It was Ned, who, clad in pajamas, was shaking his chum. The latter, dazed for a moment, sprang upright, soundly whacking his head on the upper berth, in which Elmer was snoring loudly.
"What is it?" he exclaimed, rolling out on the floor. "Who hit me? Indians?"
"Not yet," laughed Ned, shaking his "pal" into wakefulness. "Listen!"
He struck a match, lit a candle and sat down on the edge of the berth.
"You're a bum calculator," he began, eyeing Alan.
"I didn't calculate where that berth was," answered Alan ruefully, rubbing a lump on the top of his head.
"And you didn't calculate where we are now," somewhat excitedly added Ned. "And I didn't think of it until just now."
"Go on," interrupted the still sleepy Alan. "If it's a riddle I give it up."
"I suppose you know what the air pressure is to a square inch," answered Ned, like a school teacher rebuking a slow scholar.
"Why, 14.7 pounds, of course."