six more days were spent in driving holes according to harry's plan. the result was in all cases the same. sand and small stones were brought up attached to the grease. they had now sunk the holes at a much more rapid rate than at first, for they were accustomed to the work, their muscles had hardened, and they were able to strike more frequently and with greater force. they would have got on still more quickly had it not been for the trouble in sharpening the drills. these were heated in the small blacksmith's fire dias had brought. they were first placed in the fire, but this was not sufficiently hot to raise them beyond a dull red glow. when this was done a shovelful of glowing fragments was taken from the fire and placed on the hearth, and among these the small bellows raised the ends of the drills to a white heat, when of course they were easily worked. at first they had some difficulty in tempering them. sometimes, when cooled, the points were too soft, at other times too brittle; but at the end of a week they had arrived at the proper medium. but one of the party had to work steadily to keep the drills in good order.

bertie was daily employed at this work, as josé generally failed to give the proper temper to the tools. bertie, however, generally managed to get in two or three hours' work below. although perfectly ready to do his share, he was by no means sorry to be otherwise employed for a part of the day, and as he was now able to talk spanish with perfect fluency he and donna maria maintained a lively conversation whenever they were together. all the party, however, were glad when sunday came round and gave them a day of complete rest; then they would bathe, fish, shoot pigeons, or lie in the shade, each according to his fancy, and recommence work with fresh vigour the next morning.

just a fortnight after they had begun work they were about to begin a hole in a fresh stone. talking it over, they had come to the conclusion that this was the most likely spot in the cellar for the situation of an underground chamber. farther on there would scarce be width for one, for it was here but eight feet across. where they had already tried there would scarcely have been depth enough. this seemed to them to be the happy medium.

before setting to work dias passed his torch over the stone. presently he stopped. "will you light two of the candles, se?or; the torch flickers too much to see very plainly."

somewhat surprised, for no such close examination had been made before, the candles were lighted and handed to him. dias knelt down, and, with his face close to the stone, moved about carefully, examining it for some minutes without speaking.

"this stone, se?or, is broken," he said at last, "broken into a dozen pieces, and they have been so carefully fitted together again that the dust that settled upon it quite prevented our seeing it till we swept it again just now, and it was only because there was a tiny chip out where i first looked that i noticed it."

harry knelt down and also examined the stone. like all the others, it had not been faced with tools. consequently, although roughly even, there were slight irregularities in the surface. now, as dias pointed them out to him, he saw that there were lines running through it here and there.

"look here, se?or. the stone has been struck here. here are some dents."

these were scarcely noticeable. the surface had taken the same colour as the rest of the stone. they were of irregular size, and from a quarter of an inch to an inch in diameter, and nearly in the centre of the stone, from which point several of the cracks started.

"it certainly looks as if the stone had been struck with something heavy," harry said. "i should think, by the appearance, some very heavy piece of rock must have been dropped upon it."

"yes, se?or, very heavy rock—so heavy that there must have been many men to lift it."

"it must have been heavy indeed to break up this slab."

"perhaps it is not so thick as the others," dias suggested.

"i don't like it, dias. well, let us set to work. we will try the wedges there. they were no use against the solid stone, but they might move these pieces. put one of the borers just at the place from which these cracks start—at least, i suppose they are cracks—and let us drive it in for an inch. you hold it, josé. don't turn it, we want it to go in just in a line with this crack. i know we cannot drive it in far, but at least we may make it go deep enough to give a wedge a hold in it."

five such small holes were made in a crack that seemed to form a rough circle, then the wedges were put in, and they began to work with sledges. in ten minutes harry, examining the place carefully, said: "the bit of stone is breaking up. there are lines running across it from the wedges. give me the heaviest sledge." he swung it round his head and brought it down half a dozen times in the centre of the wedges. the cracks opened so far that he could see them without stooping.

"now we will try with the crowbars," he said.

in ten minutes a fragment of the stone was got up; then they hammered on the wedges again, and a piece of rock, which was roughly seven or eight inches in diameter, broke completely off.

"it is only about two and a half inches thick," harry said as he drew one of the fragments out. and, holding the candle to the hole, he went on: "and there is another slab underneath. that settles it. we are at the top of one of these vaults. the question is, is it empty? i am afraid it is. this stone has evidently been broken up and fitted in again with wonderful care."

