National Geographic : 1925 Aug
162 THE NATIONAL GEOGRAPHIC MAGAZINE Photograph by Dr. Henry W. Henshaw THE BIRTHPLACE OF MOST CLOUDS Evaporation, which furnishes the world's cloud materials, is a big drain on the seas; but water is fed back by rivers, glaciers, and showers to make good the loss. In all the world, it is estimated, more than 300 cubic miles of water fall as rain daily, or something like I6,ooo.ooo tons each second. If Nature's laws were repealed and evaporation should cease, there would be a terrible demonstration of the priceless value of clouds. Every living thing of the land and air would be doomed, and all the earth except the sea would become a seared, desolate waste.