204 EFFECTS OF FOBEST VEGETATION ON CLIMATE. 



water supply in consequence of the disappearance of mediaeval 

 forest, cleared away by the Arabs on and after their conquest. 

 Hence the periodical rains, which once fertilized the country, 

 have been replaced by heavier but rarer falls, which rush down 

 the slopes and disappear in the sands or mix with the noxious 

 v/aters of the lagoons before they can saturate the soil to any 

 depth, washing away the earth and exposing naked rock on hill 

 sides or high grounds." 



AVe shall further gain considerable information bv also con- 

 sidering the evidence offered by the East Indies : — 



One of our recent Governors, Sir William Denison, whilst 

 Grovernor of Madras, wrote thus to Sir Roderick Murchison, on 

 17th October, 1861: — "On coming down by the railway to the 

 west coast we passed through a gap in the Western Ghauts, 

 about forty miles in width and 1,200 feet above the sea. The 

 jSTeilgherries rise 8,500 feet to the north of this ; the AnamuUays 

 6,000 to 7,000 feet to' the south. The space between is a brown 

 dry plain. After passing over about twenty miles of this, on a 

 gradual descent, we, all of a sudden, plunged into the richest 

 possible tropical vegetation, there being no change in the soil. 

 On inquiring into the cause of this, I was told that the line of 

 jungle marked the limit of the south-west monsoon, but why the 

 monsoon should stop there I cannot tell. People informed me 

 that a quarter of a mile was the amount of disputed territory 

 between moisture and drought ; that I might stand at one place 

 and get but a slight sprinkling of rain, while a movement west- 

 ward of a hundred yards would bring me into a tropical downfall. 

 I have seldom seen anything which struck me as more remarkable. 

 "Why should not the wind sweep the rain up the plain, seeing 

 that it has brought it thus far ? I am dealing in questions, but 

 in point of fact, these apparently trifling questions are most 

 difficult to answer." — (Varieties of Vice-regal Life, vol. II., 



Whether Sir Roderick was able to give, or did give any answer 

 to the question does not appear in the correspondence printed 

 in the book quoted from ; but the question is not without answer, 

 for with no direct allusion to Sir William it has been made in a 

 valuable account of the "Effects of Eorest Destruction in Coorg. 

 By George Bidie, M.D., &c. ;" read before the Royal Geogra- 

 phical Society of London on 25th January, 1869, and published 

 in the 39th volume of the Society's Journal. 



Coorg is near the centre of the western Ghauts, and not very 

 far from the Neilgherries. The height of 5,000 feet is attained 

 by the crest of the hills, to the east of which the country con- 

 sists of low long-backed ranges with deep valleys, gradually 

 subsiding in the table-land of Mysore, the average elevation 

 being 3,000 feet. The Cauvery Eiver runs through in a wide 



