He took the place of his chum when the other assumed the duties of guard, and being really sleepy by this time, quickly dropped off.

Frank sat there, with his gun across his knees, also watching the fire.  He had little idea that there would anything occur to disturb the serenity of the night, but believed “an ounce of prevention better than a pound of cure.”

“The old log seems to do its duty handsomely, after all.  I wouldn’t be surprised if it was still burning at daylight,” he mused, as he continued to watch the fire creeping along the dry wood and slowly eating its way toward the other end.

Then Frank started, as he saw a distinct movement in a little shadowy spot.  It happened that the firelight did not reach this particular place, so that, strive as he might, he could not see distinctly.

“There’s something crawling along right there.  I can see a dark figure move,” he said to himself as he strained his eyesight the harder.

Of course, his first thought was of the negro whom they had just fed.  Perhaps to an irresponsible fellow like poor old George the temptation to try and steal something had been irresistible, and he was now creeping toward the motor-boat with the intention of getting aboard and laying hands on anything of value.

Then, again, it might be another entirely, some rascal much more to be feared than George.  Frank was not more than half a minute in making up his mind what the best course for him to pursue under the circumstances would be.

“I’ll give him a shot, firing far over his head.  Whoever it is, the report must make him skedaddle like hot cakes,” he thought, for he could not bear the idea of doing a fellow human being any bodily harm, no matter whether he were white or black.

Having so decided, Frank raised his gun a trifle further, so that it bore on the tops of the cabbage palms beyond.  Then his finger pressed the trigger, and with the sudden report he gave a tremendous yell.

CHAPTER VII

A FLORIDA SHERIFF

There was an upheaval of various blankets, three faces peeped forth, and then came a wild scramble for weapons.

“Wow!  What is it, Frank!” bellowed Bluff.

“My camera!  Who took it away from where I placed it?”

“Talk to me about that, will you!  That fellow will howl after his blooming box when he goes to cross the Styx after he dies,” grunted Jerry.

Frank had paid no attention to his comrades.  His eyes were glued upon the shadowy spot where he felt positive he had seen some creeping figure drawing closer to the boat, inch by inch.

They heard him laugh aloud, as though something he had seen amused him.

“Was it a thief?  And did you shoot him?” asked Will, appalled.

“A thief, all right; but I didn’t shoot the beggar.  Wish I had, now,” responded the watch, with regret in his voice.