EXPLOSIONS IN COLLIERIES, AND
THEIR CURE.

I WANT to set on foot a systematic and painstaking investigation of the nature and relations of light carburetted hydrogen (next to hydrogen itself the very lightest thing in nature), commonly called fire-damp, which shall neither slacken nor cease until we have secured for our miners security from the recurrence of further explosions; and I want to submit to public examination and criticism (which it will survive if founded upon sound inductions) a method by which it appears to me that the cause of one half—it may even happily prove to be the greater part of these explosions can be effectually and presently removed out of the way.

As to the first-to secure colliers from future explosions. There is a way to do this, I feel certain, and have felt so ever since the explosion occurred in the Warrenvale Pit, more than twenty years ago. It is not like God to bestow upon us such a priceless boon as coal, and to append as a necessary consequence to our putting out our hands to take it such dreadful disasters and suffering as now accompany its acquisition. It is not God, who in so many places in the Old Testament takes the title of the God of the fatherless and the widow,' who makes crowds of miners' wives widows, and their helpless children fatherless; no! these explosions are the penalty of our ignorance, or, as the late Canon Kingsley said in relation to something else, it is all because men will not learn nor obey those physical laws of the universe which (whether we be conscious of them or not) are all around us, like walls of iron or of adamant—say, rather, like some vast machine, ruthless though beneficent, among the wheels of which if we entangle ourselves in our rash ignorance, they will not stop to set us free, but crush us. Very terrible though very calm is outraged nature.'

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I have been striving hard for many many years to solve this great and pressing problem, and it appears to me that it might be of some use to those who may have the will to engage in this investigation if I were to explain the method and direction of my own researches, even in those directions where I have not succeeded, as, with greater knowledge of chemistry and other facts of nature than I possess, they might achieve success in directions in which I have been baffled and

turned back by want of such knowledge, or they may be able at once to see in what directions inquiry and investigation are useless, and so economise the mental energy available for the examination of this subject, and, so to speak, clear the ground for further inquiry.

The first question that suggested itself to my mind in turning to the consideration of this subject was, What is it that explodes? It is light carburetted hydrogen, CH,, now called methylic hydride, which is nearly, but not quite, identical with the gas which we obtain for lighting purposes by the distillation of coal in retorts, the difference being that the carburetted hydrogen which exudes from the face of the coal in the pit, being produced slowly and at a lower temperature, is free from the impurities which are found in the gas which is distilled at a high temperature from coal. The latter is largely impregnated with sulphur. The light carburetted hydrogen evolved from the coal in the mine is something less than half the weight of common air; that is to say, taking common air as 1, the hydrogen (fire-damp) I speak of is represented by 425. Now when this gas is mixed with common air in the proportion of 10 of gas and 90 or 100 parts of common air, the mixture is highly explosive, and, upon reaching a light, the fearful catastrophes result which we all deplore.

Hitherto all efforts to deal with this most unwelcome intruder into the workings of a colliery have been limited to efforts to get rid of it by diluting it with a strong current of atmospheric air which shall carry it off.

This gas, I may say, is entirely invisible, and has no smell; you do not therefore perceive it in breathing.

Now, as the efforts hitherto made to remove this gas have occasionally failed, with such sad results, I, and probably many others, have made many efforts to discover some other and better means of securing the safety of the men.

I will state what direction my thoughts have taken in the matter. I have said to myself that if this gas were visible to the eye like smoke, or steam, that many accidents that have occurred would have been averted by the immediate retreat of the men from its neighbourhood.

eye

Can we, then, unmask this gas? Can we make it visible to the like smoke or steam? Or, failing that, can we make it reveal its own presence by some automatic means, as sulphuretted hydrogen, for example, can be made to reveal itself by means of acetate of lead?

If you take some half-sheets of note-paper and trace upon them with a camel-hair pencil dipped in acetate of lead a single word like 'Beware,'' Run,' 'Escape,' or 'Fire,' and then take any one of these and expose it to sulphuretted hydrogen, each of these words, although up to that time totally invisible, would become black in a few seconds,

owing to the affinity which the lead has for the sulphur contained in the gas.

It is obvious that if anything analogous to this could be accomplished with the carburetted hydrogen of the pit, that much would have been done to diminish the danger which now attends the operations of the collier.

Take another example. In my hope that the resources of chemistry might supply a solution of the problem which has so long perplexed everybody, I have made it my business from time to time to seek the society of practical chemists, as well as of purely scientific men whose business it is to teach chemistry. I have seen several amongst the former who are engaged in calico-printing works, lead works, &c., and have sought, by getting them to talk about chemistry, and by, so to speak, lying in wait myself for some hint in their conversation, for something which might supply the missing link.

I had formed great expectations from the co-operation of Mr. Baker, the chemist employed at the lead works in Sheffield, as he appeared to me to possess an intellect eminently qualified to perceive latent existences and their relations, but his untimely death destroyed my hopes of help from that quarter.

In print works (calico), however, I found that the various tints which give beauty to the calico cloth are not produced by the direct imposition upon the cloth of a pigment or dye of the colour we see, but that these colours, as to far the largest number of them, are all contained or included in madder (or alizerine, an artificial madder, so to speak), just as violet, indigo, red, blue, orange, green and yellow are all contained in the white light of the sun; and that the cloth itself, previously prepared by what are called mordants, helps itself, so to speak, from this store of colour to the particular tint it wants.

