"Well, you did a lot, at that!" returned the lad.
"All right, folks, let's drop the subject," spoke up Ned. "I feel that the air in here is getting bad. Suppose we go to the surface."
"Right you are," agreed Harry. "Let's rise and fill the tanks!"
Jimmie, in compliance with this wish, steered the craft upward.
At the surface the boys found the water much smoother than they had expected would be the case. Jimmie declared that he intended painting the balance of the name "U-13" on the vessel while the other lads were occupied in airing out the vessel and refilling the compressed air tanks.
Slung in a boatswain's chair over the sloping deck the lad soon completed this task. Feeling a considerable degree of elation at the success of his undertaking Jimmie returned with his brush and paint.
"If you're ready now we'll dive again and proceed!"
"Wait a minute, Mackinder's still on deck!" stated Jack.
"He wasn't there when I came below!" protested Jimmie.
Ned looked at Jimmie in astonishment. He could scarcely credit his senses. He began ascending the iron ladder leading to the deck.
Eagerly the lad glanced about the upper portion of the submarine which now showed black and gleaming above the surface of the water.
"Harry," he called down the hatchway, "didn't Mackinder say he was coming on deck to see if he could be of service to Jimmie?"
"He certainly did!" answered Harry. "Then we went on working at the pumps. I was busy with the starboard pump because it wasn't working just as it should. I saw him start up the ladder!"
"And I saw him when he was about half way up!" put in Jack.
"I'm equally certain he didn't return, but it may be well enough to stop a minute to search the interior. Perhaps he came back."
In a moment all five boys were busily going over every corner of the craft. From stem to stern they ransacked every place where it would have been at all possible for their guest to have hidden.
At length they met in the space directly below the hatchway.
"Find anything?" queried Ned glancing about the group.
"Not a hint of anything at all resembling an Englishman!" stated Jimmie. "Perhaps it would be a good idea to put an ad. in the paper."
"Yes," scorned Jack. "Like this: 'Lost--one perfectly good Englishman. Finder please return to the "U-13" and receive reward'!"