EXTINCTION OF RIVER-SIDE FIRES.

Sir, I have been much interested by the various contrivances published in your valuable Magazine for preventing the deplorable calamities attendant upon fires. The recent event at London Bridge has suggested to me a mode by which fires in the vicinity of the river may be more readily extinguished. It is simply this: Let one, two, or more floating steam fire-engines be moored at different stations on the river, each fitted up with paddle-wheels, and having every requisite, such as fire-escapes, &c., on board, and let them be always ready for use. The facility with which they might be brought to the scene of action at any state of the tide,* and the immense body of water which a small steain-engine would be enabled to throw upon a fire when its paddles were not at work, together with the frequent scarcity of water for the supply of land-engines, even near the river, induce me to believe they would be highly advantageous. The expense, either for first cost or keeping up a sup ply of steam, I do not think would be objected to, when we reflect on the loss of property which might probably have been prevented within no very distant period, near to or upon the river and the docks, if only one floating steam fireengine had been regularly stationed at

The present floating-engine (by the report published in the Chronicle) did not reach the fire until two hours after it broke out; and although highly efficient on its arrival, it is awful to contemplate the amazing increase of a fire during such a period, and the relative difficulty of extinguishing it, in proportion to the length of time from its commencement.

+ The loss at London Bridge, by the report above referred to, is estimated at about half a million sterling.

Among other advantages likely to arise from the adoption of engines of this description, I think they might have a common fire engine on board, with convenience for landing it in situations which could not be approached from the land side, where they could be effectively use; but I must beg to refer all details to the consideration of those more practically acquainted with the subject than myself.

FIRE-PROOF STAIRCASES.

Sir,-Among the various schemes for preventing the sad havoc which is so frequently the consequence of fires (in two many instances attended with loss of life or mutilation of limb), that which to me appears the most simple and the most efficacious is scarcely ever noticed, and I much fear will never be acted upon generally without legislative interference-I mean the construction of incombustible staircases. I am a builder in a small way, and being an operative mason, have always, without reference to the size of the house, put stone, or stone and brick to the first floor; even in fourth-rate houses this is quite easy, and little more expensive than wood. Two courses of brick for riser, and a rubbed York tread with the nosing rounded; the bricks faced with cement, and when dry painted stone colour. This looks well, and is lasting. Nearly all fires originate in the lower part of the house; and a moment's reflection will convince every one of the difficulty of the flames reaching and burning through a ceiling eight or nine feet high, except by means of communication afforded by the wooden staircase. Above the first floor, stone staircases, unless geometrical, are more difficult, on account of the necessary support taking up too much room. My present object is, however, to point out the advantage of having the lower staircase fire-proof, which perhaps would, in 99 cases out of 100, prevent the fire reaching higher if it commenced on the ground-floor, or afford an easy mode of escape should the fire take place in an upper story.

I remain, Sir,
Yours, very truly,

Obelisk, Sept. 5, 1836.

P. RAYNER.

Sir,-The following is a description of a rotary steam-engine, which I think possesses many advantages over any that I have yet seen, and obviates all, or most of the objections which present themselves in these kind of engines. A is an annular cylinder, part of which is represented as broken away to show the piston and one of the sliding abutments. BB are the steam-ways from the slidebox D and steam-pipe C; E is the working shaft firmly fixed to the piston F; GG are the sliding abutments and cases, which are kept in their places by a suffi cient pressure of steam, a spring, or a counterpoise (not necessary to be shown), so that when the inclined plane on the piston F has pushed it up and has passed, it immediately returns-or shuts into its place again, having meantime reversed the slide-valve, and admitted the steam between the piston and itself, while the communication on the other side is cut off. HH are the supports to the levers Il, which, in conjunction, work the slide-valve by the continuous rod K K. It will be understood, that to allow the arm E and piston F to perform their revolutions, there must necessarily be a sufficient opening right round the cylinder

A; now there is attached to the pistor, and constantly moving with it, a true seg ment of a circle made of brass, and rather longer than half the circumference of the cylinder, a little wider than the opening, and fitting into a groove on each side, made steam-tight by the pressure C within. When the piston has passed the abutment, the steam is reversed, and the semi-circular brass passing the other abutment, allows the steam that has done its office to escape into the atmosphere. Of course the sketch is a high-pressure engine, but it may be made a condenser by boxing in the cylinder, and having a stuffing-box round the main shaft, and conducting the exhausted steam to a condensor. This kind of rotary-engine is a direct accelerated motion, no stoppages, and there is nothing left for the momentum of the flywheel to perform, the steam is always acting. It can be made either to advance or retrograde, merely by having an inclined plane on each face of the piston, and having the semi-circular brass to work easily through a guide in it, and being fitted with two projections, as shown by the dotted lines, supposing it were required to reverse the motion as shown in

the figure, the steam is let in, the piston and shaft retrograde, and the brass (or semi-circular valve) remains stationary till it is dragged round by a piston striking the projection on the opposite side. This is the engine, Mr. Editor, which, if you remember, I made a self-exacted promise long ago of forwarding for insertion in your useful pages; but many circumstances combining to drive the thing out of my mind at the time, I had nearly forgotten till a few days since. I should be glad of the opinion of some of your practical readers on the subject, and beg to state, that if the idea be of use to any person, it is at his service.

