submarine boy strolled slowly along
to the little jail, forming his plans as he went.

Arrived at the jail, Captain Jack found the keeper, as yet, in ignorance
of the dastardly attempt that had been made on the submarine boat the
night before. He listened, aghast, as Benson told him the whole story.

"Now, I've got a notion that Gaston's crowd are very likely at the
bottom of this whole deal," continued the submarine boy, in a low tone.
"For one thing, while perhaps nothing much can be done to the other
spies, this fellow, Gaston, is in here for a crime which, under the
Florida laws, will go hard with him. It means that he'll be locked up
for a few years. That may make both him and Lemaire ugly enough to put
them up to almost any mischief. Was M. Lemaire here to see the fellow
yesterday?"

"Lemaire has not been hero at all," replied the jailer.

"Was Mlle. Nadiboff here to see him yesterday?"

"No; she has been holding aloof. With the exception of his lawyer,
the only people who ye been here to see Gaston were two fellows who
came yesterday, about noon."

"Oho!" muttered Benson. "Who were they?"

The jailer turned to reach for a memorandum book.

"I keep the names given by all who come here to see prisoners, so I
shall be able to answer you."

"Ah, here are the names. One fellow called himself Leroux, the other
Stephanoulis."

"One name French, and the other Greek," muttered the submarine boy,
thinking hard. "What did they look like?"

The jailer quickly and carefully described the pair. Jack listened
attentively. Then rose, briskly.

"Did you hear any of the conversation they had with Gaston?"

"No."

"If they come again to-day can you lock them up and hold them?"

"If I have proper authority."

"If you get a telephone message from Mr. Trotter, would that be good
enough authority?"

"Yes; on that I could hold them long enough to give Trotter a chance to
come here and take them or else to get them committed on a regular
warrant."

"If you keep within sound of your telephone bell, then, I think you'll
have authority within a few minutes," replied Jack, briskly.

"That's a live, hustling boy," muttered the jailer, looking after
young Benson through a window, as the submarine boy hurried away.

Before he had gone far, Jack encountered one of the nondescript surreys,
hauled by an antiquated nag and driven by a battered darkey, that often
do duty as cab in Florida. Poor as the rig was, it