"Rivers," said Donald.
"There is water in the air—mist, fogs, and clouds—and there is much water in the air which we can not see."
"Vapor?" asked Frank.
"Sometimes water is so thin we can not see it, and again it is so thick and hard that we may walk over it."
"Ice," said Susie.
"Tiny bits of vapor come together until they become so heavy that they fall to the ground."
"Raindrops," said Donald.
"Water is sometimes frozen in the clouds in beautiful white crystals, and then they sail down to the earth."
"Snowflakes," said Susie.
"Sometimes drops start from the clouds and go through very cold air. The cold air freezes them quickly, and then they rattle on the roof and dash on the ground. They cut the corn leaves and destroy the crops."