I am, &c.

W. PEARSON.

Bishop Auckland, June 7, 1836.

of information which, when represented in the proper quarter, may prove useful; and freely accepting Mr. Howard's apology, I remain, Sir,

Your most obedient servant, WILLIAM SYMINGTON. 1, King William-street, London Bridge, September 1, 1836.

IMPROVED DOUBLE BALLOON, WITH HYDROGEN AND CARBONIC ACID GASES.

MR. SYMINGTON AND MR. HOWARD.

Sir,-Having perused Mr. Howard's rejoinder contained in your last Number, and observed that it embraces no new facts inclining me to believe that the difference between his method and mine is quite immaterial, I cannot perceive the propriety of occupying your valuable pages in useless controversy, particularly when an examination of the drawings accompanying our specifications will at once show the wide dissiinliarity of the plans in question.

To relieve Mr. Howard from suspense on one point, I have to acquaint him that it was my brother, a resident in Scotland, but then on a visit to London, who called at Rotherhithe. But concerning that call I can truly say, he never mentioned a single syllable of having seen or heard of any particular plan of condensation.

In reply to Mr. Howard's questions, I have merely to observe, that what he terms his method or principle, described in italics in his last communication, has been in practice for forty years; and should he have any anxiety to see it in operation, I am ready to direct him to where he may satisfy himself.

I was not altogether aware, until Mr. Howard has been pleased to inform me, to what cause to attribute the being deprived of the Comet, and put to so much expense and inconvenience before I could even get the wheel tried with a vessel, the Alban, for which it had not been constructed. Thanking him for a piece

balloon of the common form and material filled with coal gas. B is another of smaller dimensions filled with carbonic acid gas, until its weight is nearly sufficient to prevent the rising of the machine; C, a car suspended from the upper balloon in the usual way; D, a slender steel-rod, or a rod of twined bamboo canes passing perpendicularly through these and fastened to the silk at A and B; E, a sail fixed to D; close to the ends of the rod there is a valve at each extremity opening inwards, and acted upon by a cord running alongside the rod and affixed within the car.

This machine does not require much explanation here; it need only be said, that while the contents of the upper balloon are nearly the lightest of aeriform fluids, those of the lower are the heaviest ; consequently they will each exert a power acting differently. When the machine is afloat in the atmosphere, by permitting a certain quantity of gas to escape through the upper valve, this will diminish the ascending motion, which then yields to the heavier, and by acting similarly upon the lower valve a proportionate quantity of the carbonic acid gas will fall down and the effect will be reversed; and by a nice adjustment of both the powers, may be made to balance, and the machine will become stationary at any elevation.

Now, as the rod is continually kept in a perpendicular position by the opposing powers, and as the whole are connected together and kept uniform by it, it is obvious that when the machine is stationary it would move horizontally before any force opposed to it, consequently a sail might be applied, though the surface of the machine itself might be sufficient to cause it to move before the wind.

The above arrangement would be very suitable for taking plans and bird's-eye views. It is in the power of the voyager in the ordinary balloon to cause it to rest at any elevation, but this only by a very inconvenient process, and one that is not always practicable; but this advantage is possessed by the present to such extent, that the mere adjustment of an index may cause the effect; but all independent of the safety of it, which would bear the most severe breeze as its becoming disarranged or tossed, would be impossible.

I may mention, though well known, that carbonic acid gas is most easily pro

cured, and at an expense far below that of coal gas or hydrogen.

ON AEROSTATION.

Sir, Having, in my letter of the 1st ult. (see p. 307,) endeavoured to show the improbability of aerial machines tending to any useful purpose, while they retain their present form, I shall now add a few remarks, suggesting the form in which balloons ought in my opinion to be made.

