"Oh, I believe you when you talk like that," said the Urchin; "only it's worse than the Latin grammar. Psittacus loquitur, "the parrot talks"; but this thing seemed to be a whale; it was very like one."

"It was a whale," said Fiona. "He said his great-great-grandmother had seen the Spanish captain land his doubloons, and that it was in the west cave on Scargill Island."

"That means the big cave at the end facing the sea," said the boy.

"The cave that no one has ever got to the end of," said Fiona.

"The cave that's haunted," said the boy.

"But of course it's haunted; it's the ghosts of the Spaniards. Silly of us not to have guessed."

Fiona had a hazy recollection of things her father used to say.

"I expect the haunting is thousands of years older than the Spaniards," she said. "Urchin, are you afraid of ghosts?"

"Not a bit," said the Urchin stoutly. "They would be splendid to throw stones at. It wouldn't hurt them."

"Come on then, let's go," said the girl. "There's lots of daylight."

"None of the people here will go into it, you know," said the Urchin.

"I know," said Fiona. "All the more reason for going on our own. There might really be something there, if no one ever goes to take it away."

So the boat was launched, and the adventure also. Fiona pulled stroke; the Urchin was a clumsy and unpunctual bow, and the girl had to steer from the stroke oar, which needs more doing than you may think if you haven't tried it. But they made the end of Scargill in time, and then Fiona took both the oars and coasted, while the Urchin got out a couple of bamboo poles, garnished with white flies, and let the casts trail, occasionally getting one of the beautiful little scarlet lythe, that came at the fly with the spring and dash of a sea trout. For even adventurers need supper. And so they came, past many a smaller cave mouth in the black side of the island, to the huge bluff that fronts the full Atlantic, and the great west cave.

Atlantic was half asleep to-day, and muttered drowsily to the quiet rocks outside. But the great cave was seldom quiet. In the winter, when Atlantic turned himself restlessly and spoke aloud, the sound of his speaking came back from its depths like the roar of a heavy gun; and even in the stillness the lisp of the swell in it echoed as from the roots of the island in a low intermittent boom. Outside, on the calm water, floated the whiskered head of a seal, watching the boat with gentle, fearless eyes,—"the officer on guard," Fiona whispered;—and from the black cliff's face, like a hanging fringe over the mouth of the cave, the water splashed down, trickle by trickle, in quick, heavy drops. The children rowed in through the little shower, and Fiona paddled gently up the cave. Its huge limestone walls stood up stark on either hand, rising into the darkness above, and sinking below into the green water, as far as eye could follow them. Near the water-line grew a little seaweed, and some white whelks clung; but as they went down the waterway these vanished, and gray cliff and green water alike began to turn black. Looking back, Fiona could see a bright patch, a patch of sky and sky-reflecting sea, framed in the narrow slit of the cave's mouth. The waterway was narrowing now; she shipped her oars and stood up, using one as a paddle, and instructing the Urchin how to fend off the boat's stern with his hands. In front, on a ledge in the cave's roof, it was just possible to make out a row of blue dots in the growing darkness; as the boat drew nearer, the blue dots fluttered, detached themselves from the cliff, and a swarm of pigeons came whirring over the boat and down the cave toward the sunlight;—"Your ghosts, Urchin," said the girl. Henceforward the cave was void of life, unless some strange, eyeless fish lurked in its inky depths. Darker and darker grew the waterway, and the last gleam of light vanished. Fiona was feeling her way now, aided by the phosphorescent drip from her oar blade; the Urchin, with unusual sense, splashed his hands in the water to increase the pale glow, which just revealed the line of the cliff. Neither dare speak now; possibly, had Fiona not had some idea of what was coming, she would have turned. But already there was a faint gleam ahead, faint as a glow worm, but still a gleam; and as the boat slid forward, and the low boom in the depths of the cave grew closer, the cave walls very slowly began to grow gray again out of the blackness. A few minutes more, and the walls were an outline, and before them, a fringe of white on round wet stones, the end of the waterway. And as the boat grounded, Fiona pointed up, and the Urchin, looking, saw a little round hole; a natural shaft ran down into the cave from the surface of the island, giving light enough for their eyes, now accustomed to the darkness, to distinguish outlines.

They drew their boat up on the stones far enough for the swell not to dislodge it; then the same impulse seized them both and they burst out laughing, not aloud, for something in the place made it impossible to laugh or talk aloud, but in a kind of mirthless whisper.

"We've come without any lights," said Fiona in an undertone.

"We have," said the Urchin. "But probably the stuff is only a few yards above high-water mark; they wouldn't go far in."

"They might have," said Fiona; "they'd have had torches or something."

"Let's go as far as we can, anyway, as we are here," said the Urchin.

So they started scrambling over the stones in the gray half-light. Presently there rose before them a great mass of rock and earth, half blocking the cave; it looked like some old landslip.

"It's easy at this end, Fiona," said the boy; and up they went, to find that the rock barrier blocked most of what little light remained. Beyond was darkness.

"We must go back and get light," said Fiona. "I can't even see the stones below." A pause; then, "Stop swinging your feet, Urchin; I want to listen."

"I'm not," said the Urchin.

Another pause, and then the Urchin spoke again, in a kind of stage whisper, "I'm frightened." The words seemed squeezed out of him.

"We may as well go back, anyhow," said Fiona, in a strained voice. "Down you go, Urchin."

The Urchin did go down at a considerable pace, and ran for the boat. Fiona managed to walk, by repeating to herself all the time under her breath, "You mustn't run, you mustn't run." But once in the boat she did not rebuke the Urchin for standing up and taking the other oar; and the pair paddled out, with many bumpings and scrapings, in a more speedy and less scientific manner than that in which they had entered.

Once out in the sunlight they felt better. They started automatically to fish home, and presently were talking again. But neither of them referred to the thing that was uppermost in each mind, though each was wondering if the other knew. For as they had sat on the wall of rock, each had heard clearly, in the utter darkness of the unvisited cave, the sound of heavy footsteps.

CHAPTER IV
THE URCHIN VANISHES

To most people there is some corner of the earth which means more than all others; and there are two or three in the world whose holy place is the old house on the sea-loch which the Student's humbler neighbors called the "big house." An old square building of gray stone, that matches the gray sky and the gray sea, it has small claims to beauty; it was built in the days of blank