For quite a quarter of an hour we remained motionless ­the watcher and the watched ­Tom and I both well armed, and involuntarily our guns were pointed at the eyes; but the position was not one which justified firing.  The ravine was as free to the owner of those eyes as to ourselves, and, after all, we had no proof that this was an enemy.

I was in doubt as to our next proceeding, and had just come to the conclusion that our most sensible plan would be to turn back without going near the cavern at all, and so try to throw the enemy off the scent, for I felt certain that whether I discovered a treasure or no, I was on the right track, when Tom whispered eagerly to me: 

“Let’s show him that we know how to use our guns, Mas’r Harry.  We won’t shoot him, but only give him a start.  Look at that:  there’s a poll-parrot ­two of ’em ­settled in the tree above him!  It’s a long shot, but I think I could bring one down; so here goes!”

Tom levelled his piece and the next instant would have fired, when the parroquets began chattering, screaming, and fighting together, fluttering down towards the bushes which concealed our watcher.  Then there was a rush, a crashing of the undergrowth, and the owner of the eyes ­a good-sized deer ­bounded into sight for an instant, and then disappeared in a series of spring leaps, which soon took it out of sight in the dense growth.

“I am, blessed!” exclaimed Tom, in accents of the most profound disgust.  “If I’d known, wouldn’t I have fired, that’s all!  Had some venison to take back, Mas’r Harry.”

“I’m very glad you did not, Tom,” I said.

For I felt how the report of a gun would have published our whereabouts, if there really were any lurkers near ­a thing that I must say I now thought very probable, since the fact of there being a treasure in the cave, held sacred by the Indians, would, as a matter of course, render them very jealous of intruders.

“Where for now, Mas’r Harry?” said Tom.

“The cavern, Tom,” I said.

Finishing our descent we were not long in reaching the rocky barrier, evidently piled by Nature at the entrance of the vast frowning arch.

We stopped and looked around suspiciously; but the gorge was silent as the grave ­not a leaf stirred; there was neither the hum of insect nor the note of bird.  Heat ­glowing heat ­reflected from the rocks, already not to be touched without pain ­and silence.

“Going in, Mas’r Harry?” said Tom.

“Of course,” I replied.

“Very good, Mas’r Harry; if you will, you will.  But if we get lost, and then find ourselves right away down in no-man’s land, don’t you go and say it’s my fault.”

I was in no mood to reply, and clambering up the hot rocks, with little glancing lizards and beetles rushing away at every step, we soon stood gazing in at the gloomy chamber, our eyes, unaccustomed to the gloom, penetrating but a few yards at a time, so that had there been a host of enemies within, they would have been unseen.

“Now, Tom!” I said excitedly, as together we climbed down into the shade, to feel the cool and pleasant change from broiling heat to what was, comparatively, a very low temperature.  “Now, Tom, we are going to explore one of the wonders of the world!”

“Humph!” ejaculated Tom, who did not look at all pleased; “it’s very big, and large, and cool.  But say, Mas’r Harry,” he exclaimed, brightening up, “it wouldn’t make half a bad place for keeping tallers!  Yah! what’s that?”

“Only a bird,” I said, as with a rush a couple of large birds had flown close by us, evidently alarmed at our visit to their home.  “That’s a good sign, Tom, and shows that you need not fancy there’s an enemy behind every block of stone.  If anyone was within those birds would not be there.”

Tom grunted, and then, as if to show his unbelief, cocked both barrels of his gun, as, with eyes each moment growing more familiar with the gloom, we walked slowly forward into the darkness ahead ­slowly, for the floor was rugged in places with fragments from the roof, and stalagmite.  The roof was about fifty feet above our heads, and the span of the low corrugated arch, I should say, a hundred more than that.  The stream was rippling noisily along, threading its way amongst the massive blocks of stone, murmuring musically over pebbles and sand.  Now our way was wet and slimy, and then again rugged and dry, till, having penetrated some little distance with every precaution, we turned round to look back at the entrance, to see as pretty a picture as ever I gazed upon in my life.  We could now see plainly the nature of the roof, hung with beautiful stalactites of many graceful forms, giving to the great arch the appearance of some grand specimen of Gothic tracery, through which we looked upon the ravine lit up by the outer sunshine, with its green, and gold, and blushing floral hues.  It was a scene to be remembered for ever; but the gold in my thoughts seemed more glorious, and I turned from it without a sigh.

Another dozen yards and a curve in the cave hid the entrance from sight; we were in gloomy shades, where a light was necessary; and before going farther I paused to think.

If the treasure had been hidden there, where would it be?

Reason said directly, in the most distant and inaccessible recesses of the vast cavern.

And where was that?  How far from the light of day?

