“I have,” said Rollo’s mother.
“So have I, sir,” said Rollo.
“It is because they are polished, and so are neither good to radiate nor to receive radiation. There is another way by which the same principle is illustrated in the spring of the year, when the snow is melting away. Every little leaf, or stick, or insect, that happens to light upon the snow, soon sinks down.”
“Yes, sir,” said Rollo, “the bees do. Last spring, when I went out in the pasture on the crust one morning, I found a great many bees all down at the bottom of little holes in the snow. I couldn’t think how they happened to get into those little holes.”
“The holes were made by the heat of the sun,” said his father, “after the bee fell. The bee is of dark color, and his body receives the radiation of the sun much better than the snow, which is polished.”
“The snow polished?” said Rollo.
“Yes,” said his father. “The snow is composed of flakes, and the flakes of a great number of little needle-like crystals, and all these crystals are polished, so that they do not radiate well, nor receive radiation well. Therefore the heat of the sun has not much effect upon a pure snow bank. But the body of the bee is a good radiator, and also a good receiver of radiation. So it gets warm, and that melts the snow under it, and then it sinks down, so that after a time it gets down to the bottom of a little pit, which it has made itself.”
“That’s very curious,” said Rollo.
“Yes,” said his father; “and it is so with every little stick, or sprig, or dry leaf, which happens to fall upon the snow. You could see the effect more distinctly still, if you were to put a bright piece of tin, and a piece of sheet iron, like stove pipe of the same size, upon the snow in the sun. The iron would receive the radiation, and get warm, and would sink down in the snow, but the tin would not receive the radiation.”
“Wouldn’t it receive any at all?” asked Rollo.