It consisted of an exceptionally strong broadcasting unit that beamed the message of a tape, continuously, toward Terra. Jon made up the tape while Jak was giving the feeding. It read, "This planetary system was first discovered by Tad Carver, on fourteenth January, 2136. This is the second planet, and has been named 'Marci.'" Over and over, at five-minute intervals, the sender would broadcast that message on a beam aimed at Terra. The controlling mechanism was a marvelously precise uranium clock, and a small atomic motor with fuel enough for five years gave all the needed power. By the terms of the Terran Colonial laws, this was supposed to entitle the prime discover to certain rights in the system. For one thing, he would receive a one-half per cent share of the value of all minerals, oils, jewels and certain other natural resources later colonists might wrest from those planets, for twenty years following his discovery and the acceptance of his claim. In this way, the Colonial Board of the World Government of Terra sponsored and assured the far-flung exploration which the development of deep-space travel had made possible. The dangers and expense were so considerable that something well worth while had to be offered to make individuals or companies willing to gamble on the hardships and tremendous costs of exploration. When the boys left the ship to place the marker, they left both lockdoors open so that the fresh morning air from outside could circulate throughout the ship, replacing the somewhat stuffy, although chemically pure air that their purifiers kept renewed. "Keep your eyes and ears open, and shut the doors if you think there's any danger," both boys cautioned their mother, after making sure she knew how to work the door controls. "I will," she promised with a laugh, and couldn't help adding, "Just you be as careful as I'll be." The boys carried the signal-sender to a distant corner of the clearing, to what Jon said was a good spot. "The book says to dig a hole and plant it with the top projecting three inches above the ground, whenever such a thing is possible." "You know what to do, so take charge," Jak said simply. When they had dug the hole and placed the sender in it, they shoveled the dirt back, then Jon opened the lid. He started the tape reels and the broadcasting unit, then carefully shut and locked the cover. In digging, they found the ground here to be damp and soggy, apparently from that terrific downpour of the previous evening. It was almost like a wet clay, although, even to their inexperienced eyes, it seemed to be a very rich type of soil. "Look how wet it is, even over two feet down," Jon said. "That was a real rain last night," Jak shook his head slowly, "but somehow I can't believe it made this. Maybe this is the rainy season." They started toward the jungle, but turned to look back toward the ship. They saw their mother at the open door, and waved to her.