Flammable gas

“ Q. Why will not cinders blaze, as well as fresh coals?
A. The flame of coals is made chiefly by hydrogen gas. As soon as this gas is consumed, the hot cinders produce only an invisible gas, called carbonic acid.
Q. Where does the hydrogen gas of a fire come from?
A. The fuel is decomposed (by combustion) into its simple elements, carbon and hydrogen gas. (see p. 33)
Q. Why does not a fire blaze on a frosty night, so long as it does upon another night?
A. The air (being very cold) rushes to the fire so rapidly, that the coals burn out faster, and the inflammable gas is sooner consumed. ”

“ The increase of temperature of the water in the tinned vessel being carefully noticed before and after the experiment, gives very accurately the heating power of the given bulk of the inflammable gas.
It was thus proved that—
In all processes of the arts where a moderate heat is wanted the gas-light flame will be found very advantageous—even on a large scale this flame may be used with profit. ”

“ This last assertion requires substantiation; for it is at least a grave theoretical error to add a non-inflammable gas to a combustible one, as is seen in the lower efficiency of all flames when burning in common air in comparison with that which they exhibit in oxygen; while from the practical aspect, so harmful is carbon dioxide in an illuminating gas, that coal-gas and carburetted water-gas are frequently most rigorously freed from it, because a certain gain in illuminating power may often thus be achieved more cheaply than by direct enrichment of the gas by addition of hydrocarbons. ”

“ Fire-damp, marsh-gas, or carburetted hydrogen, is colorless, almost scentless; it burns with a blue flame, and makes respiration impossible. The miner could not live in a place filled with this injurious gas, any more than one could live in a gasometer full of common gas. Moreover, fire-damp, as well as the latter, a mixture of inflammable gases, forms a detonating mixture as soon as the air unites with it in a proportion of eight, and perhaps even five to the hundred. When this mixture is lighted by any cause, there is an explosion, almost always followed by a frightful catastrophe. ”

“ There are two causes why all the heat which fuel may furnish is not obtained. First, that the inflammable gases 329evolved by the heat are not all consumed from want of a sufficient supply of oxygen, the air drawn through the fire being only sufficient to decompose more fuel than when decomposed it could burn, or supply with oxygen. The thick smoke that escapes from a chimney when fresh fuel is thrown on a hot fire, is unconsumed gas; decomposed from the fuel, but without oxygen enough to burn—although there may have been a sufficient supply of heat. ”

“ In relation to the production of flame, we may observe, that, as sundry solid and fluid substances are inflammable, the products of combustion depend on the composition of the substance made use of, and the condition under which it is burnt. As to gaseous substances that are inflammable, the base of some gases, we may remark, as carbon and hydro [6] gen, unite in the process of combustion with the base of other gases, (as oxygen;) and in other instances, the gas itself takes fire, and exhibits the phenomena of flame. Now carbonic acid gas extinguishes flame, although its base is inflammable ”

“ When the supply of air is sufficient for the immediate and complete combustion of the whole of the combustible matter, no such precipitation takes place, and the flame is neither white nor brilliant. The richest coal-gas, mixed with sufficient air to convert all its hydrogen and carbon into water and carbonic acid, explodes with a pale blue flash; yet the same gas, when consumed in the ordinary way, burns with a rich white flame. Every one must have noticed the effect of a gust of wind upon the flaring gas-jets of a butcher’s shop ”

“ When the fire burns bright, much radiant heat will be sent off from it; but when [150] it is smothered up, very little will be generated: most of the heat produced will then be expended in giving elasticity to a thick dense vapour, or smoke, which is seen rising from the fire; and the combustion being very incomplete, the carburetted hidrogen gas of the coal being driven up the chimney without being inflamed, the fuel is wasted to little purpose. ”

