s are six-sided crystals produced by water-vapor, in the air,
cooling and crystallizing on the cold glass. Ice crystals grow from each
other quite readily. This is called twinning."

"But why are they always so regular?"

The Forecaster shook his head.

"You're always expecting everything to be regular, Ross," he said.
"They're not regular at all. There are thousands of different forms. The
United States is fortunate in having one man who's the world's expert on
snow crystals, and he examines and photographs thousands every year and
adds, perhaps, two or three new examples each season."

"Who's that, sir?" asked Fred.

"Wilson A. Bentley, of Jericho, Vermont," the Forecaster answered. "He's
made thousands of photographs of snow crystals through a microscope.
What's more, he's done it for the love of the work. Why don't you send
him a copy of the _Review_, Fred? I'm sure he'd like to see it. Perhaps
he might send you some prints of his snow crystals. He'd appreciate a
plate of Caesar's sunsets and Ralph's clouds, I'm sure."

"I'll send them to him right away," the editor answered.

"Why is it," queried Anton, "that when snow-flakes fall slowly and only
a few of them at a time, they are big, but when there's a heavy
snow-storm the flakes are small?"

"Because they are manufactured in different layers of the air," the
Forecaster answered, "in the upper air, eight or ten miles up, where
the faintest cirrus clouds are, they are not flakes at all, but tiny
needle-like crystals, called spicules. In the depth of the Arctic
winter, near the North Pole and especially on the Greenland ice-cap--one
of the coldest regions of the world--the wind is full of these spicules,
which one can't very well call snow.

"Snow-flakes that come from the cold regions of the air, three or four
miles high, generally have a solid form. All, of course, show the
six-sided form of the snow crystals. Being smaller and heavier in
proportion to their surface they fall more quickly. In the layers of the
atmosphere, one or two miles high, where the air is not as cold and
where the content of water vapor is higher, the flakes have more
opportunity to grow as they slowly sink through the air. Snow-flakes
that have been formed only a short distance above the ground become
large and feathery, the kind of which northern peoples say that 'the old
woman of the sky is plucking her geese.'"

"I suppose, in the northern part of the country, sir," Ralph sugg