ORIDIN'S FORMULA By R. R. WINTERBOTHAM The formula was a simple equation, but Caddo had to have it--for knowing its answer meant he would rule the universe. [Transcriber's Note: This etext was produced from Planet Stories March 1943. Extensive research did not uncover any evidence that the U.S. copyright on this publication was renewed.] Oridin the Recluse listened to the threat wirelessed from the spaceship that was hoving to in a landing orbit about the planetoid Azair. "I've a bead on your atmosphere plant," said the snarling voice. "One false move and I'll blast it to star dust." Oridin shrugged as he heard the words. One more fool had come to Azair looking for the secret that the Recluse of the Asteroids was supposed to possess. "Your threats are unnecessary, stranger," Oridin replied in the microphone of his radio. "Everyone is welcome here as long as he behaves. I have ways of dealing with those who don't." "I'm warning you," came the voice again, "that I will stand for no foolishness. I'll kill you if you try to resist." Oridin smiled. "Land, stranger, you need not fear me." The hermit arose and went to the galley of the warm little house that seemed to grow from the solid rocks of the tiny planet. He pressed a button, waited a second and then opened a small compartment. In the box was a steaming pot of coffee, freshly made by Oridin's automatic cook. Outside the transparent shelter, the air grew blue from the reflection of landing rockets. Oridin glanced to the leveled surface on which the ship was coming to rest. He saw a turret training on the little house. Oridin was not afraid; the visitor probably would be interesting. Even a recluse can grow lonesome on a minor planet. A figure emerged from the spaceship. He wore an oxygen helmet, although Oridin plentifully supplied the planetoid with artificial atmosphere from a small plant at the north pole. The stranger did not believe that Oridin would not resist. Again Oridin smiled. Deep in the rocks of Azair were guns that could have blasted the visitor a thousand times, had Oridin wished. But there was nothing clever about blowing a foe to pieces. The foe too often was killed before he sensed defeat. Oridin enjoyed an equal battle, or even one against odds. [Illustration: _"Open up," Caddo snarled, "or I'll blow my way in!"_] "Open up! Open up, I tell you, or I'll burn my way in!" demanded the visitor. "He's certainly not deceiving me as to his intentions," Oridin decided. The recluse pushed a button on the wall, and a giant gate swung outward admitting the stranger.