"Oh sure," said Channing expansively. "I'll admit that the similarity is of the same order as the similarity between an incandescent lamp and a ten dynode, electron-multiplier such as we use in our final beam stages. But recall this business of the cathode-dynode. In both, the emitting surface is bombarded by electrons from electron guns. They both require changing." "I know that, but the driver cathode disintegrates at a rate of loss that is terrific compared to the loss of emitting surface in the transmission tube." "The driver cathode is worth about two hundred G-hours. But remember, there is no input to the driver such as you have in the transmission tube. The power from the driver comes from the disintegration of the cathode surface--there isn't a ten thousandth of an inch of plating on the inside of the tube to show where it went. But the transmission tube has an input and the tube itself merely transduces this power to some level of radiation for transmission. It is re-transduced again for use. But the thing is this: Your tube is the only thing we know of that will accept subelectronic energy and use it. If the driver and the transmission tubes are similar in operational spectrum, we may be able to detect driver radiation by some modification." "That sounds interesting," said Wes. "I'll be darned glad to give you a lift." "Isn't that beyond your job?" asked Channing. "Yeah," drawled Farrell, "but could you stand by and watch me work on a beam transmitter?" "No--" "Then don't expect me to watch without getting my fingers dirty," said Farrell cheerfully. "Sitting around in a place like this would drive me nuts without something to do." "O.K., then," smiled Don. "We'll start off by building about a dozen miniatures. We'll make 'em about six inches long--we're not going to handle much power, you know. That's first." Kingman viewed the list with distaste. "There are a number of items here which I may not allow," he said. "For instance?" asked Channing with lifted eyebrows. "One, the manufacture or fabrication of power transmission tubes by anyone except Terran Electric is forbidden. Two, your purpose in wanting to make tubes is not clearly set forth. Three, the circuits in which you intend to use these tubes is unorthodox, and must be clearly and fully drawn and listed." "Oh spinach! How can we list and draw a circuit that is still in the embryonic stage?" "Then clarify it. Until then I shall withhold permission." "But look, Mr. Kingman, we're going to develop this circuit as we go along." "You mean that you are going to fumble your way through this investigation?" "We do not consider a cut-and-try program as fumbling," said Walt Franks. "I am beginning to believe that your research department has not the ability to reduce your problems to a precise science," said Kingman scornfully. "Name me a precise science," snapped Channing, "or even a precise art!"