"why should it be fitted in carefully if they emptied the chamber?"

"that i can't tell you, dias, and it is of no use trying to guess now. first of all, we will get the rest of the stone up. it won't be difficult, for now that we have made a start we can use our crowbars. josé, run up and tell my brother to come down. we shall want him to help with the crowbar; and besides, he would, of course, wish to be here, now that we are on the point of making a discovery one way or the other."

in a minute bertie came down with josé, and donna maria followed. "josé tells me you have broken a hole in one of the stones," bertie exclaimed as he ran up.

"we have got a bit out of a broken stone, bertie. this stone had been broken before, and evidently not by accident. it is only half the thickness of the others, and, as you can see, there is another slab underneath."

"who can have broken it, harry?"

"that question we cannot decide, but i should say probably the incas. we agreed that it was very possible they discovered the hidden treasures of the chimoos. they must have learned, as the spaniards did, how cleverly these places were hidden, and it must have been as evident to them as it is to us, that if there was a hiding-place here, this must be the spot."

when one or two more pieces of the stone had been got out by the aid of crowbars, the rest was removed without the least difficulty. another slab two feet square was exposed. in the middle of this was a copper ring, and the slab fitted, into a stone casing about eighteen inches wide. as soon as this casing was cleared, dias and josé took their places on one side, the two brothers on the other. a crowbar was thrust through the ring, and all of them, taking hold of the ends, lifted with all their strength. at first the stone did not move, but at the second effort it lifted suddenly. it was the same thickness as the one they had broken, and, on being moved, was easily handled. the torches were thrust down, and all peered eagerly into the vault. so far as they could see it was empty.

"shall i jump down, se?or?'

"no, the air may be bad, josé. run up and bring down a short length of rope, twenty feet will be ample. now, let your torch drop down, dias. if it burns, it will be safe for us to go down; if not, we must keep on dropping blazing brands into it till they burn."

as, however, the torch burnt brightly, harry lay down, and, saying, "hold my legs, bertie!" looked down into the vault. eighteen inches below the surface, the hole widened out suddenly. a minute later harry's head appeared above the surface again.

"it is empty," he said in as cheerful a voice as he could manage. "of course it is a disappointment," he went on, "but i felt certain that it would be so directly we found the stone was cracked. the only hope was that the first finders of the treasure afterwards used the place for the same purpose. that they thought it possible they might do so is clear by the care with which they fitted the stones together."

none of the others spoke. the disappointment was a heavy one. bertie broke the silence by saying; "well, better luck next time. they may have found out this place, but there may be others which they did not find."

"quite so, bertie. now we have got up one stone, it will be comparatively easy work getting up the others. we will take up every stone to the end, and then work back till we get to a place where there is not more than a couple of feet between the bottom of the stone and the top of the rock."

at this moment josé ran into the room with the rope. harry took it, and dropped one end until it nearly touched the floor below. "hold on," he said, "and i will slip down first." half a minute later he stood at the bottom of the chamber, beside the torch, which was still burning.

"it is only about three feet across at the bottom," he said; "the wall by the passage goes straight up, on the other side it is the bare rock, so it is almost wedge-shaped. it is twenty feet long, and five feet high up to its roof, that makes it nearly seven to the upper part of the mouth." the vault was absolutely empty. he moved about for a minute and then said: "gold has been stored here. there are particles of gold at the bottom, and there is gold-dust in the cracks of the broken face of the rock. now i will come up again. hold the rope tight; i will climb about a yard, and then i can get my fingers on the ledge."

he was soon up. "now, do any of you want to go down?" dias and josé shook their heads; and bertie grumbled, "i don't want to look at the beastly hole; it has been trouble enough to get at it."

"well, i think we will not do any more to-day, dias. it has rather taken the heart out of one. still, we could not expect to hit upon the treasure for the first time. we will go up and talk it over, and when we have smoked a pipe or two we shall be more inclined to take a cheerful view of the matter. we won't talk about it till we have got to the end of our second pipe."

the tobacco did its usual work, and it was with quite a cheerful voice that bertie broke the silence: "the incas must have been pretty sharp fellows to find that hole, harry?"

"well, very likely they heard that the chimoos had treasure there. indeed they must have known, because, you see, not one of the other stones is broken, so they evidently knew where that chamber was situated."

"yes, i suppose that was it. well, we are in fine working order now, and we sha'n't be very long getting the other stones up."

