They were both soon to learn something of it in a manner most startling.
III
The tunnel, as Hammond had conceived, was short. Its sepulchral gloom ended on open air at the very edge of what seemed to have been the bed of a mountain torrent, and, though only the tiniest of streams trickled down the centre of it, its sides were glistening with moisture as though swept very recently by rushing waters. On the further side rose an unbroken wall of rock.
“Oh, please don’t venture any further, Mr. Hammond,” pleaded Josephine Stone tremulously.
“Not to-day,” agreed Hammond, “but I just want to drop down and have a look up this stream-bed. Unless I miss my guess it is the pass that leads into the Cup.”
Suiting action to his words, he let himself down to the first of a series of natural stone steps on the side of the stream-bed.
His foot no sooner touched the step than the tunnel back of them was flooded with a wicked green flash, blinding in its intensity. Simultaneously, from above, in the towering cliffs of Nannabijou came a single reverberating, gonglike note. Followed a low, vibrating rumble which merged into a thunderous roaring and crashing increasing every second in volume as if the whole mountainside were tumbling down upon them.
Hammond felt the girl grip convulsively at his coat sleeve as she cried out. He drew back into the tunnel.
There was a hiss and whine of flying rock particles; then a raging, white-foaming flood, filling the stream-bed almost to its brim, swept by like a monster thing of life. The empty, silent channel was transformed in the twinkling of an eye into a mountain torrent, absolutely impassable, ready to hurl to death any living thing in its path.
The way to the Cup of Nannabijou had been effectually sealed.