There were scrapings. The outer lock-door made noises. There was what seemed to be a horribly long wait. Then they heard Burke's voice again.
"I've tried it," he reported. "The lighter burns when it's next to the slightly opened door. I'm opening wide now."
More noises from the air-lock.
"It still burns. Repeat. The lighter burns all right. The tunnel is filled with air. I'm going to crack my face-plate and see how it smells."
Silence, while Sandy went white. But a moment later Burke said crisply, "It smells all right. It's lifeless and stuffy, but there's nothing in it with an odor. Hold on—I hear something!"
A long minute, while the little ship floated eerily almost in contact with the walls about it. It turned slowly. Then there came brisk, brief fluting noises. They were familiar in kind. But this was a short message, of some fifteen or twenty seconds length, no more. It ended, was repeated, ended, was repeated, and went on with an effect of mechanical and parrot-like repetition.
"It's good air," reported Burke. "I'm breathing normally. But it might have been stored for ages. It's stale. Do you hear what I do?"
"Yes," said Sandy in a whisper to the control-room. "It's a call. It's telling us to do something. Come back inside, Joe!"
They heard the outer air-lock door closing and its locking-dogs engaging. The fluting noises ceased to be audible. The inner door swung wide. Burke came into the control-room, his helmet face-plate open. He wriggled out of the diving suit.
"Something picked up the fact that we'd entered. It closed a door behind us. Then it turned on lights for us. Then it let air into the entrance-lock. Now it's telling us to do something."