David
Guinness had designed. Its protecting insulation proved quite
inadequate, and the heat rapidly grew terrific as the borer dug down.
Phil became faint, stifled, and his body oozed streams of sweat. And
the descent was also bumpy and uneven; often he was forced to leave
the controls and work on the mechanism of the disintegrators when they
faltered and threatened to stop. But in spite of everything the needle
on the depth gauge gradually swung over to three thousand, and four,
and five....

After the first mile Holmes improvised a way to change the air more
rapidly, and it grew a little cooler. He watched the story the depth
gauge told with narrowed eyes, and, as it reached three miles,
inspected his rifle. At three and a half miles he stopped the borer,
thinking to try to hear the noise made by the other, but so paralyzed
were his ear-drums from the terrific thunder beneath, it seemed hardly
any quieter when it ceased.

His plans were vague; they would have to be made according to the
conditions he found. There was a coil of rope in the tube-like
interior of the borer, and he hoped to find a cavern or cleft in the
earth for lateral exploring. He would stop at a depth of four
miles--where he should be very near the path of the professor's
sphere.

But Phil never saw the needle on the gauge rise to four miles. At
three and three quarters came sudden catastrophe.

He knew only that there was an awful moment of utter helplessness,
when the borer swooped wildly downwards, and the floor was snatched
sickeningly from under him. He was thrown violently against the
instrument panel; then up toward the pointed top; and at the same
instant came a rending crash that drove his senses from him....

CHAPTER III

"_You Haven't the Guts_"

"Just as I thought," said James Quade in the silence that fell when
the last echoes had died away, and the splinters of steel and rock had
settled. "You see, Professor, this earth-borer belongs to me. Yes, I
built one too. But I couldn't, unfortunately, get it working
properly--that is, in time to get down here first. After all, I'm not
a scientist, and remembered little enough of your borer's plans....
It's probably young Holmes who's dropped in on us. Shall we see?"

David Guinness and his daughter were speechless with dread. Quade had
trained the searchlight on the borer, and by turning their heads they
could see it plainly. It was all too clear that the machine was a
total wreck