"Sure. They're like light--only they ain't. We're going to use a glorified meteor detector. We'll control the spread and dispersion so that we cover a healthy hundred miles or so, which will give us sufficient power, I believe. If not, we'll have to tighten the beam. At any rate, spreading from a point source to an object of a given dimension, the waves rebound as though the object were a plane mirror. That will give us a dispersion of twice the dimension of the _Empress of Kolain's_ planar projection through this axis. Twelve hundred feet isn't much, but once we get her on the beam and have confirmation, we can forget the rebound. We'll have her pinned." "And then?" asked Franks. "Then we will have left the small end, which I'll give to you, Walt, so that you can have part of the credit." Walt shook his head. "The easy part," he said uncheerfully. "By which you mean the manner in which we contact them and make them listen to us?" "That's her," said Don with a cheerful smile. * * * * * "Fine!" said Thomas. "Now what do we do?" "Clear up this mess so we can make the cam. This drawing will do, just grab the tablecloth." Joe, the operator of Equilateral's one and only establishment for the benefit of the stomach, came up as the three men began to move their glasses and dishes over to an empty table. "What makes with the tablecloth?" he asked. "Don't you want a piece of carbon paper and another tablecloth?" "No," said Don nonchalantly. "This single copy will do." "We lose lots of tablecloths that way," said Joe. "It's tough, running a restaurant on Equilateral. I tried using paper ones once, but that didn't work. I had 'em printed, but when the Solar System was on 'em, you fellows drew schematic diagrams for a new coupler circuit. I put all kinds of radio circuits on them, and the gang drew plans for antenna arrays. I gave up and put pads of paper on each table, and the boys used them to make folded paper airplanes and they shot them all over the place. Why don't you guys grow up?" "Cheer up, Joe. But if this tablecloth won't run through the blueprint machine, we'll squawk!" Joe looked downcast, and Franks hurried to explain: "It isn't that bad, Joe. We won't try it. We just want to have these figures so we won't have to run through the math again. We'll return the cloth." "Yeah," said Joe at their retreating figures. "And for the rest of its usefulness it will be full of curves, drawings, and a complete set of astrogating equations." He shrugged his shoulders and went for a new tablecloth. Don, Walt, and Charles took their improvised drawing to the machine shop, where they put it in the hands of the master mechanic. "This thing has a top requirement," Don told him, "Make it as quick as you can."