Ta-den, he of the hairless, white skin, having assumed the role of tutor, prosecuted his task with a singleness of purpose that was reflected in his pupil's rapid mastery of Ta-den's mother tongue. Om-at, the hairy black, also seemed to feel that there rested upon his broad shoulders a portion of the burden of responsibility for Tarzan's education, with the result that either one or the other of them was almost constantly coaching the ape-man during his waking hours. The result was only what might have been expected--a rapid assimilation of the teachings to the end that before any of them realized it, communication by word of mouth became an accomplished fact. Tarzan explained to his companions the purpose of his mission but neither could give him any slightest thread of hope to weave into the fabric of his longing. Never had there been in their country a woman such as he described, nor any tailless man other than himself that they ever had seen. "I have been gone from A-lur while Bu, the moon, has eaten seven times," said Ta-den. "Many things may happen in seven times twenty-eight days; but I doubt that your woman could have entered our country across the terrible morasses which even you found an almost insurmountable obstacle, and if she had, could she have survived the perils that you already have encountered beside those of which you have yet to learn? Not even our own women venture into the savage lands beyond the cities." "'A-lur,' Light-city, City of Light," mused Tarzan, translating the word into his own tongue. "And where is A-lur?" he asked. "Is it your city, Ta-den, and Om-at's?" "It is mine," replied the hairless one; "but not Om-at's. The Waz-don have no cities--they live in the trees of the forests and the caves of the hills--is it not so, black man?" he concluded, turning toward the hairy giant beside him. "Yes," replied Om-at, "We Waz-don are free--only the Hodon imprison themselves in cities. I would not be a white man!" Tarzan smiled. Even here was the racial distinction between white man and black man--Ho-don and Waz-don. Not even the fact that they appeared to be equals in the matter of intelligence made any difference--one was white and one was black, and it was easy to see that the white considered himself superior to the other--one could see it in his quiet smile. "Where is A-lur?" Tarzan asked again. "You are returning to it?" "It is beyond the mountains," replied Ta-den. "I do not return to it--not yet. Not until Ko-tan is no more." "Ko-tan?" queried Tarzan.