"Could be, but there are a couple of facts that I'd like to point out. One is that they're not interested in detection. They only want the best in driver efficiency. Another thing is that the radiation from the drivers is sufficient to ionize atmosphere into a dull red glow that persists for several minutes. Next item is the fact that we on Venus Equilateral should be able to invent a detector; we've been tinkering with detectors long enough. Oh, I'll admit that it is secondary-electronics--" "Huh? That's a new one on me." "It isn't electronics," said Channing. "It's sub-etheric or something like that. We'll call it subelectronics for lack of anything else. But we should be able to detect it somehow." "Suppose there is nothing to detect?" "That smacks of one hundred percent efficiency," laughed Don. "Impossible." "How about an electric heater?" asked Arden. "Oh, Lord, Arden, an electric heater is the most ineffic--" "Is it?" interrupted Arden with a smile. "What happens to radiation when intercepted?" "Turns to heat, of course." "That takes care of the radiation output," said Arden. "Now, how about electrical losses?" "Also heat." "Then everything that goes into an electric heater emerges as heat," said Arden. "I get it," laughed Walt. "Efficiency depends on what you hope to get. If what you want is losses, anything that is a total loss is one hundred percent efficient. Set your machine up to waste power and it becomes one hundred percent efficient as long as there is nothing coming from the machine that doesn't count as waste." "Fine point for arguing," smiled Channing. "But anything that will make atmosphere glow dull red after the passage of a ship will have enough waste to detect. Don't tell me that the red glow enhances the drive." The door opened again and Chuck Thomas came in with a crew of men. They ignored the three, and started to hang heavy cloth around the walls and ceiling. Chuck watched the installation of the barrier-cloth, and then said: "Beat it--if you want any young Channings!" Arden, at least, had the grace to blush. * * * * * The tall, slender man handed Don an envelope full of credentials. "I'm Wesley Farrell," he said. "Glad to have a chance to work out here with you fellows." "Glad to have you," said Don. He looked at the other man. "This is Mark Kingman." "How do you do?" said Channing. Kingman did not impress Channing as being a person whose presence in a gathering would be demanded with gracious shouts of glee. "Mr. Kingman is an attorney for Terran Electric," explained Wesley. Kingman's pedestal was lowered by Channing. "My purpose," said Kingman, "is to represent my company's interest in the transmission tube." "In what way?" asked Don.