Rollo’s mother said that she wished Jonas would; so it was settled that he was to try and see if he could make an ice-house.
QUESTIONS.
What phenomenon that Rollo had observed was it that Mr. Holiday was going to explain when they were seated in the carryall? Did they conclude that hay would be a good or bad radiator?—a good or bad receiver of radiation? How, then, did Mr. Holiday account for the snow and ice melting so slowly under it? What was the object of the philosophical instrument constructed? What are some of the best conductors of heat? What substances are slow conductors? Describe the plan which the boy devised for keeping ice all summer.
CHAPTER XI.
THE RIDE HOME.
After the conversation recorded in the foregoing chapter, the party in the carryall rode on for some time in silence. They were going towards the east, and the morning sun shone very pleasantly upon them, so that it was not cold riding. The air had been frosty early in the morning, but the rays of the sun brought so much warmth with them that they enjoyed their ride very much. After some time, Rollo’s father began to speak again of the conductive powers of different substances, thus:—
“I think it probable that the fibres of wool and of fur are better non-conductors of heat than the fibres of wood, and grass, and straw, and other vegetable substances.”
Rollo did not at first understand what his father meant by non-conductors. He had not heard him use that term before. So he asked him what it meant. His father told him that, as people often wanted to employ substances which would not easily conduct heat, they had frequent occasion to use a word adapted to denote such substances as were suitable to such a purpose, and that non-conductors was the term which was so used.
“There are two reasons,” said he, “why I think it probable that the fibres of the covering of animals are better non-conductors—that is, that they conduct heat more slowly—than vegetable fibres. I should like to have you tell me whether you think they are satisfactory.”
“Well, sir,” said Rollo, “if you will tell us what the reasons are.”