A group of renowned Arcadian waters may be reached in one northward excursion of three days from Tripolis. The first of these is the Lake of Pheneus, as famous for its strangeness as for its loveliness. It is so surrounded by hills that no stream can escape from it above ground, and the water issues only by two katavothras. The condition of these subterranean channels determines whether the great mountain basin of the Pheneus is a fertile plain or a broad lake. In ancient times and in our own the changes have succeeded each other with the fascination of mystery. Pausanias found a plain, and knew the lake only by tradition. From his day until the beginning of the nineteenth century there were no records. But with the ensuing careful descriptions of geographers and travellers come baffling alternations of a “swampy plain covered with fields of wheat or barley” and a “wide expanse of still water deep among the hills, reflecting black pine woods, gray crags, and sky now crimson with sunset.” To the east of Pheneus and separated from it only by a mountain ridge the Lake of Stymphalus is sunk in placid beauty within towering hills. It was the scene of the fifth labour of Heracles, who killed the monstrous man-eating birds that haunted it. They typified, probably, the pestilence which would arise whenever the underground channel that served as an outlet for the lake became stopped. Heracles was the master-engineer of mythological times. Later engineers also experimented with the water which flows into the Stymphalian Lake from the surrounding mountains and especially from Cyllene. Its purity and abundance led Hadrian to have a supply of it carried by an aqueduct to Corinth. And to-day the Athenians are contemplating importing it into their arid city.