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present occasion we shall confine our attention to the consideration of explosions of fire damp.
Fire damp, sulphur, or wild fire, as it is commonly called by the colliers, is the light carburetted hydrogen or marsh gas, which is so commonly found bubbling up in our ponds of water, wherein is much decomposing vegetable matter. This gas is often seen in
on the surface of water, and is sometimes fired by boys for the purpose of amusement. It conaists of one equivalent of carbon united to two equivalents of hydrogen. After having previously
my description of the origin of coal, by attribating it to decomposed vegetable matter buried ander water
, you will see how fire damp has been produced. It has not arisen from the decomposition of coal now going on, but is the gas formed on the first entombment of the plants. Professor Graham found in his experiments that fire damp was composed entirely of light carburetted hydrogen, but it neither contained olefiant gas nor carbonic acid
, both of which Professor Bischoff had found in gases from mines in Germany. Dr. Lyon Playfair, in his paper on the gases evolved
during the formation of coal, published in vol. 1, p. 460, of the Meznoirs of the Geological Survey of Great Britain, confirtas Professor Graham's results in the following words :-" The general result of my analysis confirms the views formerly entertained of the composition of the gases, namely, that they form a mixtoure of light carburetted hydrogen with a small mixTure of nitrogen and oxygen, as common air, but that they neither contain olefiant gas nor carbonic acid gas, both of which Bischoff had found in the gases from mines in Germany." Probably olefiant and other gas may yet be detected in the gases from the coal mines of Great Britain, but up to this time they have certainly not been
noticed. Besides fire darup, sulphuretted hydrogen gas is sometimes found in coal mines abounding in brass or iron pyrites. It
is composed of one equivalent of hydrogen, united to one of sulphur, and has a specific gravity of 1.1912. It is an explosive gas, and would be a dangerous enemy to the miner if it did not give decided evidence of its presence by its most disagreeable smell. Another most deadly gas found in mines where coal has been on fire, or where boilers are employed underground, is carbonic oxide, composed of one of carbon and one of oxygen; this gas is one of the most poisonous known, and, unfortunately, gives little evidence of its presence. Black-damp, choke-damp, or carbonic acid as it is respectively terined, composed of one of carbon and two of oxygen, is often found in badly ventilated mines, but it has not yet been proved to come out of the coal. Its specific gravity is 1.5290. After-damp, which is left in a mine after the explosion, is composed of nitrogen and carbonic acid.
A general impression prevails amongst working colliers that where flame exists there life can. This would be true as to an atmosphere of choke damp nearly pure, but if such a gas were mixed with nitrogen, a flame might burn and still a man be struck down. A flame also will burn in mixtures of atmospheric air and sulphuretted hydrogen gas, atmospheric air and carbonic oxide gas, when life will be instantly destroyed.
As it has been shown that fire damp was most probably formed at the same time as the coal in which it is contained, it will always be met with more or less in working of coal mines. In some inclined beds of coal outcropping at the surface without much cover, or lying on hill sides, the gas will gradually drain off; but in beds of coal lying in belts, separated by vertical or nearly vertical faults, the gas will be confined and pent up released by sinking shafts and working the seains, This shows the great care that ought to be observed in sinking to and working new fields so situated.
In driving main levels, and in opening the works of such fields, the utmost precaution should be used. In working back or robbing pillars, or when great falls of roof have taken place, too much care cannot be taken. Where gas is met with, no one who know anything of it will hesitate what to do. He will remove it out of the mine as quickly as he When this is done, the Davy or any other lamp should be employed by the workmen, as a precaution against any stoppage in the ventilation, by falls of roof or derangement of air courses, or by the sudden liberation of gas from the roof or other part of a
Lamps are frequently used in the opening of seams of coal, in driving fast places, and when pillars are being robbed or worked back, whilst naked lights are in common use over the greater part of the mine. This dangerous admixture should be openly condemned. The most
experienced miner, or the best scientific man, will not be able to guard against the sudden coming of so invisible, intangible, and subtle an enemy as fire damp; nay, in many cases will not be able able to detect its presence by any of his · senses, unless a light is present. Persons who do not understand the nature and properties of fire damp, often talk about the reckless conduct of poor ignorant miners, as if the latter rushed wilfully into it, just as a lot of boys would jump into a pool of water for mere mischief. The smell of gas used for the purpose of artificial illumination, gives an unmistakable evidence of its presence by its smell. Yet how many accidents are there by people who assume to be far better educated than the working colliers
, taking a lighted candle to see where it Escapes ! Fire damp, on the other hand, may exist in a most explosive state which cannot be detected by the sense of smell, even by the most experienced miners, who have long worked in fiery mines. Scarcely anything shows more clearly the indefinite
ideas the men have of this gas than the names they call it by-sulphur, wild fire, fire damp, &c. To say nothing about working colliers, speaking for myself, I should be sorry to trust any experienced underlooker or officer's mere senses as to the presenco of fire damp. I certainly once did so, and very narrowly escaped being badly burnt for my credulity.
It has been stated that every collier ought to be able to examine his own place before he commences his work. I wish they were so. So far as my knowledge extends, it will be long before they will possess such an amount of knowledge as to gas. Another circumstance, which proves how ignorant really practical men were of the nature of the enemy they had to deal with, was the fearful mode of trying a place for gas with a naked candle, and as the flame tapered up cut it off with their hands. This, it is to be hoped, is not now in use. Although doubtless some men were very clever in escaping being burnt in their investigation, their skill must be considered as that of thoroughly reckless men; just as reckless as if they were in a building full of casks containing a black powder, as well as some of the same kind of powder İying looss, with a train of it reaching all the way to the door, and they wanted to find out its nature. To do this suppose they fired the train with a match and trusted to stamping the flame out with their feet, so as to prevent its communicating with the heap. This may seemn a mad way of testing the presence of gunpowder
, but it is rot a whit more insane than trying a fiery coal mine for fire damp with a naked candle. To my mind, ignorance of the origin and properties of fire damp is the chief cause of the explosions of fire damp in mines.
This want of knowledge of the subtlo enemy they have to deal with is, I fear, alike com. mon to both officers and men. The proverb that “knowledge is power" is nowhere more applicable than when applied to fire dacap in a coal mine, for
to use it as a
so full of
no intelligent officer who knows much of that gas and also be constantly prepared for its appearance in the mine when it is known to exist, or even where there is a probability of its existence. The mixed use of Davy lamps and candles in a mine where fire damp is known to be in any part of the workings of waste, is, to say the least of it, both reckless and is a safe instrument in the hands of a careful
A securely locked Davy lamp, with a shield, structed. By this I mean that it is invaluable for
man, who knows the principles on which it is conbefore the men are sent into them, and for workmen an intelligent fireman to examine the workings with, against accidents in the ventilation; but it should
precaution in a well ventilated mine Dever be used as a substitute for ventilation, and in flame. There is no excuse in the world for working
gas as to have the gauze full of if it is persisted in, accidents sooner or later are sure with lamps full of flame for any length of time, and to occur. Often when in a dead place lamps are filled with flame, there being too much fire damp present rent of air will suddenly dilute the gas to the point to make the air explosive, the admittance of a curseven of air, and a series of explosions will take place in the lamp.
It is then said to be very sharp practical men think that the mixture
gases than fire damp and air, but all such gases, and I therefore still think that the sharp
to this time have failed to detect ness arises from its being at the mixture of greatest
It is very difficult to pass flame through good ing a considerable amount of olefiant gas, as my
even the fame of coal gas containhow exhibited clearly show; but still
and contains other investigations