who had taken a fancy to the boys, had told them glittering stories as they sat on deck under the Moon. Then they fell silent, their eyes on the strange scenes about them.

Although a great world port, and second only to San Francisco in importance on the Pacific Coast of the Western Hemisphere, Valparaiso is not a harbor as harbors go, lying open to the sea. Great numbers of ships lay about them offshore, freighters from all the world. And tugs and lighters kept coming and going in a continuous bustle between ships and shore.

As their train for Santiago, whither Mr. Hampton was bound on business, would leave in an hour, there was little time for sightseeing. Mr. Hampton, who knew the South American cities from former visits, on one of which he had taken Jack with him, assured them there was little in Valparaiso of historic or picturesque interest.

Nevertheless, the boys kept their eyes open during the trip through the narrow but noisy bustling business quarter which occupies the flats between the shore line and the thousand-foot cliffs behind upon which residential Valparaiso is situated. Ascensors took them up the sheer cliffs, and then followed a four-hour journey by train to Santiago.

They were expected, and at the Santiago station they were met by a family carriage which carried them to the home of Senor Don Ernesto de Avilar, with whom Mr. Hampton had come to transact business. With true Spanish hospitality, the latter on receiving word of his coming, had written urgently that he do not stop to a hotel, but bring the three boys with him as guests.

The way to the mansion of Senor de Avilar lay along the Alameda, a boulevard 600 feet wide, which formerly had been the bed of the Mapocho River, and as they bowled along the boys exclaimed time and again at the wonderful beauty of the surroundings and of the handsome residences. Frank and Bob, who were undergoing great changes in their preconceived notions of South America as a land of ruins and half-breeds, were especially astonished. Jack, who had been in this part of the world before, grinned with satisfaction.

“I didn’t tell you fellows much about this before,” he said. “I wanted to see your eyes pop out. Thought you were going to run into something wild and savage, didn’t you? Well, this is the most beautiful residential city in South America, and one of the most beautiful in the world. Isn’t it, father?” he appealed.

Mr. Hampton nodded.

“Santiago and Rio de Janeiro hold the palm in that respect,” he said. “Rio, however, because of its wonderful harbor and mountainous surroundings is, in my eyes at least, a bit the more beautiful. Yet, as you can see, Santiago’s natural beauties would be hard to surpass. However, here we are at Senor de Avilar’s home. Let us hope the accident to his son has not been serious. In that case, we cannot stay, as we would embarrass the family, but will go to a hotel.”

They had expected Senor de Avilar to greet them in person on arrival, but had been told by the driver that at the last moment the latter had been called to a point outside the city where his son, Ferdinand, had been injured when thrown from a runaway horse.

Fortunately, it developed, the accident had not proven serious. The young son of the house, a youth of their own age, had sustained a fractured wrist, but otherwise had escaped unharmed. He was a charming boy with a fairly good command of English, and he and the boys became warm friends during the ensuing week.

As Jack, owing to his previous visit to South America, on which occasion he had learned the language, could speak and read Spanish fluently, and as he had imparted considerable knowledge of the language to Frank and Bob, the four got along famously. Horseback rides about the city and its environs were of daily occurrence, young de Avilar managing his mount in superb fashion despite the injured wrist.

During the week, the boys saw little of Mr. Hampton and Senor de Avilar. The two older men were closeted in long conferences with others every day. For a number of reasons, the boys were curious to know the nature of these conferences.

In the first place, at the beginning of their summer vacation from Yale, Mr. Hampton, a consulting engineer of international reputation, had called Jack into his study in their home on Long Island, adjoining the Temple home at which Frank, an orphan, resided, and had smiled a little as he said:

“Well, Jack, how would you and the boys like to go with me hunting treasure this summer?”

Hunt treasure?

Jack’s eyes began to shine. Then his father explained that he had received an urgent invitation from Senor de Avilar to cast in his fortunes with him on an expedition into the fastnesses of the Bolivian mountains in search of a horde reputed buried by the ancient Incas.

“I don’t know whether anything will come of it, Jack, in the way of fortune,” his father had said, “but at least we will have plenty of adventurous travel. As you know, I am wealthy. The lure of gold does not draw me for itself. But, Jack, I’m very much afraid that in some respects I have never grown up. Buried treasure has a magical appeal; it captivates my imagination.

“When I was in South America last, in connection with the mining interests developing a new district on the borders of Peru and Bolivia, I heard many tales of Inca treasure. Those old Indians had a great civilization, and if the Spanish conquerors under Pizarro, Almagro and others had treated the Incas decently, who knows what they would have given the world. But the conquistadores were rapacious for gold, of which there are vast stores in the mountains of South America, and they slew merely to rob and thus wiped out one of the fairest races the world has ever seen. The Incas undoubtedly hid much of their golden treasures to keep it from falling into the clutches of the conquerors.

“Senor de Avilar is the head of the syndicate using my services at that time. And many a legend of Inca treasure did he tell me, for he, too, has felt the thrill. His imagination, like mine, is stirred by these departures from a workaday world. Now he writes me that he has come into possession of an ancient manuscript which he believes genuine. It purports to be the diary of a conquistadore who was captured by a band of Inca noblemen who fled far to the southward when the Spaniards invaded their country, and carried him captive with them. There is much of treasure buried in the Bolivian Andes because of the difficulties of transportation, and more of a magical city which the Incas founded in the south. This latter may have been the Enchanted City of the Caesars, the story of which I shall tell you some later day.

“At any rate, my good friend says he wants to be a boy again and to hunt for buried treasure. And he knows that I feel as he does, and offers me the chance to go along. Many men might consider me foolish, Jack, to engage in such a fantastic expedition. But your mother has been dead these many years; you and I are alone in the world; I have made a fortune big enough to take care of you for life, even if I do not add another cent to it. And I am a young man yet. Jack, I want to go. How about it?”

“How about it?” Jack gulped. He and this tall man with the twinkling eyes, and the figure as slender and hard as a boy’s, called each other father and son. But in reality they were pals. Jack stared a moment, his eyes alight, then emitted a little gasp of pure joy, and jumping up from his chair, he threw an arm over his father’s shoulders.

“Dad,” he gulped, “I’d never forgive you if you didn’t take the chance.”

A hard squeeze of his hand was his father’s reply.

“You said something about Frank and Bob?”

“Yes,” said Mr. Hampton. “They have finished their Freshman year at Yale, and they are strong, capable fellows, able to think rapidly and clearly in an emergency, as they have demonstrated many times. I am thinking of asking Mr. Temple to let them go