harry and his brother went to the edge of the pool, where they undressed and waded out. they found that the bottom of the passage sloped more gradually at the edge of the water than it did higher up, and they were able to walk out till they came to the point where the roof dipped into the water. they dived, and in a few strokes came up beyond the roof.

"this is glorious!" bertie said. "we have often bathed in pools, but this is a different thing altogether. it is more than a year since we had our last dip in the sea, the day we arrived at callao."

although there was little or no wind, the rollers were breaking on the line of rocks outside, pouring over the lower points in volumes of foam, and coming in broken waves up the passage.

"we mustn't go beyond the point, bertie, or we may be dashed against the foot of the cliff. we will climb up that rock to the left; it is not too steep, and i think we can manage it. from there we shall get a good view of this side of the house and of the situation in general."

it required considerable care to climb the rocks, and more than once they hurt their feet on sharp projections. the top of the rock, however, was smooth by the action of time and sea, and they were able to sit down on it in comfort.

"the castle is just as you described it, bertie; and certainly no one sailing past, however close he came outside these rocks, would be able to detect it. no doubt the stone of which it is built is the same as that of the cliffs. most likely it was taken from the ravine where the passage now is, and had fallen from the arch above. it might have been more noticeable at first, but now it is weathered into exactly the same tint as the cliffs. the openings are very dodgily placed, and a stranger would not dream that they went many inches in. now, from where we stand we can look up into that curious opening on the top story. i have been puzzling over that ever since i saw it, but can't think of any possible reason for its having been cut like that, except to enable them to throw stones on to any boat that came into this passage behind the rocks; and yet that can hardly have been the case, for, as i remarked, there are no stones piled up there. certainly they had a very large number of arrows, but stones would be very much more useful than arrows against a boat almost under their feet. however, that does not concern us now. this line of rocks must greatly aid in hiding the house from the sea. they are higher than you thought they were, looking down at them from above. we are quite thirty feet above the water, and at two or three points they are at least ten or twelve feet higher. of course a short way out no one would be able to see that they were detached from the cliff, or that there was any passage whatever behind them.

"besides, they break the force of the waves. if it was not for them it would be impossible for any boat to come up close to the face of the house, and a heavy storm might even break down the wall altogether. a tremendous sea would roll in here in a westerly gale; and if it hadn't been for these rocks it would have been necessary to build the lower part of the house absolutely solid to resist the sea. it is possible that the rocks were higher than they now are when the place was first constructed, in which case the house might have been almost entirely hidden from sight. well, we may as well go back again, bertie; we know all there is to be known about this side."

they swam back into the tunnel, dressed, and went out.

"we have come out, maria," bertie called. "the coast is clear for you. the water is not so deep as we thought it was, and you can walk out to the point where the roof comes down on to the water without getting out of your depth."

it did not take them long to cut a number of switches to serve as brooms, and a couple of handles. they carried them up into the house, and lashed the switches firmly on to the handles. the work was rough, but the brooms when completed were large, and, although not strong enough for heavy work, would do well to sweep aside the thin layer of almost impalpable dust on the floor below.

"shall we take wood down there, harry?"

"no; i think a fire would be a drawback rather than an assistance. it would be very valuable if we were working at one spot, but it could give no general light in a place a hundred feet long. we will take a torch down, and hold it and sweep by turns. we shall only want, to begin with, to make a clear path a couple of feet wide down the middle. of course later on we shall clear it all. that will be sufficient to enable us to see how the floor is constructed, whether with big blocks or small ones, how closely they are fitted together, and so on. it is certainly unlikely that we shall find any indication as to where chambers exist."

it took but a very short time to clear the path; the dust was so light that one sweep of the broom cleared it away. when they got to the farther end they returned to examine the floor. for four or five feet from the cistern the rock had been evidently untouched, except to cut off any projecting points. then there was a clear line running across the path. bertie held the torch down close to it. harry knelt down and examined it.

"this is a clean cut, bertie. it is evidently solid above this, but the stone is not quite the same colour on each side of it, and it looks as if they had cut away the rock here and begun to build so as to keep the floor level. the cut may be six inches deep and it may be a foot, that doesn't matter. the face of this stone is very smooth, but it is not cut; it is, i think, the face of the natural fracture. move the torch along and let us see where the next join is. ah, here it is!"

the slab was four feet across.

"you had better sweep the dust off both ways, bertie, so that we may see what size it is."

it was, they found, about eight feet long.

