had come up with the boy.

Then he dove deep down so as to come up under the shark before he could
turn and rush at the boy so near him.

Down went Jack, and presently began to rise, seeing the white belly of the
man eater just above him.

With a fierce upward thrust of his right arm, which held the knife he had
taken from the cook, he plunged the blade into the creature's vitals,
drawing it downward and toward him, and turning his hand as he drew, thus
making a jagged cut, and fairly laying open the shark's belly.

Young Smith, encouraged by Jack's shout, had darted ahead with his little
remaining strength, not again looking back, and knowing too well what was
about to happen when Jack dove.

As the shark, mortally wounded, floated away, to be eaten by others of his
kind, Jesse W. suddenly became faint and felt himself giving out.

Jack arose in a moment, however, and called out cheerily:

"Hold on a moment, young fellow, and I'll be there. You mustn't give out
yet, because they haven't put about to take us aboard."

The younger boy held out till Jack reached him, but seemed about to go
under again when Jack said quickly:

"Here, get on my back and you won't have to swim. I'll tow you all right,
and you can get rested."