"No，" said Bander， shaking its head. "My robots are not impressed with such things. Nor would my fellow-Solarians be. This unusual chance of meeting half-humans and displaying for them is most amusing."
Pelorat said， "The light in this room shone dimly when we entered. Does it shine dimly at all times？"
"Yes， a small drain of power like keeping the robots working. My entire estate is always running， and those parts of it not engaged in active labor are idling."
"And you supply the power constantly for all this vast estate？"
"The sun and the planet"s core supply the power. I am merely the conduit. Nor is all the estate productive. I keep most of it as wilderness and well stocked with a variety of animal life； first， because that protects my boundaries， and second， because I find esthetic value in it. In fact， my fields and factories are small. They need only supply my own needs， plus some specialties to exchange for those of others. I have robots， for instance， that can manufacture and install the heat-conducting rods at need. Many Solarians depend upon me for that."
"And your home？" asked Trevize. "How large is that？"
It must have been the right question to ask， for Bander beamed. "Very large. One of the largest on the planet， I believe. It goes on for kilometers in every direction. I have as many robots caring for my home underground， as I have in all the thousands of square kilometers of surface."
"You don"t live in all of it， surely，" said Pelorat.
"It might conceivably be that there are chambers I have never entered，but what of that？" said Bander. "The robots keep every room clean，well ventilated， and in order. But come， step out here."
They emerged through a door that was not the one through which they had entered and found themselves in another corridor. Before them was a little topless ground-car that ran on tracks.
Bander motioned them into it， and one by one they clambered aboard. There was not quite room for all four， plus the robot， but Pelorat and Bliss squeezed together tightly to allow room for Trevize. Bander sat in the front with an air of easy comfort， the robot at its side，and the car moved along with no sign of overt manipulation of controls other than Bander"s smooth hand motions now and then.
"This is a car-shaped robot， actually，" said Bander， with an air of negligent indifference.
They progressed at a stately pace， very smoothly past doors that opened as they approached， and closed as they receded. The decorations in each were of widely different kinds as though robots had been ordered to devise combinations at random.
Ahead of them the corridor was gloomy， and behind them as well. At whatever point they actually found themselves， however， they were in the equivalent of cool sunlight. The rooms， too， would light as the doors opened. And each time， Bander moved its hand slowly and gracefully.
There seemed no end to the journey. Now and then they found themselves curving in a way that made it plain that the underground mansion spread out in two dimensions. （No， three， thought Trevize， at one point， as they moved steadily down a shallow declivity.）
Wherever they went， there were robots， by the dozens scores hundreds engaged in unhurried work whose nature Trevize could not easily divine. They passed the open door of one large room in which rows of robots were bent quietly over desks.