“ It may be described as a rich compact flame, burning with a white and agreeable light. It is also perfectly steady, when the flame is limited to a moderate size: in large masses, it is subject to that undulation which is common to it with all flames of certain dimensions, and is caused by the agitation of the surrounding atmosphere. The gas flame is entirely free from smell. The coal-gas itself certainly has a disagreeable foetid odour before it is burnt, so has the vapour of wax, oil, and tallow, as it comes from a lamp or candle newly blown out. ”

“ That which under these conditions comes from the coal beneath, when gradually heated by the fire above, is combustible gas, and this gas is burned as it passes through the fire. In this case the formation or non-formation of smoke depends mainly on how this gas is burned, whether completely or incompletely. If the air supplied for its combustion is insufficient, smoke will be formed as it is when we turn up an Argand gas-flame so high that the gas is too great in proportion to the quantity of air that can enter the glass chimney. ”

“ A flame may be cooled in another way than by means of some cold body held in it, namely, by mixing some indifferent gas with the combustible gas. If, instead of air, a stream of carbonic-acid gas be admitted at the bottom of a Bunsen lamp, the flame becomes "non-luminous." We get the same amount of heat in the flame as before, since we burn the same amount of gas; but this heat has not only to be applied to heating the illuminating gas and the products of its combustion, but has also to heat the carbonic-acid gas. ”

“ When the flame is suffered to rise beyond the standard height, the combustion of the gas becomes imperfect, part of the gas passes through the flame unburnt, and occasions the source of the offensive odour alluded to, which the gas lights never produce when the combustion of the gas is complete. ”

“ By applying a blast of air at the ordinary gas jets, and supplying the gas by a separate pipe, or series of pipes, below the open end of the burner, this can be converted into a furnace of extraordinary power. It is quite possible to burn as much as 2,000 cubic feet of gas per hour per square foot of burner surface, producing a heat sufficient to fuse any ordinary crucible. You see its power when I place a bundle of iron wire in the flame; it is, in fact, a concentration of hundreds or thousands of powerful blowpipe flames in one mass. ”

“ In the black space gas is unconsumed, in the luminous part the combustion is only partial, but outside of all, where there is most oxygen, the combustion is complete, and the flame can hardly be discovered. Now when the flame is quite steady the tube must be gently inserted at an angle into the black cone; after a few minutes, on applying a light at the end of the tube, although the candle is still burning, we shall see that this free hydrogen will burn there too with a small bluish flame. ”

“ By forcing air into and through a body of gasoline sufficient of the gasoline is taken up to form a dense vapor, which will light and burn at the jet, similar to illuminating gas. With the admixture of air in the compound blow pipe, it gives a flame of very intense heat. But, in common with illuminating gas, it is so rich in carbon that it gives an oxidizing flame, and makes it necessary to use a flux, which should be Yager's soldering salts mixed as per the directions on the bottle. ”

“ It possesses advantages which cannot be obtained from flaming fuel, where much nicety is required; because no fuel can be managed like the flame of coal-gas. For it is well known, that when too [114] little air be given to flaming fuel it produces no flame, but sooty vapour; and if too much air be admitted to make those vapours break out into flame, the heat is often too violent. ”

“ But besides the flame, which is a peculiar gas in the state of combustion, heat expels from coal an aqueous vapour, loaded with several kinds of ammoniacal salts, a thick viscid fluid resembling tar, and some gases that are not of a combustible nature. The consequence of which is, that the flame of a coal-fire is continually wavering and changing, both in shape, as well as brilliance and in colour, so that what one moment gave a beautiful bright light, in the next, perhaps, is obscured by a stream of thick smoke. ”

“ Coloured flame may be produced by various other substances, many of which are expensive, and therefore could not be employed economically. Thus, in fire-works made with hydrogen gas, or inflammable air, which have a pleasing effect, by forcing the gas, either from a bladder, oiled-silk bag, or gas-holder, through a variety of revolving jets, which are so arranged as to exhibit stars, or through pipes furnished with small apertures, &c. ”

