“Yes, sir,” said Rollo.
“The heat comes from the fire to your hand very swiftly through the air, and makes your hand feel warm.”
“How do you know it comes so swift, sir?” said Rollo.
“I will show you,” said his father.
So his father looked about the room, and he saw a large book lying upon a table between the windows. He got the book, and brought it to the fire.
“Now,” said he, “I will hold the book between your hand and the fire. Then the heat cannot come to your hand.”
So Mr. Holiday held the book between Rollo’s hand and the fire, and Rollo said that he could not feel the heat.
“Now,” said his father, “I will take the book away suddenly, and we will observe what will be the effect. If the heat moves slowly through the air, it will be some time before you begin to feel the warmth; but if it shoots through to your hand quick, you will feel it immediately.”
So saying, Mr. Holiday suddenly withdrew the book.
“Yes, sir,” said Rollo; “I feel it immediately.”