Coal and Coal-Gas

"I F I should take it into my head," Uncle Paul resumed, "to begin my talk to-day in some such fashion as this, 'Once upon a time there lived a king and a queen,' and if I introduced into my fanciful tale a wicked ogre greedy for human flesh and a good fairy borne over the surface of the sea in a mother-of-pearl shell drawn by red fishes, I am firmly convinced that your attention would at once be riveted to my account of the deeds done by king and ogre and fairy, so that you would give me no peace until the story was finished.

"Now, real things can offer to your curiosity food that is just as wonderful and that, moreover, feeds the mind with useful knowledge. Coal, the history of which I sketched in outline at our last talk, is one example among a thousand."

"It is very true, Uncle," said Marie, "that Cinderella or Bluebeard never interested me as does the story you began to tell us about coal. Those little islands that afterward became France by changes in the ocean-bed, those ancient forests which man has never seen, but which to-day he finds transformed into coal deep down in the earth, those upheavals in the surface of the earth, turning everything topsy-turvy, all excite in me the liveliest interest, and I should very much like to hear more about them."

"Let us talk a little more, then, about coal. But what could I select humbler in appearance and less worthy of your attention than that black stone? Nevertheless there are some most astonishing things to be said about it. First of all, coal—black, dirty, with no claim to distinction in its aspect—is own brother to the diamond, the sumptuous gem that for brilliance has no equal in all the world. The diamond is made of carbon, and so is coal—the very same substance in both."

"The diamond made of carbon?" cried Claire, incredulously.

"Yes, my child, of carbon and nothing else."

"But—"

"There are no buts. Again I say the diamond is made of carbon, but in a perfectly pure and crystalline form, which explains its transparency and brilliance. I told you that coal had things to tell us of a most marvelous nature."

"I see now that it has," assented Claire.

"Furthermore, this piece of black stone traces its origin to remote ages when it made part of some elegant tree such as you will nowhere find at present unless perhaps in some tropical region enjoying an abundance of heat and moisture."

"Then it must have come from one of those ancient forests you told us about yesterday," said Emile.

"Yes, and I can prove it to you. As a rule coal occurs in shapeless masses which furnish no indication of their origin; but not infrequently there are found, in the cleavage between two layers, distinct traces of carbonized vegetable matter having perfectly recognizable outlines. Certain coal-beds are formed entirely of leaves heaped up and pressed together into a solid block, and still preserving, despite their conversion into coal, all the details of their delicate structure. These relics of a plant life as old as the world, wonderful archives which tell us the earth's history, are so well preserved that they enable us to recognize the carbonized plants with the same certainty we feel in recognizing living plants. Yesterday, while our winter supply of coal was being put in, I chanced to notice in the bin some of those venerable relics I have just been speaking about, and I put them aside to show to you. Here they are."

"Oh, what beautiful leaves!" exclaimed Marie. "How nicely they are attached to the black surface underneath! One would say they had been cut out of very thin sheets of coal." She stood lost in thought before these remains of forests so extremely old as to antedate all animal life.

"When the plant life was flourishing which you see represented here," went on Uncle Paul, "the earth was covered with a vigorous growth of vegetation unexampled in our own time. This vegetation, buried far underground by changes in the earth's surface, and carbonized in the course of a long series of centuries, has become transformed into enormous masses of coal which constitute the soul, so to speak, of modern industry. For it is coal that moves the railway locomotive, with its line of heavy cars; it is coal that feeds the furnaces of factories; it is coal that enables the steamboat to brave wind and storm; and it is coal that makes it possible for us to work the various metals and manufacture our tools and instruments, our cloth and pottery, our glassware and all the infinite variety of objects necessary to our welfare. Are you not filled with wonder, my children, as I am, that long before man's appearance upon earth everything was prepared for his reception and for providing him with the things essential to his future industry, his activity, his intelligence? Are you not impressed by this vegetation of prehistoric times which stored up in the bowels of the earth those precious deposits of coal that to-day are brought to light and made to move our machines and become one of the most active agents of civilization?"

"From now on," replied Marie, "whenever I put a shovelful of coal on to the fire, I shall think of that ancient plant life which gave us this fuel."

"Nor is the whole story of coal told yet," Uncle Paul went on. "Besides heat, coal gives us light. Cities are illuminated by street lamps which burn no oil and have no wick, but emit a simple jet of gas which, on being ignited, produces a magnificent white flame. This gas is obtained by heating coal red-hot in great air-tight ovens. Pipes laid under ground conduct the gas from the gas-works to all parts of the city and distribute it to the street lamps. At nightfall the burner is opened and the gas flows, taking fire at a little hand-lantern with exposed wick, whereupon the flame bursts forth.

"What remains in the ovens after the manufacture of illuminating gas is a modification of coal known as coke, an iron-gray substance with a dull metallic luster. Coke develops much more heat than the best wood-charcoal, but is difficult of combustion and in order to burn well must be heaped up in considerable quantity and have a good draft. For domestic heating it is used in stoves and, still oftener, in grates. It is superior to coal in giving forth no smoke, thus being cleaner.

"Together with gas there is produced in the ovens in which coal is heated a black and sticky substance called coal-tar. From this horrible pitch, which one cannot touch without soiling one's hands, modern invention knows how to extract something in the highest degree fresh and beautiful and fair to look upon. As we have seen, the splendid colors of our silks and cottons, the rich and varied tints of our ribbons—all these we owe to dyestuffs obtained from coal-tar. Common coal, therefore, far from impressive though it is in appearance, is linked with the most dazzling splendors this world can produce: on the one hand with the diamond, with which it is one in essence, and on the other with the flowers of the field, whose delicate coloring it imitates and even surpasses."