"If I might suggest, Sir John, I'd make this the farthest limit of our tramp to-day. We shall be about four hours going back; and to-morrow we might go in the other direction--sail round the island, if you like."
"I think we would prefer to explore it on foot, captain," replied Sir John.
They crossed the remainder of the solidified stream of stone, ascended to the beautiful grove of trees on the other side, where a swift stream of the purest water ran gurgling along to the sea, and here enjoyed, in the cool shade, a delicious _al fresco_ meal, to which every one did ample justice. After which a start was made for the yacht; but the heat proved to be so intense, there not being a breath of air, save a succession of hot puffs which seemed to be wafted down from the mountain, that the men began to flag and show signs of being overcome.
Consequently, first one and then another halt had to be called, and when they were still a good three miles from where they had left the boat, the sun went down, and the night came on with startling suddenness, so that at the end of a quarter of an hour it was dark as pitch beneath the trees, and the order was given to bear off to the right, so as to follow the sand.
"Can't go wrong," said the captain, "if we keep within touch of the sea."
"Hark! hark! What's that?" cried Jack.
There was no need for him to speak, for every one had stopped short, and was listening intently to the echoes which ran reverberating along a valley, after what seemed to have been the firing of a heavy gun.
CHAPTER TWENTY.
FLOATING BLACKS.
"Is that Mr Bartlett firing one of the yacht's guns for a recall?" said Sir John.
"No, sir; they could not make a noise like that."
"It could not be thunder," said Jack.
"Oh yes, it could," said the captain. "I've heard short sharp cracks like that often out here, but I don't think that was thunder."
"Must have been," cried the doctor. "Why, I saw the flash. There!
Look!"
A bright light suddenly appeared from somewhere inland, followed at a few seconds' interval by a heavy detonation, exactly like the firing of a great gun.
"Now what do you say, Captain Bradleigh?" cried Sir John.
"That it is what I thought at first, sir. The mountain yonder is firing a shot or two. If we had been out at sea, I dare say we should have seen a great red-hot stone flying up and falling back."
"Then there is going to be an eruption," cried Jack in excited tones.
"That does not follow at all. Some of these volcanoes do no more perhaps than make a rumbling, and send up a few red-hot stones now and then. Forward now, gentlemen. Close up, my lads, and follow two and two."
The mountain, if the captain was right, made no farther sign, and now began the most interesting part of the journey. With the exception of having to be careful not to stumble over the blocks of coral limestone which lay here and there in their road, it was easy walking in spite of the darkness, while this latter was modified by the brilliant stars overhead, the dazzling scintillations of the fireflies, which flittered out whenever any of the bushes which fringed the sands were approached-- and the soft, luminous, oil-like appearance at the edge of the lake.
But the sand was soft, and it seemed to Jack as if they would never reach the boat.
In the darkness Edward edged up close to his young master, and whispered--
"Tired, Mr Jack?"
"Dreadfully."
"Makes one's legs feel as if they were made of cast lead."
"Or stones," said Jack.
"Well, p'r'aps you're right, sir. Stone is more like it. Let me carry your gun, sir. Seems to get heavier every step, don't it?"
"Yes; and the cartridges too. Thank you, Ned. I should be glad to get rid of them. No, you've got your own to carry, and--I say, how do you feel now? I mean, after your fall."
"Oh, bit stiff, sir. There's nothing broken; but I don't go quite so well as usual. Shan't be sorry to get back to the yacht. Better give me your gun, sir."
"Better give me yours to carry, Ned."
"What, sir? Well, 'pon my word, Mr Jack, you do talk. I do wonder at you."
Just then Jack started, for a hand was laid on his gun.
"Who's that?" he cried.
"Only me, sir--Lenny," said a dark figure behind him. "Let me carry your gun, and pouch too. I heerd what you said. Take hold of t'other's weapon, mate," continued the man to the sailor by him, and Jack and his man tramped the rest of the way relieved of their loads, heartily glad to hear at last a hail from somewhere away in the darkness.
It came from the boat; and directly after a bright light flashed out over the calm lagoon, like a star just rising to shine across the sea, and the men gave a cheer.
"Is that the _Silver Star_, Captain Bradleigh?" said Jack eagerly.
"Yes, my lad. That's better than a figure-head, eh?"
It was extremely beautiful just then, and looked very attractive and suggestive of rest and a good meal, beside being a guide to them along the lagoon, the men as they bent to their oars having the straight path of light to follow right up to the yacht's bows, and soon after the efforts of the cook and the cheery aspect of everything made Jack forget his weariness.
"Well, gentlemen," said the captain after their late dinner, "I think that there ought to be another exploration to the east to-morrow."
"Certainly," said Sir John; "I want to feel that we can go about in safety."
"I suppose you'll be too tired to go, Jack?" said the doctor.
"Too tired? Didn't I keep up well to-day?" said the lad quickly.
"Capitally; but you look done up."
"I shall be ready in the morning," said Jack shortly.
"Don't attempt too much at first, Jack," said his father.
"Oh no, I will not do that. But I can't be left behind."
There was no need for any question about the matter, for the captain now joined in the conversation again.
"I propose, Sir John," he said, "that we should have the first cutter and the gig to-morrow morning, and let the men row gently along the lagoon, close in shore. It will be a change; we can get along faster, and land as often as you wish. I could have the awning rigged up."
"Yes, capital!" cried the doctor. "If you decide on that, Sir John, I should advise a start at daybreak, and a halt for breakfast when the sun begins to get hot. But, of course, we should have some coffee and biscuit before we start."