On the edge of the Bogota tableland, not many miles from the city that is to-day the capital of Colombia, there is a lake, Guatavita--the Sacred Lake of the Chibchas. Geologically, it is a pocket formed by a cluster of spurs near the foot of a conical mountain. It is small, circular in shape, and reaches a central depth of 214 feet. Beneath this lake, according to tradition, lived the national god, Chibchacum. To keep on the right side of this god, to make atonement for the people, a semi-annual feast was observed--the Feast of El Dorado. Twice a year the king of the Chibchas, in celebrating this Feast, was floated on a raft to the center of the Sacred Lake. He was then stripped of his royal robes, his body anointed with oil and covered with gold dust. Glittering in the sunlight this Gilded Man stood at the edge of the royal raft and was saluted by his subjects, who encircled the shores of the lake, each one bearing an offering of gold and emeralds. Then, as if dazzled by the splendor of their monarch, the people reverently turned their faces away from him and, at a signal from the priests, threw their treasures over their heads into the lake, while the Gilded Man, followed by the heaps of precious stones and metals which were with him on the raft, plunged into its waters. No god ever received such a shower of wealth at his shrine as was thus lavished twice a year, for centuries, on the god Chibchacum. All this wealth, except an insignificant sum that the Spaniards rescued, is to-day, according to the legend, at the bottom of Guatavita. Besides this semi-annual tribute, it was rumored that at the time of Sajipa's murder the entire remaining treasure of the Chibchas had been thrown into the lake, not as a votive offering, but as a means of hiding it from the Spaniards. It took fifty men, so runs tradition, to carry the gold dust to Guatavita from the king's treasury alone. All the minor chieftains of the kingdom made a similar sacrifice of their possessions on this occasion. Years afterwards, the Spaniards, stirred by these stories, attempted to drain the lake. This meant the piercing of earth and rock walls nearly nine hundred feet thick and proved too great an undertaking for the engineering machinery that they had in those days. But before they gave up the work they succeeded in lowering the level of the lake sufficiently to recover a certain amount of treasure. Since that time the secret of Guatavita has remained undisturbed. To solve it David went to Bogota. Raoul Arthur, who had done most of the practical planning for the expedition, went with him.