"Previous to the introduction of the hood or cullender to the top of the chimney, the violence of the draught occasioned sparks to rush from the top of the chimney, and which is now obviated by the use of the hood."

The ash-box will suffice, without the ashes being emptied, for fifteen or twenty miles if necessary, but of course the steam is proportioned to the quantity of water; various contrivances have been resorted to prevent the sparks coming out of the top of the funnel; they have tried wire-gauze at the bottom of the funnel, but they found the distance between the meshes of the gauze was too large, the sparks got through; they then tried one at the top much on the same principle, still some sparks did get through; they then tried another, which merely consists of a series of wires placed in a spiral manner, held together by ribs, and strapped down to the centre of the chimney; the distance between the meshes is aoout the eighth of an inch, and consequently no spark greater than the eighth of an inch can get out; and from all I have seen, and all I have heard, I think it is the most effectual protection; I have never seen any sparks get out since that. I have seen it tried on the Liverpool and Manchester Railway, and on the Greenwich Railway. I attribute the last-mentioned cap being more effectual than the former to the meshes being smaller, and the obstruction to the going out of the steam, and the smoke less. There is more obstruction in the cross net, on account of the friction of the smoke against the angles, than in the spiral form. I think it is an exceedingly difficult thing to get any furnace to consume its own smoke; but where ccke is burnt there is very little smoke, hardly any; I think that to prohibit any engines but those that do so, would be a very good restriction, as far as regards the metropolis; that those engines should not be allowed to burn coals. Supposing it were incumbent upon the person who had the management of the engine to reduce the heat upon entering a town, it would reduce the heat of the fuel and the liability to throw out sparks; and inasmuch as at the arrival at the depôt and the departure from the depôt, which are generally situated in towns, the engine moves with very moderate velocity, it is necessary to acquire the speed, which takes a considerable distance, and to slacken the speed, which also requires a considerable distance. I have no doubt that in a very short time the engines will be so improved as to prevent danger from sparks. Mr. Hancock, who travels on the high road, never suffers that inconvenience in his steam-carriage. I have a high opinion of the Llanelly coal; there is no smoke from it, nor sparks; it is rather dear, but it burns with an economy of about

twenty-five per cent. over other coal; it will produce twenty-five per cent. of steam more, than any other coal; but there is a difficulty in getting up the steam at first; it is a coal of a very peculiar nature, and requires a peculiar kind of furnace to burn it. There is an abundant supply, provided it could be brought to London. It is used in London in the Victualling-office in making biscuits; and a great many bakers use it; it would put an end to any danger in working the engines through the inhabited parts of London. The chimneys of locomotive-engines do not require much cleaning; there is not much soot comes from them; it is only where there are coals; but there is a great deal of sulphuric acid generated.

Dr. Lardner, LL.D., examined.

The only instances, I believe, in which' fires have been actually produced have occurred on the Liverpool and Manchester Railway, and on the railway in Leicestershire, between Leicester and Swannington. On the Liverpool and Manchester Railway fires have once or twice been produced in the waggons, the cargo of the waggons has been burnt; but no fire has ever been producod on the Liverpool and Manchester Line off the road; no house has been burnt, or any thing of that sort, nor is there any apprehension entertained of such a result; it is merely the waggons. The circumstances under which those fires have occurred were these:-The fire was supposed to have fallen, indeed it did fall very much-cinders in livid combustion-from the fire-bars of the grate upon the road, falling within the rails, and sometimes scattered on the sides of na: row roads to a foot or two off the immediate line of the roads. The flange of the wheels narrows, which come down inside the wheels, almost touch the ground, and in many cases actually do touch the ground between the wheels, and when the fire gets close to the rail it is caught up and thrown up against the bottom of the waggons, the hinder wheels of each waggon; these throw the sparks into the following waggon. There was no evidence how the fire took place; the fact is that the cotton waggons were burnt, but this was the way it was presumed to have happened. The chimneys are roofed or hooded with wire gauze, through which no sparks of any magnitude could pass, and therefore it could not have arisen from that. Since that a remedy has been adopted which is strictly enforced, the firebars have been put closer together, so that no sparks of any magnitude can now fall through them; at least they would not do mischief; they would be immediately extinguished by the cold air; and since this arrangement of the fire-bars has taken place, no fires have taken place upon the road; and

I understand of the directors no apprehension is entertained from fire from this cause.

