14 ON RAINFALL IN A WOODED COUNTRY 



India, to take the necessary acreage of State forest-land under its con- 

 trol, and to set it apart for the purpose. Were such a plan followed 

 out in England, a Government school of forestry might thus easily 

 be established, and young men trained there for service in the 

 Indian or other colonial forests, instead of, as at present, being under 

 the necessity of sending aspirants to Indian forest vacancies abroad 

 to the schools of Germany or France. If such an establishment be 

 found beneficial for the education of the youth of this country 

 (specially for the Indian civil service), as Cooper's Hill College, in 

 London, why should not some similar establishment be organised 

 for the Indian forestry department 1 This is, however, apart from 

 the immediate subject before us, and to return from such a digres- 

 sion, we may remark, a propos of the necessary quantity of land re- 

 quired for plantations properly distributed over the area of the 

 country with a view to equal distribution of the rainfall, that the 

 present condition of England may safely be assumed as a basis, 

 and her present supply of woodland as at least a fair normal one ; 

 and since we find that, as there are estimated to be in England 

 2,600,000 acres under wood, against a total of 57,000,000 acres, it 

 follows that we may assume 1 acre in 22 as a fair requisite pro- 

 portion for shelter, health, and climate. 



Having thus far noticed the general aspect of importance which 

 the subject presents, and passing over, in the meantime, the 

 burden of proof that trees and plantations do exert those influences 

 upon the rainfall of a country, which it has been asserted pertain to 

 their presence or absence, we may take up the question, what 

 dues influence the rainfall of a country 1 



So numerous are the causes which lend their influences to affect, 

 for increase or decrease, the quantity of rain that falls over any 

 large surface, such as the area of a country, that it is very difficult 

 to state one a priori. Even if we were in possession of an 

 accumulated mass of facts and statistical observations extending 

 over several years, such as have been collected in France and 

 Denmark, we should find that many purely local or casual circum- 

 stances intervene to throw doubts upon the results deduced from 

 even the most carefully ascertained hygrometric observations. Taken 

 in the abstract, however, we may mention what we consider the 

 four primary elements at work in increasing or diminishing rain- 

 fall generally : — 1. Atmospheric pressure ; 2. Neighbourhood of 

 the sea ; 3. Prevailing winds, according as these are dry or moist ; 

 and, i. Altitude. But while these all act more or less powerfully 