In art we generally imitate the works of nature; now, all animated bodies in tended for locomotion in the air or water have a head and a tail; man has imitated this in the ship, which has a stem and a stern; but in the balloon he has neglected his model, as at present made they have neither, and to this their mal-conformation alone must be attributed the repeated failures that have taken place in all attempts at guiding them. Upon this, I found the following observations:→→→

Balloons have two motions, a vertical and a horizontal; the former caused by the levity of the gas contained, and the latter by the prevailing current of air in which it ranges; and this latter is the movement that requires to be regulated, as the other can be varied by retaining or discharging of the gas or the ballast. Now, when it is considered how readily a vessel answers to her helm, and that water is to air as 832 to 1, I cannot conceive that it would be found so difficult a task to guide an oblong machine in such a yielding element as atmospheric air. I am aware that many scientific persons think differently; I would call the attention of such to an account in the daily papers, not many months ago, of one of his Majesty's ships, after losing her rudder and a temporary one in a hard gale of wind of several days' duration, having been steered up the Channel to Spithead by only attending to the trimming of her sails; there are also other known modes of steering by the assistance of the wind alone. In short, I am doubtful whether machines to float in the air should differ, except in the materials for their construction, from those used to float on the water.*

In comparing aerial with marine navigation, the fact is generally lost sight of, (as in the present instance by " Omri,”) that in the latter case the vessel floats in one medium and is propelled by the

It is common with aeronauts now to ascend to a most unnecessary height for any experimental purpose: if ascensions were confined to a moderate height, sufficient for all the ordinary purposes of voyaging, descents might generally be more safely and rapidly effected in cases of danger. With respect also to the proposed enlargement of balloons, I would ask, are not two or three persons suffi cient for philosophical or experimental trials? First let the aeronauts show the capability of guiding them, and capaciousness may then follow. When announcements like those of the proprietor of the Eagle" and her seventeen passengers are made, I augur unfavourably of their performances adding much to our stock of knowledge. Proofs of the points necessary to be first ascertained might be made for a tithe of the money that must be expended in making a balloon of the magnitude of that now about to ascend from Vauxhall; for the fate of which all thinking persons must feel some apprehensions, notwithstanding its being under the guidance of the most experienced aeronaut of the day.

I remain, Sir, yours, &c. OMRI. London, September 4, 1836.

MR. GREEN'S GRAND NEW BALLOON. This balloon, which, notwithstanding its great size, is inferior to the French aerial ship, which was exhibited at Kensington some time ago, has been constructed under the immediate superintendence of Mr. Green, the most experienced aeronaut of the age, he having made 220 ascents; the following particulars have been published with respect to it. It is 157 feet in circumference ; and the extreme height of the whole, when inflated, and with the car attached, will be 80 feet. It is formed of 2000 yards of crimson and white silk. The me thod of uniting the gores (the invention of Mr. Green) is by a cement of such a tenacious nature, that when once dry, the joint becomes the strongest part. It contains 70,000 cubic feet of gas. The weight of atmospheric air sufficient to inflate it, is about 5346 lbs.; and that of

help of another, whilst in the former it floats in, and is propelled by, one and the same medium.

the same quantity of pure hydrogen gas, about 364 lbs. ; the machine would con sequently, if inflated with that gas, have an ascending power of 4982 lbs. ; and allowing 700 lbs. for the weight of silk and apparatus, and 362 lbs. for ballast, would be capable of ascending with 28 persons of the average weight of 140 lbs. each. But Mr. Green in his first experiments in aerostation, seeing the great expense, difficulty, and inconvenience of using pure hydrogen gas, conceived the possibility of substituting carburetted hy drogen or coal gas, such as is used for illumination; and first used it in his balloon which ascended on the day of the coronation of George IV. From that time the use of pure hydrogen has been almost, if not entirely, discontinued, the expense of generating it being six times greater than that of coal gas. The specific gravity of coal gas being considerably greater than that of hydrogen, it gives a balloon a much smaller ascending power; and the quality of coal used, and the methods employed by different gas companies in its manufacture are so vari ous (the specific gravity having been found to vary from 340 to 790), that it is impossible to ascertain exactly what would be the power of a balloon inflated with it. It is, however, calculated that the new balloon will ascend with from eight to ten persons, besides ballast and apparatus; the power varying according to the quality of the gas, the state of the atmosphere, and a variety of causes. As a matter of curiosity, it may be stated, that the inflated silk will sustain an atmospheric pressure of 20,433,600lbs., or 9122 tons. The net which entirely envelopes the silk is of hemp, and the car of basket-work; the grapple or anchor, is of wrought-iron, and will be attached to an elastic India-rubber cord from the factory of Mr. Sievier. This will prevent, in a very great measure, any sndden jirk in stopping the balloon in rongh weather, whereby so many accidents have occurred.

The following are said to be among the advantages to be gained from the large size of this aerostatic machine:-A much greater elevation than has hitherto been attained, and the long agitated question decided as to whether there are, at a great altitude, currents of air proceeding in one direction for several months to