Did not you hear a report that a field of corn was set on fire?-Not on that road; there has been dry moss, which reached up close to the side of the railway, and therefore scorched by the engines: but on the Leicester and Swannington road, the dry corn was set fire to. The circumstances on that railway are very peculiar; they burn coal and not coke, and the Leicestershire coal which they burn, is a coal of extremely peculiar quality; a good deal of sulphur and other matter in it, in a greater proportion than in common coals; this produces a great deal of sparks, an unusual quantity; they are prevented from using a hood upon their chimney; the engines are uncovered, so that the burning coal which issues in particles from the fire is cast up the chimney with prodigious force, and scattered in all directions, almost like the bursting of a rocket, which falls on the side of the road, or the thatch, or any thing in its way, and has produced this fire; they cannot put the hood on their chimneys, because the tunnel they have to go through is so low that the chimney almost touches the roof, and they have had great trouble and uneasiness about that; and I have not found any thing has been done to remove that, except the removing combustible matter from the side of the road. From the double circumstance of the using coal and not coke, and not being able to use those proper means of precaution used elsewhere, it does not appear to me the Leicester and Swannington Railway can use them on their engines.

Did you ever hear that a field of corn was burnt on the line of the Darlington and Stockton Railway?—I think I did hear that; but there, again, I apprehend they have used the old engines unprotected; they were very rough engines, and drew nothing but coals; they do not draw passengers; they are very rough as to the construction of the locomotives.

Is it your opinion that effectual measures can be taken to prevent any danger of fire?I have not the least doubt upon that subject at all. In the first place, with respect to the chimney, the only thing that has been done with respect to the remedy is the use of wire gauze on the top of the chimney. Your lordships will see, when they use wire gauze with the meshes so very close, nothing but the minutest dust-ashes can get through, it will be objected to that, that it will stop the draught, which is very violent in those cases; but they can increase the magnitude of it to any extent if it stops the draught in its present state; it may be made ten times as large as it is; there is no limit to the extent of it. It occurs to me, with respect to the

wire gauze now actually used, to show how little possibility there is of burning matters escaping. I was making experiments on the Dublin and Kingstown Railway, and I had occasion to drive the engine with unusual speed, and therefore to get very great draught. I stood upon the tender, the carriage which accompanies the engine, and carries the water and coke; I stood upon the highest point of it, so that my head was very nearly on a level with the top of the chimney; I received in my face the ashes which escaped from the wire gauze; they were perfectly cold; there was no other inconvenience except the little bruise one's skin received.

In a case in which one of those carriages would have to go through a tunnel, would having a hood make any difference in that part of its progress ?-Not with the tunnels now proposed to be constructed; that on the Leicester and Swannington Railroad was a tunnel built of the smallest possible size, barely to let the train go through, so that it passes almost like a bullet through the barrel of a gun. Now, in the present tunnels they are making them twenty-five and thirty feet high, which would be quite sufficient for any hood placed on the chimney. Then there is another point might be mentioned: it is not only that the draught from the fire escapes from the chimney, but the waste steam that comes from the engine; the mo, ment that gets in the atmosphere, mixed with the ashes, it condenses-it is converted into water, so that the burning ashes go into the atmosphere from the chimney actually mixed with condensed steam, which, of course, must extinguish them. I am, therefore, clearly of opinion, that as to danger from the chimney it is quite out of the ques tion, and the difficulty which has arisen in the way of fire-bars is removed; the arrange

ment of fire-bars used on the Manchester road has been found, as far as I am informed, very effectual, by placing them so near that the sparks are small and are immediately extinguished; but if it were considered necessary, there might be, in addition to that, a screen at each side of the fire constructed of wire gauze, which would prevent the sparks falling, except within the rails; then, if further protection is desired, a similar screen might be let down at the back of the engine, and that would actually increase the draught, for that would, as the engine passed along, catch the air, and compel it to go up the fire-bars; the only objection to that, perhaps, would be, that it would make too great a draught; this would confine the fire strictly to the road, where it would be immediately extinguished; they might even go further, and put a basket, which would carry the burning cinders in it; but it appears to me those remedies are quite superfluous; those

fire-bars would give every essential protection.

