taking collision with the upjerking head of the
mustang. When he had recovered his feet and his presence of mind, the
charging whirlwind had dashed through the shallows of the Pannikin, and
a riderless horse was clattering across the tracks in the railroad yard.

The Mexican waited prudently to see what the camp would say to the
single shot. It said nothing; it might have been deserted for all the
indications there were of life in it. Ruiz Gregorio snapped the empty
shell from his weapon, replacing it with a loaded one, and mounted and
rode slowly through the ford. The riderless horse disappearing across
the tracks gave him good hope that the hasty shot had accomplished all
that a deliberate one might have.

There was no dead man tumbled in a heap in the railroad yard, as he had
hoped to find. Silence, the silence of desertion, brooded over the
masthead arcs. Painfully the Mexican searched, at the verge of the
river, in the black shadows cast by the crowding material cars. Finally
he crossed over to the straggling street of the camp, walking now and
leading the spent mustang. Silence here, too, broken only by the
sputtering sizzle of the electrics. The huge mess tent was dark; there
were no lights, save in the closed commissary and in the president's
car: no lights, and not a man of the camp's crowding labor army to be
seen.

At a less strenuous moment the man-killer would have been puzzled by the
unusual stillness and the air of desertion. As it was, he was alertly
probing the far-flung shadows. The engineer, if only wounded, would
doubtless try to hide in the shadows in the railroad yard.

The Mexican left his horse in the camp street and made an instant search
between and under the material cars, coming out now and again to stare
suspiciously at the president's private car, standing alone on the
siding directly opposite the commissary. The Nadia was occupied. It was
lighted within, and the window shades were drawn down. Ruiz Gregorio
could never get far from the lighted car without being irresistibly
drawn back to it, and finally he darted back in time to see a man rise
up out of the shadow of the nearest box-car, spring to the platform of
the Nadia and kick lustily at the locked door. The door was opened
immediately by some one within, and the fugitive plunged to cover--but
not before the Mexican's revolver had barked five times with the rapid
staccato of a machine gun.

When Ruiz Gregorio, dropping the smoking