As he held the helmet preparatory to putting it over Robin's head, he gave him some last-minute instructions. "We won't be able to communicate once I get this on you. You've no radio and your mouth will be full anyway. So listen carefully.

"The rocket is about a hundred yards away. I'll lead the way, and I'll tie this cord around your waist so you won't lose me. Follow me as close as you can. There's a possibility that your glass plate may fog up or ice over from the water vapor inside your helmet. If it does, hang on to the cord and keep moving after me! But don't stop ... and don't give up! All set?"

Robin's heart was beating fast, he felt strange and stifled in his bindings. This was the zero instant. He nodded, held out his hand. Peter grasped it, shook it. "When you're all set, follow me across the wind stream. It's powerful—don't let it throw you."

Robin put the end of the air tube in his mouth. Peter pushed the homemade helmet down over his head, secured it tightly, almost painfully, until no space was left for air to escape. Then Peter reached behind Robin to the small tank strapped there and turned a petcock.

Instantly Robin started to choke as he felt something being rammed down his lungs. He caught himself, recognizing that his lungs were being forcibly inflated. He struggled to get control of his diaphragm to expel the excess air pressure. He managed finally to do so, feeling a whiff of air rush through his nostrils. He fought a bit more with the unpleasant current, felt himself getting a grip on it.

Through the plate of his helmet he saw Peter watching him anxiously. Then Peter rapidly tied the nylon cord around his own waist, let it out a few feet, and tied the other end around Robin's. Peter snapped shut the visor of his own helmet, touched the air controls of his own suit, and nodding to Robin, stepped out into the tunnel.

Robin followed closely, conscious of the tight, restricting bands, still fighting the unpleasant pressure of the air tube blowing down his lungs. Peter walked a few steps, pointed a gloved hand across the passage, shone his light.

There was a narrow black gap across there. Through it Robin caught a glimpse of bright white specks—the stars!

Then Peter made a dash, seemed to be picked up by a giant hand and whirled wildly across the passage. The cord tightened and Robin jumped into the space to avoid being pulled off his feet.

He was struck at once by a terrific onrush. A hot, violent blast slammed into him. He lost his footing, felt himself being hurled headlong into a furious tornado. The cord leaped out, and Peter pulled on it hard. Robin swung about, fetched up against the other side of the wall of the cave with a bang, was pulled to his feet before he had even started to fall, and was propelled right through the gap in the wall.