IRRIGATION. 119 



of whom is the lord not of square miles, indeed, but of acres of productive soil. 



In such territories, irrigation does not injuriously affect the health of the population. 

 Malarious influences are exerted not by flowing, or even by freely-percolating water. It is 

 only when the fluid stagnates on the surface, or in the soil, that it becomes pernicious. In 

 the hills, the inclination promotes the swift flow of water over the ground, or along the 

 canals, and its descent by infiltration is also too rapid to admit it to become a cause of vege 

 table putrescence. .In Central and Southern Europe, almost all the surface of the mountains 

 which has not been swept away by torrents is irrigated through the summer; but fevers and 

 other malarious diseases do not occur in those regions, and they are regarded by many Euro 

 pean physicians as especially salubrious, even for persons affected with pulmonary complaints. 



The beneficial effects of irrigation in mountainous countries are not confined solely to 

 the watering of the crops. It checks the too rapid flow of the waters of precipitation, and 

 thus exerts an important geographical, if not climatic, influence. A large proportion of the 

 water permitted to spread over the surface, and meander along the canals in the upland 

 meadows and pastures, is absorbed by the earth and slowly filtered down, refreshing the roots 

 of the plants it encounters in its passage, until at a somewhat lower level it bursts out in the 

 form of springs. It is a familiar observation in all the older American States, that the hills 

 are growing constantly drier and the herbage less abundant, and that the springs which for 

 merly supplied this stock are disappearing. The principal cause of this disastrous change is 

 undoubtedly the destruction of the forests which once clothed the crest of every mountain, 

 and which, it is earnestly to be hoped, will soon be at least partially restored. The replanting 

 of the woods is a slow process, and the continued drying-up of the soil is every day rendering 

 it more and more difficult. In the meantime, the introduction of a general system of irrigation 

 at the highest levels where water can still be found, aided by the excavation of simple reser 

 voirs on the hill-tops, and at other higher points for retaining the water of rains and melting 

 snows until it can be applied to the surface by canals, or absorbed by the earth, would do 

 very much to retard the unfavorable change which is now taking place in the water-supply of 

 our mountain farms, and would, at the same time, greatly augment the product of our grass- 

 grounds, and often of our plow-lands. 



It has been observed in Europe, that draining the soil, either by surface or by under 

 ground conduit, tends to increase the suddenness and violence of inundations by promoting 

 a too rapid discharge of the waters into river-channels. Irrigation in the mountains, or even 

 on the plains, has the contrary effect by retaining much of the water until it can be returned 

 to the atmosphere in the form of vapor. Draining, then, deranges the harmony of nature by 

 interfering with her methods of maintaining a regular interchange and circulation of humidity 

 between the atmosphere, the earth, and the sea. Irrigation is in effect a partial return to the 

 economy of our great material parent, by regulating that circulation in a manner analogous 

 to her primitive processes. 



&quot;Where springs are numerous, as they usually are in hilly countries, only small and cheap 

 canals, easily accommodated to the accidents of surface, are needed for the diversion of 

 water from its natural channels, to flow over the surface of the ground or to moisten the 

 roots of the grass by infiltration from the artificial water-courses. But the moderate extent 

 and capacity of the necessary canals is not the only advantage of an inclined and undulating 

 surface in the supply of water for the crops. Hilly and winding slopes admit of a simple 

 and efficient mode of irrigation, or rather of a substitute for the practice which is not available 

 on level soils. The method in question has been practiced with success in many parts of the 

 United States, where it is known by the name of circling, and it is very highly recommended 

 by all European writers. 



It consists in horizontally terracing the slopes, or even simply furrowing them with 

 the side-hill plow, and leaving the surface permanently in this condition. The rains and 



