392 Eighth Memoir on the [No. 137. 



West flanks of the Eastern Ghauts on the commencement of the N. E. 

 Monsoon.* 



" The almost effectual barrier presented by the Eastern Ghauts 

 to the force of the N. E. monsoon is a proof, that this great aerial 

 current is confined, generally speaking, to the lower strata of the 

 atmosphere. The same may be perhaps said of the Madras storms, 

 which generally travel from the East. Though often commencing from 

 the N. and N. W., the current from the East first striking the Ghaut 

 line to the N. of Madras, that city thus receives this deflected South- 

 erly current previous to the arrival directly of the main body from 

 the East. The foregoing remark, of course, you must apply with 

 much modification to the true whirlwind storm, which owes its vor- 

 tical movement to far different causes. The average height of the 

 Eastern Ghauts N. of Madras is about 1,500 feet. 



" Places situate on the table lands East of the Western Ghauts ex- 

 perience still less of the S. W. Monsoon (the heavier of the two,) 

 than the tracts sheltered by the Eastern Ghauts from the N. E. 

 Monsoon. This is ascribable to the greater average height of the former, 

 (3,000 feet above the sea,) and to their more continuous character as 

 a mountain chain. The almost only exception to this remark arises 

 from a remarkable opening in them ; viz. the gap of Paulghautchery, 

 which I have already alluded to as the probable route by which 

 the Madras storm found its way across the peninsula to the Lacca- 

 dives. It may be as well here to state in corroboration of this supposi- 

 tion, that it is well known (Madras Almanac 1840) that ships navi- 

 gating the Malabar coast during the N. E. Monsoon, commonly 

 experience a stronger gale in the neighbourhood of Paniani than 

 elsewhere; and this break in the Ghauts appears to be the cause 

 of this effect.t 



" During the S. W. Monsoon, the Westerly wind, which sweeps 

 through this pass from the beginning of June until about Sep- 

 tember, is extremely violent at Darapooram and other places to 

 the Eastward in a line with its longitudinal axis, as its influence 

 is felt even farther East than Trichinopoly ; but at other places 

 a little N. or S. of the line of the pass, the current is hardly perceived. 

 The pass is from 16 to 20 feet wide, narrower at the E. than at 

 the W. extremity : lofty rocks of the Koondah and Nilgherry chains 

 on its Northern, and the Palghaut groups on its South flank — its sur- 

 face is pretty level ; the slope from the plains of Coimbatore to those on 

 the coast so gradual as to be almost imperceptible ; the height of the 

 pass above the sea about the centre (roughly approximated by means 

 of the boiling point of water) is 900 feet. 



" I will write to Salem for such information as I can procure." 



* We are forcibly reminded here of the Devil's Table Cloth preceding a S. E. 

 gale in Table Bay. — H. P. 



f This is confirmed by Horsburgh, and the experience of all navigators In that sea 



