ROLLO WARMING HIS HANDS BY THE FIRE—Page [133].
It was pretty cold that morning, and, after Rollo had pumped for some time, his hands became cold. So he went into the house. He found his father and mother in the little parlor where they had been the evening before. There was a good fire in the stove, and Rollo held his hands up before it, and warmed them by the radiation. The breakfast-table was set, and before long a girl came in bringing in the breakfast. Among the other things was a little copper tea-kettle, with a heater to set it upon, in order to keep the water hot. The heater was made in this way: There was a sort of pan of planished tin, large enough for the tea-kettle to be set into it. In the middle of this pan was a round cavity, with a bottom and sides of sheet iron, and there was a piece of cast iron, about half an inch thick, made to fit into this cavity. This piece of cast iron was to be heated in the fire, and then put into its place with the tongs, and then the tea-kettle was to be put over it, in the pan, in such a manner that the bottom of the tea-kettle rested upon the top of the heater.
Rollo was very much interested in this apparatus. It was placed upon a corner of the table, near the waiter, and Rollo’s attention was first attracted to it by observing that the tea-kettle continued to boil a little on the table. He could not think what made it boil; and, as they were about sitting down to the table, his father began to explain it to him.
“The heater, you observe,” said he to Rollo, “furnishes heat to the tea-kettle by conduction, to supply the waste by radiation.”
“What, sir?” said Rollo. He did not understand his father very well.
“Why, the tea-kettle loses its heat by radiation principally, and the heater supplies it by conduction, and so one restores what is lost by the other.”
“I don’t understand it, exactly,” said Rollo.
“Well,” said his father, “I’ll explain it to you presently, alter we have taken our seats at the table.”
Accordingly, when they were all seated at the table, Rollo asked his father about the operation of the heater and the tea-kettle.