e caught the fugitive by the arm and
dragged him back.

"Wait!" he commanded. "We must first carry the levels down to the
tunnel site. You hear that? Stick by me, and I'll pull you through.
Try to run, and, by God, I'll shoot you like a dog!"

The captive glared into the steel-white eyes of the engineer, anger
overcoming his panicky fear.

"Let go!" he panted. "Don't worry! I'll do my work--I'll do my work!"

"If you don't, you'll never get out of this canyon," grimly rejoined
Blake. He released his hold, and started up the slope, with a curt
order: "Come along. We can rod down the slope."

Ashton followed him, silent and morose. The instrument was screwed to
its tripod, and a line of levels from the foot of the last vertical
measurement was carried down the slope to the canyon. The last rod
reading was on a ledge, three feet above the water, at the corner of
the gorge. Blake considered the reading worthy of permanent record.
They had measured all the many hundreds of feet down from the top of
High Mesa to these profound depths. With his two-pound hammer and one
of the few remaining spikes, he chiseled a cross deep in the surface
of the black rock.

That mark of the engineer-captain, scouting before the van of man's
Nature-conquering army, was the sign of the first human beings that
had ever descended alive to the bottom of Deep Canyon.

When he had cut the cross, Blake took out his Colt's, and, gazing up
the heights, began to fire at slow intervals. Confined between the
walls of gorge and canyon, each report of the heavy revolver crashed
out above the tumult of the river and ran echoing and reechoing up the
stupendous precipices. Yet long before they reached the rim of those
towering walls they blurred away and merged and were lost in the
ceaseless reverberations of the waters.

Blake well knew that this would happen. But he also knew that the
flash of the shot would be distinctly discernible in the gloom of the
abyss. As he fired, he scanned the verge of the uppermost precipices.
After the fourth shot he ceased firing and flung up his hand to point
at the heights.

"Look!" he shouted. "They see! There is the flag!"

Ashton stared up with wide, feverish eyes. From an out-jutting point
of rock on the lofty rim he saw a tiny white dot waving to and fro
against the blue-black sky. The watchers above had seen the flash of
the revolver shots and were fluttering the white flag in responsive
signal. Though on the