“Let us see,” said his father; “where did we leave off?”
“About the chips,” said Rollo’s mother.
“And the hay,” said Rollo.
“Yes,” said his father. “We’ll take the case of the hay. Should you think, from what I told you, that hay would be a good or bad radiator?”
“Good,” said Rollo.
“Why?” asked his father.
“Because,” replied Rollo, “it is not bright and polished.”
“Right,” said his father. “And should you think that it would be a good or a bad receiver of radiation?”
“Yes,” added his father, “because all those surfaces which are good radiators, are good receivers of radiation.”