At ten o'clock, having snatched two hours of sound sleep, Burgoyne was awakened by Phil Branscombe and Withers.

"What's it like outside?" was Alwyn's first question.

"Quiet," replied Phil. "What little wind there is is off shore for us, an' there's just about enough starlight. I've got the pickets and the block, Withers has the rope, and Minalto and Twill are outside."

Although, with one exception, every officer, passenger and man of the Donibristle knew of what was about to take place, and offers of assistance had simply poured in, Burgoyne had been compelled to limit the exploring-party to five. It was the absolute maximum and minimum, since two were required to descend the cliff, and three to man the rope by which the others were to be lowered and hauled up again.

The only one not in the secret was the Canuk, Miles. One night recently he had not been in the compound, and, putting two and two together, Captain Blair had concluded that the fellow was in touch with one section of the pirate crew. On that occasion the prisoners had been numbered off both in leaving and returning to the compound, and although one was missing, the fact did not appear to trouble the custodians of the gate. When Captain Blair taxed the delinquent, and demanded an explanation, Miles pitched in a plausible yarn to the effect that he had been working down below on board the Donibristle, and had failed to hear the signal for the working-parties to go ashore. Then, afraid of being found on board by the pirates, he had lain low till the following day.

The Old Man accepted the statement without comment, but he fully expected that any day the "drummer" would openly join the pirates.

To prevent him from "walking in his sleep" and stumbling across the men working on the edge of the cliff, Miles was now closely watched by three of the Donibristle's crew, with instructions from the Old Man that if the fellow attempted to leave his hut before daybreak he was to be forcibly detained.

"I can't do more simply on suspicion," the skipper confided to Burgoyne. "If I were sure that the miserable blighter was playing a dirty trick, over the cliff he'd go one dark night, or my name's not Roger Blair."

In single file and with the utmost caution the five adventurers made their way to the cliff immediately above the caves that Burgoyne had noticed during the fishing expedition. From the huts where the pirates lived when ashore came the sounds of boisterous revelry. Not a light was visible on the island, but the silhouette of the look-out hill stood out sharply against the starry sky. There were alert men stationed on that lofty perch, but whether they could discern the five figures working silently on the edge of the cliff was extremely doubtful, since the latter did not cut the sky-line. Nor could the pirates on the hill command the expanse of beach below the cliff.

Muffling the head of one of the crow-bars with a piece of wet canvas Jasper Minalto drove the iron rod deeply into the ground. The operation was anxiously watched by the rest, fearful lest even the dull thuds of the wood that served as a maul would betray their presence.

"All right, so far," declared Alwyn. "Carry on, Minalto."

A second crow-bar was driven home at about a foot from the first and parallel with the edge of the cliff. Between these and about six inches from the ground the third bar was lashed horizontally. Under the fork thus formed a stout beam was thrust, until its end projected three feet into space, with fifteen feet left resting on the turf. The beam had been removed under cover of darkness from one of the tumble-down huts, and must needs be replaced before dawn.

To the outward end of the projecting piece of timber the snatch-block had been securely strapped. Then the end of the coil of rope was pressed over the sheave, a "bowline on the bight" having been made to accommodate the descending man.

"All ready, I think," said Burgoyne quietly. "Stand by, and when I'm ready, lower away handsomely."

With four men holding on to the rope the Third Officer slipped into the bowline. The rope ran slowly through the well-oiled block, and Alwyn vanished from sight.

It was an eerie sensation dangling at the end of a rope over a cliff more than two hundred feet high. The darkness destroyed the idea of distance, but the descent was none the less hazardous on that account. Although every care had been taken in the surreptitious making of the rope, and every precaution taken to test it, there might be a weak spot that had escaped detection.

Almost from the first of the descent the rope began to turn until he was spinning giddily; then, as the length of rope increased, a swaying motion was additionally imparted, until several times Alwyn bumped heavily against the face of the cliff. He was thus able to check the rotary motion at the expense of sundry and various bruises.

"By Jove," he soliloquized, in the midst of this human punch-ball performance, "it'll be rough on Young Bill if we ever have to lower her down. It would scare her stiff right away."

The actual descent took four minutes. To Burgoyne it seemed much longer, and it was with considerable relief that he felt his feet touch the soft sand, and was able to extricate his cramped and bruised frame from the embraces of the bowline.

There was no need to shout to the others to "'vast paying out!" The release of the tension on the rope told them that the descent was accomplished. Then, like a phantom, the bowline vanished as the helpers hauled the rope to the top of the cliff. Within five minutes Jasper Minalto joined Burgoyne on the beach. Since there was the possibility of the rope's shortening with the release of his weight, and contracting by the heavy dew, he took the precaution of bending in a length of light line and weighting it with a lump of coral.

Burgoyne was not likely to fail through lack of precaution or by neglecting to take proper steps to facilitate his return.

The cave exceeded the Third Officer's expectations. It was for the most part dry, the floor being above high-water mark, and the undisturbed sand at its mouth pointed to the fact that a long time had elapsed since human feet had trodden it. Darkness prevented a minute examination, and it was only by a sense of touch that the two men were able to make their investigations.

About eighty feet in length, and with a gradually shelving floor, the cave was less than five feet in height at its entrance, but soon increased until Minalto was unable to touch the roof even with his enormous reach. In width it averaged about twelve feet when half a dozen paces inside its mouth.

There was water, too. Eagerly Burgoyne groped for and found the steady trickle. Holding his hands cup-fashion he filled his palms with water and held the liquid to his lips.

"Fresh!" he exclaimed to his companion. "We're in luck this time."

"But we've nothin' in the barrel line for tu put et in," added Jasper.

"Not even a petrol tin," added Alwyn. "Ever drunk water out of a petrol tin, Minalto?"

The Scilly Islander shook his head.

"Leave ut tu you, sir," he replied. "I've a-drunk water wi' three inches o' paraffin on top of ut on the West Coast—Accra way. That wur enough for I."

Gently jerking the rope, as a signal to Branscombe for the stock of emergency rations to be sent down, Burgoyne gave his companion instructions to bury the stuff in the cave. Leaving Minalto to carry on, the Third Officer walked down to the water's edge, then, turning abruptly to the left, followed the line of wet sand left by the receding tide.

At every possible spot where the cliff might be scalable he approached the base of the rocks, always without the desired result. Carefully obliterating his footprints on the dry sand, he continued his way until farther progress was barred by the abrupt ending of the beach at a point beyond which the cliff rose sheer from the lagoon.

The secret base was an unscalable plateau with only one approach—except by means of a rope—and that was the carefully-guarded tunnel, where more than likely (although Burgoyne was not certain on that point) the double portcullis was lowered every night.

Disappointed but by no means disheartened Burgoyne returned to the cave, where Jasper had completed his task and was awaiting him. To him Alwyn related the results of his investigations.

"Lawks!" exclaimed Min............