The procedure for a combustion is as follows: - FIG.
Charcoal, coke or anthracite coal are the fuels generally used in slow combustion heating stoves.
A much better approximation to the heat of combustion of such substances is obtained by deducting the oxygen together with the amount of carbon necessary to form C02, and then ascertaining the amount of heat produced by the residual carbon and hydrogen.
The observed heat of combustion of sugar is, however, 1354000, so that the error of the rule is here 20 per cent.
In the older type the combustion chamber (of metal or glass) is sunk in the calorimeter proper, tubes being provided for the entrance and exit of the gaseous substances involved in the action.
Its fires are not volcanic, but result from the combustion of coal some distance underground, giving off much smoke and steam; geologists estimate that the burning has been going on for at least 800 years.
The maximum rate of combustion may be as much as so lb of coal per square foot of grate per hour, and in exceptional cases even a greater rate than this has been maintained.
In the newer type (which was first proposed by Andrews for the combustion of gases) the chemical action takes place in a completely closed combustion chamber of sufficient strength to resist the pressure generated by the sudden action, which is often of explosive violence.
The draught corresponding to the smallest rate of combustion shown in Table XX.
The accuracy of heats of combustion determined in the closed calorimeter is in favourable cases about one-half per cent.
- The resistance against which a train is moved along a railway is overcome by means of energy obtained from the combustion of fuel, or in some few cases by energy obtained from a waterfall.
The best form of stove is that with which perfect combustion is most nearly attained, and to which a pan of water is affixed to supply a desirable humidity to the air, the gas having the effect of drying the atmosphere.
Mayow had suggested the existence of two components, a spiritus nitroaerus which supported combustion, and a spiritus nitri acidi which extinguished fire; J.
In the first method the substance, mixed with quicklime free from chlorine, is heated in a tube closed at one end in a combustion furnace.
That vigorous chemical action is accompanied by a brisk evolution of heat is evident from such familiar examples as the combustion of fuel or the explosion of gunpowder.
The phlogistic theory, which pervaded the chemical doctrine of this period, gave rise to continued study of the products of calcination and combustion; it thus happened that the knowledge of oxides and oxidation products was considerably developed.
Carbon and hydrogen are generally estimated by the combustion process, which consists in oxidizing the substance and absorbing the products of combustion in suitable apparatus.
With exceptionally bad weather the load would have to be reduced or two engines would have to be employed, or an exceptionally high rate of combustion would have to be maintained in the fire-box.
Difficultly volatile liquids may be weighed directly into the boat; volatile liquids are weighed in thin hermetically sealed bulbs, the necks of which are broken just before they are placed in the combustion tube.
different from the observed heat of combustion of sugar.
With closed stoves much less heat is wasted, and consequ;ntly less fuel is burned, than with open grates, but they often cause an unpleasant sensation of dryness in the air, and the products of combustion also escape to some extent, rendering this method of heating not only unpleasant but sometimes even dangerous.
It is not economical to force the boiler to work at too high a rate, because it has been practically demonstrated that the boiler efficiency decreases after a certain point, as the rate of combustion increases.
Thomsen then investigated heats of combustion of various benzenoid hydrocarbons - benzene, naphthalene, anthracene, phenanthrene, &c. - in the crystallized state.
According to Liebig, man's body is a stove, and food the fuel which keeps up the internal combustion in the lungs.
Combustion meant the liberation of phlogiston..
by the combustion of the least sufficient quantity of sulphur, the rest is liquefied.
produced by the combustion of 1 lb of coal, 15,000 Xo 06 =900 only are available for tractive purposes.
- The maximum power which can be developed by a locomotive depends upon the maximum rate of fuel combustion which can be maintained per square foot of grate.
The steel combustion chamber is of about 250 c.c. capacity, and is wholly immersed in the calorimeter.
- One pound of coal requires about 20 lb of air for its proper combustion in the fire-box of a locomotive, though this quantity of air diminishes as the rate of combustion increases.
Combustion calorimeters are employed for observing the heat generated by the brisk interaction of substances, one of which at least is gaseous.
The Rocket possessed the three elements of efficiency of the modern locomotive - the internal water-surrounded fire-box and the multitubular flue in the boiler; the blast-pipe, by which the steam after doing its work in the cylinders was exhausted up the chimney, and thus served to increase the draught and promote the rapid combustion of the fuel; and the direct connexion of the steam cylinders, one on each side of the engine, with the two driving wheels mounted on one axle.
Stohmann of Leipzig; and the new data and the conclusions to be drawn from them formed the subject of much discussion, Briihl endeavouring to show how they supported Kekule's formula, while Thomsen maintained that they demanded the benzene union to have a different heat of combustion from the acetylene union.
Sublimed sulphur also results from the spontaneous combustion of coal seams containing pyrites.
At the same time a little trioxide is formed, and, according to Hempel (Ber., 1890, 2 3, p. 1 455), half the sulphur is converted into this oxide if the combustion be carried out in oxygen at a pressure of 40 to 50 atmospheres.
The violence or completeness of combustion was proportional to the amount of phlogiston present.
In the choice of a boiler of this description it should be remembered that rapid heating, economical combustion of fuel, and facilities for cleaning, are requisites, the absence of any of which considerably lowers the efficiency of the apparatus.
The relation between the heat of combustion of a hydrocarbon and its heat of formation may be readily seen from the following example.
A few experimental results are set forth in Table XX., from which it will be seen that with a relatively low rate of combustion, a rate which denotes very light service, namely lb of coal per square foot of grate per hour, the efficiency of the boiler is %, which is as good a result as can be obtained with the best class of stationary boiler or marine boiler even when using economizers.
ft., that the rate of combustion is 150 lb of coal per square foot of grate per hour, that the calorific value is 14000, and finally that n =0.06, the maximum indicated horse-power which the engine might be expected to develop would be o 06 X 150 x14000 X24 X 778/1980000 = I 190, corresponding to a mean effective pressure in the cylinders of 59.5 lb per square inch.
Chladni's experiment of strewing a vibrating bell with flour, investigated the nature of sound and the function of the air in respiration and combustion, and originated the idea of using the pendulum as a measure of gravity.
It is well known that singly, doubly and trebly linked carbon atoms affect the physical properties of substances, such as the refractive index, specific volume, and the heat of combustion; and by determining these constants for many substances, fairly definite values can be assigned to these groupings.
The heat of combustion, as first determined by Julius Thomsen, agreed rather better with the presence of nine single unions.
