"Oh!" nodded the captain. "Her heart!"
"Never mind that. When I scrambled up, that particular image was gone, and Tweel was in a twist of black ropey arms, just as when I first saw him. He'd missed a vital point in the beast's anatomy, but was jabbing away desperately with his beak.
"Somehow, the spell had lifted, or partially lifted. I wasn't five feet from Tweel, and it took a terrific struggle, but I managed to raise my revolver and put a Boland shell into the beast. Out came a spurt of horrible black corruption, drenching Tweel and me—and I guess the sickening smell of it helped to destroy the illusion of that valley of beauty. Anyway, we managed to get Leroy away from the devil that had him, and the three of us staggered to the ridge and over. I had presence of mind enough to raise my camera over the crest and take a shot of the valley, but I'll bet it shows nothing but gray waste and writhing horrors. What we saw was with our minds, not our eyes."
Jarvis paused and shuddered. "The brute half poisoned Leroy," he continued. "We dragged ourselves back to the auxiliary, called you, and did what we could to treat ourselves. Leroy took a long dose of the cognac that we had with us; we didn't dare try anything of Tweel's because his metabolism is so different from ours that what cured him might kill us. But the cognac seemed to work, and so, after I'd done one other thing I wanted to do, we came back here—and that's all."
"All, is it?" queried Harrison. "So you've solved all the mysteries of Mars, eh?"
"Not by a damned sight!" retorted Jarvis. "Plenty of unanswered questions are left."
"Ja!" snapped Putz. "Der evaporation—dot iss shtopped how?"
"In the canals? I wondered about that, too; in those thousands of miles, and against this low air-pressure, you'd think they'd lose a lot. But the answer's simple; they float a skin of oil on the water."
Putz nodded, but Harrison cut in. "Here's a puzzler. With only coal and oil—just combustion or electric power—where'd they get the energy to build a planet-wide canal system, thousands and thousands of miles of 'em? Think of the job we had cutting the Panama Canal to sea level, and then answer that!"
"Easy!" grinned Jarvis. "Martian gravity and Martian air—that's the answer. Figure it out: First, the dirt they dug only weighed a third its earth-weight. Second, a steam engine here expands against ten pounds per square inch less air pressure than on earth. Third, they could build the engine three times as large here with no greater internal weight. And fourth, the whole planet's nearly level. Right, Putz?"