The noise of a brook, you may observe, is by no means in proportion to its volume. The full March streams make far less noise relatively to their size than the shallower streams of summer, because the rocks and pebbles that cause the sound in summer are deeply buried beneath the current. "Still waters run deep" is not so true as "deep waters run still." I rode for half a day along the upper Delaware, and my thoughts almost unconsciously faced toward the full, clear river. Both the Delaware and the Susquehanna have a starved, impoverished look in summer,--unsightly stretches of naked drift and bare, bleaching rocks. But behold them in March, after the frost has turned over to them the moisture it has held back and stored up as the primitive forests used to hold the summer rains. Then they have an easy, ample, triumphant look, that is a feast to the eye. A plump, well-fed stream is as satisfying to behold as a well-fed animal or a thrifty tree. One source of charm in the English landscape is the full, placid stream the season through; no desiccated watercourses will you see there, nor any feeble, decrepit brooks, hardly able to get over the ground. This condition of our streams and rivers in spring is evidently but a faint reminiscence of their condition during what we may call the geological springtime, the March or April of the earth's history, when the annual rainfall appears to have been vastly greater than at present, and when the watercourses were consequently vastly larger and fuller. In pleistocene days the earth's climate was evidently much damper than at present. It was the rainiest of March weather. On no other theory can we account for the enormous erosion of the earth's surface, and the plowing of the great valleys. Professor Newberry finds abundant evidence that the Hudson was, in former times, a much larger river than now. Professor Zittel reaches the same conclusion concerning the Nile, and Humboldt was impressed with the same fact while examining the Orinoco and the tributaries of the Amazon. All these rivers appear to be but mere fractions of their former selves. The same is true of all the great lakes. If not Noah's flood, then evidently some other very wet spell, of which this is a tradition, lies far behind us. Something like the drought of summer is beginning upon the earth; the great floods have dried up; the rivers are slowly shrinking; the water is penetrating farther and farther into the cooling crust of the earth; and what was ample to drench and cover its surface, even to make a Noah's flood, will be but a drop in the bucket to the vast interior of the cooled sphere. IV APRIL