Theoretical speculations were revived by Lavoisier, who, having explained the nature of combustion and determined methods for analysing compounds, concluded that vegetable substances ordinarily contained carbon, hydrogen and oxygen, while animal substances generally contained, in addition to these elements, nitrogen, and sometimes phosphorus and sulphur.
At the hands of Stahl and his school, the phlogistic theory, by exhibiting a fundamental similarity between all processes of combustion and by its remarkable flexibility, came to be a general theory of chemical action.
When compressed it is also used largely as a refrigerating agent, and in virtue of its property of neither burning nor supporting combustion it is also used as a fire extinctor.
The oxygen contained in the compound was deducted, together with the equivalent amount of hydrogen, and the heat of combustion of the compound was then taken to be equal to the heats of combustion of the elements in the residue.
was primarily based upon certain experiments on combustion and calcination, and in effect reduced the number of the alchemical principles, while setting up a new one, a principle of combustibility, named phlogiston (from (PXoyun-6s, burnt).
He established as fundamental that combustion and calcination were attended by an increase of weight, and concluded, as did Jean Rey and John Mayow in the 17th century, that the increase was due to the combination of the metal with the air.
Thorpe's investigation of the products of the slow combustion of phosphorus.
Under these conditions producer gas ceases to exist as a by-product, and the gases of the blow consist merely of the incombustible products of com plete combustion, carbon dioxide and nitrogen, the result being that more than three times / the heat is developed for the combustion of the same amount of fuel, and nearly double the quantity of water gas can be made per pound of fuel than was before possible.
14 and 15 show Liegel's producer, the special object of which is to deal with any fuel (coal or coke) giving a tough, pasty slag on combustion.
It easily burns, forming arsenious oxide if the combustion proceeds in an excess of air, or arsenic if the supply of air is limited; it is also decomposed into its constituent elements when heated.
The property of the semi-drying oils to absorb oxygen is accelerated by spreading such oils over a large surface, notably over woollen or cotton fibres, when absorption proceeds so rapidly that frequently spontaneous combustion will ensue.
FURNACE, a contrivance for the production and utilization of heat by the combustion of fuel.
It does not burn, neither does it support combustion.
SULPHUR [[[symbol]] S, atomic weight 32.07 (0 = 16)], a non-metallic chemical element, known from very remote times and regarded by the alchemists, on account of its inflammable nature, as the principle of combustion; it is also known as brimstone.
As the indicated horse-power of the engine increases, the weight of steam discharged increases, and the smoke-Lox vacuum is increased, thereby causing more air to flow through the furnace and increasing the rate of combustion.
per hour, the tractive force falls to 7400 lb, and this cannot be increased except by increasing the rate of combustion (neglecting any small changes due to a change in the efficiency 7 Knowing the magnitude of R, the draw-bar pull, and hence the weight of vehicle the engine can haul at this speed, can be estimated if the resistances are known.
It might, for example, be suggested that the heat of the sun was supplied by chemical combination analogous to combustion.
He concluded that it was not common air, but the substance, "in much greater perfection," that rendered common air respirable and a supporter of combustion.
Cavendish, who had isolated the nitrogen of the atmosphere, had failed to decide conclusively what had really happened to the air which disappeared during combustion.
of these three substances yielded the same weight of carbon dioxide on combustion.
Combustion is a familiar example of the transformation of chemical energy into heat and light; the quantitative measures of heat evolution or absorption (heat of combustion or combination), and the deductions therefrom, are treated in the article Thermochemistry.
In organic chemistry it is more customary to deal with the " heat of combustion," i.e.
The researches of Julius Thomsen and others have shown that in many cases definite conclusions regarding constitution can be drawn from quantitative measurements of the heats of combustion; and in this article a summary of the chief results will be given.
The identity of the four valencies of the carbon atom follows from the fact that the heats of combustion of methane, ethane, propane, trimethyl methane, and tetramethyl methane, have a constant difference in the order given, viz.
158.6 calories; this means that the replacement of a hydrogen atom by a methyl group is attended by a constant increase in the heat of combustion.
It therefore appears that the difference between the heats of combustion of two adjacent members of a series of homologous compounds is practically a constant, and that this constant has two average values, viz.
An important connexion between heats of combustion and constitution is found in the investigation of the effect of single, double and triple carbon linkages on the thermochemical constants.
It follows that the true heat of combustion of carbon, i.e.
the heat of combustion of one gramme-atom, is 96.96+4.
The value of d can be evaluated by considering the combustion of amorphous carbon to carbon monoxide and carbon dioxide.
Theabsolute heat of combustion of a carbon atom is therefore 135.34 calories, and this is independent of the form of the carbon burned.
Consider now the combustion of a hydrocarbon of the general formula CH 2m.
Then the number of single bonds is 2n - m-2p, and the heat of combustion becomes H,=nE+m77+p(2X - Y).
This is the general equation for calculating the heat of combustion of a hydrocarbon.
It contains four independent constants; two of these may be calculated from the heats of combustion of saturated hydrocarbons, and the other two from the combustion of hydrocarbons containing double and triple linkages.
Rutherford, who showed that on removing oxygen from air a gas remained, which was incapable of supporting combustion or respiration.
It does not burn, but supports the combustion of heated substances almost as well as oxygen.
It may be liquefied, its critical temperature being -93, 5°, and the liquid boils at -153.6° C. It is not a supporter of combustion, unless the sustance introduced is at a sufficiently high temperature to decompose the gas, when combustion will continue at the expense of the liberated oxygen.
Nitrogen is a very inert gas: it will neither burn nor support the combustion of ordinary combustibles.
It does not support the combustion of a taper, but burning phosphorus and red-hot carbon will continue to burn in the gas.
The working door through which the litharge is run off lies under the flue which carries off the products of combustion and the lead fumes, the lead is charged and the blast is admitted near the fire-bridge.
Assuming the above formula to represent guncotton, there is sufficient oxygen for internal combustion without any carbon being left.
Under different pressures the relative amounts of the combustion products vary considerably.
In 1905 and following years motor omnibuses (worked mostly by internal combustion engines) began to a large extent to supplant horse traction.
The efficiency of such ventilating furnaces is low, and they cannot safely be used in mines producing fire-damp. They are sometimes the cause of underground fires, and they are always a source of danger when by any chance the ventilating current becomes reversed, in which case the products of combustion, containing large quantities of carbon dioxide, will be drawn into the mine to the serious danger of the men.
In some mining districts the coal is liable to spontaneous combustion.
The difficulty of extinguishing an underground fire in this way is, however, very great, as on account of the poisonous products of combustion it is impossible to attack it except in the rear, and even there the men are always in great danger from the reversal of the FIG.
