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 fire-damp 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 fire-damp 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 fire-damp?" asked James Starr.
"Just there, sir," returned Ford, "and I was able to light it only by bringing my lamp near to the cracks in the rock.
Harry has done it as well as I."
"At what height?" asked Starr.
"Ten feet from the ground," replied Harry.
James Starr had seated himself on a rock. After critically inhaling the air of the cavern, he gazed at the two miners, almost as if doubting their words, decided as they were.
In fact, carburetted hydrogen is not completely scentless, and the engineer, whose sense of smell was very keen, was astonished that it had not revealed the presence of the explosive gas.
At any rate, if the gas had mingled at all with the surrounding air, it could only be in a very small stream. There was no danger of an explosion, and they might without fear open the safety lamp to try the experiment, just as the old miner had done before.
What troubled James Starr was, not lest too much gas mingled with the air, but lest there should be little or none.
"Could they have been mistaken?" he murmured. "No: these men know what they are about. And yet--"
