e stopped. A dread vision filled his mind of Earth depopulated by the feebly ferocious Rogans, of rank on rank of Earth's vast armies falling in stricken rows at the shock of the Rogans' tubes.

Greca caught the vision. She nodded. "Yes, that is what would happen if they found ways of reaching your globe."

"But, God, Brand, we can't allow that!" cried Dex. "We've got to find a way to spike the guns of these walking gas-pipes, somehow!"

Brand sighed heavily. "We are two against hundreds of thousands. We are bare-handed, and the Rogans have those damned tubes. Anyway, we are on the verge of death at this very moment. What under heaven can we do to spike their guns?"

He was silent a moment: and in the silence the steady hum from the domed building outside came to his ears.

"What's in that big, round topped building, Greca?" he asked quietly.

"I do not know, exactly," replied the girl. "There is some sort of machinery in it, and to it go connecting beams from all the square metal plates everywhere. That is all I know."

Brand started to question her further, but her time was up. The two guards poked their loathsome pumpkin heads in the doorway and contemptuously beckoned her out. She answered resignedly, in the piping Rogan tongue, and went with them. But she turned to wave shyly, commiseratingly at the two men; and the expression in her clear blue eyes as they rested on Brand made his heart contract and then leap on with a mighty bound.

"We have in ally in her," murmured Brand. "Though God only knows if that will mean anything to us...."