How shall I ever forget that dreadful vigil? I could not hear a sound, not even the drawing of a breath, and yet I knew that my companion sat open-eyed, within a few feet of me, in the same state of nervous tension in which I was myself. The shutters cut off the least ray of light, and we waited in absolute darkness.
From outside came the occasional cry of a night-bird, and once at our very window a long drawn catlike whine, which told us that the cheetah was indeed at liberty. Far away we could hear the deep tones of the parish clock, which boomed out every quarter of an hour. How long they seemed, those quarters! Twelve struck, and one and two and three, and still we sat waiting silently for whatever might befall.
Suddenly there was the momentary gleam of a light up in the direction of the ventilator, which vanished immediately, but was succeeded by a strong smell of burning oil and heated metal. Someone in the next room had lit a dark-lantern. I heard a gentle sound of movement, and then all was silent once more, though the smell grew stronger. For half an hour I sat with straining ears. Then suddenly another sound became audible—a very gentle, soothing sound, like that of a small jet of steam escaping continually from a kettle. The instant that we heard it, Holmes sprang from the bed, struck a match, and lashed furiously with his cane at the bell-pull.