84 ". Rainfall, Natural Drainage, 



the air is always drier. It is in France and Spain, and more 

 especially in Greece and the Levant, that the removal of the 

 forests has been injurious. In North America also, and in 

 many of our colonies, the first business of the settler has alwavs 

 been to destroy the wood. It is probable that in many cases 

 the destruction has been carried too far, and that the climate 

 has suffered. On the other hand, there can be little doubt 

 that cultivation and planting with European trees is likely 

 to improve in a very marked manner the climate of Australia, 

 and increase the rainfall. Thus the advantages of planting, 

 though not unimportant even in England, where the land has 

 been left absolutely bare, are much more likely to be felt in 

 other countries than at home ; and the English farmer must 

 look rather to the shelter given to Inrds and other incidental 

 advantages than to alteration of climate, if land that has once 

 been cleared should be brought again under forest. 



But if the increase of forest lands is neither probable nor per- 

 haps desirable in the British islands, except, perhaps, in the High- 

 lands of Scotland, there are many important agricultural operations 

 going on that admit of modification to some extent, and that 

 also have influence on climate and water-supply. At present 

 it is usual to limit the operation of drainage to the construction 

 and keeping in order of channels that shall carry off all surface- 

 water as rapidly as possible to the sea. It may be doubted 

 whether in many places, where the form of the country lends 

 itself to such purposes, it would not be advisable to collect this 

 drained water into reservoirs, at various levels, whence in dry 

 seasons it might be made use of for irrigation, or for other pur- 

 poses. There would thus be a double advantage gained ; for the 

 presence of these reservoirs, if uncovered, would prevent the air 

 from becoming so dry as it otherwise would, and might thus 

 check the burning up of the soil and crops. A few acres, here 

 and there, occupied by a reservoir, would not be without grent 

 value, and might well be made more subservient to the orna- 

 mentation of parks and pleasure-grounds than has hitherto been 

 the case. A portion of the water that must otherwise be diverted 

 would thus also sink into the earth, and increase the springs. It 

 is evident that to be of any advantage these reservoirs should be 

 numerous, and systematically placed. It is also evident that they 

 can only be constructed in hilly or undulating districts. On the 

 other hand, it must not be forgotten that standing-water in the 

 autumn months is in many localities very unhealthy. 



There are no available artificial means at present known of 

 modifying the distribution of rainfall and its total amount, except 

 by altering the vegetation of a large extent of surface. The 

 change of climate that has taken place already may, perhaps, be 



