“Go ahead. You’ll find it as accommodating as a street car.”

“It’s all of that,” agreed Bob a moment later, when he had opened the door and stepped into the cabin. “Those comfortable deep seats appeal to me.”

“Seats aren’t as important in an airplane as in a bus,” laughed Karl. “No bumps in the air.”

On either side of the cabin were two chairs, placed several feet apart. In the middle of the floor was a small folding table, which the boys guessed had been placed there by Karl as a convenience to members of the expedition. A wide glass window separated the pilot’s cockpit from the passenger section, and the two were connected by a telephone apparatus. Three large windows were in each wall, which was slightly curving near the ceiling. At the rear was a large compartment for food, maps, and other equipment.

“Now that you’ve looked it over, how would you like to go up for a short ride?” the aviator asked, as the others examined the ship minutely.

“Like nothing better!” came from Bob. “Can we go now?”

“Yeah. Everybody hop in. Be sure that door’s tight.”

Delighted at such an opportunity, the youths and Mr. Wallace took places in the cabin, while Karl climbed into the cockpit.

A few seconds later there came the roar of the motor, and then the passengers felt themselves moving.