The Child of the Cavern, Jules Verne [diy ebook reader .txt] 📗

done? Harry had once or twice observed something remarkable in his excursions to the west end of the mine. Fire, which suddenly went out, sometimes appeared along the face of the rock or on the embankment of the further galleries. How those flames were lighted, I could not and cannot say. But they were evidently owing to the presence of firedamp, and to me firedamp means a vein of coal.”

“Did not these fires cause any explosion?” asked the engineer quickly.

“Yes, little partial explosions,” replied Ford, “such as I used to cause myself when I wished to ascertain the presence of firedamp. Do you remember how formerly it was the custom to try to prevent explosions before our good genius, Humphry Davy, invented his safety-lamp?”

“Yes,” replied James Starr. “You mean what the ‘monk,’ as the men called him, used to do. But I have never seen him in the exercise of his duty.”

“Indeed, Mr. Starr, you are too young, in spite of your five-and-fifty years, to have seen that. But I, ten years older, often saw the last ‘monk’ working in the mine. He was called so because he wore a long robe like a monk. His proper name was the ‘fireman.’ At that time there was no other means of destroying the bad gas but by dispersing it in little explosions, before its buoyancy had collected it in too great quantities in the heights of the galleries. The monk, as we called him, with his face masked, his head muffled up, all his body tightly wrapped in a thick felt cloak, crawled along the ground. He could breathe down there, when the air was pure; and with his right hand he waved above his head a blazing torch. When the firedamp had accumulated in the air, so as to form a detonating mixture, the explosion occurred without being fatal, and, by often renewing this operation, catastrophes were prevented. Sometimes the ‘monk’ was injured or killed in his work, then another took his place. This was done in all mines until the Davy lamp was universally adopted. But I knew the plan, and by its means I discovered the presence of firedamp and consequently that of a new seam of coal in the Dochart pit.”

All that the old overman had related of the so-called “monk” or “fireman” was perfectly true. The air in the galleries of mines was formerly always purified in the way described.

Firedamp, marsh-gas, or carburetted hydrogen, is colorless, almost scentless; it burns with a blue flame, and makes respiration impossible. The miner could not live in a place filled with this injurious gas, any more than one could live in a gasometer full of common gas. Moreover, firedamp, as well as the latter, a mixture of inflammable gases, forms a detonating mixture as soon as the air unites with it in a proportion of eight, and perhaps even five to the hundred. When this mixture is lighted by any cause, there is an explosion, almost always followed by a frightful catastrophe.

As they walked on, Simon Ford told the engineer all that he had done to attain his object; how he was sure that the escape of firedamp took place at the very end of the farthest gallery in its western part, because he had provoked small and partial explosions, or rather little flames, enough to show the nature of the gas, which escaped in a small jet, but with a continuous flow.

An hour after leaving the cottage, James Starr and his two companions had gone a distance of four miles. The engineer, urged by anxiety and hope, walked on without noticing the length of the way. He pondered over all that the old miner had told him, and mentally weighed all the arguments which the latter had given in support of his belief. He agreed with him in thinking that the continued emission of carburetted hydrogen certainly showed the existence of a new coal-seam. If it had been merely a sort of pocket, full of gas, as it is sometimes found amongst the rock, it would soon have been empty, and the phenomenon have ceased. But far from that. According to Simon Ford, the firedamp escaped incessantly, and from that fact the existence of an important vein might be considered certain. Consequently, the riches of the Dochart pit were not entirely exhausted. The chief question now was, whether this was merely a vein which would yield comparatively little, or a bed occupying a large extent.

Harry, who preceded his father and the engineer, stopped.

“Here we are!” exclaimed the old miner. “At last, thank Heaven! you are here, Mr. Starr, and we shall soon know.” The old overman’s voice trembled slightly.

“Be calm, my man!” said the engineer. “I am as excited as you are, but we must not lose time.”

The gallery at this end of the pit widened into a sort of dark cave. No shaft had been pierced in this part, and the gallery, bored into the bowels of the earth, had no direct communication with the surface of the earth.

James Starr, with intense interest, examined the place in which they were standing. On the walls of the cavern the marks of the pick could still be seen, and even holes in which the rock had been blasted, near the termination of the working. The schist was excessively hard, and it had not been necessary to bank up the end of the tunnel where the works had come to an end. There the vein had failed, between the schist and the tertiary sandstone. From this very place had been extracted the last piece of coal from the Dochart pit.

“We must attack the dyke,” said Ford, raising his pick; “for at the other side of the break, at more or less depth, we shall assuredly find the vein, the existence of which I assert.”

“And was it on the surface of these rocks that you found out the firedamp?” asked James Starr.

“Just there, sir,” returned Ford, “and I was able to light it