"You stated that you rode in a boat on the underground lake."
"Yes."
"With great rapidity?"
"Yes."
"Rapid motion produces friction, I believe?"
"Yes."
"And heat?"
"Yes."
"Why did not your boat become heated even to redness? You rode at the rate of nine hundred miles an hour," I cried exultingly.
"For two reasons," he calmly replied; "two natural causes prevented such a catastrophe."