"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?"