It was noon of the next day when Captain Andrews announced that they were still some two hundred miles from their destination. But, as the boys were all three of them busy over the aero-auto, adjusting and examining every part of the queer craft, the time flew swiftly. The dawn of the third day found them anchored off the jungle-clad coast, while not a mile from them the waves were breaking on the bar that marked the mouth of the shallow river, which, they subsequently learned, was called the Apak.

It would be two hours, so Captain Andrews calculated, before the tide turned and made the passage of the bar possible. In the meantime. Jack brought on deck the silver chest, which he had, of course, taken possession of, pending the time when he could deliver it to his father. The adventurers spread the three blazing gems it contained out on the deck, and revelled in the glow of light and wonderful inward fires the precious stones revealed as the bright sunlight played upon them.

The Vagrant had once been used as a passenger craft at Galveston, and her former owners had installed an iron safe in the cabin for the protection of valuables. In this receptacle Jack replaced the silver casket after they had examined the gems to their hearts content.

By this time Captain Andrews was ready to pronounce the crossing of the bar at the river mouth feasible. The tide had risen till the tempestuous breakers had subsided into long swells, with a narrow passage of smooth water marking the channel. Carefully following this, the skipper of the Sea King piloted the Vagrant through into the calm water of the estuary beyond.

The boys, grouped forward, gazing at the surroundings with eager eyes, beheld a scene full of wild, tropic beauty. The white beach, blazingly radiant in the strong light, was bordered by a dense jungle of dark, melancholy looking mangroves. Beyond these came a tangle of brilliantly green jungle, in which the broad fronds of the banana plant predominated, while here and there a tall palm reared its feathery head.

Further back still the foliage changed again. Lordly groves of mahogany trees, rosewood, and giant royal palms raised their crests. In the distant background, far withdrawn, the misty blue outlines of a range of majestic, rugged-looking mountains showed against the steely blue sky. They looked as if they were hundreds of miles off at least; but Captain Andrews explained that the distance from the shore to the foothills was not so considerable, by a great deal, as it looked. The condition of the atmosphere, laden with the moisture of the lowlands, lent them this appearance of tremendous remoteness.

“It is in those mountains,” said Captain Andrews, “that the remnants of the most ancient of the Maya tribes still live. They tell stories up the coast, in the civilized portions of Yucatan, about vast ruins and remains of splendid cities to be found back there.”

The boys gazed up at him as he stood at the wheel. A magic world of romance and adventure seemed suddenly opened before them by his words.

“I recall reading once,” said Tom, the studious, “that the Mayas were civilized long before the Aztecs or Toltecs, and that their knowledge of the building arts exceeded that of either of those races.”

“Sort of pioneer real-estate men,” chuckled Ned Bangs, who in moments when he was not oppressed by trouble, as he had been recently, possessed a whimsical vein of humor.