EVILS FOLLOWING DfiSfRUCTIOtt OF FOJREsTS. 41 



retarded by the existence of forests, has for a considerable 

 time been going on unchecked in consequence of the 

 extensive destruction of herbage and trees. Facts might 

 be cited to show that such is the case with Spain in an 

 almost equal degree, and that such is the case to a lesser 

 extent with the greater part of Central and Southern 

 Europe. 



In a second volume, entitled Water Supply of South 

 Africa, and Facilities for the Storage of it, I have shown 

 that notwithstanding the aridity of South Africa there is 

 still a sufficient supply of moisture there to fertilise 

 extensively the country, if that moisture were husbanded 

 and properly applied. The same may be said of Spain 

 where this is being done to an extent of which few have 

 any conception. By storage and irrigation, and by con- 

 servation, restoration, and extension of forests, it is sought 

 to minimise as much as possible the effects which have 

 followed the destruction of forests in that land. 



In a third volume, entitled Forests and Moisture ; or 

 Effects of Forests on Humidity of Climate, I have dis- 

 cussed many of the views which have been advanced upon 

 the subject views in regard to the action of each leaf, and 

 views in regard to the action of forest masses with the 

 conclusion that the production of forests in the localities 

 in which they have existed has been greatly influenced 

 by the distribution of the rainfall, or the humidity of 

 atmosphere upon which the rainfall depends ; and that 

 their subsequent effect upon the atmosphere has been 

 within certain limits to equalise the distribution of the 

 rainfall in time and in space. Thus : 



Where the land is densely wooded the rains may be 

 found diffused more or less equably over several months in 

 the year, and may frequently be of a drizzling character, 

 while in a land similarly situated, devoid of trees, rain 

 falls irregularly in what seems like thunder plumps, and, 

 in extreme cases, whole years may pass without rain, as is 

 the case in the Karoo, South Africa ; and the rain in the 

 forest land may fall pretty equably over the whole district, 



