"And now, to turn from generalities to particularities. I am worried as to the locality of the hidden treasure. You will remember that Vilcamapata's last words to us were that something--which I have always believed to be the treasure--lies beneath the great marble floor of this temple; and until to-day I have believed that I had but to come here and straightway find the entrance giving access to the vaults in which the treasure lies hidden. Yet I have spent the whole day in wandering among the ruins in search of that entrance--without success; I have been quite unable to find any opening which promises to lead to the underground part of the structure. And all day, too, I have been haunted by an elusive memory of some secret connected with, the hiding of the treasure, which memory continually seems to be on the point of becoming clear and illuminating, only to fade away into nothing again. We are here, however; that is the great point; and I swear that I will not go away again without the treasure, even though it should be necessary to raze the temple to its foundations, stone by stone, in order to find it!" For a time it seemed that nothing short of such drastic measures would serve the purpose of the two adventurers; for, search as they would, they could find no door or opening of any description giving access to the chambers which Vilcamapata had given them to understand existed beneath the floor of the main building; indeed, so far as their discoveries went, there might have been no such chambers at all, although Phil was most positive as to their existence. But they made a beginning of a kind, by setting the labouring gang to work to clear away all the debris and rubbish which lay piled high upon the temple floor; and in the course of a fortnight sufficient progress had been made to lay bare about one-fourth of the marble floor at the eastern end of the building, including the once beautiful but now sadly damaged altar dedicated to sacrifices to the Sun. And then the secret which had so persistently eluded Phil was revealed; for one of the rear corners of the altar had been broken away by the fall of a heavy mass of masonry from the roof, exposing the interior of the structure, which, it now appeared, was hollow. But it revealed more than that; it revealed the fact that the massive slab which formed the rear of the lower portion of the altar was movable, being pivoted on stone hinges at one end, so that by applying pressure in a certain way to the other end it could be made to swing inward, giving access to a flight of steps leading downward. The hinges, it is true, had become stiff from long non-usage, so that it now needed the united strength of half a dozen men to revolve the slab, but when once it was forced open it remained so, and there was no further trouble in that respect. Yet, even then, it was found to be impossible to penetrate to the subterranean chambers at once, for when