One small. cloud contains only a very little water and when this water has fallen as rainy the cloud is no more. Even a whole skyful of clouds do not contain enough water to dump an inch or mere of water over a large area. What happens, we believe, is this. A rainy area draws in moist air from all sides. The moist air now finds itself in a rain making area and its moisture too falls as rain.Finally all the water in the clouds .falls as rain. But meantime, more clouds have been forming in other parts of the sky. Wherever the sun shines, moisture is drawn up into the air and much of this moisture is made into clouds. Sooner or later, these clouds fall as rain while still newer ones are being made by the beaming sun. So long as the sun shines the clouds will never run out of water.