"See?" cried Nic.

"Yes; come along."

"One moment," said Nic, pausing to look upward at the arching ferns eight or ten feet overhead. "No one would think of coming down there to look for a way. But how about footmarks in this soft sand? One of the blacks would trace us directly."

"The water trickles over them and washes them full of sand directly, Nic. I am safe in that."

"But did you venture into this black darkness without knowing where you were going? One might slip down into some horrible pit."

"I slipped down into a horrible pit years ago, boy," said the convict bitterly, "and I felt that I could only lose my life in an adventurous search. But I did not go far in the dark. Come on a few yards, and I will show you. There is nothing to mind."

"Does the water get deeper?" whispered Nic, in an awe-stricken voice.

"Never more than an inch or two, except in rainy time, and then of course it becomes a rushing torrent and impa.s.sable. Come along: it is always a soft sandy or rippled path formed of petrifactions like that you saw just now."

Nic braced up his nerves and followed the _wash_, _wash_ of the convict's footsteps till his companion cried, "Halt!"

"Now," he said--"hold this."

"This" proved to be a great piece of soft, crumbling touchwood, which felt as if it had been torn from some dry, rotting gum tree; and directly after _nick_--_nick_--_nick_ came the sound of a flint against a steel: tiny bright scintillations glistened in the black darkness, and soon there was a faint glow as the convict began to blow one spark which had fallen upon the wood Nic held. Then the spark grew brighter and brighter, and at last shed a faint luminous glow sufficient to make darkness visible; and this was increased by the convict taking the piece of wood and waving it softly to and fro.

"A poor light," he said, "but it takes off the worst part of the gloom, and it is comforting. I have not begun making myself candles yet, Nic."

"What's that?" whispered the boy, as there was a peculiar fluttering noise and something swept his cheek softly.

"Only bats. There are plenty here. Don't you smell them?"

"Yes, there is a black-beetly smell; but I thought it was the wood. Are there any--any dangerous beasts down here?"

"There are no dangerous beasts in this country," said the convict, "except poisonous snakes and the crocodiles in the rivers, and I have never seen one of them. No, Nic, there is nothing to fear here but flood after a storm. Now, come along; step out boldly. It is nervous work the first time. I felt a bit scared when I explored it. I could walk through now in the darkness with my hands in my pockets. One only has to let one's feet follow the water."

"But if you did not follow the water?"

"Then you might wander away into one of the side pa.s.sages, or go down some wide rift and lose your way."

"Is it so big, then?"

"Farther on. There it opens out into huge caverns, and rises up into great cracks and chambers caused by the petrifying stony water. There are sheets and columns and hummocks of stone all made by the drip from above. This place has all been formed by the water eating away the limestone rock, dissolving it here and piling it up there."

As the convict walked on, and Nic followed close behind, the splashing of their feet echoed softly from the walls, and the man's voice sounded shut in and smothered. The air felt hot too, and oppressive, while the smouldering wood glowed and made the convict's figure stand out like a solid carved block moving dimly outlined before Nic as he went on.

Then, all at once, the echoes of the disturbed water grew louder, and went whispering away; and as Leather went on talking his voice seemed to grow free, and the air was cool and damp.

"Now listen," he said; and he paused, waved his smouldering torch, and uttered a loud _cooey_.

Nic caught at his arm, for there was a crash, and a bellowing roar as the cry went echoing away and then gradually died out in whispers.

"Startling, isn't it? But only sound. The cavern is enormous here."

"It's dreadful!" panted Nic.

"No: wonderful and grand, boy. Ah! who knows what may be deeper down in the interior of this mighty world on which we crawl! Come along; you'll have other chances of exploring here--that is, if you come to see me, Nic. Would you venture alone?"

"No," said Nic frankly. "I don't think I should dare."

"Familiarity breeds contempt--even for darkness, Nic," said the convict with a laugh, which sounded horrible. "Don't be in a hurry to say that.

I believe that with a lantern you would come. Forward, boy!"

"Is it much farther?"

"Oh yes--a long, long, long way. I was months before I got right through."

"What!" cried Nic in a startled voice; and he wished he had not spoken, for his exclamation sounded as if it would bring down the rocks upon their heads.

"No, no; not as you take it," said the convict laughingly, as he waved the torch and made it glow. "I mean that after I discovered it one day, as I told you, through a sheep falling down into that well-like opening, I made myself a rough lamp from an old pannikin, some melted mutton fat, and a bit of rag, and when I had chances I came down and followed the stream a little farther and a little farther, led on and on by the interest of the place, always expecting to find that it would end with an underground lake."

"And it did not?"

"No, this little stream joins the river in the great valley, as you will see. But we are losing time. Come on."

Nic followed in silence, but with the creepy, shivering sensation pa.s.sing off; and a feeling of intense curiosity and wonder taking its place.

"Is it much farther?" he said at last.

"Like to go back now, boy?"

"No," cried Nic firmly--"of course not."

"Well, as to being farther to go, I could turn off in several places, and we could wander on for longer than I could say. You can bring friends and explore it some day, perhaps; but down to the valley is not a great way now."

"Down! Are we going down?"

"Of course: flowing water is always going downward. There, you can hear that the rocks are farther away to right and left. Farther on they close in again till it is like a crack, and they run up to a point far above our heads. We must have a good light some day, Nic, if I am not taken. You would like to explore the place?"

"If you are taken!" cried Nic. "Why, you could defend yourself against a hundred people here, and set them at defiance."

"Yes, but I might be surprised. I can't live without sleep, Nic.

They'll take me some day. Friend Brookes will find out that you come to see me, and track you to the opening."

"He would not dare to come along here."

"No, but he would send those who did. But never mind that now. Let's enjoy life while we can, even if it is such a poor life as mine."

"I say, Frank Mayne," said Nic, after a thoughtful pause, during which he had listened to the _whish_, _whish_ of their feet through the water, and the whispering echoes, now close at hand, now far away.

"Say on, boy."

"I'm going to the port as soon as my father comes back."