"it has straight edges, harry, almost as straight as if it had been sawn."

"very likely it was sawn, bertie; they could have had no tools that would cut a hard stone like this regularly, but as they were certainly clever builders they must have employed some means to do it. possibly they used a saw without teeth, for however much they might have hardened the copper, the teeth could not have stood, but if they had a hard copper band fixed like the saw some masons use, and kept the stone moistened with fine sand, they might have cut into it. of course it would have been a slow process; but they would not have needed to go far into the stone, for when they got down two or three inches they might have broken it through by dropping a heavy weight on the end. it would not have mattered if the fracture had not been straight below the cut, for only on the surface would they have wanted to fit accurately to the next stone. in another way they might have got a straight edge, that is, by driving very dry wedges into the cut made by the saw, and then moistening them. i know that great stones can be split in that way. they may have used both methods. however, it doesn't matter to us much how they did it. it is clear that they could in some way or other cut stones. as they took the trouble to do so here, we may conclude that they were anxious to have a smooth floor that would be extremely difficult to get up.

"they would never have taken all this trouble if they had merely been making a floor for a cellar. for that purpose it would only have been necessary to throw rocks and stones of all sizes into the vacant space below, and when it was nearly full, to level it with small stones and sand. that they chose to undertake such tremendous labour as the making of so regular a floor as this must have been, shows that they had some very strong motive for doing so."

going carefully along the track they had cleared, they found that the stones were of different sizes; some were but two feet wide, others as much as ten, but all fitted so closely together that it was difficult to see the joints.

"it is going to be a hard job to get these out, bertie," harry said, when they had completed their examination, "and it is lucky for us that the room gradually narrows from sixteen feet wide to two at the other end, and when we stepped it we made it eighty feet long. we need not take up the stones near the rock wall, for the ravine would naturally narrow as it went lower, and the depth would be greatest by the side of the wall of the tunnel."

"well, we shall soon blow up the stones when we have got the powder."

"i hope so, bertie; but i see that we shall have difficulty unless these top stones are extraordinarily thick."

bertie looked surprised. "why, i should have thought the thicker they were the more difficult to break up."

"beyond a certain point that would be so. but suppose they are six inches thick, you may take it for granted that underneath there will be rubble, loose stuff, except where any chambers may be built. if we were to bore a hole through this top layer the powder, instead of splitting the stones up, would expend its force among the loose stuff beneath it; and besides, instead of remaining in its place, it might get scattered, and we would then get no explosion at all."

"then we should only have to make the hole four inches deep, harry?"

"as a result of which there would only be two inches of tamping over the powder, and this would blow right out, as if from a little mortar, and would have no effect whatever upon the stone. i have no doubt that we shall find some way to get over these difficulties, but it is evident that the work will not be all clear sailing."

"of course we shall manage it somehow, harry, even if we have to smash up all the stones with the sledge-hammers dias will bring us."

"is breakfast nearly ready, se?ora? that swim in the sea has given us a prodigious appetite. did you enjoy it?"

maria nodded.

"it is very nice, se?or; but i should have liked it better if the water had not been so blue. it seems so strange bathing in blue water."

"you will soon get accustomed to it," bertie laughed. "there are no pools except that one two miles up the valley. besides, it is much nicer to have a great bathing chamber all to yourself. here comes josé!"

"well, josé, are the mules all right?" he shouted.

"yes, but i had difficulty in catching them. they had evidently been frightened by something, and were three miles up the valley with their coats all staring. it must have been either a puma or a jaguar. of course they must have got wind of him in time; but as, fortunately, they were not tethered, they were able to get away from him."

"i should think he must be up somewhere among the bushes, josé," harry said. "we had better go down tonight and see if he returns again. we shall be losing some of the mules if we don't put a stop to his marauding. besides, it will be very dangerous for you, josé, cutting the wood up there, if he is lurking somewhere. it is fortunate that you escaped yesterday."

"i expect he was on the other side of the ravine, se?or; and even if he had not been, the sound of the chopping would have scared him. they will not often attack in the daytime."

when they had finished their breakfast josé asked what he should do next.

"there is nothing else to do, so it would be as well to take our pickaxes and get some of those brackets out of the walls. we will begin with the other rooms of this floor and leave these here till the last."

