To add to the gruesomeness of the neighbourhood, a weird, wailing cry began to rise from the high ledge above their heads, at the sound of which the Jeveros crossed themselves and mumbled a prayer. "What is it?" asked the midshipman, not without a little touch of awe. "_Alma perdida!_" said Luis, reverently lowering his voice. The words meant "a lost soul," but the boy was unaware of that, and Smyth did not think a mountain-ledge, such as this, quite the right place to choose for enlightening him. Used to Spanish and now to Indian superstition, he guessed--and rightly--that the cry was that of some bird, probably peculiar to the Andes; and he questioned Filipe, who was walking at his mule's head. "Yes; it is a bird. It passes its time in bewailing the dead, and the sins which they have committed." "It will have a chance of bewailing its own death," said the lieutenant peevishly, "as soon as I can get a shot at it," at which the guides betrayed as much horror as Smyth himself would have shown had they proposed using an albatross as a target. "What are we going to do if we meet another string of mules along here?" he asked. "One party must lie down and let the other pass over it," said Filipe indifferently. By night-time the severe nerve strain of such a passage was ended, for this ledge at last became a rock-walled mountain-path sloping at quite an easy incline. They were no sooner well along this road the following morning than the guides looked to the loading of the guns, for they said that in the neighbourhood they might expect to meet with black Indians, who were notorious cannibals, and whom it would be their duty to kill. But it happened that none thought it worth while to put in an appearance; the "cannibals" were probably imaginary, though, of course, there are blacks--negroes, not Indians--settled in various parts of the Andes, the descendants of the African slaves introduced by the Spaniards in the sixteenth century to carry packages of gold or silver which the Indians could not or would not carry. At last the most wonderful mountain-range in the world was crossed. The mules were left at a village, and the two Jeveros had an opportunity of showing that they were as expert on the water as on the mountains. For now they were in Amazonian Peru, and the Huallaga River had to be descended and examined before the sailors' task was accomplished. In this more easterly forest district of Peru there are, at this day, nearly four hundred thousand Indians, and at that time there were half a million; many of them very degraded, many more warlike and intelligent heathens, and others who led quite peaceable lives as farmers, planters, fishers, or exporters of turtle-oil. Only once were the sailors in serious danger at the hands of any of these tribes, and that was due not to themselves or to the natives, but to the Jevero guides, both of whom had an ineradicable contempt for all Indian families but their own.