y
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--"

He waited, not without some anxiety, until Simon Ford's phenomenon
should have taken place. But just then it seemed that Harry, like
himself, had remarked the absence of the characteristic odor of
fire-damp; for he exclaimed in an altered voice, "Father, I should say
the gas was no longer escaping through the cracks!"

"No longer!" cried the old miner--and, pressing his lips tight together,
he snuffed the air several times.

Then, all at once, with a sudden movement, "Hand me your lamp, Harry,"
he said.

Ford took the lamp with a trembling hand. He drew off the wire gauze
case which surrounded the wick, and the flame burne