Spontaneous INFLAMMATIONS

Spontaneous INFLAMMATIONS, which, as different substances, are liable to them, have been, and may again be, the cause of many and great misfortunes.

The spontaneous inflammation of essential oils, and that of some fat oils, when mixed with nitrous acid, are well known to philosophers; so also is that of powdered charcoal with the same acid (lately discovered by M. Proust), and those of phosphorus, of pyrophorus, and of fulminating gold. These substances are generally to be found only in the laboratories of chemists, who are perfectly well acquainted with the precautions which it is necessary to take to prevent the unhappy accidents which may be occasioned by them.

The burning of a store house of sails, which happened at Brest in the year 1777, was caused by the spontaneous inflammation of some oiled cloths, which, after having been painted on one side, and dried in the sun, were allowed to remain while yet warm; as was shewn by subsequent experiments.*

Vegetables boiled in oil or fat, and left to themselves, after having been pressed, inflame in the open air. This inflammation always takes place when the vegetable retains a certain degree of humidity; if they are first thoroughly dried, they are reduced to ashes, without the appearance of flame. We owe the observation of these facts to MM. Saladin and Carette†.

The heaps of linen rags which are thrown together in paper manufactories, the preparation of which is hastened by means of fermentation, often take fire, if not carefully attended to.

The spontaneous inflammation of hay has been known for many centuries; by its means houses, barns, &c. have been often reduced to ashes. When the hay is laid up damp, the inflammation often happens; for the fermentation is then very great. This accident very seldom occurs to the first hay (according to the observation of M. de Bomare), but is much more common to the second; and if, through inattention, a piece of iron should be left in a stalk of hay in fermentation, the inflammation of that stalk is almost a certain consequence. Corn heaped up has also sometimes produced inflammations of this nature. Vanieri, in his Prædium Rusticum, says,

Quæ vero (gramina) nondum satis insolata recedent. Imprudentes, subitiis pariunt incendia flammis.

Dung also, under certain circumstances, inflames spontaneously.

In a paper, published in the Repertory of Arts and Manufactures, by the Rev. William Tooke, F. R. S. &c. we have the following remarkable instances of spontaneous inflammation. "A person of the name of Rüde, an apothecary at Bautzen, had prepared a pyrophorus from rye-bran and alum. Not long after he had made the discovery, there broke out, in the next village of Naussitz, a great fire, which did much mischief, and was said to have been occasioned by the treat-

ing of a sick cow in the cow-house. Mr Rüde knew, that the countrymen were used to lay an application of parched rye-bran to their cattle for curing the thick neck; he knew also, that alum and rye-bran, by a proper process, yielded a pyrophorus; and now he wished to try whether parched rye-bran alone would have the same effect. Accordingly, he roasted a quantity of rye-bran by the fire, till it had acquired the colour of roasted coffee. This roasted bran he wrapped up in a linen cloth; in the space of a few minutes there arose a strong smoke through the cloth, accompanied by a smell of burning. Not long afterwards the rag grew as black as tinder, and the bran, now become hot, fell through it on the ground in little balls. Mr Rüde repeated the experiment at various times, and always with the same result. Who now will any longer doubt, that the frequency of fires in cow-houses, which in those parts are mostly wooden buildings, may not be occasioned by this common practice, of binding roasted bran about the necks of the cattle? The fire, after consuming the cattle and the shed, communicates itself to the adjoining buildings; great damage ensues; and the ignorant look for the cause in wilful and malicious firings, consequently in a capital crime."

The same author informs us, that in the spring of the year 1780, a fire was discovered on board a Russian frigate lying in the road of Cronstadt; which, if it had not been timely extinguished, would have endangered the whole fleet. After the severest scrutiny, no cause of the fire was to be found; and the matter was forced to remain without explanation, but with strong surmises of some wicked incendiary being at the bottom of it. In the month of August, in the same year, a fire broke out at the hemp-magazine at St Petersburg, by which several hundred thousand poods‡ of hemp and flax were‡ A pood consumed. The walls of the magazine are of brick, consists of the floors of stone, and the rafters and covering of iron; it stands alone on an island in the Neva, on which, as well as on board the ships lying in the Neva, no fire is permitted. In St Petersburg, in the same year, a fire was discovered in the vaulted shop of a furrier. In these shops, which are all vaults, neither fire nor candle is allowed, and the doors of them are all of iron. At length the probable cause was found to be, that the furrier, the evening before the fire, had got a roll of new cere-cloth (much in use here for covering tables, counters, &c. being easily wiped and kept clean), and had left it in his vault, where it was found almost consumed.

In the night between the 20th and 21st of April 1781, a fire was seen on board the frigate Maris, which lay at anchor, with several other ships, in the road off the island of Cronstadt; the fire was, however, soon extinguished; and, by the severest examination, little or nothing could be extorted concerning the manner in which it had arisen. The garrison was threatened with a scrutiny that should cost them dear; and while they were in this cruel state of suspense, an order came from the sovereign, which quieted their minds, and gave rise to some very satisfactory experiments.

