_What if the Brain doesn't develop along lines sympathetic to you?_ He elaborated upon it, feeding worry thoughts along with it. A second Brain might not follow the line of development of the first, any more than one human develops like another, even when they are twins. Rather than accomplishing his aim of having a second Cyberene on the other Earth in 3042, holding the human population in slavery, it might prove a more formidable enemy than the people of that Earth. And if that turned out to be the case, wouldn't it be better to have a trump card? Some way of destroying the second Cyberene at any time? Even if it were friendly to the first, it might want to be boss. Power of life and death over it would prevent that. Earl's conscious mind, entirely cooperative with the Cyberene, soon began to think very dominantly along those lines. Earl sat back and waited for some reaction from the Cyberene. It was not long in coming. At five o'clock Nadine looked him up and informed him that they were to report to the Cyberene at once. * * * * * "I have detected certain thoughts in your mind," the voice of the Cyberene sounded. "I would like to hear what you have to say." Earl sensed his mind rallying its thoughts. "I've been wondering what the other Cyberene would be like. That's all. There's no guarantee that it will have any special traits that will make it what you want it to be, and once it's started it's out of your control, isn't it?" "That's true. Time travel and even fifth dimension travel is extremely limited. Once the other Cyberene is generated, I can't contact it until 3042--now." "Can you look into your future and see--" "Unfortunately, no. I can't even see into your tomorrow. I might, perhaps, jump to the year 4104 A. D., but even that is beyond my present ability and instruments. It may be many centuries before I understand everything about hyperspace." "That's what I surmised," Earl heard himself say. He stole a glance at Nadine, who was watching him attentively. "That's why I think, for your own protection, you should be able to destroy the other Cyberene instantly--if it isn't what you hope it will be." "How?" The Cyberene's voice was vibrant with eagerness. "The basic device would be sound vibrations in the air, inside its braincase. A loud continuous sound of nearly all frequencies would cause billions of nerve strands to vibrate, and enough of them would break to destroy the functioning of the whole. That could be built into it in 1980. The problem is to decide how to trigger it. Do you have any ideas?"