He had something of a half defiant look on his small sunburned face, as he saw Andy trying to draw the wreck toward him, with the evident intention of giving him the next opening.  Perhaps he was half inclined to take his chances as he was, rather than allow these two boys to make him a prisoner.

Frank had his mind made up.  He figured that both men had been long enough in the water to have their weapons well soaked, so that they would be in no condition to threaten their rescuers.

“The box, make him pass it up first, or we leave him here!” he called out to Andy, as the latter was about to reach out and lay hold of the smaller man.

Casper Blue glared almost savagely at Frank.  For the moment the Bird boys even thought the enraged man would hurl defiance back at them, and declare that he preferred taking his chances with the wreck rather than give up the spoils.

But just then it happened, fortunately, that the remnant of the biplane began to settle more positively than before, warning him that it was folly to pin any hope on its buoying him up more than a few minutes at most.

“Here, take it!” he snarled, handing up the box; which Andy immediately passed over to his cousin before he would stretch out his hand again to render the defeated yeggman any assistance.

Then Casper Blue was drawn aboard, and lower still sank the buoyant hydroplane, until both propellers were almost wholly submerged beneath the surface of the heaving billows that came rolling on, steadily and remorselessly.

CHAPTER XXIII

BROUGHT TO BOOK—­CONCLUSION

“What time is it, Frank?” asked Andy, who w as breathing very hard after his recent exertions in helping both men to get a footing on the hydroplane.

“I think pretty close to four o’clock,” replied the other, though he made no attempt to take out the little nickel watch, he always carried nowadays.

The fact of the matter was that Frank did not dare trust Casper Blue.  He could see that the little man was a desperate character, and that he did not view the prospect of being made a prisoner, and taken back to Bloomsbury with any great show of enthusiasm.  In fact, it was a most unpleasant proposition for the bank thief to contemplate at all.

And so Frank was watching him closely.  He had, before starting on this dangerous air flight that had ended so far from home, and under such singular conditions placed a little pistol in his pocket, though hardly under the belief that he would have any occasion to make use of it.

But he was now determined not to let this man get the upper hand.  He could see that various desperate plans must be forming in that scheming brain of the one-time aviator, and now yeggman; and Frank was constantly on the watch so that he might not be caught napping.

“Four o’clock!” repeated Andy; “that would mean at least two more hours before the sun set, wouldn’t it; and even after that it might stay light enough another hour for them to see us if they steamed along?”