"We can't risk making for it now!" cried the other. "We've got to keep clear of them until the alarm is over. Hear them now?" For even as they leaped forward a rising clamor of hissing cries and rush of feet was coming from behind as scores of Martians poured out into the darkness from the great cone-building. The two fugitives had passed by then from the shadow of the mighty structure, and as they ran along the broad metal street toward the shadow of the next cone, through the light of the moons above, they heard higher cries and then glimpsed narrow shafts of crimson force cleaving the night around them. * * * * * Randall, as the deadly rays drove past him, heard the low detonating sound made by their destruction of the air in their path, and the inrush of new air. But in the misty and uncertain moonlight the rays could not be loosed accurately, and before they could be swept sidewise to annihilate the two fleeing men they had gained, with a last great leap, the shadow of the next building. On they ran, the clatter of the Martian pursuit growing more noisy behind them. Randall heard Lanier gasping with each great leap, and felt himself at every breath a knife of pain stabbing through his lungs, the rarified atmosphere of the red planet taking its toll. Again from the darkness behind them the crimson rays clove, but this time were wide of their mark. With every moment the clamor of pursuit seemed growing louder, the alarm spreading out over the Martian city and arousing it. As they raced past cone after cone, Randall knew even the increased power of their muscles could not long aid them against the exhaustion which the thin air was imposing on them. His thoughts spun for a moment to Milton, in the laboratory behind, and then back to their own desperate plight. Abruptly shapes loomed in the misty light before them! A group of three great Martians, reptilian shapes that had been coming toward them and had stopped for an instant in amazement at sight of the running pair. There was no time to halt themselves, to evade the three, and with a mutual instinct Lanier and Randall seized together the last expedient open to them. They ran straight forward toward the astounded three, and when a half-score feet from them, leaped with all their force upward and toward them, their tensed bodies flying through the air with feet outstretched before them. Then they had struck the group of three with feet-foremost, and with the impetus of that great leap had knocked them sprawling to this side and that, while with a supreme effort the two kept their balance and leaped on. The cries of the three added to the din behind them as they threw themselves forward. * * * * *