Rivets and Sprockets by Alexander Key Page A

time.”
    But Leli sang gaily to Sprockets: “Wasn’t it the most spectrumly wonderful thing to hear? We simply must get acquainted with this Something.”
    With much reluctance Dr. Bailey said, “Er, ah, were you able to get the direction of it, Sprockets?”
    â€œYes, sir,” Sprockets replied, turning off his special perceptors and pointing out into the Martian night. “It is approximately three hundred and seven miles, six hundred and fifty feet to the southeast. Shall I tell Ilium to take us there, sir?”
    â€œUm, ah, well, I suppose so,” said the doctor.
    So the saucer zipped southeastward, where the Martian dawn was paling the horizon. Presently it stopped and hung poised on the slope of a great rounded red hill. Below the hill stretched a desert that might have been a sea bottom when Mars was young. One of the ancient canals ran straight through it. In the vague light everyone could see that the distant canal was dotted with lichens.

    â€œBless me,” said the doctor. “What a lonesome spot! There’s nothing here! Are you sure this is the right place, Sprockets?”
    â€œPositive, sir.”
    Jim said: “But where could anything, even a Something, live around here? A Something has to live somewhere, if it’s only a cave.”
    â€œIt is very puzzling,” Sprockets admitted, peering out. “I see neither a cave nor an opening in the hill. Perhaps, if I signaled again—”
    â€œOh, no,” the doctor said quickly. “Don’t bother to bother. We’ll, er, look around a bit first.”
    Jim said, “I’m not putting foot outside till I know what Sprockets’ instinct button has to tell us.”
    Sprockets turned on his instinct button. “Wow!” he exclaimed. “There’s something around here—only it’s way down under us. It has to be the Something.”
    â€œIs—is it inhospitable to humans?” the doctor asked.
    â€œW-e-l-l, not exactly. I don’t feel any particular danger—at least at the moment.”
    Ilium and Leli had already snapped on their force globes and were hurrying eagerly out into the dawn to explore. The doctor peered uneasily at the hill, then his nose began to twitch. “Let’s get going!” he said.
    They turned on their force globes and followed Ilium and Leli outside.
    â€œAt least,” said Jim, “there are no lichens here on the hill. But there’s nothing else, either. I don’t know what to look for.”
    At that moment Sprockets gave a little tock , and silently pointed at something on the smooth red rock ahead.
    It was a fragment of a lichen. It looked as if it had been cut by a mowing machine.
    â€œJeepers!” came Jim’s whispered voice over the radio. “How did that get here?”
    Suddenly the voices of Ilium and Leli were singing in Sprockets’ receiver. “Something has been this way! It dropped pieces of lichen.”
    All at once the trail was plain. It led halfway up the hill, then stopped abruptly before a high, curving expanse of rock that blocked their way. Along the bottom of the rock were small pieces of dead and dried lichen. It was almost as if they had fallen from some conveyance going through a door.
    But there was no door here, not the faintest sign of a door. There was only the bare red rock of the hillside, scoured smooth by countless Martian dust storms.
    The doctor stared at the blank rock in front of him. “Sprockets, turn on your special perceptors. Maybe you can see something we can’t.”
    â€œI’ve already tried that, sir. All I can see is solid rock.”
    Then Sprockets heard Leli singing: “Isn’t this the most spectrumly clever way for a Something to hide his outer door?”
    â€œIt’s most spectrumly flumdiddling,” Sprockets sang back. “How do you know this is his outer door?”
    â€œIt just has to be. This isn’t