ries of appalling yells from without the
stockade. Mexicans seemed to spring from every clump of grass and bit
of brush. It was amazing how they could have crept so close without
being detected.

"We can't last five minutes!" gasped Walt, as he gazed out. The lad
fired grimly into the advancing rush, however, and the others stood to
their guns like veterans. Their cheeks were blanched under the tan,
though, and the corners of their mouths tightened. Each one of those
defenders realized the practical hopelessness of their positions.

Suddenly, amid the besiegers' onrushing forms, appeared a figure
mounted upon a superb black horse. The animal curvetted and plunged as
the reports of the rifles of both sides rattled away furiously, but his
rider had him in perfect control.

"There's Ramon, the scoundrel!" roared Pete, gazing at the defiant
figure. "I'll give him a shot for luck."

But for once the plainsman's aim was at fault. The bullet evidently
did not even ruffle the former cattle rustler.

"Ledt me try!" puffed the German ferociously.

He fared no better.

"Bah! Und I thought I vos a goodt shot!" he exploded.

"It ain't that," rejoined Pete superstitiously. "The Mexicans say that
Ramon bears a charmed life, and that only a silver bullet will ever lay
him low."

Before the professor could make any comment Ramon was heard issuing
commands in a sharp voice. He seemed to have the direction of the
attack. Of Madero there was no sign, unless a small figure on a shaggy
pony, far to the rear, was that of the insurrecto leader.

The result of Ramon's command was soon evident. The attackers had not
been prepared for so sharp a defense, and, anxious to lose as few men
as possible, Ramon had ordered them to drop once more into the grass.

This was good strategy, as it was apparently only a matter of time
before the mine defenders would have to surrender, and it was little
use to sacrifice lives in a mad rush against their rifles.

The attack had splintered the stockade in a score of places, but,
thanks to the toughness of the seasoned wood, the bullets that had
penetrated had lost most of their strength. Beyond a few scratches
from flying splinters, none of the defenders were injured.

"What can they be up to?" wondered Pete, as half an hour passed and no
further sign came from the besiegers.

Ramon's figure had now vanished. Perhaps he realized that the fangs of
their enemies were by no means draw