INFLUENCE OF FOKESTS ON CLIMATE. 11 



the most rapid departure of all the water that may fall in 

 the form of rain. A few showers at a certain season, may 

 produce a great amount of water, and still the section be 

 so dry as to be almost uninhabitable the remainder of the 

 year. One-half the quantity of water, if distributed 

 through a longer period, might be all that was actually 

 necessary to make the soil fertile and the climate de- 

 lightful. 



In many instances the destruction of large forests ap- 

 pears to have diminished the amount of rainfall, while in 

 others no diminution has been observed. Col. Playfair, 

 British Consul for Algiers, in a report to the home Gov- 

 ernment, instances some remarkable effects of extensive 

 destruction of forests in that country. *' During the 

 first twelve years, since 1838, from which time meteoro- 

 logical observations have been carried on in Algiers, the 

 rainfall averaged 32 inches annually. During the sec- 

 ond twelve years it had decreased to 30.8 inches, and 

 during the last fourteen years, it has been but 25. 5 inches. 

 The decrease became apparent after the principal clear- 

 iflgs of wood in 1845, and in 1876 so exhausted had the 

 soil become, that a famine seemed imminent in Western 

 Algiers." 



Similar instances in the decrease in the amount of rain- 

 fall following the destruction of forests, have been re- 

 ported by several observers in various parts of the world, 

 but principally by those residing in hot climates. Wher- 

 ever forests of any considerable extent have been de- 

 stroyed in Australia, Africa, India, Ceylon, or in the is- 

 lands of the Indian and Atlantic oceans, lying within 

 what may be termed the tropical belt, drouths seem to 

 have almost invariably followed. These drouths, however, 

 have not in all instances been traceable to a diminished 

 amount of rain, but to raj^id disj^ersion of moisture by 

 winds, ag well as evaporations from a soil exposed to the 

 direct rays of a tropical sun. In fact, all written history 



