124 EFFECTS OF FORESTS ON MOISTURE. 



June and July; at Longwood tlie wettest montlis being June and 

 September. 



The amount of Rain which fell for the undermentioned years, was : 



1841, 68-925 inches. 1842, 90*458 inches. 



1843, 37-189 „ 1844, 20-026 „ 



1845, 19-509 „ • 1846, 26-556 „ 



1847, 42.411 „ 1848, 45-630 „ 



giving the mean annual fall, 43-813 inches. 



Upon Examining the Monthly Register for these eight years, it 

 appears that October, November, December, and January, give the 

 mean driest months. The four wettest being March, May, June, 

 and July. The December of 1846 being the driest month of the 

 Avhole 96 months ; and the February of 1842 being the wettest month 

 of the whole period. 



Professor Playfair states, that when the annual fall exceeds 25 

 inches, the climate is to be classed as moist : if so, St. Helena must 

 certainly be classed as a moist climate, because this standard, com- 

 pared with St. Helena's average of eight years, is nearly in the pro- 

 portion of 25 to 43. The Professor also " supposes" the annual fall 

 of Rain near London at 24 inches ; if so, St. Helena far exceeds London 

 in its fall of Rain, this being more than half as much again at St. 

 Helena as it is at London. 



The four following observations, being the quantities of Rain 

 received at the respective stations for a period of nine months in 

 1841, are quoted as a confirmation of the theory that woods and 

 mountains tend to precipitate Rain : — 



1, At 2644 feet elevation 22-63 inches. 



2, At 1991 „ 27-11 



3, At 1782 „ 43-42 



4, At 414 „ 7-63 



The whole four stations being comprehended within a circle of little 

 more than a mile radius. 



These statements I give as I have received them. So much 

 depends on the locality and circumstances in which observations by 

 the rain gauge are made that I am unable to say whether they tend 

 to strengthen or to weaken the conclusion to which I have come. 



The Island of Mauritius supplies analogous facts. In a history of 

 that Island, embodied my informant believes in Thornton's History 

 of India, the author observes that when we obtained possession of it 

 our countrymen thought it absurd that the beautiful land on the 



