"Whew! What a lot of 'em!"

"Bless my fish line! It's a big school!"

"Look how they turn over and over, and leap from the water."

"By golly, dere is suttinly some fish dere!"

These were the exclamations made by our four friends a few days later, as they leaned over the rail of the Maderia and watched a big school of porpoises gamboling about in the warm waters of the gulf stream. It was the second porpoise school the ship had come up with on the voyage, and this was a much larger one than the first, so that the passengers crowded up to see the somewhat novel sight.

"If they were only good eating now, we might try for a few," observed Ned.

"Some folks eat them, but they're too oily for me," observed a gentleman who had struck up an acquaintance with the boys and Mr. Damon. "Their skin makes excellent shoe laces though, their oil is used for delicate machinery--especially some that comes from around the head, at least so I have heard."

"Wow! Did you see that?" cried Tom, as one large porpoise leaped clear of the water, turned over several times and fell back with a loud splash. "That was the biggest leap yet."

"And there goes another," added Ned.

"Say, this ought to bring those two mysterious passengers out of their room," observed Tom to his chum in a low voice. "Nearly everyone else seems to be on deck."

"You haven't been able to catch a glimpse of them; eh Tom?"

"Not a peak. I stayed up several nights, as you know, and paced the deck, but they didn't stir out. Or, if they did, it must have been toward morning after I turned in. I can't understand it. They must be either criminals, afraid of being seen, or they are the Fogers, and they know we're on to their game."

"It looks as if it might be one or the other, Tom. But if they are criminals we don't have to worry about 'em. They don't concern us."

"No, that's right. Split mackerel! Look at that fellow jump. He's got 'em all beat!" and Tom excitedly, pointed at the porpoises, the whole school of which was swimming but a short distance from the steamer.

"Yes, a lot of them are jumping now. I wonder--"

"Look! Look!" cried the man who had been talking to Mr. Damon. "Something out of the ordinary is going on among those porpoises. I never saw them leap out of the water like that before."

"Sharks! It's sharks!" cried a sailor who came running along the deck. "A school of sharks are after the porpoises!" "I believe he's right," added Mr. Sander, the gentleman with Mr. Damon. "See, there's the ugly snout of one now. He made a bite for that big porpoise but missed."

"Bless my meat axe!" cried the odd man. "So he did. Say, boys, this is worth seeing. There'll be a big fight in a minute."

"Not much of a fight," remarked Mr. Sander. "The porpoise isn't built for fighting. They're trying to get away from the sharks by leaping up."

"Why don't they dive, and so get away?" asked Ned.

"The sharks are too good at diving," went on Mr. Sander. "The porpoises couldn't escape that way. Their only hope is that something will scare the sharks away, otherwise they'll kill until their appetites are satisfied, and that isn't going to be very soon I'm afraid."

"Look! Look!" cried Ned. "A shark leaped half way out of the water then."

"Yes, I saw it," called Tom.

There was now considerable excitement on deck. Nearly all the passengers, many of the crew and several of the officers were watching the strange sight. The porpoises were frantically tumbling, turning and leaping to get away from their voracious enemies.

"Oh, if I only had my electric rifle!" cried Tom. "I'd make some of those ugly sharks feel sick!"

"Bless my cartridge belt!" cried Mr. Damon. "That would be a good idea. The porpoises are such harmless creatures. It's a shame to see them attacked so."

For the activity of the sharks had now redoubled, and they were darting here and there amid the school of porpoises biting with their cruel jaws. The other fish were frantically leaping and tumbling, but the strange part of it was that the schools of sharks and porpoises kept about the same distance ahead of the ship, so that the passengers had an excellent view of the novel and thrilling sight.

"Rifle!" said Mr. Sander, catching at the word. "I fancy the captain may have some. He's quite a friend of mine, I'll speak to him."

"Get me one, too, if you please," called Ned as the gentleman hurried away.