Thus, for example, if the cloth is printed with a mordant consisting of acetate of iron, wherever the cloth has been saturated with this acetate, although it is perfectly colourless when put in, it will, when it emerges from the alizerine or madder, be either black or any shade of purple varying from very dark to pale, according to the strength of the acetate which was impressed upon the cloth.

Again, if other parts of the same piece of cloth are saturated with acetate of alumina, the colours which are absorbed by those parts so saturated vary from dark red to pale pink, according to the strength of the solution employed; whilst varieties of chocolate, puce, claret, lilac, &c., are obtained by a combination of the acetates of iron and alumina in varying proportions.

The cloth, after having been fully treated and its whole surface covered with these mordants, is still colourless when put into the bath of alizerine, and upon emerging from that bath will show all the colours which you see upon it in the drapers' shops; these mor

dants having from one fount of colour attracted to themselves all the varying tints which are shown upon it.

If chemistry can do so much to reveal invisible existences, then, it appeared to me, at least, to be a hopeful thing to do, to question chemistry in relation to those explosive gases: Could it be made by itself, or in relation with something else, either to develope a latent colour or to discharge, as chlorine will, some colour already given to the paper employed?

Another branch of the inquiry was, whether advantage could not be taken of its less weight to the common air to show its pre

sence.

The first experiment that suggested itself to my mind in this connection was, that as, in any given portion of a pit where this gas is present, it overlies the common air, that if a vertical recess were chased in the side of a passage or place in the pit, in the coal, and the front were glazed, leaving open the top and bottom, and if then a small balloon of collodion, like the children's toys which are seen in the street, were filled with the light carburetted hydrogen and put into these recesses, it would float upon the stratum of common air because filled with the lighter gas, but would remain at the bottom of the stratum of the gas because kept down by the weight of the envelope enclosing it.

The presence also of carbonic acid gas-which is heavier than common air-could be demonstrated by a similar ball filled with common air, which would float upon the carbonic acid gas and at the base of the stratum of common air, for similar reasons.

But there are in chemistry forces known as Exosmose and Endosmose (diffusion of gases) which would so soon establish an equilibrium between the surrounding medium and the gas or air contained, that the hope of thus indicating the presence and quantity of the gas dis appeared.

A delicate instrument has been invented, constructed on the principle of the diffusion of gases; but as this would require the application and careful observation of anybody using it, and as all it shows can be equally ascertained by watching the elongation of the flame in a safety-lamp, I pass it by.

A third avenue of investigation which I pursued was this: Can this gas be absorbed ?-that is to say, can any means be found of absorbing it, as it escapes from the coal, in some way analogous to the following: ordinary limestone is a crystallised carbonate of lime; if it is exposed to the action of fire in a kiln, it is made to give off first its carbonic acid, and then the water which holds the lime in the form of crystals; it is then quick-lime, and has so strong an affinity for hydrogen in the form of water, that fifty-six pounds of it will absorb from eighteen to twenty pounds of water, and still remain ea perfectly dry powder (hydrate of lime)? (Any addition to this

quantity of water reduces it to the form of putty, for plasterers and whitewashing.)

This eighteen or twenty pounds would represent a very large quantity (which I have not had time to work out) of gas. Now here, you see, we have a ready means of absorbing in this quick-lime a very large volume of gas, or its equivalent in water; and I thought it was well worth a little inquiry and investigation as to whether any treatment like this could be adopted in relation to the case which is the subject of our consideration.

Next I put the question: Supposing all these branches of inquiry to result unsatisfactorily, whether this gas should be loaded or neutralised in some manner that should render it non-explosive?

Some of these inquiries may seem, and no doubt are, very crude; but those who know most of chemistry will be least likely to deride even crude suggestions on this subject, since they, at least, know some of the marvellous transformations effected by it, and know also how the sum of human knowledge does but touch the fringe -fringe did I say?—the edge of the edge of the fringe of the vast unknown.

The next question I put to myself was: Can this gas be exploded in regulated quantities with safety?—that is to say, if naked lights were kept constantly burning in those parts of the pit where the gas was found to accumulate, could it be regularly fired in regulated quantities that would not do mischief? since the results of these explosions would be to convert the light carburetted hydrogen into carbonic acid, and water (setting free of course a large volume of nitrogen), which, being heavier than the common air, would follow the water-courses to the bottom of the pit shaft and be removed without difficulty.

This expedient might certainly be adopted with safety if we could be certain that this light carburetted hydrogen or methylic hydride exuded into the workings of the pit in a continuous and regular manner; but as we cannot be sure this is the case, and as, in some few instances at least, it is thought that the operations of the miner liberate a pent-up quantity of gas, it was necessary to regard this expedient as unavailable.

In all these directions I have for many years patiently, though blunderingly, endeavoured to find a solution of the problem before us, but have been continually baffled by my ignorance of chemistry; and my object in now referring to these hitherto abortive inquiries and investigations, is the hope that someone more qualified by technical and scientific knowledge may be induced to pursue these or analogous inquiries with better results, as, if we could only make fire-damp as visible to the eye and as obnoxious to the respiratory organs as was the London fog of last January, we should have gained a great point.

I cease to appeal to individual men of science for aid-they are all