to Rio Janeiro, caught the cholera, and died there. Undaunted by the
epidemic, Frawley took the next boat and entered the stricken city by
swimming ashore. For a week he searched the hospitals and the
cemeteries. Greenfield had indeed been stricken, but, escaping with his
life, had left for the northern part of Brazil. The delay resulted in a
gain of three months for Frawley, but without heat or excitement he
began anew the pursuit, passing up the coast to Para and the mouth of
the Amazon, by Bogota and Panama into Mexico, on up toward the border
of Texas. The months between him and Greenfield shortened to weeks, then
to days without troubling his equanimity. At El Paso he arrived a few
hours after Greenfield had left, going toward the Salt Basin and the
Guadalupe Mountains. Frawley took horses and a guide and followed to the
edge of the desert. At three o'clock in the afternoon a horseman grew
out of the horizon, a figure that remained stationary and attentive,
studying his approach through a spy-glass. Suddenly, as though
satisfied, the stranger took off his hat and waved it above his head in
challenge, and digging his heels into his horse, disappeared into the
desert.

VI

Frawley understood the challenge--the end was to be in the desert.
Failing to move his guide by threat or promise, he left him clamoring
frantically on the edge of the desert and rode on toward where the
figure of Greenfield had disappeared on the horizon in a puff of dust.

For three days they went their way grimly into the parched sands,
husbanding every particle of strength, within plain sight of each other,
always at the same unvarying walk. At night they slept by fits and
starts, with an ear trained for the slightest hostile sound. Then they
cast aside their saddles, their rifles, and superfluous clothing, in a
vain effort to save their mounts.

The horses, heaving and staggering, crawled over the yielding sands
like silhouettes drawn by a thread. In the sky not a cloud appeared;
below, the yellow monotony extended as flat as a dish. Above them a lazy
buzzard, wheeling in languid circles, followed with patient conviction.

On the fourth morning Frawley's horse stopped, shuddered, and went down
in a heap. Greenfield halted and surveyed his discomfiture grimly,
without a sign of elation.

"That's bad, very bad," Frawley said judicially. "I ought to have sent
word to the department. Still, it's not over yet--his horse won't last
l