Apparently, judging from his expression, he was astonished that no hostile demonstration came from within. But the defenders had no wish to sacrifice life needlessly, and refrained from firing upon him. Suddenly he halted, and raising his voice, cried out in Spanish: "Will you foolish gringoes surrender and give up the gold peaceably, or must we attack the mine?" "Did Madero tell you to ask that?" shouted Pete through his peep-hole. "Yes; the general demanded that I should offer you this chance for your lives." "Then tell the general, with our compliments, that if he thinks he'll get Mr. Merrill's gold without a fight, he's up against the toughest proposition he ever tackled." "As you will, senors. Adios!" With a wave of his hat, the Mexican ran speedily back down the hillside, and dived into some bushes. The watchers of the stockade were of the opinion that the wave of the hat was merely a bit of Latin extravagance. They soon found out, however, that it had the significance of a signal. For, as the fellow dropped into cover, the grass became alive with human forms. Coyote Pete's finger, which had been trembling upon the trigger, pressed it. Bang! It was the first shot of the desperate battle for the defense of the mine, and the sound that had reached the two in the boiler house. The report was followed by a series 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.