"i will come and hold a torch for you, se?ors," maria said. "i like to be doing something. i will wash up first, and then i shall have nothing to do till it is time to get ready for dinner. now i know there is a savage beast about i should not like to go down the ladder."

"there is very little chance of his coming down the rocks," harry said. "he is more likely to be lying somewhere on the other side watching the mules."

no move was made until the woman was ready to start. then they lit two torches. she took one and bertie the other, while josé and harry took two picks. it was hard work, for the brackets were driven far into the pillars and walls. it was necessary to knock away the stones round them to a depth of two or three inches before they could be got out. they worked one at each side of a bracket, relieving each other by turns, and after four hours' work only eighteen brackets had been got out. as far as they could tell by lifting them, the weight was somewhat greater than they had at first supposed. harry could hold one out in each hand for a minute and a half, bertie and josé for a little over half a minute, and they agreed that they must be about twenty pounds each.

by this time their shoulders ached, and it was agreed that they had done a good day's work. for the rest of the day they did nothing but sit on the sill of the window and smoke quietly. the next day's work was similar, and twenty more brackets were got out. late in the afternoon they saw dias coming down the steps, and at once went down the ladder to meet him.

"have you got everything, dias?"

"i think so, se?or, and i can tell you that the mules have had a pretty heavy load to bring back."

"well, we will go with you at once, dias, and bring some of the things up. i expect you have had nothing to eat since the morning. before you do anything else you had better go in. your wife has been keeping a dish hot for you, as she did not know when you might arrive."

"i shall not be long before i come and help you, se?or. i have unsaddled the mules and turned them out to graze."

"it is just as well, dias, for there is a beast somewhere about that gave them a fright last night. we will get all the eatables up to-night, the powder and drills and hammers we can very well leave till to-morrow morning."

it took them four trips to bring the provisions over, for it required two of them to carry each sack of flour, and indeed all had to give their aid in getting them up the rocky slope at the foot of the wall.

"no one seemed to think it unusual, your taking so large a load, i hope, dias?" harry said as they sat down to their evening meal.

"no, se?or. the man i bought the powder of was a little surprised at the amount i wanted; but i said that i might be absent many weeks in the mountains, and might want to drive a level in any lode that i might discover. i led him to believe that i had seen a spot in the mountains that gave good indications, and that two of my comrades were waiting there for my return to begin work at it. i sold the llamas to a man who carries goods from ancon up to canta, and got the same price that you gave for them."

harry then told him the work on which he had been engaged since he had been away.

"of course there is no hurry about the brackets, but as we could do nothing else without the powder and drills, it was just as well to get them out, as otherwise we might have been delayed when we had done our other work. we think that they weigh twenty pounds each, so that altogether they will be worth nearly four thousand pounds. not a bad start. i am afraid we sha'n't make such quick work down below."

"we shall see," dias said cheerfully, for now that his fear of the demons had passed he was as eager as harry himself to begin the search for the treasure.

"has maria seen any more bats?"

"yes, she has seen some more bats," his wife said, "but no demons. dias, what do you think? don harry suggested that we might eat the bats."

"i have heard of their being eaten," dias said, "and a man who ate them raw told me that he had never enjoyed anything more. but i should not like to try it myself, unless i were driven to it as he was."

"how was that, dias?"

"he was a muleteer, se?or, and was up in the mountains. he had a cargo of silver on his mule, and during the day he had seen some men who he doubted not were brigands on the top of the ravine he passed through. he knew of a cavern where he had once taken refuge with the animals during a storm. it lay on the hillside some twenty or thirty yards away from the road. the entrance was hidden by bushes, and he had first noticed it by seeing a bear come out as he was passing along. he had his pistols, and thought that it was better to risk meeting a bear than a brigand. he arrived opposite the cave just as it became dark, and at once led the mules up there. he first lighted a torch—the muleteers always carry these with them—and then went in with his pistols ready, but there were no signs of a bear anywhere near the entrance.

"he drove the mules in and put out his torch. the entrance had been only wide enough for the laden animals to pass, but it widened out a great deal inside. he took off the loads, piled them up in the narrow part to make a barricade, and then sat down at the entrance and listened. he soon heard five or six men come down the road talking. they were walking fast, and one was saying that he could not be more than half a mile ahead, and that they should soon catch him. when they had gone, he went some distance in the cave and relighted his torch. he went on and on. the cave was a very large one, and when he had gone, as he thought, four or five hundred yards, it branched off into three. he took the middle one, and followed it for a long way. at last it opened into a large chamber from which there were several passages. here he found a large number of things that had evidently been stolen from muleteers. there were at least a dozen mule loads of silver; goods of all kinds that had been brought up from the coast; the ashes of fires, and a great many bones and skins of llamas, and some sacks of flour.