"not very long this side anyhow, bertie. we shall want some short blocks of wood to put under the stones as we raise them. i expect they are all five inches thick, and they must be a very big weight. evidently it is going to be a longish job. as we have been a fortnight without fresh meat, dias had better go off and buy half a dozen sheep. we won't have dead meat this time. he can bring them slung over the mules, and we can kill them as we want them."

"we have not had fresh meat, but we have not done badly, harry; we have generally had a good many eggs and some pigeons, and josé has brought us in fish from that pool. but they have dwindled down lately. he only brought in a couple of fish yesterday evening."

"well, the pigeons are getting scarcer too, bertie. we have killed a good many, but the rest are getting very shy, and i think most of them must have gone off and settled in new places on the face of the rocks above the ravine. while dias is away, we will try and lay in a stock of sea-fish. we can swim out and sit on the rocks during the day, and lay our lines at night. we have worked very hard for a fortnight, and we deserve a holiday."

dias, when he was spoken to, said he would start at once with four mules for huacha. "it is not above fifteen miles," he said, "and i can get there this evening. i should think that i could buy the sheep there; if not, i must go on to huaura. each mule will bring two sheep. of course i could drive them, but that would seem more singular."

"you had certainly better take the mules, dias. tie the sheep carefully on them, so that they will not be hurt."

"i will take eight of the leather bags, se?or. the sheep are not large, and i will sling one on each side of the mules."

"yes, it would be as well, while you are about it, to bring eight. you may as well get some more coffee. we drink a lot of that, and like it strong. if your wife thinks we shall want more sugar, or anything else, by all means get some."

as soon as dias started, the lines were got ready. they cut a couple of saplings to serve as rods, and josé, digging among the rocks, found plenty of worms, beetles, and grubs for bait. in addition, they took a cake or two of maize, to break up and throw in to attract the fish.

"we had better swim out in our flannel shirts and trousers," harry said. "they will soon dry, and they will keep off the sun. if we were to sit there without them, we should get blistered from head to foot."

"shall we fish outside the rocks, or inside, harry?"

"we will try both; but i think we are likelier to catch most inside. i should think a back-water like that would attract them."

they met with equal success on both sides of the rocks, and by evening had caught over forty fish, at least half of which weighed over four pounds. then they set the long lines, each carrying forty hooks, and returned to the castle with as many fish as they could possibly carry. maria was delighted with the addition to her larder, and she and josé set to work at once to clean and split them. in the morning they were hung in strings from the broad window. maria said they would get the benefit of the heat from the walls, and any air there might be would be able to pass round them.

by means of the night-lines they caught almost as many fish as they had done with their rods, and that day they had the satisfaction of bringing in more than they could carry in one journey.

"we have got plenty now to keep us going for another three weeks," harry said, "and we can always replenish our stock when we choose."

dias returned at sunset carrying one sheep over his shoulders.

"i have left the others out there, se?or; i don't think there is any fear of their straying. there is no fresh grass anywhere except near the stream, and moreover, being strange to the valley, they will naturally keep near the mules."

another month passed in continuous labour. the stones had all been taken up in the basement they had first visited, but no other chamber had been found. the parallel chamber had given them much trouble at starting, as no stone had been found showing any cracks upon it, and they had had to blast one stone to pieces before they could begin to cut up the others. no chamber whatever had been discovered until they were within six feet of the farther end. then one was found, but it showed no signs whatever of having ever been used. "so far so bad," harry said when the supper had been eaten almost in silence; "but that is no reason why we should be disheartened. if the incas buried a treasure they may have thought it prudent to choose some other spot than that used by the old people."

"but where could it be, harry? you agreed that there was not sufficient depth between the floors for any place of concealment."

"that is so, bertie, of course. i have been thinking of it a lot during the past few days, when the chances of our finding a treasure under the basement were nearly extinguished. there are still the side walls."

"the side walls!" bertie repeated. "surely they are built against the rock?"

