He held the candle close to the date: Anno 1360. Here was something peculiar. The last figure, the zero, was cut very deep into the stone—much deeper than any other figure or letter in the whole inscription. The difference was too marked to be accidental. That figure "nought," he reasoned, must have some relation to the inscription. But what? What was there in the inscription about a zero? Then in a flash it came to him.
Touch nothing—Learn everything. Now it was plain. That figure "nought" was the key to the mystery. It must be touched, pressed with the finger. The candlestick shook in his hand, he set it down on the floor beside him. Then Horatio pressed one finger firmly on the center of the figure "nought" in the corner of the big stone.
Nothing happened.
He pressed harder, still harder, still with no effect. Then, as he relaxed the pressure, there came a sharp metallic twang from some hidden place, and, with a strangely animate whine, the stone swung slowly away from him revealing a dark aperture.
Carefully guarding the flame of the candle, the curate stepped through the opening and found himself at the top of a short flight of stone steps. Before going any further, he placed one of the champagne bottles on the top step in such a way that its neck prevented the door from closing.
At the foot of the steps Horatio found himself in a passage which, from its position, he judged must lead toward the ivy covered ruin that formed the outer end of the kitchen garden.
In another moment he knew he was right. Directly overhead, at the further end of the gallery, was an irregular fissure scarcely a foot in width. The crack continued upward for a little way, and through the opening Horatio could see far above him a mountain of jagged stones over which poured a torrent of ivy. Beyond this was a triangle of blue across which flashed the blackness of a bird's wing.
As the curate was about to return, a sudden draught extinguished his candle. Moving cautiously, he probed the treacherous blackness, with outstretched hands, trusting to his sense of direction. Suddenly he stumbled against the steps and plunged heavily forward with his whole weight upon the partly open stone door.
Through the crunch and gurgle of the decapitated champagne bottle and the thud of the door, Merle heard the sharp metallic twang of a hidden lock.
"Go on," said the curate's wife.