With producer gas it is necessary to pre-heat both the gas and the air which is supplied for its combustion by passing both through heated regenerators (for an account of the principles of the regenerative furnace see article Furnace).
At first, the oil was manufactured principally for combustion in the Read-Holliday lamp and for dissolving rubber, but the development of the coal-tar colour industry occasioned a demand for benzols of definite purity.
As a verb, the word means to stifle or check; hence damped vibrations or oscillations are those which have been reduced or stopped, instead of being allowed to die out naturally; the "dampers" of the piano are small pieces of feltcovered wood which fall upon the strings and stop their vibrations as the keys are allowed to rise; and the "damper" of a chimney or flue, by restricting the draught, lessens the rate of combustion.
The constituents of tobacco, as of all other vegetable matter, can be grouped under three heads: water, mineral acids and bases (which pass into the ash on combustion) and organic substances.
(a) The gas is made from the fuel in a detached fireplace and conducted while hot into the combustion chamber of the furnace, and the air for complete combustion is heated by the products of combustion on their way to the chimney.
(b) Both the producer gas and the air are heated before they enter the combustion chamber, as in the Siemens system of regenerative firing.
This at least is true of the oxide produced from the metal by combustion; that produced from the carbonate, if once made yellow at a red heat, retains a yellow shade permanently.
To this end he examined such immediate vital products as blood, bile and urine; he analysed the juices of flesh, establishing the composition of creatin and investigating its decomposition products, creatinin and sarcosin; he classified the various articles of food in accordance with the special function performed by each in the animal economy, and expounded the philosophy of cooking; and in opposition to many of the medical opinions of his time taught that the heat of the body is the result of the processes of combustion and oxidation performed within the organism.
The electric furnace has several advantages as compared with some of the ordinary types of furnace, arising from the fact that the heat is generated from within the mass of material operated upon, and (unlike the blastfurnace, which presents the same advantage) without a large volume of gaseous products of combustion and atmospheric nitrogen being passed through it.
Sometimes reagents are placed in the combustion tube, for example lead oxide (litharge), which takes up bromine and sulphur.
In its simplest form the apparatus consists of a straight tube, made of glass, porcelain or iron according to the temperature required and the nature of the reacting substances, heated in an ordinary combustion furnace, the mixture entering at one end and the vapours being condensed at the other.
Meteors look larger than they are, from the glare and flaming effect due to their momentary combustion.
The phlogistic theory of the processes of calcination and combustion necessitated the view that many acids, such as those produced by combustion, e.g.
(2) A mixture of loo litres of spirit, 14 litres of the naphtha-pyridine mixture described above, 4 litre of methyl violet solution, and from 2 to 20 litres of benzol; this fluid is limited to combustion in motors and agricultural engines.
They all contain carbon, hydrogen, oxygen and nitrogen, forming the carbonaceous or combustible portion, and some quantity of mineral matter, which remains after combustion as a residue or " ash."
The most important class of coals is that generally known as bituminous, from their property of softening or undergoing an apparent fusion when heated to a temperature far below that at which actual combustion takes place.
By the term " ash " is understood the mineral matter remaining unconsumed after the complete combustion of the carbonaceous portion of a coal.
pyrites, which yields sulphates by combustion.
Under ordinary conditions, from s to 4 of the whole amount of sulphur in a coal is volatilized during combustion, the remaining 4 to being found in the ash.
The return air from fiery workings is never allowed to approach the furnace, but is carried into the upcast by a special channel, called a dumb drift, some distance above the furnace drift, so as not to come in contact with the products of combustion until they have been cooled below the igniting point of fire-damp. Where the upcast pit is used for drawing coal, it is usual to discharge the smoke and gases through a short lateral drift near the surface into a tall chimney, so as to keep the pit-top as clear as possible for working.
In the thick coal workings in South Staffordshire the slack left behind in the sides of work is especially liable to fire from so-called spontaneous combustion, due to the rapid oxidization that is set up when finely divided coal is brought in contact with air.
For its complete combustion a volume of acetylene needs approximately twelve volumes of air, forming as products of combustion carbon dioxide and water vapour.
When, however, the air is present in much smaller ratio the combustion is incomplete, and carbon, carbon monoxide, carbon dioxide, hydrogen and water vapour are produced.
Before the commercial production of calcium carbide made it one of the most easily obtainable gases, the processes which were most largely adopted for its preparation in laboratories were: - first, the decomposition of ethylene bromide by dropping it slowly into a boiling solution of alcoholic potash, and purifying the evolved gas from the volatile bromethylene by washing it through a second flask containing a boiling solution of alcoholic potash, or by passing it over moderately heated soda lime; and, second, the more ordinarily adopted process of passing the products of incomplete combustion from a Bunsen burner, the flame of which had struck back, through an ammoniacal solution of cuprous chloride, when the red copper acetylide was produced.
Phosphuretted hydrogen, one of the most important impurities, which has been blamed for the haze formed by the combustion of acetylene under certain conditions, is produced by the action of water upon traces of calcium phosphide found in carbide.
When carbide is acted upon by water considerable heat is evolved; indeed, the action develops about one-twentieth of the heat evolved by the combustion of carbon.
When acetylene was first introduced on a commercial scale attempts were made to utilize its great heat of combustion by using it in conjunction with oxygen in the oxy hydrogen blowpipe.
became so heated as to cause the decomposition of some of the gas before combustion, the jet being choked up by the carbon which deposited in a very dense form; and as the use of acetylene under pressures greater than one hundred inches of water was prohibited, no advance was made in this direction.
COMBUSTION (from the Lat.
The term "spontaneous combustion" is used when a substance smoulders or inflames apparently without the intervention of any external heat or light; in such cases, as, for example, in heaps of cotton-waste soaked in oil, the oxidation has proceeded slowly, but steadily, for some time, until the heat evolved has raised the mass to the temperature of ignition.
The explanation of the phenomena of combustion was at tempted at very early times, and the early theories were generally bound up in the explanation of the nature of fire or flame.
The idea that some extraneous substance is essential to the process is of ancient date; Clement of Alexandria (c. 3rd century A.D.) held that some "air" was necessary, and the same view was accepted during the middle ages, when it had been also found that the products of combustion weighed more than the original combustible, a fact which pointed to the conclusion that some substance had combined with the combustible during the process.
Mayow perceived the similarity of the processes of respiration and combustion, and showed that one constituent of the atmosphere, which he termed spiritus nitro-aereus, was essential to combustion and life, and that the second constituent, which he termed spiritus nitri acidi, inhibited combustion and life.
At the beginning of the 18th century a new theory of combustion was promulgated by Georg Ernst Stahl.
The Stahlian theory, originally a theory of combustion, came to be a general theory of chemical reactions, since it provided simple explanations of the ordinary chemical processes(when regarded qualitatively) and permitted generalizations which largely stimulated its acceptance.
Its inherent defect - that the products of combustion were invariably heavier than the original substance instead of less as the theory demanded - was ignored, and until late in the 18th century it dominated chemical thought.
Its overthrow was effected by Lavoisier, who showed that combustion was simply an oxidation, the oxygen of the atmosphere (which was isolated at about this time by K.
OXYHYDROGEN FLAME, the flame attending the combustion of hydrogen and oxygen, and characterized by a very high temperature.
The study of calcination and combustion during the 17th and 18th centuries culminated in the discovery that air consists chiefly of a mixture of two gases, oxygen and nitrogen.
Prairie fires or spontaneous combustion have ignited many coal seams. Some have already burnt out; others still emit smoke and sulphurous fumes from the crevices in the hillsides, and through the fissures may be seen the glowing coal and rock.
It does not support combustion; and it does not burn readily unless mixed with oxygen, when it burns with a pale yellowish-green flame.
He also studied the chemistry of combustion and of respiration, and made experiments in physiology, where, however, he was hampered by the "tenderness of his nature" which kept him from anatomical dissections, especially of living animals, though he knew them to be "most instructing."
But the shot advances during the combustion of the cordite, and the chief problem in interior ballistics is to adjust the G.D.
It is found experimentally that m = 1.2 is a good average value to take for cordite; so now supposing the combustion of the charge of the 6-in.
The thermochemical properties of the constituents of an explosive will assign an upper limit to the volume, temperature and pressure of the gas produced by the combustion; but much experiment is required in addition.
Lampblack is prepared by burning tar, resin, turpentine and other substances rich in carbon, with a limited supply of air; the products of combustion being conducted into condensing chambers in which cloths are suspended, on which the carbon collects.
The combustion of the wood is conducted from the top downwards, and from the exterior towards the centre; great care has to be taken that the process is carried out slowly.
Carbon dioxide, C02, is a gas first distinguished from air by van Helmont (1577-1644), who observed that it was formed in fermentation processes and during combustion, and gave to it the name gas sylvestre.
It is also formed in ordinary fermentation processes, in the combustion of all carbon compounds (oil, gas, candles, coal, &c.), and in the process of respiration.
It does not burn, and does not support ordinary combustion, but the alkali metals and magnesium, if strongly heated, will continue to burn in the gas with formation of oxides and liberation of carbon.
The reaction may be written 2K+ 211 2 0= 2K0H+H2, and the flame is due to the combustion of the hydrogen, the violet colour being occasioned by the potassium vapour.
On ignition the reaction, 8A1+3Fe 3 O 4 =9Fe+4Al 2 O 3, gives a temperature estimated to be between 2,300° and 2,700°C. The reaction, stated in weights, means that 217 parts of aluminium plus 732 parts magnetite (iron oxide) equals 540 parts steel plus 409 parts slag, or approximately 3 parts of aluminium plus 10 parts of magnetite will produce, on combustion, 7 parts of steel.
One of the chief observations recorded in it is that the atmosphere is composed of two gases - one which supports combustion and the other which prevents it.
This waste, however, is decreasing, the coal abandoned in the mine having averaged, in the beginning of mining, two or three times the amount taken out; and the chief part of the remaining waste is in imperfect combustion in furnaces and fire-boxes.
BLOWPIPE, in the arts and chemistry, a tube for directing a jet of air into a fire or into the flame of a lamp or gas jet, for the purpose of producing a high temperature by accelerating the combustion.
The heat is greatest just beyond the point of the inner cone, combustion being there most complete.
Accepting as proved by Boyle's experiments that air is necessary for combustion, he showed that fire is supported not by the air as a whole but by a "more active and subtle part of it."
In combustion the particulae nitro-aereae - either pre-existent in the thing consumed or supplied by the air - combined with the material burnt; as he inferred from his observation that antimony, strongly heated with a burning glass, undergoes an increase of weight which can be attributed to nothing else but these particles.
In effect, therefore, Mayow - who also gives a remarkably correct anatomical description of the mechanism of respiration - preceded Priestley and Lavoisier by a century in recognizing the existence of oxygen, under the guise of his spiritus nitro-aereus, as a separate entity distinct from the general mass of the air; he perceived the part it plays in combustion and in increasing the weight of the calces of metals as compared with metals themselves; and, rejecting the common notions of his time that the use of breathing is to cool the heart, or assist the passage of the blood from the right to the left side of the heart, or merely to agitate it, he saw in inspiration a mechanism for introducing oxygen into the body, where it is consumed for the production of heat and muscular activity, and even vaguely conceived of expiration as an excretory process.
Aristotle had imputed to all living beings a soul, though to plants only in the sense of a vegetative, not a sensitive, activity, and in Moleschott's time many scientific men still accepted some sort of vital principle, not exactly soul, yet over and above bodily forces in organisms. Moleschott, like Lotze, not only resisted the whole hypothesis of a vital principle, but also, on the basis of Lavoisier's discovery that respiration is combustion, argued that the heat so produced is the only force developed in the organism, and that matter therefore rules man.
The metal in the form of thin turnings is charged into hard glass or iron tubes heated to a full red in a combustion furnace.
A memoir in the volume for 1783 relates to the production of water by the combustion of hydrogen; but Monge's results had been anticipated by Henry Cavendish.
Pyrites low in sulphur is incapable of sustaining its own combustion without the aid of an external source of heat, and 45% of sulphur is, for economic reasons, usually regarded as the lowest admissible for sulphuric acid manufacture.
carbonic oxide from the combustion of the coke by that blast.
Now the heat developed by the combustion of coke to carbonic oxide with cold air containing the usual quantity of moisture, develops a temperature only slightly above this critical point; and it is only the heat represented by this narrow temperature-margin that is available for doing this critical work of fusion and deoxidation.
If by pre-heating the blast we add to the sum of the heat available; or if by drying it we subtract from the work to be done by that heat the quantity needed for decomposing the atmospheric moisture; or if by removing part of its nitrogen we lessen the mass over which the heat developed has to be spread - if by any of these means we raise the temperature developed by the combustion of the coke, it is clear that we increase the proportion of the total heat which is available for this critical work in exactly the way in which we should increase the proportion of the water of a stream, initially too in.
