Using a pointed splinter of obsidian, O'Hara tediously worked out the design for a rudimentary still, sufficient, he was certain, for refracting kerosene. "This part must be copper," he explained to the Elder. "A retort to contain the black water." "I see it, O'Hara." "And here we must have pipes. Like a hollow reed, like the barrel of Colt. Can you do this?" "It can be done. We will make a rod of clay and dip it into molten copper. When it cools we will wash out the clay." "That will do it. You must have a very hot fire here--I think that if we spray black water on a bed of coals--with perhaps a bellows here--" "You must draw that." "Here it is. And we will need these coils--we will bend the copper pipes for this--" O'Hara rapidly continued drawing. The sketches were making some kind of sense to the Elder. "They are like the bright clear metal that I showed you in the old place," he suggested, and O'Hara nodded--like the glass retorts in the abandoned laboratory. "This is the machine," he said. "The black water will become colorless, and with it, then, the flying thing will soar into the sky. But first we must have black water." "We will go for it in the morning," said the Elder. "It will take two days to reach the lake that has it. I must go now--your woman is angry. Women do not like these secret things." When the Elder left, Nedra seized O'Hara's arm. "It was evil of you to make these drawings," she burst out, angry. "They are like the drawings of women who design new pots. They are unmanly." "You think I am unmanly, Nedra?" "When you draw these things, yes." "You think so, Nedra?" He moved backward quickly, seizing the carved club and then walking very slowly toward her. When at last it was over, and she turned sleepily on the bearskin at his side, her voice, for once, seemed almost gentle. "We have begun our babies, O'Hara. And I will never leave you now." With dawn, the Elder marshaled his caravan for the journey to the lake that had the black water--a natural pool of petroleum, O'Hara felt certain. And Nedra, alone of all the women, was going. The Elder had his say upon that issue--a scornful speech, addressed to O'Hara, concerning the proper management of women. But Nedra ignored it. Her arms were taut around O'Hara's neck, her face obstinately buried against the brilliant blue of his jacket. "She will delay us," the Elder insisted. "And we must travel swiftly a great distance. We must cross the valley below us, and if there is trouble we cannot wait for a woman to keep pace." O'Hara smoothed Nedra's hair. "Nonetheless, she is going." "Then she is your burden." "Yes, my burden. I understand."