creek," he said, quietly.

"Twelve minutes till four, it was, sir,"
replied Jimmie, promptly.

"Oh! what made you take such exact notice
of the time, may I ask?" the officer went on,
curiously, though plainly interested.

"We are compelled to make a memorandum
of our stoppings. The conditions of the race
forbid any boat to be moving south before
eight in the morning, or after four in the
afternoon. So I can show you in my notebook how
an exact record is kept of such things. It will
be figured on when the race is decided. We are
going by stations you see, Captain, that are
about two hundred miles apart. At each
station we wait for the slowest boat, and then
make a new start."

"It was about four-twenty when the gentleman
called me up," observed the police officer;
"and he had a long way around to go after
leaving here. He could never have made it if
it was your boat he saw."

"There's another thing, Captain," said
Jack, smiling.

"Please let me hear what it is, my boy,"
returned the other, eagerly now, for he was
beginning to comprehend that this was no
ordinary young chap with whom an error of
judgment had thrown him in contact.

"Did the gentleman in the auto say that the
motor boat went _under_ the bridge at the time
he saw it?" Jack pursued.

"That's just what he did say," replied the
captain. "Of course he only had one quick
look as his machine traveled over the bridge
crossing the creek; but even then it seemed to
him the boat had a familiar look. And then,
later on it suddenly dawned on him that it just
fitted a description he had been reading in a
St. Louis paper about the mysterious motor
boat of the bank thieves."

"All right, Captain. We have not been up
as far as the bridge, as we anchored right here
when we came in. But, Captain," Jack
continued, earnestly, "both of us believed at the
time that there must be some sort of a motor
boat up yonder, for we saw a piece of oiled
waste floating down on a chip of wood, as if
some one had been wiping an engine, and
thrown it aside."

"Well, what do you think of that?" exclaimed
one of the listening officers. "It beats
anything our best detectives could have done.
But say, Cap, I hear something moving close
by. There it is again! There's a boat coming
down, and being poled, too."

"Turn your lights around that way, quick!"
cried the police captain, as though he grasped
the true significance of the sound.

As the men did s