It was a hot day, even for the tropics, and everybody felt the heat intensely. Awnings had been stretched over the deck, and under their inviting shade the passengers tried to find relief from the burning sun, but with little success. A slight accident to the machinery had caused the ship to heave to, so that they were deprived of the artificial breeze caused by the vessel’s motion. The oppressive heat rivaled anything the boys had ever felt, and for once even their effervescent spirits flagged. They lolled about the deck in listless attitudes, and were even too hot to cut up the usual “monkeyshines” that gave the passengers many a hearty laugh. Dick looked longingly at the green, cool-appearing water, that heaved slowly and rhythmically, like some vast monster asleep.

“Make out it wouldn’t feel good to dive in there, and have a good, long swim,” he exclaimed, in a wistful voice. “Just think of wallowing around in that cool ocean, and feeling as though you weren’t about to melt and become a grease spot at any moment. Gee, I’d give anything I own to be able to jump in right now.”

“Go ahead,” grinned Bert, “only don’t be surprised if we fish you out minus a leg or two. Those two sharks that have been following the ship for the last week would welcome you as a very agreeable addition to their bill of fare.”

“Yes,” chimed in Ralph, “and that’s not the only thing, either. I’ve felt sorry for those poor old sharks for quite a while. Here they follow our ship around for a week, hoping that somebody will fall overboard and furnish them a square meal, and then everybody disappoints them. I call it pretty mean conduct.”

“That’s my idea exactly,” agreed Bert, “and I think it would only be doing the gentlemanly thing for Dick to volunteer. You won’t disappoint your friends on a little point like that, will you, Dick?”

“No, certainly not,” responded Dick, scornfully. “Just ring the dinner bell, so that the sharks will be sure not to miss me, and I’ll jump in any time you say. Nothing I can think of would give me greater pleasure.”

“Well, on second thought,” laughed Bert, “I think we’d better save you a little while, and fatten you up. I’m afraid you haven’t got fat enough on you at present to give entire satisfaction. We might as well do this thing up right, you know.”

“O, sure, anything to oblige,” grunted Dick. “Just dispose of me any way you think best. Naturally, the subject has little interest for me.”

“Aw, you’re selfish, Dick, that’s what’s the matter with you,” said Ralph. “I’d be willing to bet any money that you’re thinking more of yourself than you are of those two poor, hungry fish. Gee, I’m glad I’m not like that.”

“All right, then,” responded Dick, quickly, “as long as you feel that way, and I don’t, why don’t you serve yourself up to the suffering sharks? Besides, you’re fatter than I am.”

Apparently Ralph could think of no satisfactory answer to this profound remark and so changed the subject.

“Well,” he exclaimed, “all this doesn’t get us any nearer to a good swim. I wish this were one of the steamships I was on not long since.”

“Why, how was that?” inquired Bert.

“Well, on that ship they had a regular swimming tank on board. Of course, it wasn’t a very big one, but it was plenty large enough to give a person a good swim. Gee, I used to just about live in that tank on a day like this.”

“I suppose that was what you might call a tank steamer, wasn’t it?” said Bert, and his remark raised a general laugh.

But now an elderly man among the passengers, who up to now had listened to the boys’ conversation with a smile on his face, but had not spoken, said, “Why don’t you ask the captain to rig up the swimming nets? I’m sure he would be willing to do it for you, if you asked him in the right way.”

“Swimming nets!” exclaimed Dick, “what’s a swimming net?”

“Why, it’s simply a sort of a cage that they rig up alongside the ship, and anybody that wants to can swim to their heart’s content inside it. The net keeps sharks out, and makes it safe.”

“Say, that would certainly be great,” exclaimed Ralph. “Come along, fellows, and we’ll see if we can’t persuade the captain to fix us up. The idea of a good swim certainly hits me where I live.”

The rest were nothing loath, and they jumped to their feet and rushed off in search of Captain Manning. He was soon found, and listened smilingly to Ralph, who acted as spokesman for the others.

“I guess we can arrange that, all right,” he said, after Ralph had finished. “It will be at least two hours before our repairs are finished. Between you and me, I’d like to jump in myself,” he added, regretfully.

He gave orders accordingly, and the crew soon had the netting rigged. Before they had finished, news of what was going on had flown through the ship. All who felt so disposed or had bathing paraphernalia with them, appeared on deck attired for a dip. Needless to say, Bert, Dick, and Ralph were among the first to put in an appearance, and great was their impatience while the crew were putting the finishing touches to the “cage.” While they were waiting, Ralph said, “Look at that, fellows. Those two sharks that we were talking about a little while ago have disappeared. I guess they must have overheard our conversation, and given us up for a bad job.”

“They’re certainly not in sight, at any rate,” said Dick. “However, I think I shall manage to control my grief at their desertion.”

“It always gave me a creepy feeling,” said the passenger who had first suggested the swimming nets, “they hung on so persistently, just as though they felt sure that their patience would be rewarded some time. It seemed uncanny, somehow.”

“It certainly did,” agreed another. “I guess they’re gone for good, this time, though.”

This seemed to be the general opinion among the crew, also, and the boys felt relieved in spite of themselves, for swimming in close proximity to a couple of hungry sharks, even when separated from them by a net, is not a particularly cheerful experience.

