Trevize stared at Pelorat for a long moment， and with an expression of clear displeasure. Then he said， "Is there something you saw that I did not， and that you did not tell me about？"
"No，" answered Pelorat mildly. "You saw it and， as I just said，I tried to explain， but you were in no mood to listen to me."
"Well， try again."
Bliss said， "Don"t bully him， Trevize."
"I"m not bullying him. I"m asking for information. And don"t you baby him."
"Please，" said Pelorat， "listen to me， will you， and not to each other. Do you remember， Golan， that we discussed early attempts to discover the origin of the human species？ Yariff"s project？ You know， trying to plot the times of settlement of various planets on the assumption that planets would be settled outward from the world of origin in all directions alike. Then， as we moved from newer to older planets，we would approach the world of origin from all directions."
Trevize nodded impatiently. "What I remember is that it didn"t work because the dates of settlement were not reliable."
"That"s right， old fellow. But the worlds that Yariff was working with were part of the second expansion of the human race. By then，hyperspatial travel was far advanced， and settlement must have grown quite ragged. Leapfrogging very long distances was very simple and settlement didn"t necessarily proceed outward in radial symmetry. That surely added to the problem of unreliable dates of settlement.
"But just think for a moment， Golan， of the Spacer worlds. They were in the first wave of settlement. Hyperspatial travel was less advanced then， and there was probably little or no leapfrogging. Whereas millions of worlds were settled， perhaps chaotically， during the second expansion， only fifty were settled， probably in an orderly manner， in the first. Whereas the millions of worlds of the second expansion were settled over a period of twenty thousand years； the fifty of the first expansion were settled over a period of a few centuries almost instantaneously， in comparison. Those fifty， taken together， should exist in roughly spherical symmetry about the world of origin.
"We have the co-ordinates of the fifty worlds. You photographed them，remember， from the statue. Whatever or whoever it is that is destroying information that concerns Earth， either overlooked those co-ordinates， or didn"t stop to think that they would give us the information we need. All you have to do， Golan， is to adjust the co-ordinates to allow for the last twenty thousand years of stellar motions， then find the center of the sphere. You"ll end up fairly close to Earth"s sun， or at least to where it was twenty thousand years ago."
Trevize"s mouth had fallen slightly open during the recital and it took a few moments for him to close it after Pelorat was done. He said，"Now why didn"t I think of that？"
"I tried to tell you while we were still on Melpomenia."
"I"m sure you did. I apologize， Janov， for refusing to listen. The fact is it didn"t occur to me that " He paused in embarrassment.
Pelorat chuckled quietly， "That I could have anything of importance to say. I suppose that ordinarily I wouldn"t， but this was something in my own field， you see. I am sure that， as a general rule， you"d be perfectly justified in not listening to me."
"Never，" said Trevize. "That"s not so， Janov. I feel like a fool，and I well deserve the feeling. My apologies again and I must now get to the computer."
He and Pelorat walked into the pilot-room， and Pelorat， as always，watched with a combination of marveling and incredulity as Trevize"s hands settled down upon the desk， and he became what was almost a single man computer organism.
"I"ll have to make certain assumptions， Janov，" said Trevize， rather blankfaced from computer-absorption. "I have to assume that the first number is a distance in parsecs， and that the other two numbers are angles in radians， the first being up and down， so to speak， and the other，right and left. I have to assume that the use of plus and minus in the case of the angles is Galactic Standard and that the zero-zzzzzzzzz mark is Melpomenia"s sun."