. She almost screamed, when the
electric bell suddenly rang out again, its sound intensified by the
stillness until it seemed as though it must wake everyone in the house.

The nurse rose sleepily, glanced at the indicator on the wall which
informed her from which room the summons had come, and started down the
corridor toward the west wing of the building. As she passed beyond the
circle of light cast by the electric globe in the central hall, Grace
pushed her door open and slipped noiselessly out. For a moment she
hesitated, saw the woman enter a room midway of the corridor, then flew
like the wind toward the door which gave entrance to the passageway
leading to the laboratory. Her bare feet made no sound, she gained the
door without being discovered, and in an instant had swung it open, and
was standing in the long covered way outside. She drew the door to after
her noiselessly, then sank upon her knees and listened. In a short while
she heard the nurse come shuffling down the corridor, and the creaking
of her chair as she sank heavily into it. So far, she felt that she was
safe.

She advanced along the corridor with great caution. Her chief fear was
that the door of the laboratory might be locked, in which case, she
would be unable to proceed further. When she reached it, and felt it
yield as she slowly turned the knob, she heaved a sigh of relief. In a
moment she was in the laboratory.

The room was unlighted, save for a faint glow which came from a small
black box in the center of the floor. She had no idea what this box was,
but noticed that heavy wires ran to it, from each side, and that there
were several protuberances upon its top, which shone like brass. She did
not stop to examine it further, however, but looked about for some means
of reaching the room below. The idea of recovering the snuff box had
suddenly occurred to her. With that in her possession, Richard, she
believed, need no longer hesitate to escape at the first opportunity. He
had told her that it was hidden in the room beneath. She ran quickly
down the steps which she observed in one corner, feeling a glow of
excitement at the daring of her quest.

At the bottom of the stairs she found a narrow little corridor with a
heavy door opening on it which she judged led into the room she desired
to enter. The corridor was lighted by a single window at the end
opposite the staircase, through which came a faint light from without.

She groped about i