In fact, the cat was quite alert despite its assumed laziness. This was proven when the
animal rose and arched its back when it detected the sound of footsteps from the corridor
outside the study. Then, as the door opened, the cat nestled back on the window sill. It had
recognized the approach of its master.
PROFESSOR WHITBURN entered the study. Old, stooped and thin, he was a man of
curious appearance. His hair formed an untrimmed mass of white. His mustache —also
white—was long, with drooping ends. But the professor's eyes were keen. His sharp gaze
noted the cat settling back upon the window sill.
'Hello, Quex,' chuckled the professor, approaching to stroke the cat. 'What is the trouble?
Has something disturbed you?'
The cat responded with a plaintive meow. The old man studied the animal closely. Quex
blinked and emitted another meow. Then the cat subsided under the professor's friendly
strokes. While he quieted his pet, Whitburn stared about the room in suspicious fashion.
A glare appeared upon the old man's countenance. With sharp eyes, the professor surveyed
the stacks of books and heaps of papers. He moved away from the window sill and
approached the desk. He lifted the telephone and looked at the manuscript beneath it. He
picked up books and replaced them. Nodding, the old man turned toward the cat.
'You are right, Quex,' declared Professor Whitburn. 'Some one has been intruding here.
You know when matters are wrong, don't you, old fellow?'
Pausing, Whitburn again looked about the room. He muttered to himself, then spoke half
aloud, as if addressing the cat.
'Whoever came here was a fool,' asserted the Professor. 'He thought that I would not know.
He believed that this disarray was pure carelessness on my part. Others have thought the
same. They do not realize that I remember the exact place where I lay each object.'
Again, a brief inspection. The cat watched the professor go to the bookcase and look at
volumes that rested there, at an angle. Then the professor chuckled. His tone, however,
betrayed anger along with mirth. Wheeling, he stalked to the door and opened it.
'Polmore!'
The professor paused after calling the name. He waited a few seconds; then heard a
response from somewhere in the house. Footsteps followed. A frail, peak-faced man
appeared from the corridor.
Whitburn beckoned the fellow into the study.
'Polmore,' he cackled, 'you are my secretary. Your services, however, are limited to
handling my correspondence. You would find it difficult to locate objects in this room, would
you not?'
'Yes, sir,' responded Polmore.
'Do you think that I could discover anything if I looked for it?' demanded Whitburn.
'Perhaps, sir,' assented the secretary. 'But I should class a search as difficult.'
'You are wrong, Polmore,' chuckled the professor. 'I could locate any book —any
paper—almost instantly! That surprises you? I thought it would.'
'Is anything missing, sir?'
'No. But articles have been moved. Polmore, I tell you some one has been prying in this
study!'
'Impossible, sir! I was in here only a short while ago -'
'And you saw nothing amiss? That is no argument, Polmore. Not unless you disturbed my
arrangements.'
'No indeed, sir. I came in here only to learn if you had instructions for this evening.'
'And you saw no one?'
'No one, sir.'
The professor eyed his secretary sharply. Then, in a raspy tone, he demanded:
'Where is Stephen?'
'In the laboratory, sir.'
'And Bragg?'
'Upstairs, I believe.'
'Summon them, Polmore. At once.'
The secretary departed, closing the door behind him. Old Whitburn advanced to the window
sill and began to stroke the cat. All the while, the old man's roving glance kept moving about
the room. Then, with a crafty smile upon his face, Whitburn went to the desk.
From a drawer, he produced an automatic. Placing it on the desk, Whitburn drew a large
watch from his pocket. He detached the timepiece from its chain. He opened the back and
removed a tiny key that lay within.
Turning to the bookcase, the professor ran his hand along an ornamental molding at the top.
His fingers stopped and pressed; then moved to the left. A portion of the molding went
inward and slid beneath the next section. An opening showed; within it was a strip of metal,
with a tiny keyhole.
WHILE Whitburn was going through this procedure, the door of the room was slowly
opening. Some one was peering into the study. A watcher was observing the old man's
actions.
Whitburn turned to the desk and picked up the key with his left hand; the automatic with his
right. Intent, the old man did not know that a spy was watching everything he did.
Swinging to the bookcase, Whitburn unlocked the metal strip that had been hidden by the
woodwork. The metal slid away. With his free left hand, the old man drew forth a small stack
of papers. Chuckling, he brought his prize into the light. All the time, the man outside was
watching.
Quex was looking toward the door. From his perch on the window sill, the cat noticed the
moving barrier. Slowly, the animal had begun to arch its back. Suddenly, Quex emitted a
fierce spit. Instantly, the door closed.
Professor Whitburn swung about. Holding the papers in his left hand, he leveled his
automatic toward the door. His sharp eyes caught a tremble of the knob. Grimly, the
professor waited. Silence followed; then a slight creak, from far beyond the door. It meant
the departure of an intruder.
Across the study was a fireplace. The glow of a dying flame showed from burned logs.
Stepping across the room, the old man stretched out his left hand and let the papers fall into
the fireplace. The flames caught the dry sheets. Fire crackled as the papers burned.
Satisfied that he had destroyed his documents, Professor Whitburn went back to the
bookcase. He locked the metal slide and closed the molding. He replaced the little key in
the watch and put the timepiece in his pocket.
Footsteps from the corridor. This time, the professor caught the sound of approach. Quex
arched his back. Whitburn chuckled in challenge. Then some one knocked at the door.
'Who is it?' rasped the professor.
'Stephen, sir,' came the response from beyond the door.
'Come in,' ordered Whitburn.
THE door opened. A stocky, honest-faced man stepped into the room and stared puzzled
as he saw the gun in Whitburn's hand. The professor lowered the weapon. He moved over
by the window sill and began to soothe the tiger-cat.
'Where is Polmore?' inquired the professor, mildly.