"And I'll also try my luck at potting a shark. Bless my gunpowder if I won't!" said Mr. Damon.

The captain did have several rifles in his stateroom, and he loaned them to Mr. Sander. They were magazine weapons, firing sixteen shots each, but they were not of as high power as those Tom had packed away.

"Now we'll make those sharks sing a different tune, if sharks sing!" cried the young inventor.

"Yes, we're coming to the rescue of the porpoises!" added Ned.

The passengers crowded up to witness the marksmanship, and soon the lads and Mr. Damon were at it.

It was no easy matter to hit a shark, as the big, ugly fish were only seen for a moment in their mad rushes after the porpoises, but both Tom and Ned were good shots and they made the bullets tell.

"There, I hit one big fellow!" cried Mr. Damon. "Bless my bull's eye, but I plugged him right in the mouth, I think."

"I hope you knocked out some of his teeth," cried Ned.

They fired rapidly, and while they probably hit some of the innocent porpoises in their haste, yet they accomplished what they had set out to do--scare off the sharks. In a little while the "tigers of the sea" as some one has aptly called them, disappeared.

"That's the stuff!" cried Mr. Damon. "Now we can watch the porpoises at play."

But they did not have that sight to interest them very long. For, as suddenly as the gamboling fish had appeared, they sank from sight-- all but a few dead ones that the sharks had left floating on the calm surface of the ocean. Probably the timid fish had taken some alarm from the depths into which they sank.

"Well, that was some excitement while it lasted," remarked Tom. as he and Ned took the rifles back to the captain.

"But it didn't bring out the mysterious passengers," added Ned. Tom shook his head and on their return to deck he purposely went out of his way to go past Stateroom No. 27, where the "Wilsons" were quartered. The door was closed and a momentary pause to listen brought our hero no clew, for all was silent in the room.

"It's too much for me," he murmured, shaking his head and he rejoined his chum.

Several more days passed, for the Maderia was a slow boat, and could not make good time to Mexico. However, our travelers were in no haste, and they fully enjoyed the voyage.

Try as Tom did to get a glimpse of the mysterious passengers he was unsuccessful. He spent many hours in a night, and early morning vigil, only to have to do his sleeping next day, and it resulted in nothing.

"I guess they want to get on Mexican soil before any one sees their faces," spoke Ned, and Tom was inclined to agree with his chum.

They awoke one morning to find the sea tempestuous. The ship tossed and rolled amid the billows, and the captain said they had run into the tail end of a gulf hurricane.

"Two days more and we'll be in port," he added, "and I'm sorry the voyage had to be marred even by this blow."

For it did blow, and, though it was not a dangerous storm, yet many passengers kept below.

"I'm afraid this settles it," remarked Tom that night, when the ship was still pitching and tossing. "They won't come out now, and this is likely to keep up until we get to port. Well, I can't help it."

But fate was on the verge of aiding Tom in an unexpected way. Nearly every one turned in early that night for it was no pleasure to sit in the saloons, and to lie in one's berth made it easier to stand the rolling of the vessel.

Tom and Ned, together with Mr. Damon, had fallen into slumber in spite of the storm, when, just as eight bells announced midnight there was a sudden jar throughout the whole ship.

The Maderia quivered from stem to stern, seemed to hesitate a moment as though she had been brought to a sudden stop, and then plowed on, only to bring up against some obstruction again, with that same sickening jar throughout her length.

"Bless my soul! What's that?" cried Mr. Damon, springing from his berth.

"Something has happened!" added Tom, as he reached out and switched on the electric lights.

"We hit something!" declared Ned.

The ship was now almost stopped and she was rolling from side to side.

Up on deck could be heard confused shouts and the running to and fro of many feet. The jangling of bells sounded--hoarse orders were shouted--and there arose a subdued hubbub in the interior of the ship.

"Something sure is wrong!" cried Tom. "We'd better get our clothes on and get on deck! Come on, Ned and Mr. Damon! Grab life preservers!"