low out a tire, and if
we do we'll all go back in the ambulance together, what's left of
us!"

Even as he spoke, there came a swift change in the even drone of their
engine,--a jarring, discordant note, slight but unmistakable, and a
series of irregular thudding knocks.

"One of the cylinder's missing, sir." Ross turned to the detective,
and spoke with eager anxiety.

"We'll make it on five." The quiet confidence in Blaine's voice, with
its underlying note of grim, indomitable determination, seemed to
communicate itself to the other men, and no further word was said,
although they all heard the thunder of the approaching car behind.

The Doctor restrained with difficulty the impulse to look backward,
and instead kept his eyes sternly fixed upon the trees and hedge-rows
flying past, more sharply defined shadows in the lesser dark.

Then, all at once, the shriek of a locomotive burst upon his ears, and
the roar and rattle of a train going over a trestle.

"The railroad bridge!" he cried, excitedly. "We're there, Mr.
Blaine!"

The noise of the passing train had scarcely died away, when from just
behind them the hideous shriek of Mac Alarney's motor-horn rose
blastingly three times upon the night air, the last fainter than the
others, as if the pursuing car had dropped back.

"He's beaten! He couldn't keep up the pace, much less better it,"
Blaine remarked. "Those three blasts sounded a warning to the guards
of the retreat. It was probably a signal agreed upon in case of
danger. We're in for it now!"

They swerved abruptly, between two high stone gateposts, and up a
broad sweep of graveled driveway. Lights gleamed suddenly in the
windows of the hitherto darkened house, which loomed up gaunt and
squarely defined against the sullen sky.

"Your men, in the other cars--" Doctor Alwyn stammered, as they came
to a crunching stop before the door. "Will they arrive in time to be
of service? Mac Alarney will reach here first--"

"My men will be at his heels," returned Blaine, shortly. "They held
back purposely, acting under my instructions. Come on now."

He sprang from the car and up the steps, and the Doctor found himself
following, with Ross and Suraci on either side. The driver turned
their car around and ran it upon the lawn, its searchlight trained on
the circling drive, its engine throbbing like the throat of an
impatient horse.

In response to the detective's vigorous ring, the door was opened by a
short, s