"Come to the window, Norah," said Will, "and you can see the very thing we were talking about the other day. The rain is over now, and there is so much vapor rising that the ground seems to be steaming. The air must be very dry and thirsty, for the sun has been hot, and a great deal of the rain which has fallen will evaporate. But will it all evaporate, Norah?""No," said Norah. "Some of it will sink into the ground, and after a time bubble up again in the form of a spring. We can see too some of it is running away in streams along the gutters to the drains.""Yes," said Fred, joining in, "and the drains will carry it away to the river, and so to the sea. The whole of the water which drains off the land flows away and forms rivers, and the rivers pour their water into the sea. So that in the end it all comes to the sea.
"Teacher made us think about those great bodies of water-rivers, lakes, oceans-all over the world, with the thirsty air all round. You have seenevaporation going on from the wet ground after this shower of rain.
"What an immense amount of vapor must be always rising from the great surface of the sea. The air gets most of its vapor from this one source.
