* * * * *

Ten minutes later he was there, and off to the side he found the marks
of their scuffle--and small black blotches that could be nothing but
blood. The other was wounded: could probably not get far. But he might
still have his gun, so Phil kept his rifle handy, and tempered his
impatience with caution as he set out on the trail of the widely
spaced footprints.

They led off towards the nearby hills, and in the bright moonlight
Phil did not use his flashlight at all, except to investigate other
round black blotches that made a line parallel to the prints. As he
went on he found his quarry's steps coming more closely together:
becoming erratic. Soon they showed as painful drags in the sand, a
laborious hauling of one foot after the other.... Phil put away his
light and advanced very cautiously.

He wondered, as he went, who in the devil was behind it all. The
radium-finding project had been kept strictly secret. Not another soul
was supposed to know of the earth-borer and its daring mission into
the heart of the earth. Yet, obviously, someone had found out, and
whoever it was had laid at least part of his scheme cunningly. An old
man and a girl cannot offer much resistance: he, Phil, would have been
well taken care of had it not been for the water jug. So far, there
were at least two in the plot: the man who had ambushed him and the
unknown who had evidently kidnapped both Professor and Sue Guinness.
But there might be still more.

There might be friends, nearby, of the man he was tracking. The fellow
might have reached them, and warned them that the scheme hadn't gone
through, that Phil was loose. They could very easily conceal
themselves alongside their partner's tracks and train their rifles on
the tracker....

The trail was leading up into one of the canons in the cluster of
hills to the west. For some distance he followed it up through a slash
of black below the steep moonlit heights of the hills to each
side--and then, suddenly, he vaguely made out the forms of two huts
just ahead.

Immediately he stooped low, and went skirting widely off up one side.
He proceeded slowly, with great caution, his rifle at the ready. At
any moment, he knew, the hush might be split by the cracks of
waylaying guns. Warily he advanced along the narrow canyon wall above
the huts. No lights were lit, and the place seemed unoccupied. He was
debating what to do next when his attention was att