you hear?"

"I thought I heard it, too," cried Frank. "The Bob White call."

"Where could it have come from? It must be that some of the men around
here use that whistle," Jack decided. "We've heard it before."

Although the boys discussed the matter thoroughly they could not decide
where the call could have been sent from and finally again composed
themselves for sleep, after extinguishing all but the riding or anchor
light gleaming at the head of their signal staff.

Morning was just breaking when they were again aroused. This time a tap
at a window brought Rowdy to attention and made Jack spring to his feet
in alarm. In a boat sat Doright, the negro.

"What do you want?" demanded Jack. "Can we do anything for you?"

"No sir, Boss, youall caint do nothin' for me," answered the negro,
rolling his eyes upward. "Mebbe youall kin do something for them
pardners of yourn! They done gone away."

"Gone away!" gasped Frank, now joining Jack. "Gone away!"

"Yaas, sir, Boss, dey done goned away on a ship named the 'Walkfast.' I
done holp Mister Pete put 'em on board."

"Where is this ship now?" demanded Frank crisply.

"She done lef' a hour or two ago," answered the negro. "If youall wants
to know where she gwine, go ax de man at de custom house."

"That's a sensible thing to do," declared Jack. "Take this fellow
aboard, while I go up to the custom house and find where the ship
Walkfast was bound for and if this chap is not lying, we'll take a
little cruise for an appetizer. Don't let him get away."

In a few minutes Jack came running back breathless. He made haste to get
aboard, signaling for the boys to hoist the anchor.

Not a second was lost in getting the Fortuna under way with her nose
pointed out to sea. After the engines had been set whirling Jack
recovered his breath and explained that the vessel had been the schooner
"Quickstep," that had so nearly wrecked the Fortuna. Her clearance was
for New York and she was heavily laden with lumber.

"We can make about three miles to his one," Jack explained. "We're about
three hours behind him so we ought to catch him in about an hour or so
from now unless he steers a course different from that taken by other
vessels. He's heading for the Dry Tortugas."

"Shall we boost the engines a little?" urged Tom.

"No; better let them go as they are," replied Jack. "Every machine has
what I'd call an 'economy notch.' Beyond that on either side more work
may be done, or le