“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.