"But surely there would not be wild boars and sows in an island like this?" said Sir John.
"No," said the captain, "but pigs that have run wild. You see, the old voyagers left two or three pairs in a good many places, and they have increased largely. This must have been one of the favoured islands."
Further proof was given a short distance farther on, for they had a glimpse of a herd which seemed to be fifty or sixty strong, whose leaders stood grunting and staring at the new-comers for a moment or two before whisking round and dashing off among the trees, to be hidden directly by the low growth, a head or a tail being seen at intervals; and then every sign was gone.
"Well," said the doctor to Jack, "that's another discovery to the good: fresh pork and poultry."
"You can't eat parrots," said Jack, laughing.
"Why?" said the doctor.
"Oh, those highly-coloured birds can't be good."
"Wait a bit, my young philosopher. I never knew that gaily-coloured barn-door cockerels were 'bad', and I know that a young peacock is as good as a pheasant; so where is your theory now?"
"Yes, Jack, you are beaten," said Sir John merrily.
"Oh, but I meant parrots and cockatoos and birds of paradise," said the lad hurriedly.
"Parrots and cockatoos live on fruit," said the doctor; "fruit is good, ergo parrots and cockatoos are good, and I'll have a curry made of the first I skin."
"You are right about the birds of paradise though, my boy," said Sir John. "I should not like to try one of those, because they are so nearly related to the crow."
"A bird of paradise related to a crow--a black crow?"
"Oh yes, you'll find some of the most gaily painted birds out here in the tropics very nearly related to some of our more common friends at home."
"Yes; look, there goes one, Jack. I could bring him down easily."
The lad had already caught sight of a lovely bird upon the ground, which stood looking at them for a few moments before hopping away beneath the bushes and undergrowth, appearing again farther on, and then spreading its wings for a short flight, and displaying the lovely colours with which it was dyed, the most prominent being shades of blue relieved by delicate fawn and pale warm drab.
"What's that?" cried Jack eagerly.
"That's a thrush," said the doctor.
"A thrush!"
"Yes; not one of our olive-green, speckled-breasted fellows, but a thrush all the same, and saving its colouring, wonderfully like one of ours."
There was plenty to say about bird and insect as they went on, keeping just where the sand gave place to firm ground, for the birds were excessively tame, and gave evident proof that they were not much disturbed; while every now and then amid the lovely insects which thronged wherever there were flowers, appeared some magnificent butterfly, several inches across its wings, tempting Sir John to cease exploring for the sake of making captures.
But everything was given up to the main object, and mile after mile was tramped, every step seeming to reveal some new beauty--peeps through the groves at the broad blue sea, or wonderful landscapes up ravines, with the mountain towering up behind.
The natural history objects they encountered were plentiful enough. In fact very few steps were taken without something attracting attention.
Lizards which seemed as they basked on pieces of the heated rock to have been cut out of glittering metal, till, at the jar of a footstep, or the shadow of any one cast across them, they darted away. In one place the doctor pointed out sinuous markings on the sandy ground which looked as if freshly made.
"Yes, a snake," said Sir John, "and a good-sized one too."
"How large?" said Jack with suppressed excitement.
"Seven or eight feet long, I should say," replied his father.
Jack looked with an expression of mingled dread and longing at the patch of dense growth into which the track led, and directly after Edward exchanged glances with him, the man's look seeming to say--
"I've marked down that spot, sir."
Glen after glen was passed, every one full of beauty and interest, and at last they were brought up short by what looked like some huge pier running right across their way, down over the sands, and ending suddenly about a hundred feet out in the beautiful blue lake. At the first sight it seemed like some great landing-place or wharf, but there was no sign of handiwork about it, and the lad gazed at it in awe, as the doctor explained that it was the end where it had cooled and solidified in the lake of a huge lava-stream which had flowed down from the mountain, high up on their right.
"But that means it must have run like so much liquid fire for miles."
"Yes, that's exactly what it does mean, Jack," said Sir John; "six or seven or eight. We shall know some day, when we have explored the place."
"And that will be like a high-road to the top," said the doctor, "only I'm afraid it would be a rather rough one."
"We'll try it some day," said Sir John.
"Rather hard for your boots, sir," said the captain. "Look at it: like glass, and as sharp in places."
"Why, it must be quite fresh," said Jack.
The captain smiled and shook his head.
"But some of these pieces look quite bright," said Jack.
"Yes; and these trees look quite green, and many of them may be a hundred or two hundred years old."
"What has that got to do with it?" said Jack. "Oh yes, I see now: they would have been burned up. Of course."
"Yes," said Sir John, as he stood looking at the huge solidified stream; "everything about here must have been burned to ashes, and it would, even with the rapid tropic rate, have taken fully a hundred years for these trees to grow."
"How wide is the stream?" said the doctor; and he led the way to climb up, startling something, which went off with a tremendous rush inland.
"What's that?" said Sir John.
"Couldn't catch a glimpse of it; but it wasn't a man. Four-legged creature of some kind. There, that's its cry."
A peculiarly weird howl rang out, and was answered from a distance off; but though the party waited in the hope of seeing what it was that had been started, they were disappointed.
"Never mind," said the doctor; "we have proof that there are animals about. Now then, how wide do you make the lava-stream to be?"
"About four hundred paces," said Sir John.
"Quite that," said the captain. "Well, gentlemen, what do you say to making a halt just beyond the lava there--under one of those trees, say, beside that stream?"
"Couldn't be a better place," cried Jack. "I am getting hungry."
"I think we all are," said the doctor, smiling, "for we have been tramping quite two hours since Edward had his adventure on the cocoa-nut tree."