"Randy," said McCauley protestingly. "Get in suit! Leak!" He himself was incredibly feeble. Had there been weight in the ship, he could not have lifted his helmet to his head. He settled it over his shoulders, but his fingers failed to turn the thumbnuts tight. Even so, there was the familiar feel of air blowing across his face. Strength came to him. Not instantly, but with the first breaths of air from the suit tank his head seemed to clear a little. After more breaths, his hands moved assuredly. He began to realize the change in himself and gulped down deep lungfuls of the dry, curiously flat-smelling stored air. Randy hadn't finished getting into his suit; he seemed to have gone to sleep. But when McCauley approached him in the space suit, Randy's eyes turned toward him incuriously. McCauley thrust him into the space suit and clamped down the helmet. Randy suddenly stared. "Something's been wrong with the ship's air!" snapped McCauley, feeling more like himself every second. "It's no good! Breathe deep, Randy! Breathe deep!" Randy obeyed. His eyes cleared. "Bramwell!" snapped McCauley. "Get him in a suit! He hasn't sense enough to do it himself!" He flung himself at the control board. The leak was.... But there was no leak. The leak alarm had rung, but every pressure indicator in every part of the ship showed the same figure. It was.... McCauley gazed incredulously at the dials. The ship's interior pressure was 12.8 pounds to the square inch as against a normal 14.7. The difference was enough to set off the leak alarm, but a thinning of the air like this was not enough to cause the stupidity, the lethargy, the confused and helpless thinking which McCauley--marveling--realized had appeared during the past three weeks. He heard a howling noise between the clamors of the gongs. It was Bramwell. "You're making a noise!" wailed Bramwell. "I can't have a noise! I must have quiet...." McCauley spoke crisply into the transmitter, sending a tight-beam message back to Earth. It would be minutes before it was received, as against the less-than-two-second lag in a message sent from the moon to Earth. "We were suffering from oxygen starvation," said McCauley briskly. "The plants in the air-system's hydroponic garden absorbed carbon dioxide and gave off oxygen, but not quite cent per cent. There was a steady small loss of oxygen in the ship, caused by the use of oxygen as well as carbon by the growing plants. This small loss should have been made up by the addition of oxygen to keep the volume of the ship's air constant. But it happened that the oxygen flutter valve became jammed...."