Still I knew that this phantom approach must be unknown to my
companion--and I knew that it was impossible for me to advise him of
it unseen by the dreaded visitor.

A third time the dark patch--the hand of one who, ghostly, silent, was
creeping down into the hallway--vanished and reappeared on a level
with my eyes. Then a vague shape became visible; no more than a blur
upon the dim design of the wall-paper . . . and Nayland Smith got his
first sight of the stranger.

The clock on the mantelpiece boomed out the half-hour.

At that, such was my state (I blush to relate it) I uttered a faint
cry!

It ended all secrecy--that hysterical weakness of mine. It might have
frustrated our hopes; that it did not do so was in no measure due to
me. But in a sort of passionate whirl, the ensuing events moved
swiftly.

Smith hesitated not one instant. With a panther-like leap he hurled
himself into the hall.

"The lights, Petrie!" he cried--"the lights! The switch is near the
street-door!"

I clenched my fists in a swift effort to regain control of my
treacherous nerves, and, bounding past Smith, and past the foot of the
stair, I reached out my hand to the switch, the situation of which,
fortunately, I knew.