The man lay for a few seconds striving to collect himself. He could not return the way he had come. He would be caught like a rat in the trap with the arrival of dawn, if not before. Perhaps his pursuers were on his trail already. The thought spurred his numbed body to action, and lifting his head he glanced along the flat roof. Toward the center of it rose a box-like structure with apparently an arched skylight above it. A little distance away from the structure, he distinguished the outlines of what appeared to be a scuttle. Warily he approached it, and using every precaution to make the least possible sound, he attempted to raise the scuttle. A long sigh of relief escaped him as he succeeded. The scuttle was not locked. He paused long enough to glance keenly about him. There was no sign of another human being, but a sound smote his ear. Someone was moving on the pebbled roof of the building he had just left. Without an instant's delay he groped about until his feet touched the rung of a ladder, and drawing to the scuttle behind him, he made his way down the ladder. On reaching the bottom he paused in indecision. He could make out nothing in the inky blackness, and with every sense alive to danger, he waited. But apparently his entrance had disturbed no one, and taking heart of grace, he pulled out a tiny flashlight and pressed the button. The light revealed a large attic partly filled with trunks and worn furniture. A large wine closet, the bottles shining as the light fell on them through the slat partition, occupied one part of the attic, while a wall partition, with closed door, ran across the entire western side. To his right, the man made out the head of a narrow staircase. He was making his way to the staircase when his acute hearing caught the sound of a softly closing door on the floor below and approaching footsteps. Casting a hunted look about him, he spied a closed closet door. He doused his light while making his way to the closet, and jerked open the door, at the same time throwing out his right hand, the better to judge the depth of the dark closet. His groping fingers closed on cold steel. His heart lost a throb, then raced madly on, as he clung weakly to the metal. An elevator shaft, and he had mistaken it for prison bars! For a second his chilled body was shaken with hysterical desire for laughter; then his strong will conquered. He had not forgotten the advancing footsteps. A desperate situation required desperate chances. Stepping back he closed the outer door of the elevator shaft and pressed the button for the elevator. Which would reach him first--the person creeping upstairs or the automatic electric elevator? CHAPTER XII A SINISTER DISCOVERY Mrs. Whitney sat up in bed and contemplated her husband reproachfully as he entered her room. "Have you been working all night?" she inquired.