for myself, I find all that is required to raise water is a common zinc or other metal tube, with a valve at the bottom opening upwards. The enlarged space at the bottom is only to give more water way than would be afforded if the tube was of the same diameter throughout. There is one particular part which I wonder escaped the scrutinizing eye of your correspondent, and that is, the mode of putting a new leather or plate on the valve, when required, without a joint or flange on the pipe. There is no attempt in this instance to improve the ordinary pump, for every thing connected with it is thrown overboard, and an entirely new principle substituted of immense value, which will only be duly appreciated as it becomes known. A new field is opened for the expansive powers 263 of never-tiring genius. Mr. Baddeley's account of it is very good; but it appears to me impossible to judge of its real merits without seeing it in action. I have no doubt the shipping interest will be the first to examine into the principles of this wonderful invention; as it appears to me well adapted for maritime purposes, and may no doubt be applied with certain success in all works of magnitude where hydraulic machines are indispensable, or where water is to be raised. I have given Mr. W. two orders for the purpose of raising water from foundations of buildings, which I have no doubt will be a great saving of labour, and also in repairs. THE LEEDS SMOKE NUISANCE REPORT. The promised Pamphlet on the Smoke Nuisance, by Mr. West-the fruit of the great meeting at Leeds is at length published, and we must confess that we are sadly disappointed with it. It is, in effect, little more than a gratuitous advertisement of all the schemes of all the smoke-doctors throughout the kingdom, with their names, addresses, prices, testimonials, &c.; differing chiefly from the useless Report of the sage Committee of the London Corporation in this, that whereas the London Report contained only seven plans, the Leeds contains, (with much vaunting of the numerical superiority,)"upwards of forty." The question of the practicability of annihilating the smoke nuisance, without prejudice to the many important manufacturing interests involved in it, is left, just where it was; and instead of the pamphlet furnishing any help to manufacturers or others, to see their way through the labyrinth of assertions and tes timonials—which last the most worthless, An Account of the Patent and other Methods of Preventing or Consuming Smoke; with Acts of Parliament on the Subject, Evidence on Indictments for Smoke Nuisances, and the Proceedings at a Public Meeting of Patentees and others for Exhibiting and Explaining Models. By William West, Professional Chemist, Leeds. Simpkin and Marshall, London; Baines and Newsome, Leeds. as well as the best, have at command-it only makes "confusion worse confounded." Many inventions, which had deservedly fallen into obscurity, are here resuscitated with the stamp of official notice, if not recommendation. The descriptions of several deviate materially from the original specifications of the patentees, the inventors having, apparently, availed themselves of what appeared to be the favourable points of others. One and all are depicted in the most glowing colours. Every one is just the thing for economy, and for consumption of smoke-though, whether it be possible to consume smoke at all is still a question in dispute among men of science. We had expected, at the hands of Mr. West, something like a rational, deliberate, and scientific analysis-something that should lead, rather than puzzle the practical part of the public-something that should at least have separated the dross from the ore, and have thus circumscribed the field of inquiry-something that might have served to take the subject out of the range of mere mechanical invention, which has too long usurped the place of science in all that relates to this matter. The merely enabling each pretender to throw his rubbish into the heap-thus overwhelming the little there is of a sound, useful, and practical character-has effected nothing towards clearing the way for those who are really desirous of abating the nuisance, or of enabling Parliament to legislate with safety. The Leeds Meeting should either have done more, or done nothing much embarrassment, possibly much mischief, seems likely to result from this originally well-intentioned, but most abortive effort. He Some general remarks of a cautionary nature are indeed made by Mr. West, but not greatly to the purpose. seems, evidently, to have been a good deal embarrassed by his position-between a desire to do his duty, as a reporter, with literal fidelity, and a dread of lending his authority, as a man of science, to any one scheme more than another. He has not thought it to be within his province even to analyze, much less to condemn or recommend. The pamphlet, as it is, seems to have cost him no little trouble, but it has been trouble thrown away, for the whole will The writer of the Note in the Mechanics' Magazine of the 19th instant, on the AntiJohn-Scott-Russell experimental steam-boat, presents his compliments to Mr. John Beningfield. He admires Mr. Beningfield for his boldness in backing his friend Mr. Beale's "whirligig" against "the world," for a trip "from Greenwich to Richmond, and back again;" but begs respectfully to submit whether it would not have been as well to choose ground for the match, where "all the world," if so inclined, might enter into the competition. He presumes it must have been from mere oversight that Mr. Beningfield has pitched on a portion of the river where notoriously the swifter steam-boats do not, and are not, able to ply. What does Mr. Beningfield say to a trip the other way, from Greenwich to Gravesend, or from Gravesend to the Nore, or from the Nore to Calais ? If he will amend his challenge, so as to give all "the world" plenty of room and fair play, it will very probably be accepted. Even then Mr. Beningfield, with his "considerable experience in steam-engines generally," must no doubt be well aware, success on either side would affect but little, if at all, the question raised in the Note to which his challenge is a reply. That question is this, simply-whether there is any thing in the construction of Mr. Beale's rotary engine to make it probable that it will, in the long run, work better than any of the numerous engines of the same class which have gone before it-to oblivion? The writer of the Note thinks there is not; and he is prepared to state his reasons, if Mr. Beale, or his champion Mr. Beningfield, will first of all, (to prevent any future cavilling about the facts of the case,) state in what respects the Anti-John-Scott-Russell "whirligig" differs from preceding rotary engines, and the special grounds on which the inventor flatters himself that he has succeeded, in so extraordinary a degree, where so many others have utterly failed. London, March 28, 1842. METROPOLITAN MUSIC HALL-HANSOM'S NEW SYSTEM OF BUILDING. A plan is now before the public for the erection of a Metropolitan Music Hall, of truly colossal dimensions. It is to be half as large again as Westminster Hall-"the noblest hall (as yet) perhaps in the world;" and is to be capable of containing fifteen thousand persons. The organ too is to be of corresponding magnitude-"an organ exceeding in dimensions, power, and grandeur, all that the Continent, 'so great in this respect, can exhibit"-"the ORGAN of London, of England, of Europe, of the World!" And the cost of the building (the most surprising part to us of the whole affair) is to be no more than £30,000. The author of this design is Mr. Joseph Hansom, the architect of the universally admired Town Hall of Birmingham-one of the very finest of our modern public buildings; and the means by which he calculates on being able to erect a hall of such unparalleled magnitude, at a smallness of cost so equally unparalleled, is the application to roof building of the suspension principle, followed in the construction of the Menai, Vauxhall, and other iron bridges. We quote the following explanatory details from a lecture delivered last week by Mr. Hansom, at the Music Hall, Store Street. "According to the ordinary system of building, the sides are made to receive, to all intents and purposes, the whole weight of the roof, and pressing unequally, that is, at points, the beams or principals of the roof lying transversely upon the walls, and the weight increasing by confluence, as it were, towards the middle, that is, in the very weakest part of the building. The ends, too, be it observed, equal in all the features, and capacity to sustain pressure, yet not loaded at all, or at most, by the ends of a few rafters, resting on a dangerous and insecure gable. But the corners of the building -those towers of latent strength, if I may so term them, for all the purposes for which they are so eminently designed, seem as superfluous as the strength contained in them -that is, the present system of building is such as to so regard them; but mind you, there is only one plan by which this great fund of strength and sufficiency can be called into action, and it is by proceeding on that beautiful principle of making force converge to a centre, instead of diverging from it, tending inwards, as gravitation does, instead of pushing outwards, as incohesive and dis. turbed elements operate. And what think you is that mode of construction, which so calls into action this latent strength? It is neither more nor less than that of the suspension bridge.* "By suspending, therefore, the great weight of the roof from the four corners, we not only impose the pressure upon fixed and equal points-and to impress equally-but we make use of the natural abutments, which the walls of the corners supply by their meeting, to prevent any derangement of the upright position; that is, if one of the walls could experience a draught inwards through the pulling force of the suspension rods, the other wall is pushing against to resist it; and so of each wall, mutually and reciprocally, and of each corner. "Here then we fall again on another beautiful principle of the ancient masons. In their groined vaultings, they regarded walls merely as a means of inclosure, not of support; and hence we find, that the arch ribs were collected together at a small number of bearing points, or piers, (they might be termed the legs of the building), and their tendency to thrust outwards was counteracted by buttresses, sometimes flying over, from a distance of several feet, and crowned by heavy pinnacles to increase their resistance by weight. Yet beautiful, magically beautiful as was their device, we have no need of it; the very thing, which they resorted to, as an expedient, exists in the nature of the construction of all square buildings; and had they known of the principle of suspension, as they knew of that of the arch, of which their early predecessors were ignorant, they would no doubt have adorned and used it with similar triumphs. 'Away then with the necessity of outward buttresses, and massive side walls-away with columns of support-away with inequalities of pressure, and their consequence, fracture and derangement-all we require are the corners of our building; or, if we would lighten them still more, we interpose a strut between; but indeed the very outward frame of the roof performs this office; resisting compression, it also stays the corner piers in their place; it is their best, I may call it, their faithful auxiliary. "Away also with high pitched roofs, and the steep sloping sheets of tiles and slatesthe forest of timber, which so large a roof as this would require, loaded by its mass of "A building of great dimensions has recently been erected at Paris, called "La Rotonde des Panoramas." The roof, which is pitched, and partly on the old construction, is suspended by iron cables. The design is by M. Hittorf, architect of the French Government, under whose patronage it was built." |