"he thought he would now return to the mules; but apparently he entered the wrong passage, for he went on till he felt sure he ought to be in the chamber where he had left the animals, and he was turning to go back when he tripped over a stone and fell, and his torch went out. then he felt in his pocket for his box of matches, and to his horror found that it had gone. it must have dropped out when he was examining the passages. he did not think much of it at first, but he had passed several openings on his way, and in the dark he probably turned down one of these. at any rate he lost his way somehow, and wandered about, he thinks, for hours; but it might have been much less, for he told me that he quite lost his head. at last he came out into a place where he could only feel the rock on one side of him, and knew that he must be in a large chamber.

"looking up he saw, to his joy, a faint light, and moving a little, caught sight of a star. he was utterly worn out, and threw himself down. he was awakened by a strange rustling sound, and looking up saw that daylight was breaking, and that a stream of bats was pouring in through a hole, which was about three feet wide. he made several efforts to climb up to it, but failed. the bats hung thickly from every projecting point in the rocks. he hurt himself badly in one of the attempts to get up, and twisted his foot. all day he lay there. then the idea struck him that he would kill a bat, cut it open, and use it as a poultice to his foot. the creatures did not move when he touched them, and he cut off the head of one of them and split it open. he did this three or four times during the day, and felt that the application was easing the pain of his ankle.

"when it became dusk the bats flew out again, and he knew his only chance was to keep his ankle perfectly rested. in the morning he killed some more bats. he was by this time tortured with thirst, and sucked the blood of one of them, and in the afternoon ate one raw. another night passed, and in the morning he felt so much better that he could make another trial. he ate another bat to give him strength, and in the middle of the day made a fresh attempt. he had while lying there carefully examined the wall of rock, at the top of which was the opening, and had made up his mind at what point would be best to try. this time he succeeded. he made his way down the hillside, and found that he was a quarter of a mile higher up the pass than the spot at which he had left the mules. he hobbled down, and to his delight found his animals still in the cavern.

"he had when he first got there opened their sack of grain in order to ensure their keeping quiet. there was still some remaining at the bottom. he lost no time in loading them and leading them out, and made his way down the pass without seeing anything of the robbers. afterwards he went back there with a good supply of torches, found his way to the cave, and brought down two mule-loads of silver. gradually he brought the rest of the goods down, and today he is a rich man."

"well, i think under those circumstances, dias, i would have eaten bats myself. it was certainly a clever idea of his to convert them into poultices, though the general opinion is that cold bandages are the best for a sprained ankle."

then they discussed their plans for the next day. "i know nothing about blasting, se?or. you give me instructions, and i will do my best to carry them out; but it is useless for me to talk of what i know nothing about."

"there is a lot of common sense in that, and yet in every work, dias, sometimes while a skilled man is puzzling how to do a thing a looker-on will suggest a satisfactory plan. that treasure has been buried there i have no doubt whatever. they would never have gone to the labour of paving those cellars as carefully as they have done unless for some special purpose. the floor was undoubtedly made when the house was built, and if we find treasure-chambers there they will be those of the old people. of course they may have been discovered by the incas, and when they in turn wanted to bury treasure this place might occur to them as being particularly well fitted to escape search by spaniards. however, to-morrow we shall learn something more about them. the first thing to do in the morning, when we have brought up the rest of the goods, is to sweep the floors of those chambers carefully. when we have done that we will determine where to set to work."

two trips brought up the powder and instruments.

"we will take one of the kegs of powder down with us," said harry, "and leave the other five in the empty room behind this. it is just as well not to have them in this room; the sparks fly about, and some things might catch fire. i don't think there is any real danger, but, at the same time, it is best to be on the safe side."

"there are a dozen pounds of candles in this bundle, se?or. you did not tell me to get them, but i thought they might be useful."

"thank you, dias! they certainly will be useful. what are they?—tallow?"

"yes, se?or."

"then before we go down we will get a couple of pieces of flat wood, and drive a peg into each, sharpened at the upper end. candles stuck on these will stand upright, and we can put them down close to where we are working. they will give a better light than a torch, and leave us all free to use the tools. did you think of buying some more tinder?"

