"And if the fellow gives a perfectly corroborated statement, and claims damages for illegal arrest, where would the funds of the troop go, eh? No, no, Atherton, we must get to work more cautiously. I am quite in agreement with you that the action of these two men on the yacht is suspicious, and that they ought to be kept under observation. All the same, I do not like the idea of so much night work. Before I took over for Mr Trematon, you had more than one restless night." "If it has to be done, sir, it must be," replied Atherton earnestly. "The other fellows are of the same mind." "Very well, so long as the yacht remains of the Island we will keep her under observation. I'll send Simpson and the 'Wolves' out till sunset, and then the 'Otters' can carry on till morning. Only, mind you, it is to be distinctly understood that your patrol must rest this afternoon and also to-morrow morning. Seven hours' sleep in every twenty-four is essential." "Very good, sir," said Atherton. "And," continued Mr Buckley, "I mean to take the night watch with you. We must find a likely spot whence we can command the approach to the Tea Caves as well as the yacht. Now tell the 'Otters' to turn in. No talking, mind. I'll see that Simpson has his instructions, and then I'll have a nap myself." Two hundred yards to the south-west of the Tea Caves a rocky headland afforded all the shelter the Scouts required. The place seemed as if it had been a Titan's playground, for huge flat boulders, some weighing more than twenty tons, had been piled up in picturesque and even grotesque formations. On one group of rocks the Scouts had bestowed the name of "The Mushrooms," and the designation was not inapplicable. Three separate columns, composed of discshaped rocks twelve feet in diameter, rose to the height of twelve feet above the general ground level. On the summit of these were still broader rocks with slightly rounded upper surfaces, their edges overlapping the bases by three to five feet, and two of the top rocks touched each other; the third was separated from the other by a space of less than a foot. On the lee--side of "The Mushrooms" there was sufficient shelter for the four Scouts of the "Wolves," for Hayes and Tenderfoot Basil Armstrong were left behind in camp while the "Otters" were resting in their tent. The yacht still remained close inshore, in the same position as when the Scouts had first sighted her. The tide had long since changed, but the crew had made no attempt to shift her, either by means of the motor or sweeps. Throughout the rest of the afternoon the "Wolves" kept on the watch. The shadows lengthened as the sun sank down in the west; but the two men on board gave no signs of their presence. "Anything wrong?" asked Atherton, as the "Otters" came to the relief of their comrades, Sayers and Scott being left in camp to perform a like duty to the one Hayes and Armstrong had been detailed to do.