y so desired.

For at least a full minute the duel of eyes continued. The mysterious
man outside seemed putting all his strength of soul and will into the
struggle.

Was it a flickering flare of the gas jet, or did the midnight eyes waver
the least bit?

Without moving his head or his body, Dade Morgan turned his glance
toward Merriwell. What he saw in Frank's face gave him a feeling of
relief and unspeakable satisfaction.

Merriwell wore the look of a conqueror. He was the same undaunted,
undismayed Merry as of old. He was master of this mysterious foe beyond
the closed door.

Again Morgan lifted his eyes to the midnight orbs beyond the transom. A
sensation of triumph thrilled him like an electric shock.

The deadly eyes wavered!

The silent duel was ended!

Something like a muttered curse and a choking cry of rage came from the
lips of the man beyond the door.

Then the deadly eyes suddenly vanished.

There was a thud, as if some one had leaped down from a chair on which
he had stood.

At the same instant Merriwell sprang up and attempted to open the door.

It was locked.

On entering the room Morgan had left the key in the lock, and this key
had been softly turned by the mysterious eavesdropper.

There was the sound of fleeing feet in the corridor and a soft laugh,
which trailed away and grew fainter in the distance.

Frank Merriwell stepped back from the door and flung his shoulder
against it with fearful force.

With a splintering crash, the door gave way before the shock, and Merry
staggered into the corridor. He was followed by Starbright and Morgan.

Recovering his equilibrium, Frank straightened up and whirled to follow
and overtake the mysterious unknown if possible.

The man of the midnight eyes had disappeared.

The smashing of the door had startled and aroused others in adjacent
rooms, and they now came swarming into the corridor. One of them
clutched at Frank, but was flung aside; others dodged back to let him
pass.

Merry ran to the head of the stairs, down which he leaped.

A man was coming up the second flight.

"Anybody run past you just now?" asked Frank.

"Naw. Wot's der matter?"

Merriwell did not pause to answer the question, but whirled into the
office.

He was met at the door by a man in shirt sleeves, who grabbed at him and
demanded to know what was "doing."

One glance about the place was sufficient to convince Frank that the
eavesdropper had not fled in ther