It took several days to collect the material, after which Peter called Andrews. By the time the other man arrived, Peter was finishing off the main part of the trap. He handed the thing to Andrews, who looked at it, squinted through the circlet of wire, and then poked a pencil into it. Where it came level with the plane of the circlet, it ceased to exist in a slick plane of cleavage. Andrews withdrew the pencil and it was complete again. "Great Harry," he shouted. "Where did you get that?" "That," smiled Peter, "is something out of Campbell by Edward E. Smith." "Who?" "Writers of science fiction that turned out millions of words dealing with strange minerals, space warps, and the like. They used to spend their leisure hours thinking up something that would outdo the other. Actually," he said, becoming serious again, "the thing was discovered in our lab during the war. We were working on a closed means of radio communication--a method of wireless connection that would not only prevent the enemy from decoding or unscrambling, but which would be impossible to detect unless you were set up properly. Too many things happened under radio-silence that a means of communication might have prevented. Anyway, in our search for a new level of communications, we got this effect." "Seems to me that it should be good for something." "The trouble is that it can't be made any bigger. Once that loop size is changed, the effect is no longer there. We worked on it for about a month and gave it up because there it is and that's all that could be done with it." "How about using it to pump water out of a sinking ship?" "Can't fasten anything to the ring," said Peter. "But the thing that bothers me is where does it go?" asked Andrews, poking his finger through the ring and withdrawing it hastily as he saw the clean-cut cross section. "Haven't the vaguest idea." "You haven't worked on it much, then?" Peter shook his head. "There were a lot of things that had priority," he said. "We had that scheduled for about three years from now, even. Anyway--what are you doing?" "I'd like to know where the stuff goes," said Andrews. "How are you going to find out?" * * * * * Tony Andrews handed Peter a key ring tag. It was an advertisement for an automobile salesroom, and it stated that any possible finders should merely drop the key ring and chain into the nearest mailbox; that the addressee would pay the postage. It then gave Tony Andrews' name and address and telephone number. "Think ... if it's found anywhere ... it'll be returned?" "That's how they sent them out," he said. "Darned good advertisement, too." "But--" "Look, Peter, if this ... and it must go somewhere ... lands close by, it'll be returned. Perhaps we'll get a letter, too, telling us where. If it lands in some distant country, we'll probably get it back with a letter telling us that I sure did get around."