EFFECTS OF FOKEST VEaETATIOIS' OiS" CLIMATE. 193 



the Island Almanac of that year, the rain had increased, which 

 was attributed to the increase of wood. Floods had also 

 decreased during the last eight years. It is said that during the 

 present century the rainfall has nearly doubled. (Bombay 

 Geogr. Society's Eeport, 1849-50, p. 55.) 



A gradual decay of Grreat Britain was predicted in the Times 

 newspaper in 1862 from exhaustion of vegetable mould, and 

 Liebig exploded the idea that such mould, with tillage and 

 manure, will suffice to prevent exhaustion ; but Daubeny remarks, 

 that many countries that once were fertile enough to maintain a 

 large population are now barren and desolate admits no dispute, 

 and he adds : — " To me the cause of this deterioration appears 

 obvious as arising from the denuded state of those countries as 

 regards timber, for which we need not go further than to many 

 of the islands of the Archipelago, to parts of Greece, and even of 

 Italy." 



On the other hand, he maintains that where a country enjoys 

 sufficient humidity, and the natural soil supplies suitable and 

 sufficient mineral constituents, as proved by the Nile and by 

 Naples, Tuscany, and even parts of Sicily, there will be no general 

 exhaustion. And where the reverse is the case, he attributes it 

 rather to the aridity occasioned by the destruction of forests than 

 to the exhaustion of the vegetable matter itself. 



Lastly, he cites Lower Egypt, where it has been usual to say 

 no rain ever falls and the Nile does all the work ; but since the 

 late Pasha took to the planting of trees heavy showers have fallen 

 about Cairo and Alexandria and in other parts of Lower Egypt. 



As plague, locusts, and other vexations used to trouble the 

 Egyptians when the Nile did not rise, it is surely as satisfactory 

 to our medical as to our meteorological Section to know that an 

 amelioration of the climate of Egypt has been partially effected 

 through the instrumentality of trees ; and who can tell what 

 would be the further effect upon sanitary methods if some of our 

 Eucalypti were brought as much into request in Egypt as, I 

 understand, they have been in certain parts of Italy and else- 

 where r 



In addition to previous references to America, I may men- 

 tion here that in Kentucky many brooks have become dry in 

 summer which, for thirty years before the clearing of timber, 

 w^ere never known to fail ; and in New Jersey, where the clear- 

 ings were more extensive, some streams entirely dried up. On 

 the other hand there are examples of the contrary — but the 

 ex;planation given by the writer, to w^hom I am indebted for this 

 statement is, that the tillage of the soil allowed the water to 

 penetrate deeper, and cleared away the mass of leaves that caused 

 the water to be moi'e exposed to evaporation, though there has 

 been no alteration in the rainfall. — [J. E. Mag. Nat. Hist., 1834.] 