John Walker, examined.

Is a fireman on the London and Greenwich Railway. Has had his clothes burnt by sparks from the railway.

Robert Stephenson, Esq., C. E., examined.

On the first introduction of locomotiveengines on the Liverpool Railway, an extension took place in using the steam and creating an artificial blast and a very intense combustion; the blast was so much increased, it brought on us the difficulty of throwing out the hot cinders and ashes on the passengers. The inconvenience was so great that the Directors made, I believe, every species of experiment to reduce the evil, and in a degree accomplished it, not however so as to render it entirely harmless. Some ac cidents have recently occurred on that line; the destruction of cotton and some silk goods took place not long ago. The most effectual thing that has been done is that of covering the chimney, the orifice of the chimney, with a cap of gauze, very rough gauze.

At the

first introduction of that species of gauze covering the apertures were reduced gradually until they were found to reduce the draught of the engine so much as to render it almost useless; therefore, that was the point to which we could advance, and no further-the apertures in that case, however, were not sufficient to prevent the escape of the ashes in a state of incandescense, to three-eighths or half an inch in diameter. Before the gauze was applied, I have seen them fly out an inch in diameter. When the engine is pushed to the speed of thirty miles an hour, the action is so violent that the whole of the fire may be said to be in a state of equilibrium; the rushing of the air through the fire is so great, and the violence of the ignition is so intense, it is impossible, looking into the fire, to distinguish one cinder from the other, for the whole is in a state of white heat; and I have seen the cinders go from the fire, and the moment they enter the tubes of the engine, which are short, and lead them directly from the fire into the chimney, they are immediately carried up. My father, in the first instance, in his attempts to cure the evil, made the hot air to pass very near a bucket or reservoir of water at the bottom of the chimney, so that the current of air was changed in its direction, and brought very near the surface of the water; it caught all the small cinders, but not the large ones. Charles John Blunt, Esq., C. E., examined. I have no opinion that there is danger from the passage of locomotive-engines through

such streets as will be necessarily opened on either side of a railway coming into London, or through a populous district; but should there exist that difficulty, which I do not apprehend, from the practical experience on which my arguments are founded, it may be obviated in some two or three ways. I have obviated it myself in Belgium and in France practically, and I should propose it in this country in a similar way, that is, by a shield' at the back of the chimney, perhaps three times the diameter of this (the crown of the witness's hat). It is a shield with meshes of three-eighths of an inch, which would hold sponges, closely packed, and saturated by a small jet of water, and a little contrivance turns the action of this jet towards the shield. This, with the action of the engine, has been found to be practically efficient, not a single spark has escaped; one is now in use on an engine at work on the Antwerp line. It does not diminish the draught. It is moveable, according as the wind blows, by a mechanical contrivance. The efficacy of that depends much on the moisture in the sponge; but that can always be kept moist by a pipe communicating with the force-pump already in existence at the bottom of the locomotiveengine. It would not be found in practice an addition of 40s. to the cost of any engine. The shield rather inclines over the top of the chimney. Suppose my hat to be the top of the chimney, the shield is moveable, and inclines in this direction; and in the chimney also I have a little shield, against which the sparks coming are turned towards the shield; they are taken by the shield, which is a meshshield, as I have already explained, and stuffed with wet sponge, and which being always moist, almost in a dripping state, the sparks are put out on the instant; and I have found the velocity with which the sparks and steam from the blast-pipe leave the chimney of the engine, and next the velocity of the engine itself, essential to the perfect action of the contrivance; for when by this contrivance the engine is stationary, the sparks from the fires go up, and then I have had to put the shield over it; but then, the engine not being in action, the speed of the engine and danger from sparks is no longer a matter of question. My shield is about one-fourth or one-fifth of the diameter of the chimney. It stands parallel almost to the chimney, or is a little inclined to it; but it is immediately on the edge, the shield, and is inclined, according to circumstances. It is two feet above the mouth of the chimney. When there is occasion to alter the position of the shield, it is done by a wire; a man at the bottom can do it without going up; it would not shift with the wind; the only resistance this shield offers is the resistance to the wind, which is in a proportionate ratio

