Ten yards off, just under the surface, appeared the glittering outlines of a great fish. It moved leisurely, its projecting fin making a silver ripple. "Twelve feet, if he's an inch! I'd hate to fall overboard while he's around." "Think he's a man-eater?" "Don't know! But I'd rather let somebody else find out. There's another! I've heard fishermen say the sea round here's alive with 'em. I haven't a doubt but those two fellows that chased us to-day are somewhere about. Once they get after a boat, they'll follow it till the cows come home. Guess I'll let Ole Bull give us a few notes!" He pulled his handkerchief out of the intake tube. Presently the voice of the whistle was echoing across the sea. After a half-dozen screeches Spurling stopped up the tube again. "That'll do for now! We'll give him another chance in ten minutes." Up and down went the buoy, pitching and reeling dizzily. An occasional wave-crest buried the boys to the waist. "No place for a man with a weak stomach, hey, Perce," said Spurling. "You couldn't have stood this two months ago." Percy was gazing intently southward. "What's that white spot?" he asked, suddenly, pointing to a glittering patch fifty or sixty yards square. "School of herring! Now look out for some fun! Something's liable to be after 'em any minute." Hardly had the words left Jim's mouth when a great white streak moved rapidly toward the schooling fish. "Whale!" shouted Spurling, excitedly. "Watch out!" With a tremendous rush the huge, gleaming body shot suddenly clear of the water. For an instant it hung suspended, ten feet above the surface. Then, with a mighty splash, it dropped back, right amid the herring. The glittering school dispersed in a thousand directions, and the monster moved slowly off to the south. "Biggest whale I ever saw," observed Jim. "Fully seventy feet long! Well, he's had one good meal. Wish we could say the same! Hungry, old man?" "Yes; but more thirsty." "Stick to it! Somebody's likely to show up at any time to-morrow and take us off." "But if they don't--" "We'll have to hang on till they do." Percy could hardly stand upright. His joints ached. His eyelids sagged heavily for want of sleep. He would have given anything if he could have lain down. But that was impossible. Something of his father's doggedness enabled him to set his teeth and stand clinging to the bails. Their plight was bad enough, but it might have been much worse. Percy shivered a bit as he looked at the wallowing dory and the breaker beyond it. The buoy could not drift. It could not founder. It afforded them a safe refuge from wind and sea; but it could not give them food or drink.