"yes, but we don't know how straight the wall of rock is. you see, they did not build against it at all in the basement, but above that the side walls begin. the rock must have been irregular, and as the walls were built the space behind may have been filled in or may not. when they came to build they may have found that there was a cavern or caverns in the rock—nothing is more likely—and they may have left some sort of entrance to these caverns, either as a place of refuge to the garrison if the place were taken, or as a hiding-place. they might have thought it more secure for this purpose than the underground chamber, which was their general hiding-place. at any rate it is possible, and to-morrow i vote that we have a thorough inspection of the walls of the storeroom below this. that would be the most likely place, for near the sea-level the chances of finding caverns would be much greater than higher up."

bertie's face brightened as harry proceeded.

"it certainly seems possible, harry. of course the other place seemed so much more likely to us that we have never given the side walls a thought. we may find something there after all. i do hope we may, old boy. i cannot believe that after things have gone altogether so well with us, and we have been twice so near finding treasure, that we should fail after all. which side shall we begin on?"

"we will have a look at them before we decide, bertie. we have not really examined them since the first day; i really forget what stores we found in the two side-rooms."

an examination in the morning showed that the passage near the entrance to the rock on the left-hand side had been used for fuel, that on the other side was filled at the upper end with skins for some distance, and spears and sheaves of arrows were piled against the outer wall along the rest of the distance.

"which do you think is the most likely hiding-place?"

"i should say the right-hand passage. the other with the fire-wood in it might be visited every day, but the spears and arrows would only be wanted in case of any attacks upon the castle, or to arm a large force going out to give battle there. they would naturally put anything they wanted to hide in the passage less likely to be visited."

"that does seem probable," bertie agreed; "therefore, hurrah for the right-hand side!"

"i still think, se?or," dias said, "that there must be treasure concealed somewhere. i should not think a guard would have been placed here, and remained here so many years still keeping watch, as we find they did at that big loophole on the top floor, unless there was something to watch."

"quite so, dias. i have thought that over in every way, and i can see no possible motive for their being here except to prevent the place from being examined. that was needless if there was nothing to guard, and nothing to take away, except these silver brackets, which in those days would scarcely have been worth the trouble of getting out and carrying away. there must be treasure somewhere. we know now that it is not in the basement, and we will try these side walls, even if we have to blow half of them in; there is no doubt that the stones are at least as thick as those at the end, but they will not be difficult to manage. i noticed in the upper story that they had not taken the trouble to fit them nearly so accurately as they did those of the outer walls. i don't say that they didn't fit well, but the stones were of irregular sizes, and i have no doubt that in many places we could prize them out with a crowbar. once an opening is made, there will be no difficulty in getting a lot of them out, as the old people did not use cement or mortar. well, to-morrow morning we will move all the spears and arrows across to the other side of that passage and have a good look at the stones, but we will go up first and look at the side walls of all the other rooms and see if they are of the same build. there may be some difference which we have not noticed. you see all the side walls of this room are built like those in front. i didn't notice whether it was the same in the other rooms."

"i will look at once," dias said, lighting a torch at the fire.

"no, se?or," he said, when in ten minutes he returned; "none of the walls on this floor are built of stone like this. this was the grand chamber, the stones are all nearly one size, and so well fitted that you can hardly see where they join each other. in the other rooms they are not so, but the stones are, as you noticed above, irregular in size, and although they fit closely, there is no attempt to conceal the cracks."

"thank you, dias! well, we won't look any more to-night; we shall see in the morning if the room below us is built in the same way. i have no doubt it is. at any rate we have done enough for to-day. there is some whisky left in that bottle, bertie, and we may as well make ourselves a glass of grog. maria, you had better get down that jar of pulque. we will drink to better luck next time."

the woman smiled faintly. she did not often do so now, her spirits had gradually gone down as the hopes of success faded.

"now, maria," harry said, "you had better take a glass of pulque for yourself. i know you don't often touch it, but you have been working so of late that i think you want it more than any of us."

"i cannot help feeling low-spirited, se?or," she said. "i have so hoped that you would find the treasure you wanted, and marry this lady you love, and it would be such joy for us to have in some small way repaid the service you rendered us, that i felt quite broken down. i know i ought not to have been, when you and your brother bear the disappointment so bravely."

