the shore and across the
acres of sand and clay and mud, came a body of men armed with rifles.
They were making directly toward the scene of conflict as fast as
they could find their difficult way.

"Who are they? Where have they come from?" Billy wondered.

And then, like a flash, he understood. "Oh!" he gasped. "Oh, I know,
I know now! They're the men from the _Petrel_! Marines, I
guess---if that's what you call 'em."

It was true; the new arrivals were the Revenue Service men, and as
it chanced, they had come just in the nick of time. For Joe Durgan,
Branks, Harry Mole, Max, the villainous half-breed, and others at the
huts, were being reinforced by Bego's followers who had hurried up
from the bonfire; and they were beating back the soldiers, whom they
now outnumbered.

Suddenly Billy heard another yell, a wild, eerie, shrill call, and
Dave, leading Norton and the Boy Scouts, sprang from their boat
which had crept up to the farther side of the clearing, and dashed
forward to meet the crew of the _Petrel_.

Recognizing them even in the darkness---which now began to be relieved
by stray gleams of moonlight struggling out of the clouds---the
revenue men turned to the left under Dave's guidance, and took a
short-cut, coming up in the rear of the battle.

Alone on the little mound, Billy realized that he was separated from
his reunited scout friends and their allies by a small mob of
desperately fighting men. He was cut off from the rest by reason
of Dave's having steered the boat along a watercourse of which he,
Billy, knew nothing; in fact, he had lost his bearings and knew not
in which direction the improvised camp lay.

However, the conflict before him absorbed his thoughts and left him
no time to worry about his own predicament. He was still wondering
how the revenue men had happened to arrive at a critical time.

The explanation was as follows:

Unknown to Billy or to any of his friends, the _Petrel_ had steamed
full speed to Palmetto Key; and Captain Vinton, sighting the cutter
from the deck of the concealed _Arrow_, had signaled to her captain,
telling him just where to land his men. This accounted for their
unexpected arrival, which soon turned the tide of battle in their
favor.

Creeping forward, Billy saw the smugglers fleeing in all directions,
after setting fire to the two smaller cabins. As they ran, they
exchanged shots with the soldiers and the revenue men; but, owing
to the gloom,