He stopped rowing and turned half around to look.

"That, Trot," he slowly replied, "looks to me mighty like a whirlpool."

"What makes it, Cap'n?"

"A whirl in the air makes the whirl in the water. I was afraid as we'd meet with trouble, Trot. Things didn't look right. The air was too still."

"It's coming closer," said the girl.

The old man grabbed the oars and began rowing with all his strength.

"'Tain't comin' closer to us, Trot," he gasped; "it's we that are comin' closer to the whirlpool. The thing is drawin' us to it like a magnet!"

Trot's sun-bronzed face was a little paler as she grasped the tiller firmly and tried to steer the boat away; but she said not a word to indicate fear.

The swirl of the water as they came nearer made a roaring sound that was fearful to listen to. So fierce and powerful was the whirlpool that it drew the surface of the sea into the form of a great basin, slanting downward toward the center, where a big hole had been made in the ocean—a hole with walls of water that were kept in place by the rapid whirling of the air.

The boat in which Trot and Cap'n Bill were riding was just on the outer edge of this saucer-like slant, and the old sailor knew very well that unless he could quickly force the little craft away from the rushing current they would soon be drawn into the great black hole that yawned in the middle. So he exerted all his might and pulled as he had never pulled before. He pulled so hard that the left oar snapped in two and sent Cap'n Bill sprawling upon the bottom of the boat.

He scrambled up quickly enough and glanced over the side. Then he looked at Trot, who sat quite still, with a serious, far-away look in her sweet eyes. The boat was now speeding swiftly of its own accord, following the line of the circular basin round and round and gradually drawing nearer to the great hole in the center. Any further effort to escape the whirlpool was useless, and realizing this fact Cap'n Bill turned toward Trot and put an arm around her, as if to shield her from the awful fate before them. He did not try to speak, because the roar of the waters would have drowned the sound of his voice.

These two faithful comrades had faced dangers before, but nothing to equal that which now faced them. Yet Cap'n Bill, noting the look in Trot's eyes and remembering how often she had been protected by unseen powers, did not quite give way to despair.

The great hole in the dark water—now growing nearer and nearer—looked very terrifying; but they were both brave enough to face it and await the result of the adventure.

Chapter Two

The Cavern Under the Sea

The circles were so much smaller at the bottom of the basin, and the boat moved so much more swiftly, that Trot was beginning to get dizzy with the motion, when suddenly the boat made a leap and dived headlong into the murky depths of the hole. Whirling like tops, but still clinging together, the sailor and the girl were separated from their boat and plunged down—down—down—into the farthermost recesses of the great ocean.

At first their fall was swift as an arrow, but presently they seemed to be going more moderately and Trot was almost sure that unseen arms were about her, supporting her and protecting her. She could see nothing, because the water filled her eyes and blurred her vision, but she clung fast to Cap'n Bill's sou'wester, while other arms clung fast to her, and so they gradually sank down and down until a full stop was made, when they began to ascend again.

But it seemed to Trot that they were not rising straight to the surface from where they had come. The water was no longer whirling them and they seemed to be drawn in a slanting direction through still, cool ocean depths. And then—in much quicker time than I have told it—up they popped to the surface and were cast at full length upon a sandy beach, where they lay choking and gasping for breath and wondering what had happened to them.

Trot was the first to recover. Disengaging herself from Cap'n Bill's wet embrace and sitting up, she rubbed the water from her eyes and then looked around her. A soft, bluish-green glow lighted the place, which seemed to be a sort of cavern, for above and on either side of her were rugged rocks. They had been cast upon a beach of clear sand, which slanted upward from the pool of water at their feet—a pool which doubtless led into the big ocean that fed it. Above the reach of the waves of the pool were more rocks, and still more and more, into the dim windings and recesses of which the glowing light from the water did not penetrate.

The place looked grim and lonely, but Trot was thankful that she was still alive and had suffered no severe injury during her trying adventure under water. At her side Cap'n Bill was sputtering and coughing, trying to get rid of the water he had swallowed. Both of them were soaked through, yet the cavern was warm and comfortable and a wetting did not dismay the little girl in the least.

She crawled up the slant of sand and gathered in her hand a bunch of dried seaweed, with which she mopped the face of Cap'n Bill and cleared the water from his eyes and ears. Presently the old man sat up and stared at her intently. Then he nodded his bald head three times and said in a gurgling voice:

"Mighty good, Trot; mighty good! We didn't reach Davy Jones's locker that time, did we? Though why we didn't, an' why we're here, is more'n I kin make out."

"Take it easy, Cap'n," she replied. "We're safe enough, I guess, at least for the time being."

He squeezed the water out of the bottoms of his loose trousers and felt of his wooden leg and arms and head, and finding he had brought all of his person with him he gathered courage to examine closely their surroundings.

"Where d'ye think we are, Trot?" he presently asked.

"Can't say, Cap'n. P'r'aps in one of our caves."

He shook his head. "No," said he, "I don't think that, at all. The distance we came up didn't seem half as far as the distance we went down; an' you'll notice there ain't any outside entrance to this cavern whatever. It's a reg'lar dome over this pool o' water, and unless there's some passage at the back, up yonder, we're fast pris'ners."

Trot looked thoughtfully over her shoulder.

"When we're rested," she said, "we will crawl up there and see if there's a way to get out."

Cap'n Bill reached in the pocket of his oilskin coat and took out his pipe. It was still dry, for he kept it in an oilskin pouch with his tobacco. His matches were in a tight tin box, so in a few moments the old sailor was smoking contentedly. Trot knew it helped him to think when he was in any difficulty. Also, the pipe did much to restore the old sailor's composure, after his long ducking and his terrible fright—a fright that was more on Trot's account than his own.

The sand was dry where they sat, and soaked up the water that dripped from their clothing. When Trot had squeezed the wet out of her hair she began to feel much like her old self again. By and by they got upon their feet and crept up the incline to the scattered boulders above. Some of these were of huge size, but by passing between some and around others, they were able to reach the extreme rear of the cavern.

"Yes," said Trot, with interest, "here's a round hole."

"And it's black as night inside it," remarked Cap'n Bill.

"Just the same," answered the girl, "we ought to explore it, and see where it goes, 'cause it's the only poss'ble way we can get out of this place."

Cap'n Bill eyed the hole doubtfully

"It may be a way out o' here, Trot," he said, "but it may be a way into a far worse place than this. I'm not sure but our best plan is to stay right here."