That evening a few men were gathered in Van Schaick's private office at the building of the American Exploration Society. One was a celebrated anthropologist, another a historian who had come that day from Washington. A financier whose name figured in the newspapers was a third. And a European orientologist. To these men, Van Schaick introduced Gray, explaining briefly what had passed in their interview. "Captain Gray," he concluded, "wishes proof of what we know. If he can be convinced that the Wusun are to be found in the Gobi Desert, he is ready to undertake the trip." For an hour the three scientists talked. Gray listened silently. They were followers of a calling strange to him, seekers after the threads of knowledge gleaned from the corners of the earth, zealots, men who would spend a year or a lifetime in running down a clew to a new species of human beings or animals. They were men who were gatherers of the treasures of the sciences, indifferent to the ordinary aspects of life, unsparing in their efforts. And he saw that they knew what they were talking about. In the end of the Bronze Age, at the dawn of history, they explained, the Indo-Aryan race, their own race, swept eastward from Scandinavia and the north of Europe, over the mountain barrier of Asia and conquered the Central Asian peoples--the Mongolians--with their long swords. This was barely known, and only guessed at by certain remnants of the Aryan language found in Northern India, and inscriptions dug up from the mountains of Turkestan. They believed, these scientists, that before the great Han dynasty of China, an Indo-Aryan race known as the Sacæ had ruled Central Asia. The forefathers of the Europeans had ruled the Mongolians. The ancestors of thousands of Central Asians of to-day had been white men--tall men, with long skulls, and yellow hair, and great fighters. The earliest annals of China mentioned the Huing-nu--light-eyed devils--who came down into the desert. The manuscripts of antiquity bore the name of the Wusun--the "Tall Ones." And the children of the Aryan conquerors had survived, fighting against the Mongolians for several hundred years. "They survive to-day," said the historian earnestly. "Marco Polo, the first European to enter China, passed along the northern frontier of the Wusun land. He called their king Prester John and a Christian. You have heard of the myth of Prester John, sometimes called the monarch of Asia. And of the fabulous wealth of his kingdom, the massive cities. The myth states that Prester John was a captive in his own palace." "You see," assented Van Schaick, "already the captivity of the Wusun had begun. The Mongolians have never tolerated other races within their borders. During the time of Genghis Khan and the Tartar conquerors, the survivors of the Aryans were thinned by the sword."