FORESTS IN THEIR RELATION TO RAINFALL. 215 



are ruins of enormous irrigating ditches and canals in Babylonia 

 where history indicates that there was once a teeming population 

 and great fertility, but where now only a sandy desert greets the 



eye." 1 



The late Sir William Hooker wrote : — 



"That from Ascension there continued to be received encourag- 

 ing accounts of the increased fertility and moisture of the island, 

 consequent on the extension of the plantations." 2 



It is proper to point out that in this statement it is not 

 asserted that the rainfall is alleged to have been increased. 



"It is remarked by Marsh, that " it has long been a popularly 

 settled belief that vegetation and condensation and fall of atmos- 

 pheric moisture are reciprocally necessary to each other, and even 

 the poet sings of 



"Afric's barren sand, 



Where nought can grow, because it raineth not, 



And where no rain can fall to bless the land, 



Because nought grows there." 



Here we have an illustration of the converse fact: one measure 

 of humidity promoting vegetation, and vegetation not only arrest 

 ing the desiccation but so reversing the process that an increased 

 humidity is the consequence." 3 



While the extract just quoted may be interpreted as not 

 stating that forests increase rainfall, the same work con- 

 tains many instances (not well classified), of the effects of 

 the destruction of the forests and of varying degrees of 

 value, but affording a lengthy list from which a writer 

 working up a case can obtain his illustrations. 



"In connection with the systematic destruction of timber in 

 Australia, it is mentioned that in the Ballarat district this destruc- 



1 Professor H. A. Hazen before Annual Meeting of American Forestry 

 Assoc, Nashville, Tenn., U.S.A., Sept. 22ad, 1897; quoted in " Nature," 

 30th December, 1897, p. 213. 



2 Report of the Director of Kew Gardens for 1864. 



3 J. Croumbie Brown's "Forests and Moisture," p. 144-5. 