"yes, se?or, i have five boxes, and half a dozen more flints."

they carried the keg of powder, the sledges, drills, and wedges downstairs, and then dias and josé set to work to sweep out the two chambers. the work was easy, but they were obliged to stop several times, being almost choked with the light dust. harry and bertie offered to take their turn, but the others would not hear of it, and they were glad to go up to what they called their drawing-room until the work was done and the dust had settled a little. then they examined the pavement carefully with their torches. they had hoped that they might find either copper rings, or at least holes where rings had been fastened, but there were no signs whatever of such things in either of the chambers.

"we will begin to work half-way down," harry said. "of course the treasure may lie near the cistern end, but the depth below the floor would be very shallow there. more likely the chambers would be at the deep end. if we begin in the middle we may be pretty sure that we have not passed them. we will begin rather nearer the passage wall than the other, as the depth there will be greater. it does not matter which stone we take, one is as likely as another. step ten paces from the cistern, bertie, and the stone you stop on we will try first."

when bertie came to a stand-still they carefully examined the pavement. "you are standing on one of the cracks, bertie; i will stay there while you all bring the tools along."

"shall i open the powder?" bertie asked.

"no. it is no good doing that until we have quite decided what we are going to do. the wedges certainly won't go into this crack. i think our best plan will be to sink a bore-hole about two inches from the crack. we will drive it in in a slanting direction towards the edge, and in that way it will have more chance of blowing a piece out. first of all, we must make a slight indentation with a pick, otherwise we sha'n't get the bore to work. i will begin."

he took a pick and struck several blows.

"it is very hard stone," he said. "i have scarcely made a mark upon it."

he worked for some time, and then let bertie take the pick. the lad struck a blow with all his strength, and then dropped the pick with a loud cry, wringing his hands as he did so.

"you have jarred your hands, bertie; you should not hold the haft so tightly."

"it did sting!" bertie said. "i feel as if i had taken hold of a red-hot poker. it has jarred my arm up to the shoulder; i can't go on at present."

"you try, dias."

dias went more carefully to work, knelt down on one knee, and proceeded to give a number of what seemed light blows.

"that is better than i did, dias. the stone is crumbling into dust, and we shall be able to use the borer in a short time. perhaps it will be better after all to drive the hole down straight. it will be easier to begin with; when we see how thick the stone is we shall know better how to proceed."

in ten minutes dias had made a hole a quarter of an inch deep.

"now, give me one of the borers—that one about two and a half feet long. i will hold it, and you strike to begin with, dias, only mind my fingers. keep your eye fixed on the top of the borer, and take one or two gentle strokes to begin with; then, when you know the distance you have to stand from it, do your best. you needn't really be afraid of striking my fingers. i shall hold the drill at least a foot from the top."

dias began very carefully, gradually adding to the strength of the blows as he got the right distance, and was soon striking hard. after each blow harry turned the borer a slight distance round. when he heard the native's breath coming fast he told josé to take a turn. the lad was nervous; the first blow he struck only grazed the top of the borer, and narrowly missed harry's fingers. josé dropped the sledge. "i can't do it, se?or; i am afraid of hitting your fingers. i will sit down and hold it; it does not matter if you hit me."

"it would matter a good deal, josé. no, no; you have got to learn."

"would it not be well, se?or," dias said, "to take the borers and three hammers outside, and try them in soft ground? we could work them there till we all got accustomed always to hit them fair. there would be no occasion for them to be held, and we should get confident. i could have hit twice as hard as i did, if i hadn't been afraid of missing it."

"i think that is a very good plan, dias. the loss of a day or two will make no difference. we shall make up for it afterwards."

accordingly the drills and hammers were all taken up, and they were soon at work. two or three gentle taps were given to the borers, to make them stand upright, and then all four began work. at first they often either missed the heads of the borers or struck them unevenly.

"it is well, dias, that we carried out your suggestion, as i see i should have had an uncommonly good chance of getting my fingers smashed, or a wrist broken. i have missed as often as any of you."

they stopped frequently for breath, and at the end of an hour were glad to lay down their hammers. dias was comparatively fresh; his practice as a woodsman now did him good service.

"i should have thought from the number of trees that i have helped to cut down," bertie said, "that i could hit pretty hard, but this is a great deal stiffer work. i should say that this hammer is at least twice the weight of the axe, and it is the lightest of the four. i ache a good deal worse than i did when i first chopped that tree down."

