Edward A. Martin

“ Sometimes in an unexpected moment there is a great dislodgement of coal, and a tremendous quantity of gas is set free, which may be sufficient to foul the passages for some distance around. The introduction or exposure of a naked light for even so much as a second is sufficient to cause explosion of the mass; doors are blown down, props and tubbing are charred up, and the volume of smoke, rushing up by the nearest shaft and overthrowing the engine-house and other structures at the mouth, conveys its own sad message to those at the surface, of the dreadful catastrophe that has happened below. ”

“ This is not yet eighty years ago, and amongst the many wonderful things which have sprung up during the present century, perhaps we may place in the foremost rank for actual utility, the gas extracted from coal, conveyed as it is through miles upon miles of underground pipes into the very homes of the people, and constituting now almost as much a necessity of a comfortable existence as water itself. ”

“ And when we consider the thicknesses of sandstone and shale which intervene beneath the coal-seams, we can realise to a certain extent the vast lapses of years which must have taken place between the existence of each forest; so that although now an individual passing up a coal-mine shaft may rapidly pass through the remains of one forest after another, the rise of the strata above each forest-bed then was tremendously slow, and the period between the growth of each forest must represent the passing away of countless ages. ”

“ We can scarcely, therefore, expect that the vegetable world had made any great advance in complexity of organism at this time, otherwise the supplies of graphite or plumbago which are found in the formation, would be attributed to dense forest growths, acted upon, after death, in a similar manner to that which awaited the vegetation which, ages after, went to form beds of coal. At present we know of no source of carbon except through the intervention and the chemical action of plants. Like iron, carbon is seldom found on the earth except in combination. ”

“ Everybody has doubtless noticed that, when a stagnant pool which contains a good deal of decaying vegetation is stirred, bubbles of gas rise to the surface from the mud below. This gas is known as marsh-gas, or light carburetted hydrogen, and gives rise to the ignis fatuus which hovers about marshy land, and which is said to lure the weary traveller to his doom. The vegetable mud is here undergoing rapid decomposition, as there is nothing to stay its progress, and no superposed load of strata confining its resulting products within itself. ”

“ It took many years before those interested in mines came thoroughly to understand how properly to secure ventilation, and in bygone days the system was so thoroughly bad that a tremendous amount of sickness prevailed amongst the miners, owing to the poisonous effects of breathing the same air over and over again, charged, as it was, with more or less of the gases given off by the coal itself. Now, those miners who do so great a part in furnishing the means of warming our houses in winter, have the best contrivances which can be devised to furnish them with an ever-flowing current of fresh air. ”

“ When the river enters a large body of water, such as the ocean or a lake, in losing its individuality, it loses also the velocity of its current, and the silt tends to sink down to the bottom. But being less heavy than the sand, about which we have previously spoken, it does not sink all at once, but partly with the impetus it has gained, and partly on account of the very slight velocity which the current still retains, even after having entered the sea, it will be carried out some distance, and will the more gradually sink to the bottom. ”

“ In the whole realm of natural history, in the widest sense of the term, there is nothing which could be cited which has so benefited, so interested, I might almost say, so excited mankind, as have the wonderful discoveries of the various products distilled from gas-tar, itself a distillate of coal.
Coal touches the interests of the botanist, the geologist, and the physicist ”

“ Great Britain has long been the centre of the universe in the supply of the world's coal, and as a matter of fact, has been for many years raising considerably more than one half of the total amount of coal raised throughout the whole world. There is, as we have seen, an abundance of coal elsewhere, which will, in the course of time, compete with her when properly worked, but Britain seems to have early taken the lead in the production of coal, and to have become the great universal coal distributor. ”

“ Just as some of the animals known popularly as the zoophytes, which are attached during life to rocks beneath the sea, are fed by means of currents of water which bring their food to them, so the leaves, which inhale carbon-food during the day through their under-surfaces, are provided with it by means of the currents of air which are always circulating around them; and while the fuel is being taken in beneath, the heat and light are being received from above, and the sun supplies the motive power to digestion. ”

“ Evaporation by the sun was at one time the sole means of obtaining salt from seawater; now coal is used to boil the salt pans and to purify the brine from the salt-mines in the triassic strata of Cheshire. The extent to which gas is used for illuminating purposes reminds us of another important product obtained from coal. Paraffin oil and petroleum we obtain from coal, whilst candles, oils, dyes, lubricants, and many other useful articles go to attest the importance of the underground stores of that mineral which has well and deservedly been termed the "black diamond." ”

“ From processes, therefore, which are to be seen going on around us, it is easily possible to satisfy ourselves that vegetation will in the long run undergo such changes as will result in the formation of coal.
There are certain parts in most countries, and particularly in Ireland, where masses of vegetation have undergone a still further stage in metamorphism, namely, in the well-known and famous peat-bogs. Ireland is par excellence the land of bogs, some three millions of acres being said to be covered by them, and they yield an almost inexhaustible supply of peat. ”