It having been found, upon juridical examination, as well as private inquiry, that in the ship's cabin, when the smoke appeared, there lay a bundle of matting, containing Russian lamp-black prepared from fir-oot, moistened with hemp oil varnish, which was perceived

to have sparks of fire in it at the time of the extinction, the Russian admiralty gave orders to make various experiments, in order to see whether a mixture of hemp-oil varnish and the forementioned Russian black, folded up in a mat and bound together, would kindle of itself.

They shook 40 pounds of fir-wood foot into a tub, and poured about 35 pounds of hemp oil varnish upon it; this they let stand for an hour, after which they poured off the oil. The remaining mixture they now wrapped up in a mat, and the bundle was laid close to the cabin, where the midshipmen had their birth. To avoid all suspicion of treachery, two officers sealed both the mat and the door with their own seals, and stationed a watch of four sea-officers, to take notice of all that passed the whole night through; and as soon as any smoke should appear, immediately to give information to the commandant of the port.

The experiment was made the 26th of April, about 11 o'clock A. M. in presence of all the officers named in the commission. Early on the following day, about six o'clock A. M. a smoke appeared, of which the chief commandant was immediately informed by an officer: he came with all possible speed, and through a small hole in the door saw the mat smoking. Without opening the door, he dispatched a messenger to the members of the commission; but as the smoke became stronger, and fire began to appear, the chief commandant found it necessary, without waiting for the members of the commission to break the seals and open the door. No sooner was the air thus admitted, than the mat began to burn with greater force, and presently it burst into a flame.

The Russian admiralty, being now fully convinced of the self-kindling property of this composition, transmitted their experiment to the Imperial Academy of Sciences; who appointed Mr Georgi, a very learned and able adjunct of the academy, to make farther experiments on the subject. Previous to the relation of these experiments, it is necessary to observe, that the Russian fir-black is three or four times more heavy, thick, and unctuous, than that kind of painters black which the Germans call kien-rahm. The former is gathered at Oehta, near St Petersburg, at Mosco, at Archangel, and other places, in little wooden huts, from resinous fir-wood, and the unctuous bark of birch, by means of an apparatus uncommonly simple, consisting of pots without bottoms set one upon the other; and is sold very cheap. The famous fine German kien-rahm is called in Russia Holland's black. In what follows, when raw oil is spoken of, it is to be understood of linseed-oil or hemp oil; but most commonly the latter. The varnish is made of five pounds of hemp oil boiled with two ounces and a half of minium. For wrapping up the composition, Mr Georgi made use of coarse hemp-linen, and always single, never double. The impregnations and commixtures were made in a large wooden bowl, in which they stood open till they were wrapped up in linen.

Three pounds of Russian fir-black were slowly impregnated with five pounds of hemp-oil varnish; and when the mixture had stood open five hours, it was bound up in linen. By this process it became clogged; but some of the black remained dry. When the bundle had lain sixteen hours in a chest, it was observed to emit a very nauseous, and rather putrid, smell, not quite

unlike that of boiling oil. Some parts of it became warm, and steamed much; this steam was watery, and by no means inflammable. Eighteen hours after the mixture was wrapped up, one place became brown, emitted smoke, and directly afterwards glowing fire appeared. The same thing happened in a second and a third place, though other places were scarcely warm. The fire crept slowly around, and gave a thick, grey, stinking smoke. Mr Georgi took the bundle out of the chest, and laid it on a stone pavement; when, on being exposed to the free air, there arose a slow burning flame, a span high, with a strong body of smoke. Not long afterwards there appeared, here and there, several chaps or clefts, as from a little volcano, the vapour issuing from which burst into flame. On his breaking the lump, it burst into a very violent flame, full three feet high, which soon grew less, and then went out. The smoking and glowing fire lasted for the space of six hours; and afterwards the remainder continued to glow without smoke for two hours longer. The grey earthy ashes, when cold, weighed five ounces and a half.

In another experiment, perfectly similar to the foregoing, as far as relates to the composition and quantities, the kindling did not ensue till 41 hours after the impregnation: the heat kept increasing for three hours, and then the accension followed. It is worthy of remark, that these experiments succeeded better on bright days than on such as were rainy; and the accension came on more rapidly.

In another experiment, three pounds of Russian fir-black were slowly impregnated with three pounds of raw hemp-oil; and the accension ensued after nine hours.

Three quarters of a pound of German rahm were slowly impregnated with a pound and a half of hemp-oil varnish. The mixture remained 70 hours before it became hot and reeking; it then gradually became hotter, and emitted a strong exhalation; the effluvia were moist, and not inflammable. The reaction lasted 36 hours, during which the heat was one while stronger, and then weaker, and at length quite ceased.

Stove or chimney foot, mostly formed from birch-wood smoke, was mingled with the above-mentioned substances and tied up; the compound remained cold and quiet.

Russian fir-black, mixed with equal parts of oil of turpentine, and bound up, exhibited not the least reaction or warmth.

