The detectors were set up and the recorders started. The tripod of anchors set themselves in the star's core. The solar intake beams worked well and the torrents of power increased as the automatic control slid up the scale. "The stuff may be different," observed Hendricks, "but we can still get power from their stars." "Darned good thing, too," said Thompson. "I don't know how else we'd swing it." Again came that feeling of wrenching. And it increased as before. "Does it feel left-handed or right-handed?" asked Lane nervously. "I don't know and if I did I wouldn't remember which way it was the last time," grumbled Downing. And then the warp formed, and there was the impression, just before it snapped-quick, that the stars in that universe were flowing like spots on a watery surface. And they emerged into a space completely devoid of anything. Not a star, not a speckle in the complete sphere of utter blackness. "Obviously went the other way again," grunted Lane. Jack Rhodes looked up from his calculations. "We had a fifty-fifty chance, according to the Law of Probabilities. But tossing one head does not make the next toss any better than fifty-fifty chance for tails. In fact," mused Rhodes, "tossing a hundred coins may bring you forty heads and sixty tails--plus or minus ten percent of the true chance. Tossing a thousand coins may give you four hundred seventy against five hundred thirty--a three percent error. But though the latter is more to the true division, the numerical deviation from zero is only ten in the first case but thirty in the second." "I hate mathematicians," grunted Downing. "They're all pessimists. So the longer we try the more distant we get, huh?" "Unless we can get something to upset the Law of Probability." "And," added Hendricks sourly, "something to pull against. This universe is completely devoid of anything material." "Let's put that as a matter of our being able to detect it at present. It might be teeming with suns indigenous to this universe and completely invisible to us." "We're wasting time," said Thompson. "What's with the detectors and recorders?" "About the only thing I can determine from here is a definite lengthening of the wave length that the puller-sphere propagates on." "Huh?" asked Billy. "Definitely." "When did it lengthen?" "Its wave length increased on an exponential curve to the time of warp--" "Well, now we know--I think--how to get back." "How?" "Instead of pulling, we'll push." * * * * * Hendricks shook his head. "I think I get you, but I'm not too certain. Has to do with the wave length-propagation factor, hasn't it?"