In centuries long gone, he explained, the Incas must have chosen this as one of their water-reservoir links. They had wonderfully perfect systems of aqueducts as the chums knew.
“At any rate,” he proceeded, “Bill is engineer enough to surmise that the ruined and blocked-up stone depression we saw half a mile away is part of an old Inca ‘pipe line’ or aqueduct, and that this one communicates with others. In fact, when he came here the first time he saw that it was possible to pretend to give up and retrace our way, and then to dive into a sort of stone subway and go around to come out beyond the place where there might be an ambush.”
“But the others will be caught,” Cliff said, in dismay.
“I warned Pizzara several days ago that the Incas were watching for us,” Bill declared. “He thought I was trying to frighten him. We can’t chase him! I think the worst that can happen will be that the Incas will drive him back.”
Which, in fact, was a good guess.
A week later, after they had plunged into a rock-buttressed cut and explored its communicating cuts, always working by compass to pass around the frozen lake, they came to a place where Bill halted them while he climbed the jagged, crumbled side of their cut to spy out the lay of the land.
It had been no fun, that week in the cut. Packs were all exceedingly heavy since five had to carry the loads of ten, even though depleted by weeks of travel during which the food had dwindled rapidly. So they struggled over rock debris, up sloping walls, over obstacles, sometimes in dark tunnels for a short distance; but as Bill returned to them they knew that it had been an effort well repaid.
“Trampled snow,” he said. “Abandoned packs. Signs of a fight. Rocks dropped. Arrows stuck in the snow. I guess they turned our Spanish friend back, and turned him quick!”
Perhaps Bill did not tell quite all he had seen; nor did the boys press him for details.
Bill and Mr. Whitley decided that it was safe to go on; there were no signs of Indians. It was supposed that Huayca had joined his own forces; no doubt, seeing the white party turn and retrace its steps, he and the others decided that they had turned back; at any rate they were not to be seen, those Incas, though a sharp lookout was maintained.