The sight of this sign swinging from a small sea tree close to Samuel's air bowl sent a wave of rage up Tandy's back. Rubbing his palms briskly together, the little boy seized the saw and struck it with all his might against the unyielding surface of the slide. The noise attracted Samuel's attention, and looking up he began waving his arms, yelling out wild orders and commands. Not being able to hear any of them and being quite sure Samuel was telling them to leave the air shaft before the Seeweegians shot another slide above their heads and caught them, too, Tandy proceeded grimly with his task. Roger helped, scraping away with both claws and bill. For five desperate minutes they worked without success, then a tiny crack split the slide from edge to edge. Wedging the saw into the narrow opening, Tandy began sawing away like a little wild man, for a fresh batch of snails and crabs tossed in to Samuel had let in another rush of sea water. Immersed to his chin, Samuel started to swim round and round, dodging the end of the saw as it flashed up and down above his head. "Oh!" gasped Tandy, stopping a moment to blow on his fingers. "I'll never be able to make this opening large enough. Look, look, Roger, they're opening that trap door again. Oh, Oh! I can't bear it!" "Help! Help!" yelled the Read Bird, looking despairingly up the empty air shaft. "Help, for the love of sea salt and sailor men!" His cry, increased by the curious nature of the compressed air in the air shaft, increased a hundredfold and fell with a hideous roar upon the anguished ears of Ato and Nikobo. Almost instinctively and without thought of her own safety, or Ato's, or the dire consequences, the hippopotamus jumped bodily into the sea hole. Roger, still glaring upward, had a quick flash of an immense falling object. Realizing at once what had happened, the Read Bird had just time to snatch Tandy and drag him to the opposite side of the slide before Nikobo landed--broke through the thick glass, plunged into Samuel's aquarium and shot out through the side into a group of horrified Seeweegians. Now do not suppose for an instant that Tandy, Roger or Samuel himself saw all this happen. Indeed, after Nikobo struck the slide, none of them remembered a thing, for the ocean, rushing in through the puncture the hippopotamus had made in the vacuum, rose like a tidal wave, carrying them tumultuously along. Nikobo came up at a little distance from the others, with Ato, completely wrapped and entangled in seaweed, clinging tenaciously to her harness and looking like some queer marine specimen himself. Too shocked and stunned to swim, the five shipmates bobbed up and down like corks on the surface of the sea. Then Roger, spreading his wet and bedraggled wings and coughing violently from all the salt water he had swallowed, started dizzily back to the _Crescent Moon_. Nikobo had several long gashes in her tough hide, but still managed to grin at Tandy.