"It is possible," replied Edwards, "but it will probably put us out of commission altogether."

"In any case," put in Erickson, "we will be rid of this damnable shield, and can communicate with our companions."

It certainly was the only plan, for, as soon as the pirates had repaired their ship, another unequal battle would be waged, with the result very little in doubt.

All hands set to work completing repairs on the main stern tubes, the only ones necessary to drive the San Francisco forward. In less than three hours, Edwards pronounced the work done to his satisfaction.

As the light began to creep in toward the base of the cliff, the huge ship rose slightly off the ground, the tubes glowed red and, guided by a powerful searchlight installed on the bow, Edwards pointed his craft toward the gleaming metal patch that marked the position of the pirate cave.

At short range, Holden, Linet, and Erickson opened with the three hexoxen guns. They saw the bursts take effect on the metal. Edwards turned the power on full, and they felt the floor leaping under them. Would the bow of the San Francisco hold? Would they all be crushed to death at the impact? Another moment would tell. Holden saw the metal plates dead ahead, could distinguish the seams marking the air-lock.

He fired one final shot, and flung himself to the floor of the pilot room, endeavoring to find some means of bracing himself for the shock. Then it came! Torn from his position, he saw the plates buckling and heaving about him. The lights went out. A great crash sounded in his ears, and everything went black. In a moment he regained consciousness, and staggered to his feet, bruised and dizzy. Thank God, his space suit had not been harmed! A faint glow from the outside made things visible and he saw that the shock had torn a huge piece out of the plating of the pilot room.

A hand clutched his elbow, and through the phone in his space suit he heard Linet's voice.

"Erickson and Edwards are knocked out. Let's see what we did to these chaps here."