drops. If the night is very cold when dew forms, the little dew-drops are frozen on the plants. Then we have Jack Frost.
Jack Frost is busy with you, too. He takes the vapor of your breath and per-spi-ra-tion, as you lie warm in bed, and makes pictures with it on the cold window pane. Such pretty pictures! They are all mosses and ferns and grass spears, and spangles to trim fairy queen's dresses.
Cold is a wonderful artist with water. It makes snow crystals and hailstone pearls. Snow is made by rain drops falling through air that is at the freezing point. The drops burst, when they freeze. Now, when things burst they make noises. You know how it is when fire crackers ex-plode? And pop-corn? If you were away up in the clouds, when it was snowing, and you had the ears of a fairy, no doubt you could hear the tiny rain drops explode into snow.
The Indians called pop-corn the corn that flowers. So snow is rain that blossoms. The next time you see a quiet snow storm, when the snow falls in large soft flakes, ask your mother for a piece of black velvet or cloth. Put it out of doors to get cold, but keep it dry. Then catch some snow flakes on it and study them through your pocket microscope. Most of them will look like little broken feathers. But if you are patient, you will be sure to find some that are perfect, six-pointed stars. The points will be veined and fringed like the petals of a flower. All snow flakes should be six sided or pointed crystals. Most of them are torn by the wind, or get their points knocked off by falling against other flakes.
Hailstones are made in quite a different way from snow flakes. Snow falls only in the winter, but hail storms come in summer, on hot days. Weather men think that when rain drops are formed in clouds, and are all ready to fall, they are suddenly pulled up much higher, into freezing air. The rain drops freeze but do not burst. Then they fall through other rain clouds, and more water freezes on the balls of ice. They are tossed up and down until they become so heavy that they drop like bullets. They drop so fast that they pass through the warm air near the earth without melting. Sometimes they are as big as pigeon's eggs. Find a very big one, some day, and ask papa to cut it across quickly, with his strong knife. You will find that the hailstone was made in layer rings like a lily bulb. The oyster makes the beautiful pearl in the same way. Around a hard center it puts layers of the pearl with which it lines its shell house. The hailstone pearl is just as beautiful as the shell pearl, but it melts so fast it is hard to study it.