with its size; that is very inconsiderable, when you observe that the breast of the engine is so large; but I have not found it necessary to provide against sudden gusts; for the extreme velocity with which the smoke or sparks leave the chimney, as well as the velocity of the machine itself, will, without regard to whatever wind may be stirring, cause the sparks to go into the shield per force.

John Urpeth Rastrick, Esq., C.E., examined.

The principal danger to be apprehended from fire is from the coke being blown out of the top of the engine chimney, but that has been guarded against by the application of caps to it; and all the observations I have made in all the opportunities I have had, I have never seen sparks come out sufficiently large to produce fire from the top of the chimney. In fact, I have frequently rode in the Bolton waggons, which run between the Liverpool and Manchester Railway and Bolton, on the outside, and I have not otherwise been annoyed than by small particles of dust which came through the cap at the top of the chimney in one's face. Coke is a material that requires a very great degree of heat to consume it; in fact, it will not answer the purpose without a very strong blast.

On

board of steam-boats it wouid be very desirable to get quit of the smoke if possible; but sufficient draught cannot be got to produce that intensity of heat necessary for generating steam without some other means to render the blast stronger than that of a mere chimney. I have been connected with the ironworks all my lifetime; and perhaps I might call the attention of noble lords to a circumstance of one particular operation in the ma-. nufacture of iron, which is the second process; that is done by putting a certain quantity of pig iron into a furnace called a finery; then it is blown upon with a very strong blast, and coke is the material that is used. There the sparks come out at the top of the chimney to a most extraordinary extent; in the night it looks like a large firework. Now, I have always observed that these sparks, though they appear to be quite ignited when they come out in that great (strength of the blast, the moment they come out they begin to die away immediately; in fact, in a great many buildings connected with ironworks, where there has been a long time of dry weather, these small particles of coke, which rise up into the atmosphere in an ignited state, fall, and fill up the spouts by the sides of the roof, and lie on the buildings till there is a shower of rain to wash it away. From that circumstance I conclude that the small particles of coke that are enabled to fly up into the air to any extent must be very soon completely cooled down, especially, with loco

motive engines, where a guard is put over the top of the chimney, more particularly if coke is ignited. At the time they come out they must be so remarkably small that before they have gone a few yards, they completely lose that degree of heat necessary to give them an appearance of sparks.

(To be continued.)

NOTES AND NOTICES.

Glass Cloth.-Signor Olivi, of Venice, has recently succeeded in bringing to perfection a manufacture which may prove of great value, and may be applied to many purposes of usefulness and luxury. It is the art of weaving a tissue from threads made of glass. The process of which the Signor is the inventor differs from all the attempts of the same kind which have been previously made in other countries, as it is made to take every degree of shade, from the most perfect transpareney to the deepest opaque. The thread is also rendered so perfectly flexible as to allow ttself to be tied, or the tissue, when manufactured, to be folded like silk. Another great advantage attending it is, that it resists the action of fire. The specimens which have been exhibited have called forih the highest admiration, and the brilliancy of colour given to them is altogether surprising. Although the Institution of Arts at Venice has awarded medals to Signor Olivt for his invention, it is said that he does not meet with the encouragement from the Austrian Government which he expected its singularity and beauty would ensure.

Effect of a Comet's impinging on the Earth.-If a comet were to impinge on the earth, so as to destroy its centrifugal force, it would fall to sun in 64 days. What the earth's primitive velocity may have been it is impossible to say; therefore a comet may have given it a shock without changing the axis of rotation, but only destroying part of its tangential velocity, so as to diminish the size of the orbit, a thing by no means impossible, though highly improbable; at all events there is no proof, that such has been the case.-Mrs. Somerville.

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