by his protestations of loyalty and tribal pride that he followed von Harben with no outward show of the real terror that was consuming him.
The descent through the fissure was less difficult than it had appeared from above. The tumbled rocks that had partially filled it gave more than sufficient footing and in only a few places was assistance required, and it was at these times that von Harben realized how fortunate for him had been Gabula's return.
When at last they reached the bottom of the cleft they found themselves, at its outer opening, flush with the face of the cliff and several hundred feet below the rim. This was the point beyond which von Harben had been unable to see and which he had been approaching with deep anxiety, since there was every likelihood that the conditions here might put a period to their further descent along this route.
Creeping over the loose rubble in the bottom of the fissure to its outer edge, von Harben discovered a sheer drop of a hundred feet to the level of the next terrace and his heart sank. To return the way they had come was, he feared, a feat beyond their strength and ingenuity, for there had been places down which one had lowered the other only with the greatest difficulty, which would be practically unscalable on the return journey.
It being impossible to ascend and as starvation surely faced them where they were, there was but one alternative. Von Harben lay upon his belly, his eyes at the outer edge of the fissure, and, instructing Gabula to hold tightly to his ankles, he wormed himself forward until he could scan the entire face of the cliff below him to the level of the next terrace.
A few feet from the level on which he lay he saw that the fissure lay open again to the base of the cliff, its stoppage at the point where they were having been caused by a large fragment of rock that had wedged securely between the sides of the fissure, entirely choking it at this point.
The fissure, which had narrowed considerably since they had entered it at the summit, was not more than two or three feet wide directly beneath the rock on which he lay and extended with little variation at this width the remaining hundred feet to the comparatively level ground below.
If he and Gabula could but get into this crevice he knew that they could easily brace themselves against its sides in such a way as to descend safely the remaining distance, but how with the means at hand were they to climb over the edge of the rock that blocked the fissure and crawl back into the fissure again several feet farther down?
Von Harben lowered his crude alpenstock over the edge of the rock fragment. When he extended his arms at full length the tip of the rod fell considerably below the bottom of the rock on which he lay. A man hanging at the end of the alpenstock might conceivably swing into the fissure, but h would necessitate a feat of acrobatics far beyond the powers of either himself or Gabula.
A rope would have solved their problem, but they had no rope. With a sigh, von Harben drew back when his examination of the fissure convinced him that he must find another way, but he was totally at a loss to imagine in what direction to look for a solution.
Gabula crouched back in the fissure, terrified by the anticipation of what von Harben's attempted exploration had suggested. The very thought of even looking out over the edge of that rock beyond the face of the cliff left Gabula cold and half paralyzed, while the thought that he might have to follow von Harben bodily over the edge threw the Negro into a fit of trembling; yet had von Harben gone over the edge Gabula would have followed him.
The white man sat for a long time buried in thought. Time and again his eyes examined every detail of the formation of the fissure within the range of his vision. Again and again they returned to the huge fragment upon which they sat, which was securely wedged between the fissure's sides. With this out of the way he felt that they could make unimpeded progress to the next terrace, but he knew that nothing short of a charge of dynamite could budge the heavy granite slab. Directly behind it were loose fragments of various sizes, and as his eyes returned to them once again he was struck with the possibility that they suggested.
'Come, Gabula,' he said. 'Help me throw out some of these rocks. This seems to be our only possible hope of escaping from the trap that I have got us into.'
'Yes, Bwana,' replied Gabula, and fell to work beside von Harben, though he could not understand why they should be picking up these stones, some of which were very heavy, and pushing them out over the edge of the flat fragment that clogged the fissure.
He heard them crash heavily where they struck the rocks below and this interested and fascinated him to such an extent that he worked feverishly to loosen the larger blocks of stone for the added pleasure he derived from hearing the loud noise that they made when they struck.
'It begins to look,' said von Harben, after a few minutes, 'as though we may be going to succeed, unless by removing these rocks here we cause some of those above to slide down and thus loosen the whole mass above us—in which event, Gabula, the mystery of The Lost Tribe will cease to interest us longer.'
'Yes, Bwana,' said Gabula, and lifting an unusually large rock he started to roll it toward the edge of the fissure. 'Look! Look, Bwana!' he exclaimed, pointing at the place where the rock had lain.
Von Harben looked and saw an opening about the size of a man's head extending into the fissure beneath them.
'Thank Nsenene, the grasshopper, Gabula,' cried the white man, 'if that is the totem of your clan—for here indeed is a way to salvation.'
Hurriedly the two men set to work to enlarge the hole by throwing out other fragments that had long been wedged in together to close the fissure at this point, and as the fragments clattered down upon the rocks below, a tall, straight warrior standing in the bow of a dugout upon the marshy lake far below looked up and called the attention of his comrades.
They could plainly hear the reverberations of the falling fragments as they struck the rocks at the foot of the fissure and, keen-eyed, they could see many of the larger pieces that von Harben and Gabula tossed downward.
'The great wall is falling,' said the warrior.
'A few pebbles,' said another. 'It is nothing.'
'Such things do not happen except after rains,' said the first speaker. 'It is thus that it is prophesied that the great wall will fall.'
'Perhaps it is a demon who lives in the great rift in the wall,' said another. 'Let us hasten and tell the masters.'
'Let us wait and watch,' said the first speaker, 'until we have something to tell them. If we went and told them that a few rocks had fallen from the great wall they would only laugh at us.'
Von Harben and Gabula had increased the size of the opening until it was large enough to permit the passage of a man's body. Through it the white man could see the rough sides of the fissure extending to the level of the next terrace and knew that the next stage of the descent was already as good as an accomplished fact.
'We shall descend one at a time, Gabula,' said von Harben. 'I shall go first, for I am accustomed to this sort of climbing. Watch carefully so that you may descend exactly as I do. It is easy and there is no danger. Be sure that you keep your back braced against one wall and your feet against the other. We shall lose some hide in the descent, for the walls are rough, but we shall get down safely enough if we take it slowly.'
'Yes, Bwana. You go first,' said Gabula. 'If I see you do it then, perhaps, I can do it.'
Von Harben lowered himself through the aperture, braced himself securely against the opposite walls of the fissure, and started slowly downward. A few minutes later Gabula saw his master standing safely at the bottom, and though his heart was in his mouth the Negro followed without hesitation, but when he stood at last beside von Harben he breathed such a loud sigh of relief that von Harben was forced to laugh aloud.
'It is the demon himself,' said the warrior in the dugout, as von Harben had stepped from the fissure.
From where the dugout of the watchers floated, half concealed by lofty papyrus, the terrace at the base of the fissure was just visible. They saw von Harben emerge and a few moments later the figure of Gabula.
'Now, indeed,' said one of the men, 'we should hasten and tell the masters.'
'No,' said the first speaker. 'Those two may be demons, but they look like men and we shall wait until we know what they are and why they are here before we go away.'
For a thousand feet the descent from the base of the fissure was far from difficult, a rough slope leading in an easterly direction down toward the canyon bottom. During the descent their view of the lake and of the canyon was often completely shut off by masses of weather-worn granite around which they sometimes had difficulty in finding a way. As a rule the easiest descent lay between these towering fragments of the main body of the cliff, and at
