With another bang the hissing of the inrushing air began once more and the hand on the dial began to creep around again, passing the figure five, then the figure ten, then fifteen. March began to feel uncomfortably warm, and then he saw that most of the other men were beginning to sweat. Stan leaned over and put his lips close to March’s ear so that he could be heard over the sound of the air.
“Air under pressure gets hot,” Stan said. “Remember your physics? It’s the whole basis of a Diesel engine, incidentally, but the pressure is considerably greater. The temperature in a cylinder gets up to about a thousand degrees.”
“Around a hundred in here now, I’d say,” March replied in a loud whisper, and Stan nodded in agreement. Then he swallowed with some difficulty, and smiled in some surprise afterward.
“My ears popped when I swallowed;” he said. “Feels better.”
“That’s right,” boomed the CPO, who had apparently noticed what Stan did. “Everybody try swallowing a few times if your ears feel funny.”
March swallowed and then almost laughed as he saw the two rows of students earnestly swallowing. Then he realized he had not looked at the pressure dial for some time. He was startled to see it at thirty-five pounds. It was a good deal hotter now and everyone was sweating profusely. March looked around at the others carefully, forgetting his concern about himself in his interest in the others.
There seemed to be less tension now than at the very beginning. A few of the men talked to each other, comparing their reactions, laughing at the way their ears popped, expressing surprise at the increasing heat. Suddenly there was another banging on the wall of the chamber, and the hissing stopped. Everyone’s eyes went to the pressure dial, and saw the hand standing at fifty pounds.
So this was it! Well, it wasn’t so bad. March felt that way himself and saw the same feeling spreading to all the others, who smiled slightly as they knew they had withstood the pressure test successfully.
“So far, anyway,” March told himself. “Some things happen occasionally, I guess, when the pressure is reduced.”
Already the hand on the dial was moving downward again, as the air was released from the chamber by a man handling the valves on the outside. March began to feel cooler, and in a few minutes he shivered suddenly.