“ The size, form and intensity of the gas flame, are regulated by simply turning the stop-cock which admits the gas to the burner or lamp. The flame may at command be made to burn with an intensity sufficient to illuminate every corner of a room, or so low and dim, as barely to be perceived. ”

“ The chief danger with an apparatus of this sort is its liability to accident by the careless use of the gas, and, as a mixture of hydrogen and air is very explosive, great care must be taken to exhaust all the air in the generator and tubes before attempting to light the gas at the blow pipe. The only way to make sure that the air is exhausted is to test the gas, as described under the head of “The Flame and Its Management.” ”

“ A tissue which, when red-hot, will not interrupt the flame of hydrogen, will still intercept that of olefiant gas; and a heated tissue, which would communicate explosion from a mixture of olefiant gas and air, will stop an explosion of fire-damp. Fortunately for the success of the Safety-lamp, carburetted hydrogen requires so high a temperature to carry on its combustion, that even metal, when white-hot, is far below it; and hence red-hot gauze, 147 in sufficient quantity, and of the proper degree of fineness, will abstract heat enough from the flame to extinguish it. ”

“ The gases leaving the luminous flame show that the diluting action of the nitrogen is so great that considerable quantities even of the highly inflammable and rapidly burning hydrogen escape combustion, while the products of incomplete combustion are present in sufficient quantity to account perfectly for the deleterious effects of gas burners in ill-ventilated rooms. ”

“ When hydrocarbons form a part of the combustible gas, as they do in nearly all illuminating gases and oils, some carbon is usually set free in the process of combustion. This is made very hot by the flame and becomes incandescent, giving out light. In a well-regulated flame it is afterward burned up, but when the supply of oxygen is insufficient it escapes from the flame as lampblack or soot. That it is temporarily present in a well-burning luminous flame may be demonstrated by holding a cold object, such as a small evaporating dish, in the flame for a few seconds. ”

“ There has never been any form of combustion devised which consumes all the fumes. No such thing can be, because the products of combustion are not combustible. The so-called "wickless blue flame" stoves do burn all the oil, and a properly regulated gas stove will burn all the gas, but that simply means that it turns the oil and gas into carbon dioxide, the very substance which your lungs are working day and night to get out of your body. ”

“ Oxygen gas will not burn of itself, but it aids the decomposition by fire of bodies that are combustible. It is therefore called a supporter of combustion. But hydrogen gas, though it burns of itself [Pg 35] will extinguish a flame immersed in it. It is therefore said to be a body which will burn, but will not support combustion.
"As coals are to burning coals, and wood to fire; so is a contentious man to kindle strife."—Proverbs xxvi.
46. What becomes of the nitrogen that is inhaled with the air? ”

“ The combustible gas has to make its own inflammable mixture with the circumambient oxygen, and we may suppose the column of gas to be burned through as it ascends. The core of unburned gas thus becomes thinner as it ascends and the flame tapers to a point. The external surface of a flame of this kind will for the same consumption of gas be larger than that of a flame where the ready-made mixture of gases is used. If a jet of one gas be sent with a sufficient velocity into another, turbulent admixture takes place and an unsteady sheet of flame of uniform colour is obtained. ”

“ The conditions requisite, therefore, for burning illuminating gas are, first, just such a supply of air as will prevent particles of carbon from escaping unconsumed in the form of smoke, and yet not enough to burn up the carbon before it has separated from the hydrogen, and passed through the flame in the solid state; second, the attainment of the highest possible temperature in the flame, compatible with the former condition. ”

“ The different methods for extinguishing fire in chimnies, by using salt, sulphur, &c. to smother the flame, as it is called, depend on one principle, that of producing either a gas or vapour, which supplies the place of atmospheric air, and as it is a non-supporter of combustion, extinguishes the flame. Carbonic acid gas would have the same effect as the sulphurous acid gas, produced by the combustion of sulphur, or the vapour of salt. ”