The light pouring out from beneath the shade of the table-lamp scarcely touched upon the door at all. Only the edges of the lower panels were clearly perceptible; the upper part of the door was masked in greenish shadow.
Intent, tensely strung, he stood; then advanced in the direction of the switch in order to light the lamp fixed above the mantel-piece and to illuminate the whole of the room. One step forward he took, then ... the soft rapping was repeated.
This time he cried the words loudly, and acquired some new assurance from the imperative note in his own voice. He ran to the switch and pressed it down. The lamp did not light!
"The filament has burnt out," he muttered.
Terror grew upon him--a terror akin to that which children experience in the darkness. But he yet had a fair mastery of his emotions; when--not suddenly, as is the way of a failing electric lamp--but slowly, uncannily, unnaturally, the table-lamp became extinguished!
Darkness.... Cairn turned towards the window. This was a moonless night, and little enough illumination entered the room from the court.
Three resounding raps were struck upon the door.
At that, terror had no darker meaning for Cairn; he had plumbed its ultimate deeps; and now, like a diver, he arose again to the surface.
Heedless of the darkness, of the seemingly supernatural means by which it had been occasioned, he threw open the door and thrust his revolver out into the corridor.
For terrors, he had been prepared--for some gruesome shape such as we read of in _The Magus_. But there was nothing. Instinctively he had looked straight ahead of him, as one looks who expects to encounter a human enemy. But the hall-way was empty. A dim light, finding access over the door from the stair, prevailed there, yet, it was sufficient to have revealed the presence of anyone or anything, had anyone or anything been present.
Cairn stepped out from the room and was about to walk to the outer door. The idea of flight was strong upon him, for no man can fight the invisible; when, on a level with his eyes--flat against the wall, as though someone crouched there--he saw two white hands!
They were slim hands, like the hands of a woman, and, upon one of the tapered fingers, there dully gleamed a green stone.