"But one must remain on board," declared Ned.
"Then let Frank stay," laughed Jack. "Somehow, I always get into trouble when I am left on guard."
Frank looked disappointed, but said nothing, and Ned and Jack prepared to go ashore. When they were ready the submarine was carefully raised so that the conning tower was out of water.
The boys did not know, while they were doing this, that the signal to stop was an involuntary one on the part of the boy who was exploring the ocean floor. They did know, however, that Jimmie had a very long air-and signal-system, and that under ordinary circumstances it could do no harm to lift the Sea Lion to the surface. The exact effect of this action on the little fellow will be seen in a short time.
When the conning tower was out of water, the point showed still ahead of the submarine, and Ned wondered why Jimmie had ordered a halt there. In one way this was an advantage, as the people at the head of the bay, if any were there, would not be able to see what was going on at the spot where the Sea Lion lay.
As soon as the hatch was opened Ned and Jack brought up a small boat and launched it. It was a narrow boat and seemed almost too small to carry two husky boys, but she was capable of harder service than that.
"Keep a sharp watch for the line," Ned warned, as they left Frank looking sadly over the rim of the tower. "Jimmie would be in a bad box down there if you should forget him."
"All right!" Frank answered, cheerfully. "I'll take care of the little scamp, but I don't believe there is water enough in the ocean to drown him!"
The boys, paddling the boat softly, proceeded to the west of the point of land near which the Sea lion had stationed herself. Ahead of them they saw a sloping shore, running white and smooth as to surface for some distance from the water. Then, at the back, rose a line of wooded hills. There were no natives in sight.
"I'd like to know what kind of people live on this island," Jack said as they landed and drew the boat up on the beach. "Whoever they are, they don't appear to have houses."