222 INFLUENCE OF THE FOEEST ON SPEINGS. 



except in a tliread of water in rainy weather, greatly inferior in. 

 quality to that of the old fountain. The beeches were succeeded 

 by firs, and as soon as they had grown sufficiently to shade the 

 soil, the springs began again to flow, and they gradually returned 

 to their former abundance and quality." * 



This and the next preceding case are of great importance both 

 as to the action of the wood in maintaining springs, and particu- 

 larly as tending to prove that evergreens do not exercise the 

 desiccative influence ascribed to them in France. The latter 

 instance shows, too, that the protective influence of the wood 

 extends far below the surface, for the quality of the water was 

 determined, no doubt, by the depth from which it was drawn. 

 The slender occasional supply after the beeches were cut, was 

 rain-water which soaked through the superficial humus and oozed 

 out at the old orifices, carrying the taste and temperature of the 

 vegetable soil with it; the more abundant and grateful water 

 which flowed before the beeches were cut, and after the firs were 

 well grown, came from a deeper source and had been purified, 

 and cooled to the mean temperature of the locahty, by filtering 

 through strata of mineral earth. 



" The influence of the forest on springs," says Hummel, " is 

 strikingly shown by an instance at Heilbronn. The woods on 

 the hills surrounding the town are cut in regular succession 

 every twentieth year. As the annual cuttings approach a cer- 

 tain point, the springs yield less water, some of them none at 

 all; but as the young growth shoots up, they flow more and 

 more freely, and at length bubble up again in all their original 

 abundance." f 



Dr. Piper states the following case: ""Within about half a 

 mile of my residence there is a pond upon which mills have been 

 standing for a long time, dating back, I beheve, to the first 

 settlement of the town. These have been kept in constant 

 operation until within some twenty or thirty years, when the 

 supply of water began to fail. The pond owes its existence to 

 a stream that has its source in the hills which stretch some miles 

 to the south. Within the time mentioned, these hills, which 



* Manuale d'Arte Forestale, 2<'* edizione, p. 492. 

 f Physiche Oeographie, p. 32. 



