The Terrestrials quickly donned their bathing suits and all went through the observatory and down a winding path, bordered with the peculiarly beautiful scarlet and green shrubbery, to the "pool"--an artificial lake covering a hundred acres, its polished metal bottom and sides strikingly decorated with jewels and glittering tiles in tasteful yet contrasting inlaid designs. Any desired depth of water was available and plainly marked, from the fenced-off shallows where the smallest children splashed to the forty feet of liquid crystal which received the diver who cared to try his skill from one of the many spring-boards, flying rings, and catapults which rose high into the air a short distance away from the entrance. Orlon and the others of the older generation plunged into the water without ado and struck out for the other shore, using a fast double-overarm stroke. Swimming in a wide circle they came out upon the apparatus and went through a series of methodical dives and gymnastic performances. It was evident that they swam, as Orlon had intimated, for exercise. To them, exercise was a necessary form of labor--labor which they performed thoroughly and well--but nothing to call forth the whole-souled enthusiasm they displayed in their chosen fields of mental effort. The visitors from the Country of Youth, however, locked arms and sprang to surround the four Terrestrials, crying, "Let's do a group dive!" "I don't believe that I can swim well enough to enjoy what's coming," whispered Margaret to Crane, and they slipped into the pool and turned around to watch. Seaton and Dorothy, both strong swimmers, locked arms and laughed as they were encircled by the green phalanx and swept out to the end of a dock-like structure and upon a catapult. * * * * * "Hold tight, everybody!" someone yelled, and interlaced, straining arms and legs held the green and white bodies in one motionless group as a gigantic force hurled them fifty feet into the air and out over the deepest part of the pool. There was a mighty splash and a miniature tidal wave as that mass of humanity struck the water. Many feet they went down before the cordon was broken and the individual units came to the surface. Then pandemonium reigned. Vigorous informal games, having to do with floating and sinking balls and effigies: pushball, in which the players never seemed to know, or to care, upon which side they were playing; water-fights and ducking contests.... A green mermaid, having felt the incredible power of Seaton's arms as he tossed her lightly away from a goal he was temporarily defending, put both her small hands around his biceps wonderingly, amazed at a strength unknown and impossible upon her world; then playfully tried to push him under. Failing, she called for help.