Since many such items may be ambiguous it makes no difference whether the plate voltage is developed by batteries, rectifier-filter supplies, generators or a vibrator-pack that develops high voltage from a six-volt battery. It is sensible to omit them and merely label the "input" terminal with a symbol. But couple a text with a complete knowledge of the language, especially a dictionary that is complete in its scientific sense, and you learn of batteries, voltage, generators and the like. You discover that an electron tube has this and that and perhaps why. Using a good sensible knowledge of physics plus ingenuity the science becomes less puzzling. Similarly James Forrest Carroll was able to reproduce the science of the aliens. All of this took time, of course--weeks. Weeks of testing and trying and fumbling. As Volta might be baffled by a common transformer where, though the input is shorted together through loops of wire and the output is similarly shorted, yet there is transfer of energy, so Carroll was baffled by the strange and bizarre thing that grew in the cellar of his Wisconsin home. It was a large circular loop of silver-plated copper tubing. It was mounted on a cylindrical slug of high-permeability alloy which was magnetized to a high charge. The crystal was common enough but its connection made little sense from the Terran point of view. The Ancients used to use crystals for jewelry and would have been bewildered at the modern idea of cutting them in slabs to make standards of frequency. Finally he surveyed his work with a satisfied smile. He snapped it on and a shining plane of totally reflecting energy filled the circular loop of wire. "It isn't Lewis," he said. "It's James Forrest Carroll Through The Looking Glass!" Rhinegallis shook her head. "The proper title is 'Alice Through The Looking Glass'," she told him. "You have a rather extensive Terran education," he observed. "Would any Terran be without an education?" she countered. "Doubtless far superior to any normal person," he grunted, "thanks to that mental educating dingus of yours." "And partly due to hard work," she said. "Give me some credit." He smiled wanly. Then he snapped the instrument on and off and looked at the perfect plane with interest. "Wonder if it might be possible to warp it into a perfect parabola," he said thoughtfully. "I wouldn't know," she replied, "but it would make a fine telescope, wouldn't it?" "Whole gear weighs about five pounds." He grinned. "The thousand-inch mirror would be a definite practicality. What we couldn't see with that!" "Might as well go," she said humorously. "You're like the man who discovered motive power and then used it to yell over great distances with instead of going there." "So far," he said seriously, "there's little to be gained by this gimmick. I'm like the first man on earth to own a telephone. I've no one to talk to." "But tell me, what did he do?"