This heating was formerly done by burning part of the gases, after their escape from the furnace top, in a large combustion chamber, around a series of cast iron pipes through which the blast passed on its way from the blowing engine to the tuyeres.
They are heat-filters or heat-traps for impounding the heat developed by the combustion of the furnace gas, and later returning it to the blast.
The large combustion chamber B permits thorough combustion of the gas.
B, B, Combustion chamber.
Moreover, the quality of the resultant steel depends upon the temperature of the process, and this in turn depends upon the proportion of silicon, the combustion of which is the chief source of the heat developed.
The coke thus at once supplies by its combustion the heat needed for melting the iron and keeping it hot, and by itself dissolving in the molten metal returns carbon to it as fast as this element is burnt out by the blast, so that the " refined " cast iron which results, though still rich in carbon and therefore easy to melt in the puddling process, has relatively little silicon.
Indeed, no limit has yet been found to the temperature which can be reached, if matters are so arranged that not only the carbon and silicon of the pig iron, but also a considerable part of the metallic iron which is the iron itself, are oxidized by the blast; or if, as in the Walrand-Legenisel modification, after the combustion of the initial carbon and silicon of the pig iron has already raised the charge to a very high temperature, a still further rise of temperature is brought about by adding more silicon in the form of ferro-silicon, and oxidizing it by further blowing.
But no part of the Bessemer converter is of a shape easily affected by the heat, no part of it is exposed to the heat on more than one side, and the converter itself is necessarily cooler than the metal within it, because the heat is generated within the metal itself by the combustion of its silicon and other calorific elements.
The unbroken arrows show the direction of the incoming gas and air, the broken ones the direction of the escaping products of their combustion.
In these, bricks in great numbers are piled loosely, in such a way that, while they leave ample passage for the gas and air, yet they offer to them a very great extent of surface, and therefore readily transfer to them the heat which they have as readily sucked out of the escaping products of combustion in the last preceding phase.
As they are so hot at starting, their combustion of course yields a very much higher temperature than if they had been cold before burning, and they form an enormous flame, which fills the great working chamber.
The products of combustion are sucked by the pull of the chimney through the farther or right-hand end of this chamber, out through the exit ports, as shown by the dotted arrows, down through the right-hand pair of regenerators, heating to perhaps 1300° C. the upper part of the loosely-piled masses of brickwork within them, and thence past the valves K and K' to the chimney, flue 0.
enormous surface of brickwork the heat of the escaping products of combustion, and in the following phase restoring the heat to the entering air and gas.
22), below the uptakes, are provided to catch the dust carried out of the furnace proper by the escaping products of combustion, lest it enter and choke the regenerators.
Hence in the intermittent system most of the heat generated within the furnace escapes from it with the products of combustion.
ducts of combustion pass.
Lavoisier making many experiments with the object of finding an acid among the products of combustion.
Hydrogen burns with a pale blue non-luminous flame, but will not support the combustion of ordinary combustibles.
Similar, but somewhat different markings are produced by the combustion of diamond in oxygen, unaccompanied by any rounding of the edges.
Experiments on the combustion of diamond were made by Smithson Tennant (1797) and Sir Humphry Davy (1816), with the object of proving that it is pure carbon; they showed that burnt in oxygen it yields exactly the same amount of carbon dioxide as that produced by burning the same weight of carbon.
The kilns commonly employed are "chamber kilns," circular structures not unlike an ordinary running lime kiln, but having the top closed and connected at the side with a wide flue in which the slurry is exposed to the hot products of combustion from the kiln.
At this middle portion and in the upper part of the lower shaft the burning proper proceeds; the upper shaft is full of unburnt raw material which is heated by the hot gases coming from the burning zone, and the lower shaft contains clinker already burned and hot enough to heat the incoming air which supplies that necessary for combustion at the clinkering zone.
At a given moment one of these compartments is burning and at its full temperature; the air for combustion is drawn in through one or more compartments behind it which have just finished burning, and is thereby strongly heated; the products of combustion pass away through one or more compartments in front of it and heat their contents before they are subjected to actual combustion.
In each case the clinker which has just been burned and is fully hot serves to heat the air-supply to the compart ment where combustion is actu ally proceeding; in like manner the raw materials about to be burned are well heated by the waste gases from the compartment in full activity before they them selves are burned.
On its way down the cylinders the clinker meets a current of cold air and is cooled, the air being correspondingly warmed and passing on to aid in the combustion of the fuel used in heating the kiln.
Keene's cement and its congeners are made in fixed kilns so constructed that only the gaseous products of combustion come into contact with the gypsum to be burnt, in order to avoid contamination with the ash of the fuel.
OV)s, sour, yevv&cw, I produce) to denote that in a large number of cases, the products formed by the combustion of substances in the gas were of an acid character.
Oxygen does not burn, but is the greatest supporter of combustion known, nearly all the other elements combining with it under suitable conditions (cf.
Then, perceiving that in combustion and the calcination of metals only a portion of a given volume of common air was used up, he concluded that Priestley's new air, air eminemment pur, was what was absorbed by burning phosphorus, &c., "non-vital air," azote, or nitrogen remaining behind.
In a memoir presented to the Academy in 1777, but not published till 1782, he assigned to dephlogisticated air the name oxygen, or "acidproducer," on the supposition that all acids were formed by its union with a simple, usually non-metallic, body; and having verified this notion for phosphorus, sulphur, charcoal, &c., and even extended it to the vegetable acids, he naturally asked himself what was formed by the combustion of "inflammable air" (hydrogen).
Knowing that the water produced by the combustion of alcohol was not pre-existent in that substance but was formed by the combination of its hydrogen with the oxygen of the air, he burnt alcohol and other combustible organic substances, such as wax and oil, in a known volume of oxygen, and, from the weight of the water and carbon dioxide produced and his knowledge of their composition, was able to calculate the amounts of carbon, hydrogen and oxygen present in the substance.
A paper discovered many years after his death showed that he had anticipated later thinkers in explaining the cyclical process of animal and vegetable life, for he pointed out that plants derive their food from the air, from water, and in general from the mineral kingdom, and animals in turn feed on plants or on other animals fed by plants, while the materials thus taken up by plants and animals are restored to the mineral kingdom by the breaking-down processes of fermentation, putrefaction and combustion.
In the case of the two former elements the combination is accompanied by combustion of the metal.
The latter was formerly often constructed as a reverberatory furnace, which is easy to build and to work, but the hydrochloric acid given off here, being mixed with the products of the combustion of the fuel, cannot be condensed to strong acid and is partly, if not entirely, wasted.
