"Don't be ridiculous."
"Well, suppose it is very hot at a place A—"
"I thought we were keeping the thermometer out of this."
"It comes in indirectly. But don't keep interrupting. If it is very hot at the place A, the air at A rises. You see?"
"No."
"Obviously it does. If you light a candle—"
"Yes, yes, I do see that. Don't begin about candles."
"Well, the result of that is that there is less pressure at A. In other words, there is more room for the air to move about. When that happens the air at the place B—"
"Where is that?"
"Oh anywhere. I told you to think of two places, A and B."