Spontaneous combustion

“ The very best way not to have fires is not to set them. If you stop to think of it, there are not so very many different things that will start fires. Matches, kerosene, gas, gasoline, hot sparks, burning tobacco, fires in stoves, furnaces, and fire-places, hot ashes, lightning, and fires [Pg 118] which start themselves by "spontaneous combustion," are the common causes of our losses ”

“ Harrington asked. “Read it aloud, Professor, so we can all hear it.”
“'Spontaneous human combustion, or catacausis ebriosus,'” began Craig, “'is one of the baffling human scientific mysteries. Indeed, there can be no doubt but that individuals have in some strange and inexplicable manner caught fire and been partially or almost wholly consumed.
“'Some have attributed it to gases in the body, such as carbureted hydrogen. Once it was noted at the Hotel Dieu in Paris that a body on being dissected gave forth a gas which was inflammable and burned with a bluish flame. ”

“ It is without doubt a case of spontaneous human combustion, such as is recorded beyond dispute in medical and medico-legal text-books of the past two centuries. Scientists in this city consulted for the Record agree that, while rare, spontaneous human combustion is an established fact and that everything in this curious case goes to show that another has been added to the already well-authenticated list of cases recorded in America and Europe. The family refuse to be interviewed, which seems to indicate that the rumours in medical circles in Saranac have a solid basis of fact. ”

“ Thus, phosphorus at 150°, and sulphur at 550°, are said to take fire, and two acid products are formed; at 800°, hydrogen gas explodes with oxygen, and produces water; and, according to Ure's view, the flame of combustible bodies may in all cases be considered as the combustion of an explosive mixture of inflammable gas, or vapour, with air; and as to the change of quiescent into distributable heat, and the causes that modify combustion and flame, the facts on these heads are numerous and very important. ”

“ 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. ”

“ This liquid is used as a solvent for phosphorus and other substances, and is extremely volatile and combustible, and burns silently with a pale blue flame. The combustion of its vapour, mixed with certain gases, offers a good example of the fact that slow burning may be a peaceful experiment, whilst very rapid combustion often resolves itself into an explosion. ”

“ When air is applied in too great quantity, and especially if some of the tubes convey oxygen gas, then a violent combustion and flame is excited, which will, in all probability, consume or burn out the furnace or grate, or if it do not, it will burn out the fuel, and thus exhaust itself. ”

“ There cannot, therefore, exist, as far as relates to us, any combustible body but such as are non-combustible at the ordinary temperature of the earth, or, what is the same thing in other words, that it is essential to the nature of every combustible body not to possess the property of combustion unless heated, or raised to a degree of temperature at which its combustion naturally takes place. When this degree is once produced, combustion commences, and the caloric which is disengaged by the decomposition of the oxygen gas keeps up the temperature which is necessary for continuing combustion. ”

“ 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 ”

“ Every reaction which takes place rapidly, if it be accompanied by so great an evolution of heat as to produce incandescence, is termed combustion. Thus combustion ensues when many metals are plunged into chlorine, or oxide of sodium or barium into carbonic anhydride, or when a spark falls on gunpowder. A great many substances are combustible in oxygen, and, owing to its presence, in air also. ”

“ And first, every body knows that combustible matters will not burn or consume unless they have a free communication with the air; insomuch that if they be deprived thereof, even when burning most rapidly, they will be extinguished at once: that consequently combustion is greatly promoted by the frequent accession of fresh air, and that a stream of air, directed so as to pass with impetuosity through burning fuel, excites the fire to the greatest possible activity. ”

“ The result of imperfect combustion is not only the loss of a part of the fuel and the production of smoke, which in some respects is inconvenient and injurious to health, but also a low flame temperature, which means that a less amount of heat is transmitted to the object heated. Imperfect combustion is not only always accompanied by the formation of soot or unburnt particles of charcoal, but also by that of carbonic oxide, CO, in the smoke (Chapter IX.) which burns, emitting much heat. ”

“ While these gases are rising in hot condition, the air comes in contact with them and effects their combustion. The dark portion, c, of the flame is where the carbon and gases have not a sufficiency of air for their thorough combustion; but gradually they become mixed with air, although not then sufficient for complete combustion. The hydrogen is first oxidized or burnt, and then the carbon is attacked by the air, although particles of carbon are separated, and it is these, in a state of intense ignition, which produce the illumination. ”

“ 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. ”

“ No: ignition is quite independent of combustion. Clay, chalk, and indeed all incombustible 120 substances, may be made red hot. When a body burns, the light emitted is the effect of a chemical change which takes place, whilst ignition is the effect of caloric alone, and no other change than that of temperature is produced in the ignited body. ”

“ Soot therefore always indicates an imperfect combustion. Hence [9] flame is produced from those inflammable substances only, which are either totally volatile when heat is applied to them, so as not to alter their chemical habitudes—or which contain a quantity of combustible matter that is readily volatilized into vapour by heat, or the elements necessary for producing such vapour or gazeous products, when the chemical constitution of the body is altered by an increase of temperature. ”

