After registering, the Kentons were assigned their new home.

“I’m afraid you’ve got the house farthest out, Dr. Kenton,” the clerk said. “You’re the last family to arrive, and they’re not building any more until more materials are sent from Earth.”

“That’s all right,” Dr. Kenton replied. “I knew about that.”

“Your boat is waiting for you outside the building at Air Lock Forty-seven,” the clerk went on. “One of our men will show you how it operates and take you home. Your baggage and certain equipment for your home will be sent out later.”

The Kentons walked down a long corridor to the air lock. On their way they had time to see just how many kinds of service were carried on in this most important center on Mars. If anything should happen to the functions of this building, none of the homes could survive for very long.

Outside the air lock, the Kentons found their boat awaiting them beyond a narrow strip of ground. The space-suited man inside the boat introduced himself as Martin Cooper. The Kentons climbed in and took their seats in the bottom of the boat, which was long and deep.

Ted was anxious to see how the boat was operated. He saw Mr. Cooper take a marble-sized tablet out of a box and drop it into a small tube at the rear of the boat. Then the man turned some switches. In a moment a steady popping was heard underwater, and the boat glided off.

“Is that all there is to it?” Ted asked in amazement.

“That’s all,” Mr. Cooper answered.

“But how does it work?” Ted wanted to know.