The mechanical ears of the metal things may have picked up the sound of his voice: but in any event, green flame flashed about them on the instant. Feeling a sudden protective impulse, Dan started toward Helen. That was his last recollection, before what seemed a terrific concussion swept him into the abyss of unconsciousness....
is first thought, when he awakened, was of the girl. But he was alone in the silence of the canyon. He sat up, realizing that many hours had passed, for the air was growing cool again, and the sun was low behind the peak at the head of the ravine. The huge, mysterious machine of the purple ring and the vibrating white needle were blazing splendidly.
He took more detailed stock of his immediate surroundings. The tangle of brush that had sheltered them had been cut away by the green annihilating ray. Charred stumps remained to show where it had fired bushes beyond the trail. His own shoulder was blistered, a hole was burned in the sheet wound about him, and the hair was singed from the back of his head.
Suddenly trembling with horror, he looked about for anything to show that Helen had perished by the ray. Discovering nothing, he breathed a sigh of relief.
"She must be still alive, anyhow," he muttered. "And I've had another lucky break! The ray was too high to get me. They must have left me for dead."
Presently he became conscious of torturing thirst. He retired through the brush, along the rocky wall of the canyon. By sunset he came upon a little natural basin in a rock, half full of rain water. It was none too clean, but he drank his fill of it, and felt relief.
Looking up the canyon, he could see the great mechanism on the peak, gleaming in the dusk. Intensely-glowing purple mist clung about the great metal ring, and the slender, delicate needle swung below it, still vibrating, still throbbing with brilliant, white radiance. It pointed at the red eye of Mars, which had just winked into view.
Dan stared at it a long time.