"'it is of no use crying over spilt milk', which is an english saying, maria. besides, it is possible that the milk may not be spilt yet, and until lately your good spirits have helped us greatly to keep ours up. if i were once convinced that we had failed, i have no doubt i should feel hard hit; but i am a long way from giving up hope yet. there is treasure here, and if i have to blow up the whole of the old place i will find it. i have got six months yet, and in six months one can do wonders. anyhow, these brackets will pay us very well for our work. i certainly should not have earned half the sum in any other way in the same time. and even if i fail in my great object, i shall have the satisfaction of knowing that i have done all in my power to gain it. she will know that i have done my best. i have always told her, when i have written, how much i owe to you and dias, how faithfully you have served me, and how you have always been so bright and pleasant. i have no doubt it has cheered her up as well as me."

maria was wiping her eyes now. "you are too good, se?or; it is so little i can do, or dias either, to show our gratitude."

"nonsense! you show it in every way, even in the matter-of-fact way of always giving us excellent food, which is by no means unimportant. now we will all turn in, and make a fresh start to-morrow morning."

they were up at daybreak, and after taking their usual cup of coffee lit the torches and descended the stairs to the floor below.

as soon as they reached the right-hand wall, harry exclaimed: "why, this is built in the same way as the one we have left! the stones are squared and fitted together as closely as those in the drawing-room. then why should that be, except in that one room? the side walls all the way up are roughly built. why should they have taken the trouble on this floor to build these, which are only meant as store-rooms, when even in the rooms above, which were meant for the habitation of the chief and his family, the rough work was deemed sufficiently good? there must have been some motive for this, dias."

"there must have been, se?or; it is certainly strange."

"first of all, let us clear the wall and take a general view of it. guessing won't help us; but i have the strongest hopes that behind one of these stones lies a cavern. by the way, dias, take a torch and go into the next chamber and see if the stones are solid there."

"they are just the same as those here," dias said when he returned.

"i would rather that it had been the other way," harry said, "for then i should have been more sure that there was some special reason for their building them in this way here."

it took them all half an hour's work to move the spears and arrows to the other side.

"do you think, harry, if we were to tap the stones we should be able to find whether there is a hollow behind any of them?"

harry shook his head.

"not in the least. i have no doubt these stones are two or three feet thick, and there could be no difference in the sound they would make if struck, whether they were filled in solid behind or had no backing. to begin with, we will make a careful examination of the walls. possibly we shall see some signs of a stone having been moved. it would be very much more difficult to take one of the great blocks out and put it in again than it would be to get up one of the paving-stones."

when they had gone about half-way along, examining each stone with the greatest care, bertie, who was ahead of the rest, and passing the candle he held along the edge of every joint, said, "look here! this stone projects nearly half an inch beyond the rest."

the others gathered round him. the stone was of unusual size, being fully two and a half feet wide and four feet long, the bottom joint being two feet above the floor.

bertie moved along to let the others look at the edge. he was keeping his finger on the joint, and they had scarcely come up when he said, "the other end of the stone's sunk in about as much as this end projects."

"something certainly occurred to shift this stone a little," harry said, examining it carefully. "it is curious. if others had been displaced, one would have put it down to the shock of an earthquake—a common enough occurrence here—but both above and below it the stones are level with the others, and nowhere about the house have we seen such another displacement. look! there is a heap of rubbish along the foot of the wall here. stir it up, dias, and let us see what it is."

"it is sand and small stones, and some chips that look like chips of rock."

"yes, these bits look, as you say, as if they had been chipped off a rock, not like water-worn stones. though how they got here, where everywhere else things are perfectly tidy, i cannot say. however, we can think that over afterwards. now for the stone! let us all put our weight against this projecting end. i don't in the least expect that we can move it, but at any rate we can try."

they all pushed together.

"i think it moved a little," harry said, and looked at the edge.

"yes, it is not above half as far out now as it was."

"that is curious, for if it is as thick as we took it to be, it would weigh at least a couple of tons. we won't try to push it in any farther. i am sorry we pushed it at all. now, give me that heavy sledge, josé, possibly there may be a hollow sound to it. i will hit at the other end, for i don't want this to go in any farther."

he went to the stone beyond it first and struck two or three blows with all his strength. then he did the same with the stone that they were examining.

"i don't think it gives such a dead sound," he said.

the others were all of the same opinion.

"good! this is another piece of luck," he said. "we have certainly hit on something out of the way."

"your hammering has brought this end out again, harry," bertie said.

"so it has, and it has pushed this end in a little. let us try again." but although all took turns with the sledges, they could make no further impression on the stone.

