"Hold the fort," he bawled over his shoulder, "break out a big bottle and small glasses! We got a contract, lad, we got a contract!" He vanished triumphantly into the night. * * * * * Old 29 was homing. Travis felt the great soft peace of deep space close over him. All was right with the world. A clean and sparkling Navel, well-bathed now and almost frighteningly beautiful, sat worshipfully at his feet dressed in a pair of Dahlinger's pajamas. Both Trippe and Dahlinger were regarding him with wonder and delight, and as he sat gazing down at them fondly he recalled with pleasure the outraged faces of the men from Unico, that robber outfit. "Pat Travis," he chuckled, patting the fat contract in his pocket, "the luckless Pat Travis rides again." He turned an eye on the staring Trippe. "My boy," he said paternally, "speaks me no speaks about luck, from this day forth. All the material was in your hands, there was no luck involved. All you had to do was use it." "But Trav, I still don't get it. I've been thinkin' all night, all the while you were gone...." "The planet Pluto," Travis said evenly, "was discovered by Earthmen, finally, in the year 1930. At that time we were approximately 300 years ahead, technologically, of the people of Mert. A similar case exists for Neptune, which was not discovered, although adequate telescopes had long been in use, until 1846." He paused and gazed happily around. "Does the light dawn?" "Holy cow!" "Exactly. Diomed is a nine planet system. For which 'fack' thank old Ed Horton, who returned a favor done many years ago. Luck? Only if doing favors for people is lucky. Which I suppose you could make a case for. But in the astrology of Diomed III--an astrology I took great pains to understand--how many planets are considered? Let us examine. Rym, Fors, Lyndal, Bonken, Huck, Weepen, and Sharb. And then there are also the two 'lights,' that is, the sun and the moon. But how many _planets_ are there? Counting Mert as one, add them up. It comes out eight. Not nine. Eight. But Diomed is a nine planet system. Bless Ed Horton. What happened to the missing planet?" Dahlinger w h o o p e d. "They didn't know they had one!" Travis grinned. "With surety. They didn't know it existed. If they had their astrology would certainly have shown it. So it had obviously, like our own Pluto at a similar time, never been discovered." He paused once again while Dahlinger and Trippe regarded him with delight. "And you," Trippe said, "you showed them where it was." Travis clucked. "I did not. For one thing, I didn't know where it was. I simply told him, very regretfully, that there _was_ one, but the situation being what it was, I couldn't allow him to use our telescopes to plot its orbit. Unless, you see, there existed a concrete agreement between us.