“I know a riddle about that,” said Ronald, repeating:—
“My father is the Northern Wind,
My mother’s name was Water:
Old Parson Winter married them,
And I’m their hopeful daughter.”
“Did you know that snow-flakes are usually crystals of regular and beautiful forms?” inquired Marcus.
Kate and Oscar had read of this, but it was new to the other children. Marcus took down a volume from the library, and showed to them some drawings of these snow crystals, as seen under a microscope, a few of which are here given. There is an endless variety of these crystals, the most beautiful of which are found in the polar regions; but sometimes the flakes present no traces of crystallization.
“My geography says it never rains in the Great Desert of Sahara; what is the reason of that?” inquired Ronald.
“The Sahara,” replied Marcus, “is a vast ocean of sand, in the torrid zone. The air which arises from it is so scorching hot, that it burns up, as it were, the clouds of rain that blow towards it from the Mediterranean, as soon as they come within its reach. There are several other deserts in Africa, and in North and South America. Some of these are cut off from their supply of rain by mountains. When the clouds come in contact with a chain of high mountains, they are driven up their sides, into a colder region, and the vapor is pretty thoroughly wrung out of them. By the time the current of wind reaches the other side of the mountains, the clouds have all disappeared, and there is nothing left but a cold, dry air. That explains why it is that there is a desert region on the western coast of South America, on the very borders of the Pacific Ocean. The eastern sides of the Andes rob the clouds of all the rain brought from the Atlantic by the trade wind, and as the dry wind keeps on its course, the vapors of the Pacific are driven back to the ocean, before they can discharge themselves. Thus there is a paradise on one side of the mountains, and a desert on the other.”