“ For a town it really is. The various roads and passages which are cut through the solid coal as excavation of a coal-mine proceeds, represent to a stranger all the intricacies of a well-planned town. Nor is the extent of these underground towns a thing to be despised. There is an old pit near Newcastle which contains not less than fifty miles of passages. Other pits there are whose main thoroughfares in a direct line are not less than four or five miles in length, and this, it must be borne in mind, is the result of excavation wrought by human hands and human labour. ”

“ Gas is an institution of the utmost value to the artisan; it requires hardly any attention, is supplied upon regulated terms, and gives, with what should be a cheerful light, a genial warmth, which often saves the lighting of a fire. ”

“ The cloud which, under certain atmospheric conditions, rests like a pall over our great cities, will not even permit at times of a single ray of sunshine permeating it. No one knows whence it rises, nor at what hour to expect it. ”

“ Should such a thing at any time actually come to pass, it will indeed be a retribution to those who have for years been squandering their inheritance in many a wasteful manner of coal-consumption.
Thirty years ago, when so much small coal was wasted and wantonly consumed in order to dispose of it in the easiest manner possible at the pitmouths, and when only the best and largest coal was deemed to be of any value, louder and louder did scientific men speak in protest against this great and increasing prodigality. ”

“ CHAPTER VI. HOW GAS IS MADE—ILLUMINATING OILS AND BYE-PRODUCTS. Accustomed as we are at the present day to see street after street of well-lighted thoroughfares, brilliantly illuminated by gas-lamps maintained by public authority, we can scarcely appreciate the fact that the use of gas is, comparatively speaking, of but recent growth, and that, like the use of coal itself, it has not yet existed a century in public favour. Valuable as coal is in very many different ways, perhaps next in value to its actual use as fuel, ranks the use of the immediate product of its distillation—viz., gas ”

“ It is assumed that it is, within the knowledge of all that, for the origin of the various seams and beds of coaly combinations which exist in the earth's crust, we must look to the vegetable world. If, however, we could go so far back in the world's history as the period when our incandescent orb had only just severed connection with a gradually-diminishing sun, we should probably find the carbon there, but locked up in the bonds of chemical affinities with other elements, and existing therewith in a gaseous condition. ”

“ It will be seen at once how that, in sinking a new shaft into a coal-seam, the possibility of an unknown fault has to be brought into consideration, since the position of the seam may prove to have been depressed to such an extent as to cause it to be beyond workable depth. Many seams, on the other hand, which would have remained altogether out of reach of mining operations, have been brought within workable depth by a series of step-faults, this being a term applied to a series of parallel faults, in none of which the amount of down-throw is great. ”

“ The formation of shales will now demand our attention. When a river is carrying down with it a quantity of mud or clay, it is transported as a fine, dusty silt, and when present in quantities, gives the muddy tint to the water which is so noticeable. We can very well see how that silt will be carried down in greater quantities than sand, since nearly all rivers in some part of their course will travel through a clayey district, and finely-divided clay, being of a very light nature, will be carried forward whenever a river passes over such a district. ”

“ The last great danger to which we have here to make reference, is the explosive action of a quantity of coal-dust in a dry condition. It is only now commencing to be fully recognised that this is really a most dangerous explosive. As we have seen, large quantities of coal are formed almost exclusively of lepidodendron spores, and such coal is productive of a great quantity of dust. Explosions which are always more or less attributable to the effects of coal-dust are generally considered, in the official statistics, to have been caused by fire-damp. ”

“ The process is of course the same in a fire-grate, only that here more complete combustion of the wood takes place, owing to its being intimately exposed to the action of the flames. If we adopt the same experiment with some pieces of coal, the action is similar, only that in this case the quantity of gases given off is not so great, coal containing a greater proportion of carbon than wood, owing to the fact that, during its long burial in the bowels of the earth, it has been acted upon in such a way as to lose a great part of its volatile constituents. ”

“ Peat-bogs have in no way ceased to be formed, for at their surfaces the peat-moss grows afresh every year; and rushes, horse-tails, and reeds of all descriptions grow and thrive each year upon the ruins of their ancestors. The formation of such accumulations of decaying vegetation would only be possible where the physical conditions of the country allowed of an abundant rainfall, and depressions in the surface of the land to retain the moisture. ”

“ Caking coal and the varieties of coal which exist between it and anthracite, are familiar to every householder; the more it approaches the composition of the latter the more difficult it is to get it to burn, but when at last fairly alight it gives out great heat, and what is more important, a less quantity of volatile constituents in the shape of gas, smoke, ammonia, ash and sulphurous acid. For this reason it has been proposed to compel consumers to adopt anthracite as the domestic coal by Act of Parliament. ”

“ Yet the smoke itself, including as it does all the many impurities which exist in coal, is not only evil in itself, but is evil in its influences. Dr Siemens has said:—"It has been shown that the fine dust resulting from the imperfect combustion of coal was mainly instrumental in the formation of fog; each particle of solid matter attracting to itself aqueous vapour. These globules of fog were rendered particularly tenacious and disagreeable by the presence of tar vapour, another result of imperfect combustion of raw fuel, which might be turned to better account at the dyeworks. ”