Soon everything was ready, and the swimmers descended the steps let down alongside the ship, and plunged into the water. It was very warm, but a good deal cooler than the air, and you may be sure it felt good to the overheated passengers. Bert and Ralph were expert swimmers, and dove and swam in a manner to bring applause from the passengers up above. Dick was not such a very good swimmer, having had little experience in the water. He enjoyed the dip none the less on this account, however, and if he could not swim as well as the others, at least made quite as much noise as they.

After half an hour or so of this the boys ascended to the deck to rest a little before continuing their aquatic exercises.

“My, but that felt good, and no mistake,” said Bert.

“It sure did,” agreed Ralph. “The only objection I can find is that you can’t swim far enough in any one direction. I like to have enough space to let me work up a little speed. I’ve half a mind to take a chance and dive off here outside the net. There’s no sign of those pesky sharks around now. I’m going to take a chance, anyhow,” and before anybody had a chance to stop him he had made a pretty dive over the side. He struck the water with scarcely a splash, and in a few seconds rose to the surface and shook the water out of his eyes. Bert yelled at him to come back on board, but he only shook his head and laughed.

Then he struck out away from the ship with bold, rapid strokes, and soon had placed a considerable distance between himself and the vessel. Bert and the others watched his progress with anxious eyes.

“The young fool,” growled one of the passengers, “hasn’t he got any more sense than to do a thing like that? Those sharks are likely to show up any minute. They don’t usually give up so quickly, once they’ve started to follow a ship.”

It seemed, however, as though Ralph would experience no bad results from his rash act. He had swum several hundred yards from the vessel, and had turned to come back, when a cry went up from one of the women passengers.

“Look! Look!” she screamed, and pointed wildly with her parasol. All eyes followed its direction, and more than one man turned white as he looked. For there, not more than five hundred feet from the swimmer, a black fin was cutting the water like a knife-blade. It was not headed directly for Ralph, however, but was going first in one direction, then in another, showing that the shark had not yet definitely located his prey.

A few seconds later a second fin appeared, and there was little doubt in the minds of all that these were the two sharks that had followed the ship for the last few days.

In the meantime, Ralph had drawn nearer the ship, but was swimming in a leisurely fashion, and evidently had no inkling of the deadly peril that threatened him. Bert was about to yell to him and point out his danger, when he thought better of it.

“If he knew those two sharks were on his trail,” he said in a strained voice to Tom, “he might get frightened and be unable to swim at all. I think we had better leave him alone and hope that he gets to the ship before the sharks locate him.”

“Let’s go after him in a boat,” suggested one of the sailors, excitedly, and this was no sooner said than done. Without even waiting for orders from the captain, several of the crew started to launch a boat, but it became evident that this could be of no avail. For at that moment the two searching fins suddenly stopped dead for a second, and then started straight for the unconscious swimmer.

A cry went up from the passengers, which reached Ralph’s ears. He glanced behind him, and for a second seemed paralyzed at what he saw. Bert yelled wildly. “Swim for your life, Ralph,” he shrieked. “Here,” turning to the sailors, “get a long rope, and stand by. We’ll need it when he gets near the ship.”

Now Ralph had recovered from his panic to some extent, and struck out as he had never done before. At every stroke he fairly leaped through the water, but the two black fins overhauled him with lightning-like rapidity. Closer and closer they came, and still the swimmer was a good forty or fifty yards from the ship. Now he started a fast crawl stroke, and it was a lucky thing for him that day that he was an expert swimmer.

He was soon almost under the ship’s side, and one of the sailors threw the rope previously secured in his direction. Ralph grasped it with a despairing grip, but now the two fins were terribly close, and approaching at express train speed. A dozen willing hands grasped the rope, and just as the two man-eaters were within ten feet of him the exhausted swimmer was swung bodily out of the water. There was a swish alongside, two great white streaks flashed by, and the passengers caught a glimpse of two horrible, saw-like rows of gleaming teeth. Then Ralph was drawn up on a level with the rail, and strong hands pulled him safely inboard.

No sooner did he realize that he was safe, than he collapsed, and it was some time before he recovered from the strain. When he was once more himself, he grinned weakly at Bert. “Next time I’ll follow your advice,” he said.

“Oh, well, ‘all’s well that ends well,’” quoted Bert. “Just the same, it was more than you deserved to have us work ourselves to death a hot day like this trying to keep you from doing the Jonah act. It would have served you right if we had let the shark take a bite or two.”

“Sorry to have troubled you, I’m sure,” retorted Ralph. “But say, fellows, just as soon as I can get enough nerve back to think, I’m going to dope out some way of getting even with those man-eaters. I’ll be hanged if I’m going to let even a shark think he can try to make hash of me and get away with it. In the meantime, you and Tom might set your giant intellects to work and see if you can think of a plan.”

A sailor had overheard this, and now he touched his cap, and said:

“Excuse me for buttin’ in, but I think me and my mates here can fix up those sharks for you, if the captain’s willin’. On a bark I sailed in once we caught a shark that had been annoyin’ us like these has, just like you’d catch a fish. We baited a big hook, and pulled him in with the donkey engine. If the captain ain’t got no objections, I don’t see why we couldn’s sarve these lubbers the same trick.”

This idea met with instant approval, and Captain Manning was soon besieged by a fire of entreaty. At first he seemed inclined to say no, but when he found that the majority of the passengers were in favor of capturing the sharks, he gave a reluctant consent.

The sailors grinned in happy anticipation of a good time, and set about their preparations with a will, while an interested group that surrounded them watched the development of their scheme with intense interest.