Before he left the hills, the moon had disappeared behind a bank of clouds. During the last ten minutes, a tempest had been driving up from the west, which now burst with all its force upon the valley of the Hidden River.
Africa is the land of mighty storms. The sky grew so dark that it was impossible for Max to see one yard before him. Then, there approached in one wild, savage gust, a roaring, raging wind that bent the great trees of the forest like saplings and picked up the water in the lake before Makanda in little driving waves, whilst the rain came down in sheets. The suspension bridge swung to and fro like a kite. There came flash upon flash of lightning which illumined the quarry, so that the bare walls of rock were blazing like a furnace.
The lightning lasted for seconds at a time, and at such times the scene stood for all that was barbarous and fantastic. The dark, mysterious river flowed upon its course through the narrow gorge where the lightning beat upon the rocks. The electricity in the air flashed, died out, and flashed again, like thousands of sparks in the wind. And there, upon the white sand, writhing in torture, were the dark forms of those who had been stricken by the pestilence.
Max had never felt so powerless. He was in the heart of the Unknown. Close at hand, lay those who had been stricken by a force which all the resource of modern science had entirely failed to conquer. Overhead, echoed and mirrored by the rocks, the typhoon rent the sky with sheets of fire, whilst peal upon peal of thunder caused the earth to tremble.
Yet Max was by no means disposed to forget the object of his quest. He was determined to find out the nature of the work which was carried on at the quarry. He hastened forward, and presently blundered into one of the great heaps of sifted débris.
He picked up a handful of this and examined it in the light of the lightning. As far as he could make out, it was composed of a kind of fine gravel, in which appeared great quantities of a green stone, known as serpentine.
Being unable to find out anything definite from the heaps of debris, he resolved to examine the quarry. The wind was too great to permit him to strike a match, even had that been prudent. He was obliged to rely upon the lightning to guide him in his search. He availed himself of the opportunity of a series of flashes to run to the quarry, and there he found himself in impenetrable darkness.
He stood waiting for the lightning to return. It seemed that the storm was already passing. These tropical hurricanes, that often uproot the trees of the forest, are seldom of long duration. They are too violent to last for many minutes.
Max was beginning to think that the storm was passed, when the sky immediately overhead burst into a lurid glow, and almost simultaneously a deafening peal of thunder rolled across the valley. Max leaned forward to examine the face of the rock; and as he did so, he was seized suddenly from behind.
As quick as thought, he whipped his revolver from its holster; and immediately the weapon was struck from his hand.