44 



ings and inundations, than was the case while the woods stood, as is explicitly testified 

 by the aforementioned tabulated observations of river levels. 



" 4. Through the extensive clearing away of forests the heat of the summer months 

 and the desiccation of the ground becomes increased, then, as a consequence of this, the 

 duration of droughts is prolonged, and from this there follows naturally a diminished 

 productiveness of the land. 



" These most disastrous effects of the clearing away of forest show themselves in a 

 very marked degree in these countries, once blessed with a luxurant vegetation, Palestine, 

 Persia, Greece, Sicily, Spain, and the Canary Islands." 



Mr. Marsh in his treatise on " The Earth as Modified by Human Action," in writ- 

 ing of the influence of forests on the flow of springs,says : — "It is an almost universal 

 and, I believe, well-founded opinion, that the protection afforded by the forest against 

 the escape of moisture from its soil by superficial flow and evaporation insures the per- 

 manence and regularity of natural springs, not only within the limits of the woods, but 

 at some distance beyond its borders, and thus contributes to the supply of an element 

 essential to both animal and vegetable life. As the forests are destroyed, the springs 

 which flowed from the woods, and, consequently, the greater water-courses fed by them, 

 diminish both in number and volume. This fact is so familiar in the American States 

 and the British Provinces, that there are few old residents of the interior of those dis- 

 tricts who are not able to testify to its truth as a matter of personal observation. My 

 own recollection suggests to me many instances of this sort, and I remember one case 

 where a small mountain spring, which disappeared soon after the clearing of the ground 

 where it rose, was recovered about twenty years ago, by simply allowing the bushes and 

 young trees to grow up on a rocky knoll, not more than half an acre in extent, immedi- 

 ately above the spring. The ground was hardly shaded before the water reappeared, and 

 it has ever since continued to flow without interruption. The hills in the Atlantic States 

 formerly abounded in springs and brooks, but in many parts of these States which were 

 •cleared a generation or two ago, the hill-pastures now suffer severely from drought, and 

 in dry seasons furnish to cattle neither grass nor water." 



Effects of Porests and of the Destruction of these on Rivers, and Streams, 

 AND Springs, by John Croumbie Brown, LL.D. 



"It is a somewhat prevalent opinion that as rain proceeds from the clouds, rivers 

 have their primary source in springs ; and along with this opinion it is held by many, 

 that the primary function of rivers is to carry moisture to lands which otherwise would 

 be barren, and there to diffuse fertility. But, in point of fact, no water springs from the 

 ground which has not previously been deposited from the atmosphere ; and the primary 

 function of streams, brooklets, and rivers, is simply to carry off surplus moisture in excess 

 of what the soil can retain. 



" As rain is produced by the gravitation to the earth of surplus moisture in the 

 atmosphere in excess of what the air can contain suspended in a state of invisible vapour 

 at the temperature to which it has been reduced, rivers are produced by the gravitation 

 to a lower level of the surplus water so precipitated in excess of what is absorbed by the 

 earth or evaporated again into the atmosphere. 



" The popular phraseology in regard to many things is far from being inexact accord- 

 ance with scientific conceptions. We speak of catching cold, of the rising sun, and of the 

 new moon. And so we speak of the little spring of water at the greatest distance on the 

 highest elevation from the mouth of a river as its source ; but no one supposes that the 

 whole of the waters of the river come from this. It may be that there is not an inch of 

 its course, or of the courses of its numerous tributaries and affluents, which does not pass 

 many of its sources, channels of capillary dimensions, through which, from time to time, 

 such excess of rainfall has drained off, or may drain off, into its bed, by which the 

 accumulated drainings are drained off into the sea, if they be not absorbed or evaporated 

 by the way. 



