Then their eyes met another sight that made them shudder. On the far end of an open, arena-like plot masons were constructing a short wall. The stones were being dragged to the spot by long lines of men. As the work progressed, earth was banked up against the structure and tamped down to form an inclined plane up which other stones could be hauled into position on top of the last layer of the wall. The ingenuity displayed would have been interesting to the Americans had they not known the sinister meaning of the work. It was against this wall that they were to be chained, with the deadly snakes at their feet. Copper rings on long spikes had been incorporated in the wall between the stones to receive the chains that would hold them in their helpless, hopeless position. After surveying the various activities for a short time they went back into their prison tent. “One of us will have to accompany Soncco to-night,” Stanley announced when they were inside, “to see that the dynamite is placed where it will do the most damage.” “I will go,” Ted volunteered, “but I doubt if I can get past the guards, even in the company of Soncco. The soldiers get their orders higher up.” “That is why I asked him to bring along some one he trusts absolutely. That one must change clothes with one of us and remain here while the work is being done. Perhaps I had better go.” “It isn’t fair to let you face all the danger.” “There is no danger, but even if there were, it would be up to me because I started the thing, and I shall have to see it through. You entertain the substitute while I am away.” “It is all a capital idea. How easy everything is when you know just how to do it! You are a better general than Pizarro. He killed the Inca and caused the death of millions of the people. You will bring the whole nation to its knees through strategy, and they will respect you instead of hating you as they did the Spaniard.” “Never mind that kind of talk. We haven’t done a thing yet.” “But we shall, to-morrow,” Ted said confidently. Stanley suppressed a sigh and turned away. Soncco arrived in due time. “You see, I have kept my promise,” he said without enthusiasm. “And I have brought a man who can neither hear, see, nor speak.” “You are a wonder, Soncco,” Stanley returned gleefully. Then he told him what was expected of him. At first the aged teacher was absolutely set against allowing Stanley to accompany him after exchanging clothes with the man he had brought. He was certain that it must be part of a plot to escape, the far-reaching branches of which he could not foresee. “But,” they argued, “what good would it do one of them to get away while the other remained a prisoner in the valley? Could he not quickly take revenge on the hostage who was left to his mercy? From what he had seen of them, did it seem possible that one of them would desert the other in such a position?”