Birch oil, mixed with equal parts of Russian fir-black, and bound up, began to grow warm and to emit a volatile smell; but the warmth soon went off again.

From the experiments of the admiralty and of Mr Georgi, we learn, not only the decisive certainty of the self-accension of foot and oil, when the two substances are mixed under certain circumstances, but also the following particulars:

Of the various kinds of foot, or lamp-black, the experiments succeeded more frequently and surely with the coarser, more unctuous, and heavier, like Russian painters black, than with fine light German rahm, or with coarse chimney-foot. In regard to oils, only those experiments succeeded which were made with drying oils, either raw or boiled. The proportions of the foots to the oils were, in the successful experiments, very various; the mixture kindled with a tenth, a fifth, a third, with

Inflamma-tion. with an equal, and likewise with a double, proportion of oil. In general, however, much more depends on the mode of mixture, and the manipulation, and, as Mr Georgi often observed, on the weather; for in moist weather the bundles, after becoming warm, would frequently grow cold again.

The instances of spontaneous inflammation hitherto mentioned have been only of vegetable substances; but we have examples of the same thing in the animal kingdom. Pieces of woollen cloth, which had not been scoured, took fire in a warehouse. The same thing happened to some heaps of woollen yarn; and some pieces of cloth took fire in the road, as they were going to the fuller. These inflammations always take place where the matters heaped up preserve a certain degree of humidity, which is necessary to excite a fermentation; the heat resulting from which, by drying the oil, leads them insensibly to a state of ignition; and the quality of the oil, being more or less defecative, very much contributes thereto.

The woollen stuff prepared at Sevennes, which bears the name of Emperor's stuff, has kindled of itself, and burnt to a coal. It is not unusual for this to happen to woollen stuffs, when in hot summers they are laid in a heap in a room but little aired.

In June 1781, the same thing happened at a wool-comber's in a manufacturing town in Germany, where a heap of wool-combings, piled up in a close warehouse seldom aired, took fire of itself. This wool had been by little and little brought into the warehouse; and, for want of room, piled up very high, and trodden down, that more might be added to it. That this combed wool, to which, as is well known, rape-oil mixed with butter is used in the combing, burnt of itself, was sworn by several witnesses. One of them affirmed that, ten years before, a similar fire happened among the flocks of wool at a clothier's, who had put them into a cask, where they were rammed hard, for their easier conveyance. This wool burnt from within outwards, and became quite a coal; it was very certain that neither fire nor light had been used at the packing, consequently the above fires arose from similar causes. In like manner, very credible cloth-workers have certified, that, after they have bought wool that was become wet, and packed it close in their warehouse, this wool has burnt of itself; and very serious consequences might have followed, if it had not been discovered in time.

Nay, there are instances, though they be but rare, of human bodies being consumed by spontaneous inflammation. In the Philosophical Transactions, and in the Memoirs of the Academies of Paris and Copenhagen, it is related that an Italian lady (the Countess Cornelia Bandi) was entirely reduced to ashes, except her legs; that an English woman, called Grace Pitt, was almost entirely consumed by a spontaneous inflammation of her viscera; and, lastly, that a priest of Bergamo was consumed in the same manner. These spontaneous inflammations have been attributed to the abuse of spirituous liquors; but though the victims of intemperance are indeed very numerous, these certainly do not belong to that number.

The mineral kingdom also often affords instances of spontaneous inflammation. Pyrites heaped up, if wetted and exposed to the air, take fire. Pitcoal also, laid in heaps, under certain circumstances, inflames sponta-

neously. M. Duhamel has described two inflammations of this nature, which happened in the magazines of Brest, in the years 1741 and 1757. Cuttings of iron, which had been left in water, and were afterwards exposed to the open air, gave sparks, and set fire to the neighbouring bodies. For this observation we are obliged to M. de Charpentier.

The causes of these phenomena the chemist will assign; but they are here recorded as a warning to tradesmen and others. It is evident, from the facts which have been related; that spontaneous inflammations being very frequent, and their causes very various, too much attention and vigilance cannot be used to prevent their dreadful effects. And consequently it is impossible to be too careful in watching over public magazines and storehouses, particularly those belonging to the ordnance, or those in which are kept hemp, cordage, lamp-black, pitch, tar, oiled cloths, &c. which substances ought never to be left heaped up, particularly if they have any moisture in them. In order to prevent any accident from them, it would be proper to examine them often, to take notice if any heat is to be observed in them, and, in that case, to apply a remedy immediately. These examinations should be made by day, it not being advisable to carry a light into the magazines; for when the fermentation is sufficiently advanced, the vapours which are disengaged by it are in an inflammable state, and the approach of a light might, by their means, set fire to the substances whence they proceed. Ignorance of the fore-mentioned circumstances, and a culpable negligence of those precautions which ought to be taken, have often caused more misfortunes and loss than the most contriving malice: it is therefore of great importance that these facts should be universally known, that public utility may reap from them every possible advantage.