It is mixed with fresh air containing sufficient oxygen for the combustion of the hydrogen, and the mixture is passed through red-hot iron oxide (burnt pyrites) which by its catalytic action causes the reaction H2S+O= H 2 O+S to take place.
One of the purposes of the expedition was to discover whether the rate of combustion of a candle varies with the density of the atmosphere in which it is burnt, a question which was answered in the negative.
Roald Amundsen sailed from Norway in the "Fram " (which had been fitted with internal combustion engines) in Aug.
The continuous flow method is specially applicable to the important case of calorific value of gaseous fuel, where a large quantity of heat is continuously generated at a nearly uniform rate by combustion.
The heated products of combustion from the burner B impinge on a metal box H, through which water is circulating, and then pass downwards and outwards through a spiral cooler which reduces them practically to the atmospheric temperature.
flows through the spiral coolers N and M, and finally through the box H, where it is well mixed before passing the outflow thermometer P. As soon as a steady state is reached, the difference of temperature between the outflow and inflow thermometers, multiplied by the current of water in grammes per minute gives the heat per minute supplied by combustion.
A, 1901, " On The Variation Of The Specific Heat Of Water"; For Combustion Methods, See Article Thermochemistry, And Treatises By Thomsen, Pattison Muir And Berthelot; See Also Articles Thermodynamics And Vaporization.
At the same time he was working with Thenard at the improvement of the methods of organic analysis, and by combustion with oxidizing agents, first potassium chlorate and subsequently copper oxide, he determined the composition of a number of organic substances.
This objection to the air-engine arises from the fact that the heat comes to it from external combustion; it disappears when internal combustion is resorted to; that is to say, when the heat is generated within the envelope containing the working air, by the combustion there of gaseous or other fuel.
Gas-engines and oil-engines and other types of engine employing internal combustion may be regarded as closely related to the air-engine.
They differ from it, however, in the fact that their working substance is not air, but a mixture of gases - a necessary consequence of internal combustion.
It is to internal combustion that they owe their success, for it enables them to get all the heat of combustion into the working substance, to use a relatively very high temperature at the top of the range, and at the same time to escape entirely the drawbacks that arise in the air-engine proper through the need of conveying heat to the air through a metallic shell.
Another of his papers dealt with the delusions of the philosopher's stone, but nevertheless he believed that iron could be artificially formed in the combustion of vegetable matter.
He determined the specific gravity of these gases with reference to common air, investigated the extent to which they are absorbed by various liquids, and noted that common air containing one part in nine by volume of fixed air is no longer able to support combustion, and that the air produced by fermentation and putrefaction has properties identical with those of fixed air obtained from marble.
This is effected by stirring the molten metal with a pole of green wood (" poling "); the products which arise from the combustion and distillation of the wood reduce the oxide to metal, and if the operation be properly conducted " tough-pitch " copper, soft, malleable and exhibiting a lustrous silky fracture, is obtained.
The heat generated by the oxidation of iron and sulphur has always been used to maintain combustion in the kilns or stalls for roasting pyrites.
Two types of pyritic smelting may be distinguished: one, in which the operation is solely sustained by the combustion of the sulphur in the ores, without the assistance of fuel or a hot blast; the other in which the operation is accelerated by fuel, or a hot blast, or both.
These bacteria therefore employ SH 2 as their respiratory substance, much as higher plants employ carbohydrates - instead of liberating energy as heat by the respiratory combustion of sugars, they do it by oxidizing hydrogen sulphide.
The idea that this film of bacteria oxidizes the alcohol beneath by merely condensing atmospheric oxygen in its interstices, after the manner of spongy platinum, has long been given up; but the explanation of the action as an incomplete combustion, depending on the peculiar respiration of these organisms - much as in the case of nitrifying and sulphur bacteria - is not clear, though the discovery that the acetic bacteria will not only oxidize alcohol to acetic acid, but further oxidize the latter to CO 2 and 01-1 2 supports the view that the alcohol is absorbed by the organism and employed as its respirable substance.
Even when the light is not sufficiently intense, or the exposure is too short to kill the spores, the experiments show that attenuation of virulence, That bacterial fermentations are accompanied by the evolution of heat is an old experience; but the discovery that the " spontaneous " combustion of sterilized cotton-waste does not occur simply if moist and freely exposed to oxygen, philous bacteria.
The bitter taste of morphine is not noticeable when smoking opium, and it is therefore possible that the pleasure derived from smoking the drug is due to some product formed during combustion.
At Genoa he investigated the electricity of the torpedo-fish, and at Florence, by the aid of the great burning-glass in the Accademia del Cimento, he effected the combustion of the diamond in oxygen and decided that, beyond containing a little hydrogen, it consisted of pure carbon.
China was in his eyes drifting from its ancient moorings, drifting on a sea of storms " to hideous ruin and combustion "; and the expedient that occurred to him to arrest the evil was to gather up and preserve the records of antiquity, illustrating and commending them by his own teachings.
When exposed to the air a stick of phosphorus undergoes slow combustion, which is revealed by a greenish-white phosphorescence when the stick is viewed in the dark.
140, p. 444) suggested that it is due to the combustion of an oxide more volatile than phosphorus, a view which appears to be supported by the observations of Scharff (Zeit.
Phosphorus oxide, P 4 0 6, discovered by Sage in 1777, is a product of the limited combustion of phosphorus in air.
It may be conveniently prepared by passing a rapid current of air over burning phosphorus contained in a combustion tube, and condensing the product in a metal condenser, from which it may be removed by heating the condenser to 50 0 -60° (Thorpe and Tutton, Jour.
Jungfleisch has obtained it by carrying out the combustion with oxygen under reduced pressure, or diluted with an inert gas.
Phosphorus tetroxide, P204, was obtained by Thorpe and Tutton by heating the product of the limited combustion of phosphorus in vacuo as a sublimate of transparent, highly lustrous, orthorhombic crystals.
The combustion probably follows the equation PSF3+02 = PF3+S02, the trifluoride at a higher temperature decomposing according to the equations: 10PF3+502=6PF5+2P205, 2PF3+02=2P0F3, the complete reaction tending to the equation: IoPSF3+1502=6PF5+2P205+ 10SO 2.
If we examine chemical sources for maintenance of the sun's heat, combustion and other forms of combination are out of the question, because no combinations of different elements are known to exist at a temperature of 6000°.
The first step in its manufacture is the combustion of sulphur.