"well, we will try the drills," harry said. "in the first place, we will find out how thick it is."

they at once set to work with the drill. progress was slower than it had been before, because, instead of striking down on the head of the drill, they had now to swing the hammer sideways and lost the advantage of its weight; and they were obliged to work very carefully, as a miss would have seriously damaged the one holding the drill. it took them four hours' steady work to get the hole in three inches. ten minutes later, to their astonishment, the drill suddenly disappeared. dias, who was striking, nearly fell, for instead of the resistance he had expected, the drill shot forward; the hammer hit josé, who had this time been holding the drill, a heavy blow on the arm, causing him to utter a shout of pain.

harry, who was sitting down having breakfast, having just handed his hammer to bertie, jumped to his feet.

"how did you manage that, dias? i suppose it slipped off the head. you must have hit josé a very heavy blow."

"i have hit him a heavy blow, se?or, and nearly tumbled down myself; but i struck the drill fairly enough, and it has gone."

"gone where, dias?"

"i think it must have gone right through the hole, se?or."

"then there is an empty space behind!" harry shouted joyfully. "however," he went on in changed tones, "we must see to josé first. that blow may have fractured his arm. let me look, josé. no, i don't think anything is broken, but there is a nasty cut on the wrist. it is fortunate that you were not striking straight down, dias, for i am sure we have not put anything approaching the strength into our blows, now we are hitting sideways, that we exerted before. you had better go up to maria, josé, and get her to bathe your wrist with cold water, and put on a bandage."

"now, se?or, what shall we do next?"

"well, now that we know that its weight cannot be anything very great, and that certainly to some extent it can be moved, we will try hammering again at that end. do you stand three or four feet beyond it, so as to be able to bring your sledge down with all your strength just on the lower corner. i will face you and strike six or eight inches above where you hit. of course we must both bring our hammers down at the same instant. we shall be able to do that after two or three trials. stand at the other end of the stone, bertie, and tell us if it moves at all."

after one or two attempts the two men got to swing their hammers so as to strike precisely at the same moment, and when half a dozen blows had fallen, bertie said: "it comes out a little at each blow. it is not much, but it comes."

three or four minutes later he reported, "it is an inch and a half out now, and there is room to get the end of a crowbar in here."

"that is curious," harry said as he lowered his sledgehammer, and, taking up the candle, examined the end where he had been striking.

"this is sunk about the same distance, bertie. the stone must work somehow on a pivot."

they now put a crowbar into the end bertie had been watching, and all three threw their weight on the lever. slowly the stone yielded to the pressure, and moved farther and farther out. it was pushed open until the crowbar could act no longer as a lever, but they could now get a hold of the inside edge. it was only very slowly and with repeated efforts that they could turn the stone round, and at last it stood fairly at right angles to the wall, dividing the opening into equal parts about two feet four each.

"there is a pivot under it; that is quite evident. it may be a copper ball in the stone below, or it may be that a knob of the upper stone projects into a hole in the lower. however, it does not matter how it works. here is an opening into something. dias, will you go upstairs and tell your wife and josé to come down? they had better bring half a dozen more torches. our stock here is getting low, and we shall want as much light as possible. it is only fair that we should all share in the discovery."

dias went off.

"now, bertie, we must not let our hopes grow too high. i think it is more likely than not that we shall find nothing here."

"why do you think so, harry? i made sure we had as good as got the treasure."

"i think, if there had been treasure," harry went on, "that this stone would have been closed with the greatest care. they would hardly have left it so carelessly closed that anyone who examined the wall would have noticed it, just as we did. we found the other places most carefully closed, though there was nothing in them."

"perhaps there was something that prevented them from shutting—a little stone or something."

"but we know that that wasn't so, bertie, because the stone yielded to our weight; and if it did so now, it could have been shut with the greatest ease originally, when no doubt the pivot was kept oiled, and the whole worked perfectly smoothly. it is almost certain that they were able in some way to fasten it securely when it was shut. what is that piece of square stone lying there?"

"it fell down from above just as the slab opened."

harry took it up. it was about six inches long by two inches square.

"it is a very hard stone," he said—"granite, i should say. i expect you will find that it fits into a hole in the stone above."

"yes, there is a hole here," bertie said, feeling it; "the stone goes right in."

"well, i think, bertie, you will find a hole in that end of the stone we moved that it will fit."

bertie crept in, and felt along the top of the stone.

"yes, there is a hole here about the same size as the stone, but it is not more than three inches deep."

