Frank, now that the boats were close enough together not to call for instructions to his men, left them to do their own fighting and opened with his revolver.

Now Frank was a crack shot, as he had proved on more than one occasion, and this time his aim was deadly.  He found himself opposite the boat in which Davis stood erect and he picked off the men about the British traitor with ease.

At last there remained but Davis.  Frank trained his weapon on him carefully, but at the moment he would have pulled the trigger a bullet struck one of the British sailors in Frank’s boat a mortal wound.  The man jumped and fell sidewise.  The boat tipped over and Frank was flung into the water.

Frank’s mouth was open as he went under, and when he came up gasping there was no boat near him.  Ahead he could see Davis still standing erect.  The latter discovered the lad at the same time, levelled his revolver, took careful aim, and pulled the trigger.

But there was no report.  The chamber of the weapon was empty.

CHAPTER XXIX.

THE END OF A TRAITOR.

Frank smiled grimly to himself as he floated in the water.

“No more bullets, eh?” he muttered.

He struck out vigorously, but instead of making for the nearest British boat, he swam directly toward the craft in which Davis remained standing.

“I’ll get you this time, Mr. Davis,” the lad muttered through his teeth.

Davis saw him coming and something must have told him that this time the lad would overcome him.  He stooped over and picked up a second revolver.  This, too, he levelled directly at the lad and pulled the trigger.  But this weapon also was empty.

Now fear suddenly took possession of Davis.  He dropped to the thwart, seized a pair of oars and began to row.

But he had delayed too long; for at that moment Frank’s left hand grasped the gunwale.  Quickly Davis raised himself in the boat, and, brandishing an oar aloft, brought it down in an effort to crush the lad’s head.  Frank saw the blow coming and dived just in time.  Davis again sat down and began to row.

A minute later Frank came up by the side of the boat and seized it in both hands.  In vain Davis tried to steady the craft.  Frank’s effort was too powerful to resist and the little craft capsized, hurling Davis into the water.

Frank, treading water—­now that he had his enemy on even terms—­smiled as he waited for the traitor to come up; but what was his surprise when he felt himself suddenly seized by the legs and drawn beneath the surface.  So sudden and unexpected was this movement that the lad did not have time to catch a breath before his head went under.

He kicked out desperately with his left foot and felt it strike something soft; and at that moment the hold upon his legs relaxed.  The lad rose rapidly to the surface, where he inhaled great draughts of fresh air.  Then he swam away a few strokes and waited for Davis to rise, for he knew he could not remain under water much longer.