96 THE NEW AGRICULTURE. 



rise to a stream which is not so broad as either of the two from 

 which it flows. But it becomes swifter and deeper. 



"Let us return to the illustrations of the roadway and rain. 

 Starting from the foot of the slope, you found the streamlets of 

 rain getting cmaller and smaller, and when you came to the top 

 there were none at all. If, however, you were to descend the road on 

 the other side of the ridge, you would probably meet with other 

 streamlets coursing down hill in the opposite direction. At the 

 summit the rain seems to divide, part flowing off to one side, and 

 part to the other. 



" In the same way, were you to ascend some river from the sea, 

 you would watch it becoming narrower as you traced it inland, and 

 branching more and more into tributary streams, and these again 

 subdividing into almost endless little brooks. But take any of the 

 branches which unite to form the main stream, and trace it upward. 

 You come in the end to the beginning of a little brook, and going 

 a little farther, you reach the summit, down the other side of 

 which all the streams are flowing to the opposite quarter. The 

 line which separates two sets of streams in this way is called the 

 watershed. In England, for example, one series of rivers flows 

 into the Atlantic, another into the North Sea. If you trace upon a 

 map a line separating all the upper streams of one side from those 

 of the other, that line will mark the water shed of the country. 

 But there is one important point where the illustration of the road 

 in rain quite fails. It is only when rain is falling, or immediately 

 after a heavy shower, that the rills are seen upon the road. "When 

 the rain ceases the water begins to dry up, till in a short time, the 

 road becomes once more firm and dusty. But the brooks and 

 rivers do not cease to flow when the rain ceases to fall. In the 

 heat of summer, when perhaps there has been no rain for many 

 days together, the rivers still roll on, smaller usually than they 