That was the problem I had set myself to solve, and, in spite of a feeling of awe with which the place inspired me, I prepared for the solution.  It was no light task, and I have no shame in owning that I felt a strange reluctance to proceed along a rugged path wherein might at any time be yawning some fearful bottomless chasm, ready to swallow up the adventurer; but I would not show my dread, and if Tom felt any he was too obstinate to show his.

By means of string we tied each a candle to our pistol barrels, and then set forward, walking slowly, now with the floor of the cavern ascending, now with it sloping down with a steep and rugged gradient, but always with the little river gurgling in darkness by our side, sometimes almost on a level with our feet, at others, where the path rose, running in a deep chasm whose black darkness made one shudder.

We must have penetrated, I should say, the greater part of a mile when the narrow rocky shelf upon which we were walking came to a sudden end, and holding down our candles, we tried to penetrate the depth before us, but in vain; we could only see a vast black abyss, over which we were standing upon a tongue of rock, while to right, to left, it was precisely the same ­an awful falling away of all that was palpable ­and we knew that a slip would have sent us to a horrible death.

“This is a fearsome, unked place, Mas’r Harry,” whispered Tom; but his words went floating around as if taken up by a chorus of mocking voices, and a strange shudder crept through me.

It was indeed awful, that vast obscurity, with death threatening us if we took another step; and I could not help thinking how easy it was for a people of a low order of intellect, blindly superstitious, to make this solemn hall the home of their poor idol.  It was a place that took no little courage to explore, and often I felt my heart fail me ere I recalled the errand upon which I had come.

Was it likely that, sooner than it should fall into the hands of the Spaniards, gold almost invaluable had been cast into this awful gulf?  It was probable; but, as far as I could see, recovery would have been impossible, unless, after all, it was not so profound as the darkness made it appear.  But then, how to descend?  To swing by a rope over the fearful chasm would have unnerved the stoutest of heart, and I felt that I hardly could have dared such an adventure.

This, then, must be the extent of the cavern ­or rather of our power to explore it in this direction ­for, as I have before said, we stood right out upon a projecting piece of rock from which descent was absolutely impossible, and there was nothing for it but to turn back.

“Think it’s deep, Mas’r Harry?” whispered Tom loudly.

“Deep ­deep ­deep ­deep ­deep ­deep!” came whispering back from all sides, making Tom shiver; but he recovered himself directly, and taking a piece of greasy newspaper from his pocket he loosely crumpled it together, knelt down close to the brink of the abyss, lit the paper, and then threw it from him to blaze out brightly, and fall down ­down rapidly ­as it burned lower, and lower, and lower, till at a vast depth it burned out, but without illuminating anything.  We saw no reflection from rocky point or gleaming water, and our feeling of awe was increased.

“I’ll have another try, anyhow,” said Tom.  “Ears will sometimes tell us what eyes won’t.  Just lend a hand here, Mas’r Harry.”

For a moment or two I shrank from assisting him, on seeing his object, but directly after applied one hand to a rough block of stone that lay at our side, weighing, I should think, a hundred pounds.

We had about a couple of yards to move it, and then it rested upon the very brink, a shrinking sensation coming over me as I saw Tom stand, candle in hand, with one foot resting upon the rock ready to thrust it over.

“Now, then, Mas’r Harry,” he said, “this’ll find the bottom if anything will.  We shall soon know now.  Say when!”

I did not speak, for I was wondering whether that rough block was going down where that I coveted had been cast, and for a moment I was about to restrain Tom; but I thought that the fall of that stone would teach me whether the bottom was at an attainable depth or no, and I signed to Tom to thrust the fragment off.

“Over, Mas’r Harry?”

“Over!” I said in a whisper; and the next moment there was a grating noise and the stone had been thrust off to fall ­fall ­fall in silence, while with awe-stricken countenances we leaned over the gulf and listened, second after second, without avail, for no sound came up.

“It’s gone bang through to the other side of the world, Mas’r Harry!” whispered Tom.  “There ain’t no end to this place, for if it had been ever so deep you must have heard it touch bottom some time.  Ain’t it awful!”

It was awful, and a hand seemed clutching my heart as I thought of falling, ever falling like that, or of some enemy dashing me over into the fearful gulf.  There seemed to be indeed no bottom within ordinary range, and the idea of descending by rope in search there of treasure was absurd.

How long the stone had been falling I cannot say; but just as we had given up all thought of hearing of it more there came from the depths below a faint whisper of a splash, or of some pebble falling in water, but only for that whisper to be echoed and re-echoed from distant parts till it increased to a fearful roar that was some seconds in dying away.

It was impossible to help a shudder upon hearing those horrible reverberations, each one telling of the awful profundity of the place ­ one which, without extensive mining apparatus, I felt that any fathoming for search was out of the question.