“ Completeness of combustion can only be obtained by admitting considerably more air to the fire than is theoretically necessary fully to oxidize the combustible portions of the fuel, and by providing sufficient time and opportunity for a thorough mixture of the air and furnace gases to take place before the temperature is lowered to that critical point below which combustion will not take place. ”

“ In the non-luminous flame, owing to the air being admitted and mixed with the gas, the increased supply of oxygen renders combustion more complete, greatly increases the heat of the flame, but renders it incapable of giving light. ”

“ In short, in every instance of combustion, the oxygen combines with the combustible body, and at the same time gives out its heat, which supported it in the form of gas. This is the case of the combustion of coal in a common fire, as well as in other cases of combustion; the heat comes from the air, and not from the coal.
When we examine the phenomena of respiration with attention, we shall find them very analogous to those of combustion. A candle will not burn in an exhausted receiver: an animal in the same situation ceases to live. ”

“ The combustion of gas and kerosene in living rooms rapidly vitiates the air. Each burner will use up as much oxygen as several persons, besides generating heat, moisture and often sulphurous acid gas, specially injurious to nose and throat. Stoves or grates for heating or cooking by gas should invariably be connected to a-flue to carry off the products of combustion. ”

“ It is the contact of the body to be heated with the flame before combustion is complete which gives rise to the greatest mischief; any cooling of the flame extinguishes a portion of the flame, and the gases present in the flame at the moment of extinction creep along the cooled surface and escape combustion. ”

“ It may be well here if, before passing to the more immediate object of this paper—viz. a sketch of the probable progress of pyrotechny—we explain to those of our readers who are unacquainted with chemistry, the philosophy of explosive combustibles.
Combustion is nothing else than rapid chemical union, taking place between two dissimilar substances, which have what is called an affinity for each other, i.e. a tendency to unite and form a new compound. ”

“ If more than a normal supply of air is forced into the flame, a greater heat and more active burning follows. If the amount of air, and consequently oxygen, is reduced, the flame becomes smaller and weaker and the combustion is less rapid. A flame may be easily extinguished by shutting off all of its air supply. ”

“ When the lamp is lighted the oil burns with a heavy, smoky flame, because it is not able to obtain sufficient oxygen to complete the combustion, and not only are soot flakes produced, but products of incomplete combustion, such as carbon monoxide and even petroleum vapour, escape—the first named highly injurious to health, and the second of an offensive odour. ”

“ The combustion, when once begun, continues for a considerable time, but weakens gradually, in proportion as the quantity of azotic gas remaining from the combustion increases, till at last the azotic gas is in such over proportion that the combustion can no longer be supported, and the flame goes out. ”

“ 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. ”

“ If its temperature be below that of ignition, it will not, in many cases, burn when it comes into the open air. And there is a certain velocity at which the quantity of atmospherical air which comes in contact with the vapour will be neither too great nor too small; for too much air will diminish the temperature of the stream of combustible matter so much as very considerably to impede the desired effect, and too little will render the combustion languid. ”

“ The oxygen in the solar atmosphere, like the hydrogen, is simply glowing with intensity of heat. No process of combustion is taking place. Ignition, strictly speaking, means the initiation of the process of combustion, and a substance can only be said to be ignited when it has been set burning. ”

“ First, a slow combustion is the most perfect, because it produces less clinker, which saves fuel and also saves a large amount of fire cleaning and therefore of admission of cold air to the fire box. A high temperature is necessary to combustion, and the temperature of the fuel is most difficult to keep up at the sides of the fire box. ”

“ Combustion may be retarded by using those substances, which are not in themselves inflammable, and which, if used in too large a quantity, would effectually prevent it. [190] Clay, wood ashes, &c. as in the blind fuse, act on this principle; and serve, also, in particular cases, to produce that succession of explosions, which renders the effect of some fire-works, more grand and impressive. Rope, soaked in a solution of saltpetre and dried, would burn rapidly, were it not for the after immersion in potash ley, or urine, either of which acts by retarding the progress of combustion. ”

“ Wherever a forced stream of air is employed for combustion, the resulting temperature must evidently be impaired by the coldness of the air injected upon the fuel. The heat developed in combustion is distributed into three portions; one is communicated to the remaining fuel, another is communicated to the azote of the atmosphere, and to the volatile products of combustion, and a third to the iron and fluxes, or other surrounding matter to be afterwards dissipated by wider diffusion. ”

“ The same occurs when the temperature of any portion of the hydrogen is reduced below that intensity required for the combustion of the newly separated charcoal. Solid bodies, as tallow, oils, and fats, which burn with flame, are converted into the state of gas by the heat required to kindle them, and it is this gaseous matter which suffers combustion, and not the substance which produces it. ”