"so do i, bertie. we will stick at this till we get accustomed to the work. by doing so we shall gain strength as well as skill."

"i will get some grease, se?or, from maria, and then i will rub your shoulders, and arms; that will do you a great deal of good."

"thank you, dias! it would be a good plan."

dias did this to josé as well as to the brothers, and then josé in turn rubbed him.

they waited half an hour, and then harry said: "let us have another spell." this time a quarter of an hour sufficed. "it is of no use, harry; i can't go on any longer," bertie said. "i feel as if my shoulders were broken."

"i am beginning to feel the same, bertie. however, we are all hitting straighter now. we will go up into the shade and take it quietly for two or three hours; then we will have a spell again."

however, after the rest, they all agreed that it would be useless to try again, for they could not lift their arms over their heads without feeling acute pain. three days were spent at this exercise, and at the end of that time they had gained confidence, and the heads of the drills were no longer missed.

after the first day they only worked for a quarter of an hour at a time, taking an hour's rest. the pain in their arms had begun to abate. on the following day they practised striking alternately, three standing round one borer. they found this at first awkward, but by the end of the day they were able to strike in regular order, the blows falling faster after each other on to the drill.

"i think we shall do now," said bertie. "no doubt we shall hit harder with a fortnight's practice, and shall be able to keep it up longer. however, i think that even now we have sufficient confidence in striking to be able to hold the borer without any fear of an accident."

the next day they began work early in the cellar. josé volunteered to take the first turn to hold the drill.

"you understand, josé, you must turn it round a little after each stroke, and in that way it will cut the hole regularly."

harry took his place on one side of josé, who sat with a leg on each side of the drill. dias stood facing harry, bertie behind josé holding the torch so that its light fell strongly on the head of the drill. at first the two men struck gently, but gradually, as they grew confident, increased the weight of their strokes until they were hitting with their full power. after ten minutes they stopped. "let us look at the hole," harry said. "how far has it got down?"

josé moved his position and harry examined the hole. "about an eighth of an inch," he said. "let us scrape the dust out of it."

"shall we take a spell now, harry?" bertie said.

"no, we will wait five minutes and then go on again, and after that we will change places with you, relieving each other every twenty minutes."

the work went on, and at the end of two hours the hole was three inches deep. another hour and a half and the drill suddenly went down.

"we are through it," bertie said, "and i am not sorry."

"now i will lift the drill up gently, bertie; do you kneel down, and when i stop, take hold of it close to the floor, so that we may see the thickness of the stone."

"five inches," he said as he measured it. "now put on a little grease, dias. i will lower it again, and we shall be perhaps able then to get some idea of what is underneath."

he lowered the drill and turned it round two or three times, and then carefully raised it. some sand and little stones were sticking to it.

"sand and gravel," he said. "that settles that point. now we have done a good morning's work, and let us go up and have breakfast."

maria looked enquiringly at them. "i was just coming down for you. well, what have you done?"

"we have drilled one hole, maria, and none of us have got our fingers smashed, so i think we have every reason to be satisfied with our first experience at the work."

as they breakfasted they talked matters over. harry said that he was certain that the thickness of the stone was not sufficient for them to break it up by blasting. "we shall have to try some other plan. it is equally certain that we cannot smash the stone with the sledge-hammers, and i don't think that the wedges would break it. of course if we got one stone out it would be comparatively easy to lift the next, as we could put the crowbars under it. if we can do it in no other way, we must drill a line of holes close to each other right across the stone, and we might then break off the piece between them and the crack and get our crowbars under the slab. it might be worth while to drill holes a foot apart, from the point where we have begun to the other end of the room. of course if we found that gravel and stones were everywhere under the slabs we should learn nothing; but the opening to the chambers is probably covered by another stone, and if we found that, we could put in one or two more holes so as to be sure that it was flat, in which case we might smash it somehow. of course, if we don't come upon a flat stone we shall conclude that they put a layer of sand and fine gravel over the slabs covering the vaults, and must then, as i say, get up one stone and gradually lift all the rest, clearing out the gravel as we go to the depth of a foot or so. in that way we shall make sure that we shall not miss any chamber there may be.

"i think that would certainly be the best plan. at present we are groping altogether in the dark, and it will take us a fortnight at least to make that row of holes close to each other, as you propose."