"I'll try not to," Arcot laughed. "Anyway, let's get on to the main power plant. Remember that our condenser coil is a gadget for storing energy in space; we are therefore obliged to supply it with energy to store. Just forming the drive field alone will require two times ten to the twenty-seventh ergs, or the energy of about _two and a half tons_ of matter. That means a whale of a lot of lead wire will have to be fed into our conversion generators; it would take several hours to charge the coils. We'd better have two big chargers to do the job. "The controls we can figure out later. How about it? Any suggestions?" "Sounds okay to me," said Morey, and the others agreed. "Good enough. Now, as far as air and water go, we can use the standard spacecraft apparatus, Fuller, so you can figure that in any way you want to." "We'll need a lab, too," Wade put in. "And a machine shop with plenty of spare parts--everything we can possibly think of. Remember, we may want to build some things out in space." "Right. And I wonder--" Arcot looked thoughtful. "How about the invisibility apparatus? It may prove useful, and it won't cost much. Let's put that in, too." The apparatus he mentioned was simply a high-frequency oscillator tube of extreme power which caused vibrations approaching light frequency to be set up in the molecules of the ship. As a result, the ship became transparent, since light could easily pass through the vibrating molecules. There was only one difficulty; the ship was invisible, all right, but it became a radio sender and could easily be detected by a directional radio. However, if the secret were unknown, it was a very effective method of disappearing. And, since the frequency was so high, a special detector was required to pick it up. "Is that all you need?" asked Fuller. "Nope," said Arcot, leaning back in his chair. "Now comes the kicker. I suggest that we make the hull of foot-thick lux metal and line it on the inside with relux wherever we want it to be opaque. And we want relux shutters on the windows. Lux is too doggone transparent; if we came too close to a hot star, we'd be badly burned." Fuller looked almost goggle-eyed. "_A--foot--of--lux!_ Good Lord, Arcot! This ship would weigh a quarter of a million tons! That stuff is _dense_!" "Sure," agreed Arcot, "but we'll need the protection. With a ship like that, you could run through a planetoid without hurting the hull. We'll make the relux inner wall about an inch thick, with a vacuum between them for protection in a warm atmosphere. And if some tremendous force did manage to crack the outer wall, we wouldn't be left without protection." "Okay, you're the boss," Fuller said resignedly. "It's going to have to be a big ship, though. I figure a length of about two hundred feet and a diameter of around thirty feet. The interior I'll furnish with aluminum; it'll be cheaper and lighter. How about an observatory?"