THE XEW AGRICULTURE. 95 



force of attraction. "When it reaches the ground it is still, as 

 much as ever, under the same influence, and it flows downward in 

 the readiest channel it can find. Its fall from the clouds to the 

 earth is direct and rapid, its descent from the mountains to the 

 sea as part of a stream is often long and slow; "but the cause of the 

 movement is the same in either case. The winding to and fro of 

 streams, the rush of rapids, the roar of cataracts, the noiseless flow 

 of the deep sullen currents, are all proofs how paramount is the 

 sway of the law of gravity over the waters of the globe. 



" Drawn down in this way by the action of gravity, all that por- 

 tion of the rain which does not sink into the earth must at once 

 begin to move downward along the nearest slopes, and continue 

 flowing until it can get no farther. On the surface of the land 

 there are hollows, called lakes, which arrest part of the flowing 

 water just as there are hollows on the road which serve to collect 

 some of the rain. But in most cases they let the water run out at 

 the lower end as fast as it runs in at the upper, and therefore do 

 not serve as permanent resting-places for the water. The streams 

 which issue from lakes go on as before, working their way to the 

 sea-shore. So that the course of all streams is a downward one, 

 and the sea is a great reservoir into which the water of the land is 

 continually pouring. 



" The brooks and rivers of a country are thus the natural drain, 

 by which the surplus rainfall, not required by the soil, or by 

 springs, is led back again into the sea. When we consider the 

 great amount of rain, and the enormous number of brooks in the 

 higher part of the country, it seems, at first, hardly possible for all 

 these streams to reach the sea without overflowing the lower 

 grounds. But this does not take place, for when two streams unite 

 in one, they do not require a channel twice as broad as either of 

 their single water courses. On the contrary, such an union gives 



