To Lake and the men with him the climb back up the long, steep slope of the mountain was a stiff climb to make in one day but no more than that. It was hard to believe that it had taken Humbolt and Barber almost three days to climb it and that Barber had died in the attempt. It reminded him of the old crossbows that Humbolt and the others had used. They were thin, with a light pull, such as the present generation boys used. It must have required courage for the old ones to dare unicorn attacks with bows so thin that only the small area behind the unicorn's jaws was vulnerable to their arrows.... * * * * * When the caves were reached, a very gradual reduction of pressure in the mocker cages was started; one that would cover a period of weeks. One pair of mockers survived and had two young ones that fall. The young mockers, like the first generation of Ragnarok-born children of many years before, were more adapted to their environment than their parents were. The orange corn was planted, using an adaptation method somewhat similar to that used with the mockers. It might have worked had the orange corn not required such a long period of time in which to reach maturity. When winter came only a few grains had formed. They were saved for next year's seeds, to continue the slow adaptation process. By the fifth year the youngest generation of mockers was well adapted to the elevation of the caves but for a susceptibility to a quickly fatal form of pneumonia which made it necessary to keep them from exposing themselves to the cold or to any sudden changes of temperature. Their intelligence was surprising and they seemed to be partially receptive to human thoughts, as Bill Humbolt had written. By the end of the fifteenth year their training had reached such a stage of perfection that a mocker would transmit or not transmit with only the unspoken thought of its master to tell it which it should be. In addition, they would transmit the message to whichever mocker their master's thought directed. Presumably all mockers received the message but only the mocker to whom it was addressed would repeat it aloud. They had their method of communication. They had their automatic crossbows for quick, close fighting, and their long range longbows. They were fully adapted to the 1.5 gravity and their reflexes were almost like those of prowlers--Ragnarok had long ago separated the quick from the dead. There were eight hundred and nineteen of them that year, in the early spring of one hundred and fifty, and they were ready and impatient for the coming of the Gerns. Then the transmitter, which had been in operation again for many years, failed one day. George Craig had finished checking it when Lake arrived. He looked up from his instruments, remarkably similar in appearance to a sketch of the old George Ord--a resemblance that had been passed down to him by his mother--and said: