“There’s young Jesse, enjoying himself and seeming ready to say with the fellow in the poem that he is monarch of all he sees,” laughed Dick.

“That was supposed to be Alexander Selkirk, the original Robinson Crusoe, Dick,” said Jack.  “The line is ‘I am monarch of all I survey.’  You must have recited it more than once in your younger days.  That is not altogether a safe place for young Jesse W., though.  That rail is not very high, and if we should happen to give a roll——­”

“You don’t think there is any danger, Jack!  Hadn’t you better warn him!”

“No, but I will go down and——­” and Jack started to go to the main deck and speak quietly to the boy.  But before he had hardly said the words there was a sudden startled cry and Jack, looking down quickly, saw that the very thing he had feared had taken place.

How it came about no one knew, but all of a sudden there was a loud cry of “man overboard!” and Jack saw the boy just going down in the water.

He was on the lower deck in a moment, and in another had thrown aside his coat and kicked off his shoes, running to the rail as he did so.

The cook had just been killing chickens on the forward deck, and was going aft with two or three fowls in one hand, a knife in the other.

As Jack reached the rail he saw something out on the water, just where the boy had gone down that made him turn icy cold in a moment.

Snatching the knife from the cook’s hand, he sprang to the rail and leaped overboard, taking neither rope nor life preserver with him.

“By George! that’s just what Jack feared, and there he is going to the rescue before any one has shouted, almost!” exclaimed Percival, as he hurried below.

“H’m! pretty clever of Sheldon,” sneered a stout, unprepossessing boy, who seemed to be always scowling.  “Knocks the kid overboard, and then goes to his rescue to make himself solid with the father.  Very clever stroke, that, and just like him!”

“If you say anything like that of Jack Sheldon, Pete Herring,” stormed Dick, who had heard the ill-natured remark, “I’ll knock you overboard!”

Herring, who was by no means a favorite in the Academy, quite the reverse, in fact, had not supposed that Percival had heard his uncalled for and utterly false assertion, and now hurried away with a snarl, evidently fearing that Dick would carry out his threat.

The captain, as soon as possible, gave orders to stop the engines, and to hold the yacht near to the place where the boys had gone down, being ready to turn and go to their assistance when they should appear again.

All was excitement on board, for, until now, nothing had happened out of the ordinary, and no one thought of being seasick or of complaining of the monotony of the voyage.

Jack came to the surface, looked around him, saw young Jesse W. just coming up and shouting for help while he swam, and then, not far behind, what had caused him to take the knife with him, the sharp dorsal fin of a good-sized shark moving rapidly through the water.