The chief applications are found in the analysis of flue gases (in which much information is gained as to the completeness and efficiency of combustion), and of coal gas (where it is necessary to have a product of a definite composition within certain limits).
These gases enter the combustion chamber around the retorts at a high temperature, and are there supplied with sufficient air to complete their combustion, this secondary air supply being heated by the hot products of combustion on their way to the exit flue.
The primary air necessary for the partial combustion of the coke to "producer" gas enters between these bars.
The gases are conducted from the furnace to the combustion chamber E through the nostrils D D, and the secondary air is FIG.
Complete combustion takes place at this point with the production of intense heat, the gases on rising are baffled in order to circulate them in every direction round the retorts, and upon arriving at the top of the setting they are conducted down a hollow chamber communicating with the main flue and shaft.
It was for some time debated as to whether naphthalene added materially to the illuminating value of the gas, and whether an endeavour should be made to carry it to the point of combustion; but it is now acknowledged that it is a troublesome impurity, and that the sooner it is extracted the better.
The gas obtained by the Young process, when tested by itself in the burners most suited for its combustion, gives on the photometer an illuminating value averaging from 50 to 60 candle-power, but it is claimed, and quite correctly, that the enriching power of the gas is considerably greater.
Coke or anthracite is heated to incandescence by an air blast in a generator lined with fire-brick, and the heated products of combustion as they leave the generator and enter the superheaters are supplied with more air, which causes the combustion of carbon monoxide present in the producer gas and heats up the fire-brick baffles with which the superheater is filled.
Furnaces are constructed according to many different patterns with varying degrees of complexity in arrangement; but all may be considered as combining three essential parts, namely, the fire-place in which the fuel is consumed, the heated chamber, laboratory, hearth or working bed, as it is variously called, where the heat is applied to the special work for which the furnace is designed, and the apparatus for producing rapid combustion by the supply of air under pressure to the fire.
In the simplest cases the functions of two or more of these parts may be combined into one, as in the smith's forge, where the fire-place and heating chamber are united, the iron being placed among the coals, only the air for burning being supplied under pressure from a blowing engine by a second special contrivance, the tuyere, tuiron, twyer or blast-pipe; but in the more refined modern furnaces, where great economy of fuel is an object, the different functions are distributed over separate and distinct apparatus, the fuel being converted into gas in one, dried in another, and heated in a third, before arriving at the point of combustion in the working chamber of the furnace proper.
Furnaces may be classified according as the products of combustion are employed (i) only for heating purposes, or (2) both for heating and bringing about some chemical change.
(2) Substance heated by products of combustion = reverberatory furnaces.
(3) Substance is not directly heated by the fuel or by the products of combustion.
By continuing the walls of the hearth above the tuyere, into a shaft or stack either of the same or some other section, we obtain a furnace of increased capacity, but with no greater power of consuming fuel, in which the material to be treated can be heated up gradually by loading it into the stack, alternately with layers of fuel, the charge descending regularly to the point of combustion, and absorbing a proportion of the heat of the flame that went to waste in the open fire.
In all cases, therefore, where it is desired to do the work out of contact with the solid fuel, the operation of burning or heat-producing must be performed in a special fire-place or combustion chamber, the body of flame and heated gas being afterwards made to act upon the surface of the material exposed in a broad thin layer in the working bed or laboratory of the furnace by reverberation from the low vaulted roof covering the bed.
A third class of furnaces is so arranged that the work is done by indirect heating; that is, the material under treatment, whether subjected to calcination, fusion or any other process, is not brought in contact either with fuel or flame, but is raised to the proper temperature by exposure in a chamber heated externally by the products of combustion.
These are almost invariably air furnaces, though sometimes air under pressure is used, as, for example, in the combustion of small anthracitic coal, where a current of air from a fan-blower is sometimes blown under the grate to promote combustion.
In this way a very large surface is exposed to the heat, and the ore, if containing sufficient sulphur to maintain the combustion, is perfectly burned when it arrives at the bottom; if, however, it is imperfectly sized or damp, or if it contains much earthy matter, the result is not very satisfactory.
- The calorific intensity of fuel is found to be very considerably enhanced, if the combustion be effected with air previously heated to any temperature between that of boiling water and a dull red heat, the same effect being observed both with solid and gaseous fuel.
In every system of artificial heating, the amount of heat usefully applied is but a small proportion of that developed by combustion.
As soon as the bricks have become red hot, the current is diverted to an adjacent chamber or pair of chambers, and the acquired heat is removed by a current of cool gas or air passing towards the furnace, where it arrives at a temperature sufficiently high to ensure the greatest possible heating effect in combustion.
Owing to the conditions of the work, which require the maintenance of a sensibly reducing atmosphere, they contain a very notable proportion of carbonic oxide, and are drawn off by large wrought iron tubes near the top of the furnace and conveyed by branch pipes to the different boilers and air-heating apparatus, which are now entirely heated by the combustion of such gases, or mixed with air and exploded in gas engines.
The pressure switch monitors flow and shuts down the heater in the event of flue or combustion air blockage.
alkane combustion mechanisms.
Fuel nozzle -- device to inject fuel into the combustion chamber in a highly atomized and accurately shaped spray.
The combustion of benzene in gasoline engines accounts for 70% of all benzene emissions.
brominated compounds) frequently greatly increase the harmful by-products of combustion.
The differences in performance create conditions that allow combustion byproducts to more easily enter home living spaces.
Know that the products from the incomplete combustion of hydrocarbons include carbon monoxide.
Heating System Most vans have space heaters in which the combustion chamber is sealed off from the living area.
You see it is not combustible, nor does it support combustion.
combustion of hydrocarbons include carbon monoxide.
combustion of fossil fuel.
combustion of gasoline.
combustion of coal.
combustion of hydrogen to form water the following reaction takes place.
Westfield was the first chicken litter fuelled plant in the world to use advanced fluidized bed combustion.
Different injection mapping for the two cylinders so as to optimize combustion in each cylinder.
I saw a pair of shoes by the bushes: spontaneous human combustion?
CO is produced by the incomplete combustion of fossil fuel.
His research interests are in the areas of turbulent combustion modeling.
The number of cloud droplets is found to be higher in regions of fossil fuel combustion.
It is produced by incomplete, or inefficient, combustion of fuel including ' cold ' or badly tuned engines.
combustion chamber is sealed off from the living area.
combustion engines are used in cars to make the wheels go round.
combustion appliances are added together.
However, various systems intended for direct coal combustion, which may be less complex, are also being developed.