"then, that stone was the bolt, bertie. you see it was pushed up, and the door then closed; and when the stone was exactly in its place, it would drop into the hole and keep it from moving, and nothing short of breaking up the bolt would give an entrance. it is lucky that we did not push it quite to; another quarter of an inch and that bolt would have fallen, and we could not have moved it unless by smashing the whole thing into bits. that was why they did not quite close the stone; they wanted to get in again."

"here come the others!"

maria had been washing some clothes in the stream, and they had therefore been longer in coming than if she had been in the room. they all looked greatly excited.

"so you have found it, se?or!" dias exclaimed in delight.

"we have found an entrance into somewhere, but i am afraid it will be as empty as the other chambers."

"why do you think so, se?or?" dias asked in dismay.

harry repeated the reasons he had given bertie for his belief that the stone must have been left in such a position as to be easily opened when required.

"why should it have been left so?"

"because the treasure they expected had never arrived. it is possible that when the incas discovered the treasure in that chamber we searched, they may also have found this entrance. it may have been shown to them by one of the prisoners, and they may have broken the stone here into pieces as they broke that over the chamber afterwards. seeing what a splendid hiding-place it was, they may have, when the spaniards first arrived, made another stone to fit, with the intention of using it for a hiding-place themselves. the fact that the stone was left so that it could be at once opened is conclusive proof to my mind that the treasure never came. that heap of sand, small stones, and chips of rock is another proof that they were ready to receive treasure, and it was probably swept out of the chamber that is behind here, and would, of course, have been removed when the treasure was put in and the door closed; but as the treasure never did come, it was left where it lay. however, we will now go and see. i have only kept you waiting because i did not want you to be disappointed."

one by one they crept through the opening. for four feet in, the passage was the same width as the stone, but two feet deeper; then it at once opened into a large cavern.

"this wall was four feet thick, you see, dias. apparently squared stone was only used for the facing, as the stones are of irregular shape on the back. this would be a natural cavern, and a splendid hiding-place it makes. no doubt its existence was one of the reasons for building this castle."

the cavern was some twelve feet wide and thirty feet high at the mouth; the floor sloped up sharply, and the sides contracted, and met forty feet from the mouth. the floor had been cut into steps two feet wide, running across the cave and extending to the back. these steps were faced with a perfectly flat slab of stone. the cave was empty.

the natives uttered loud exclamations of disappointment and regret.

harry had so thoroughly made up his mind that nothing would be found there that he surveyed the place calmly and in silence. bertie imitated his example with some difficulty, for he too was bitterly disappointed.

"you see, dias," harry went on quietly, "this place was prepared to receive treasure. the steps have all been swept perfectly clean. you see, the gold could be piled up, and no doubt the steps were cut and faced with stone to prevent any gold-dust that might fall from the bags, in which, no doubt, it would be brought, and small nuggets, from falling into the cracks and crevices of the rock. i should say that in all probability they expected that treasure ship that was lost, and had everything in readiness for hiding the cargo here directly it came. it never did come. the door was shut as far as it could be without the bolt falling down and fastening it; then they waited for the ship; and if it did not arrive, other treasure might be brought by land. well, it cannot be helped. so far we have failed. there may still be treasure hidden somewhere. we cannot say that we have searched the place thoroughly yet."

for another six weeks they worked hard. the wall was broken through in several places, but no signs of the existence of any other cavern or hiding-place was discovered.

"i should give it up," harry said, when at the end of that time they were sitting gloomily round the fire, "but for one thing: i can see no possible explanation why a party of men should have been left here, and a guard kept, for perhaps a hundred years, perhaps more, and the stories about demons been circulated, and people who ventured to approach been murdered, unless there had been some good reason for it. that reason could only have been, as far as i can see, that there was a treasure hidden here. i have turned it over and over in my mind a thousand times, and i can think of no other reason. can you, bertie, or you, dias?"

"no," bertie replied. "i have often thought about it; but, as you say, there must have been some good reason, for no people in their senses would have spent their lives in this old place, and starved here, unless they had some cause for it."

dias made no reply beyond shaking his head.

"you see," harry went on, "they kept up their watch to the end. there were those two skeletons of men who had died at their post at that curious window where nothing could be seen. i hate to give up the search, and yet we seem to have tried every point where there was a possibility of a hiding-place existing."