On the morning following the departure of the U.S.S. Yosemite from the vicinity of the secret base the forced labour parties turned out to find the rain descending in torrents. It was the first rainy day since the arrival of the Donibristle's crew, and they viewed the climatic conditions with marked disfavour.

There was no wind. Overhead from a mirky, dark-grey sky the heavy drops were falling vertically, thudding upon the corrugated iron sheets like the beating of a hundred kettle-drums and rebounding from the puddles already formed, until as far as the eye could see—a distance of less than fifty yards—everything appeared to be a confused blurr of moisture.

"There'll be wind behind this lot," remarked Captain Blair. "Let's hope it'll blow over before Thursday."

It was his first day outside the compound. Partly owing to the desire to share the discomforts with his men and also to make himself acquainted with the harbour, he had insisted upon taking charge of the working-party told off to proceed to the beach.

Ramon Porfirio was in a hurry to complete the operations hindered by the appearance of the Yosemite, which were to result in the blocking-up of the southern approach channel by sinking the Donibristle in about eight fathoms of water between the detached ridge and the southern arm of the cliff enclosing the harbour. It was for this purpose that buoys had been laid down in order to warp the Donibristle to the position chosen for the act of scuttling.

Already the vessel's masts and derricks had been taken out of her, and the wreckage of the funnels and bridge removed. Almost everything of a portable nature likely to be of use to the pirates had been landed, until with the exception of her engines and boilers very little remained but the hull and a few fittings considered of no value for removal.

Ill-equipped for the wet weather the Donibristle's company turned out and awaited the arrival of Fernando, who invariably superintended the calling of the roll. About fifty feet away and just visible through the rain were the Kittiwake's crew, who for the last week or more had been engaged in excavating dug-outs and trenches on the cliff through which the approach-tunnel had been driven. Farther away and lost to view, the remnants of the Alvarado's men were mustering for their daily toil.

Presently the skipper of the Kittiwake, seeing Captain Blair with his men, strolled over to him.

"Mornin', Blair," said Captain Davis. "Not a nice sort of morning for you to be turning out. Feelin' fit?"

"Fairly," admitted Captain Blair. "Eh, what is it?"

For the Kittiwake's Old Man had taken the Donibristle's skipper by the arm, and was leading him away from the rest of the party.

"A word in your ear, Blair," replied Captain Davis, lowering his voice "You've got a young woman amongst your crowd, haven't you?"

"How on earth did you get to know that?" demanded the astounded skipper.

"'Taint a question of my knowing," rejoined Captain Davis. "There are others in the know also I'm just warning you, Blair; you can count on Captain Davis and the Kittiwakes to help you put up a fight if need be, although the lot of us don't stand a dog's chance."

"Thanks for the warning, Davis," replied Captain Blair grimly. "I'll act upon it."

The arrival of the half-caste overseer terminated the conversation. Captain Blair, greatly perturbed, walked slowly back to his men.

An hour later the soaked and dispirited prisoners were launching several of the boats, amongst them the lifeboat that Burgoyne had definitely in view for the projected flight from the island. It was raining so heavily that by the time the boats ran alongside the Donibristle the bottom-boards were floating, in spite of the fact that the plugs had been withdrawn and the water allowed to drain out before launching.

Wearing an almost new dark blue bridge-coat that looked suspiciously like the skipper's, Black Strogoff was sheltering under the boat-deck when the working-party arrived. With him were half a dozen pirates armed with automatic pistols.

"You there!" shouted Black Strogoff on catching sight of Captain Blair. "Come you here. Do you know what is to be done? Run out warps ahead and astern, buoy and slip the cables to move the ship round that point. You understand? Good; then do it, and tell me when the work is finished."

There was no option but to obey. Calling Burgoyne and Branscombe Captain Blair allotted them their respective posts, sending the former away in a large pulling cutter to pass the bow warp to the nearmost buoy. He also took the opportunity of conferring hurriedly with Alwyn on another matter.

In the absence of steam the work of warping out had to be carried out by hand. The cable was slipped, and, under the united efforts of the score of men walking away with the bow warp, the Donibristle moved slowly, almost reluctantly, through the rain-beaten waters of the harbour.

As the battered hulk passed within a cable's length of the pirate cruiser, Ramon Porfirio stepped to the rail of the Malfilio and shouted a curt order to the sheltering Strogoff. Apparently the command was to the effect that the work must be hurried up, for the pirate lieutenant, emerging from his retreat, gave a brief and surly reply. Then, bawling to Captain Blair to tell the men to haul away quicker, he retired to his temporary den.

"Meaning, I suppose," observed Captain Blair to Branscombe, "that the Malfilio is about to sail and that Porfirio wants the job finished before he weighs. How is that fractured steam-pipe getting on, by the by, Angus?"

"It's patched up," reported the Chief Engineer with a dry chuckle. "She'll be raising steam I've nae doot, but she'll blaw yon patch clean out when they wark up tae onything like a pressure."

Captain Blair's surmise was a correct one. Porfirio, having picked up the wireless messages exchanged between the British, American, and Japanese cruisers engaged in searching for the missing merchant vessels, was aware that they had given up hope of finding the survivors and were returning to their respective bases. He was a believer in the old adage "Men and ships rot in port ", and was loth to keep the Malfilio and her polyglot crew in harbour any longer. Inactivity not only meant no prizes; the pirates, lawless except for the iron rule of their captain, were particularly apt to get out of hand when their enthusiasm flagged by standing idle.

But before he set sail he wanted to see the Donibristle sunk in the South Approach Channel. That entrance, he considered, was a weak spot in the natural defences of the secret base, and by sealing it agains............