Of the multiple stages that occur during biomass combustion, the char combustion is most relevant in alkali metal release.
Flue gases leave the combustion chamber but will be cooled to below 50 ° C by incoming air in the secondary heat exchanger.
A prototype 5.7-litre pushrod V-8 engine featuring hemispherical combustion chambers and two spark plugs per cylinder powers the Super8.
This reduced vibration, the limiting factor with parallel twins and made for an efficient combustion chamber.
The starter motor combustion chamber is scavenged by compressed air.
combustion chamber in the head.
Dioxins are produced during various combustion processes and are also unwanted by-products in the manufacture of certain chlorinated compounds.
The four-valve unit has a high compression ratio of 12:1 and a combustion chamber based on that of the new K1200 S engine.
This is true of all woodstoves, but with dirty combustion this contains corrosive creosote and soot as well.
The process also reduced the environmental impacts normally associated with coal combustion, such as particulate matter, sulfur dioxide and mercury.
Top of Page Combustion the use as fuels of some of the products from crude oil distillation.
By contrast fossil fuels only get 28m ECU in total - mainly for work on clean combustion technology.
Indeed they may simply help to extend the lifespan of the internal combustion engine longer than it would otherwise survive.
enthalpy of combustion for a number of alcohols.
equilibrates with preheated incoming air entering the combustion chamber.
fossil fuel combustion.
gas turbine combustion chambers.
halocarbon gases, like Halons, react directly with the fire to terminate the combustion process.
It is preheated in a high capacity heat exchanger by the combustion products.
incomplete combustion of fossil fuel.
inefficient, combustion of fuel including ' cold ' or badly tuned engines.
Rechargeable electric cells offer a clue, but remain ludicrously inefficient in power to weight ratios when compared to the internal combustion engine.
infernal internal combustion engine) win?
lighter-than-air vehicle with internal combustion engine and air propeller was the obvious route.
melt at the combustion temperatures used.
He seems to be suggesting that others do use the moiety of Jupiter or presumably the moiety of the other planet moving into combustion.
nan publications on www.a-n.co.uk include Amorphous combustion (2004 ), Quo Vadis (2004 ), Close proximity (August 2005 ).
NOx reduction is now a major focus of combustion research.
Historically, Lavoisier's discovery of oxygen and its role in combustion dramatically replaced earlier explanations using phlogiston.
Draw the carbon cycle to show the processes including photosynthesis, respiration, combustion, and fossilization.
This consists of sparking plug with a transparent top which enables you to see the color of the combustion taking place.
polynuclear aromatic hydrocarbons (PAHs) could also be detected, derived from anthropogenic combustion sources.
preheat the incoming air for combustion.
ramjet (engine)c combustion ramjet, or scramjet, operated for about 10 seconds - the duration of its hydrogen fuel supply.
Most dealers leave the combustion area alone then retard the ignition more or over jet to compensate for the over high compression.
twin spark plugs per cylinder also make for faster, more efficient combustion and cut polluting emissions.
speciation of mercury in coal combustion flue gas.
spontaneous human combustion?
spontaneous combustions by the bushes: spontaneous human combustion?
high-pressure steam from this combustion process expands out a rocket nozzle or drives a turbine that turns a propeller screw.
thermal expansion in the combustion chamber.
One houses the combustion chamber with a specially constructed air flow passage and burner head to eliminate combustion air turbulence and flame roar.
turbulent combustion modeling.
Higher atmospheric water vapor would be expected near cities on a continuing basis, as a result of the combustion of fossil fuels.
water vapor production via combustion.
wavelets in computational combustion.
Taking the carbon exhumed by industrial combustion from the geologic past and stacking it into overripe living woodpiles is an approach of questionable wisdom.
The matter leaving the conductor, whether the products of combustion or the drops of a liquid, supplies the means of securing equality of potential between the conductor and the air at the spot where the matter quits electrical connexion with the conductor.
the element is melted, either by the heat of its own combustion or other means, and runs off from the earthy residue.
The first cell is heated and the products of combustion are led into the second cell where they give up part of their heat to the contained ore, so that by the time the first cell is exhausted the mass in the second cell is at a sufficiently high temperature to ignite spontaneously when air is admitted.
The second method is analogous to the calcarone method of liquation: the ore is placed in a limekiln-like furnace over a mass of kindled fuel to start a partial combustion of the mineral, and the process is so regulated that, by the heat generated, the unburnt part is decomposed with elimination of sulphur, which collects in the molten state on an inverted roof-shaped sole below the furnace and is thence conducted into a cistern.
The most usual way of providing this power is by the combustion of coal in the fire-box of a boiler and the utilization of the steam produced in a steam-engine, both boiler and engine being carried on a frame mounted on wheels in such a way that the crank-shaft of the steam-engine becomes the driving-axle of the train.
A limit is reached to the rate of combustion when the draught becomes strong.
Thus the conversion of yellow into red phosphorus evolves about one-sixth of the heat of combustion of the latter in oxygen, and so the knowledge of which variety of phosphorus has been employed is of essential importance in the thermochemistry of that element.
The thermochemical magnitude which is universally determined for organic compounds is the heat of combustion, usually by means of the calorimetric bomb.
Since the heat of combustion of a hydrocarbon is equal to the heat of combustion of the carbon and hydrogen it contains minus its heat of formation, those hydrocarbons with positive heat of formation generate less heat on burning than the elements from which they were formed, whilst those with a negative heat of formation generate more.
Thus the heat generated by the combustion of acetylene, C 2 H 2, is 316000 cal., whereas the heat of combustion of the carbon and hydrogen composing it is only 256900 cal., the difference being equal to the negative heat of formation of the acetylene.
For substances consisting of carbon, hydrogen and oxygen, a rule was early devised for the purpose of roughly calculating their heat of combustion (J.
According to Welter's rule, we deduct II 0 with the equivalent amount of hydrogen, namely, 22 H, and are left with the residue 12 C, the heat of combustion of which is 1131600 cal.
Of the analogy between combustion and respiration - both true phlogistic processes in his view - he had convinced himself three years before, and his paper, "On Different Kinds of Air" (Phil.
The former substituted for the salt, sulphur and mercury of Basil Valentine and Paracelsus three earths - the mercurial, the vitreous and the combustible - and he explained combustion as depending on the escape of this last combustible element; while Stahl's conception of phlogiston - not fire itself, but the principle of fire - by virtue of which combustible bodies burned, was a near relative of the mercury of the philosophers, the soul or essence of ordinary mercury.
The length of time and other disadvantages attending the combustion method have caused investigators to devise other processes.