“Well, we have done our best,” said Foy, as he washed his mud-stained boots in the water, “and now the stuff must take its chance.”

Then once more they entered the boat and rowed away somewhat wearily, Martha steering them.

On they went and on, till Foy, tired out, nearly fell asleep at his oar.  Suddenly Martha tapped him on the shoulder.  He looked up and there, not two hundred yards away, its tapering mast showing dimly against the sky, was the vessel that had pursued them from The Hague, a single lantern burning on its stern.  Martha looked and grunted; then she leant forward and whispered to them imperiously.

“It is madness,” gasped Martin.

“Do as I bid you,” she hissed, and they let the boat drift with the wind till it came to a little island within thirty yards of the anchored vessel, an island with a willow tree growing upon its shore.  “Hold to the twigs of the tree,” she muttered, “and wait till I come again.”  Not knowing what else to do, they obeyed.

Then Martha rose and they saw that she had slipped off her garment of skins, and stood before them, a gaunt white figure armed with a gleaming knife.  Next she put the knife to her mouth, and, nipping it between her teeth, slid into the water silently as a diving bird.  A minute passed, not more, and they saw that something was climbing up the cable of the ship.

“What is she going to do?” whispered Foy.

“God in Heaven knows,” answered Martin, “but if she does not come back good-bye to Heer Brant’s treasure, for she alone can find it again.”

They waited, holding their breaths, till presently a curious choking sound floated to them, and the lantern on the ship vanished.  Two minutes later a hand with a knife in it appeared over the gunwale of the boat, followed by a grey head.  Martin put out his great arm and lifted, and, lo! the white form slid down between them like a big salmon turned out of a net.

“Put about and row,” it gasped, and they obeyed while the Mare clothed herself again in her skin garment.

“What have you done?” asked Foy.

“Something,” she replied with a fierce chuckle.  “I have stabbed the watchman—­he thought I was a ghost, and was too frightened to call out.  I have cut the cable, and I think that I have fired the ship.  Ah! look! but row—­row round the corner of the island.”

They gave way, and as they turned the bank of reeds glanced behind them, to see a tall tongue of fire shooting up the cordage of the ship, and to hear a babel of frightened and angry voices.

Ten minutes later they were on board the Swallow, and from her deck watching the fierce flare of the burning Spanish vessel nearly a mile away.  Here they ate and drank, for they needed food badly.

“What shall we do now?” asked Foy when they had finished.

“Nothing at present,” answered Martha, “but give me pen and paper.”