"You almost cheer me, Doctor. Almost, but not quite."
"Actually," Entman said, "I've been wondering about something else."
"What's that?"
"When and how they came here before."
"You mean, where did they get the model for the ten androids?"
"Yes. They had to have not only a model, but also some knowledge concerning our geographical and atmospheric conditions. The two hearts indicate that they knew the elements contained in our air—the pressures and so forth necessary to our existence—and were unable to construct a working model that would function under our conditions with a single heart. So they put in two."
"It looks as though they missed on some other things, too. Seven of the androids have expired."
Entman shrugged. "Still—a remarkable job, particularly since they would have no chance for a trial-and-error test under the conditions that would prevail. It's surprising that any of the androids were able to keep functioning."
"The eighth one is pretty sick. He may be gone by now. And about their earlier coming, I can give you one point. They came quietly, probably at night, grabbed their model, and moved out fast."
"How do you know that?"