"It's a little complicated," the Weather Man answered, "but maybe I can give you an idea of it. Suppose you were on a big steamboat in a choppy sea. As the steamer's length would extend over several of these waves, none of them would be big enough to make the vessel heave. If you were on that same choppy sea in a small canoe, you would be tossed in every direction. Now, if you think of the long red wave of light as a steamer and the blue as a canoe, you can see that in a ripple of small particles of dust the blue is going to be more affected than the red. In other words, the blue will be scattered. It will be diffused all over the sky and the light that comes through will be less blue."
"Then I should think the sun would look red," said Anton.
"It does," the Forecaster explained, "when there's a fog, which simply means, when there's more obstruction in the air. Sunlight is never white, as you know, it's yellow-white and the golden effect is due to dust. It's the same way at sunset. Then the rays of the sun which reach you pass through a larger amount of air, because you're looking at them from an angle, so they have to strike more grains of dust, and more of the blue rays are scattered. Then, too, when the sun, at sunset is, to you, shining obliquely on the atmosphere, it is passing through several layers of air and these bend the rays differently."
"I still don't see," said the author of the sunset-color article, "why there should be so much pink, or rose-color, and why the clouds should generally be pink."
"There's not much pink in a clear sky," the Forecaster answered, "and as for the pink clouds, you've never seen them in the west when the sun was still above the horizon, have you?"
"No—no," said the other, "I don't think so. The pink generally comes after the sun had disappeared."
"Scientifically, of course," the Weather Man said, "the sun has gone below the horizon at least two minutes before you see it disappear. You're looking at a sun that isn't there at all. That's due to refraction. The reason of the pink glow is that when you see it, the earth and the air for several thousand feet above you are in the shadow of the edge of the earth. The sun, therefore, is not shining on the thicker dust of the lower part of the air, but the finer dust of the upper part, the particles of which are small and more uniform in shape.
"The glow is of a rose-color because the particles are of the size to diffuse the rays of this wave-length. That's why rose colors appear in the east, before the west, and why the color lasts in the sky, which may be reflected on dust twelve miles high, after it has disappeared from the upper clouds, which are not more than eight miles high."
"'Tis the illigant hand ye are at explainin'," put in the Irishman, "but I c'n remember, when I was learnin' me trade, about thirty-four years ago, the sunsets were much finer than annything I've seen since. We don't have such sunsets now as when I was a boy."
"They were sho' brighter," agreed Dan'l. "Ah can remember when the skies used to look like they was all burning up. Ah thought the end of the world was a-comin', sho'!"