42 



MANUAL OF THE NILAGIRI DISTRICT. 



CHAP. IV, 

 PART I. 



Climate, &c 



Col. Sykea' 

 remarks. 



llurricaues. 



Effect of 

 wind on 

 barometer. 

 Col. Sjkes' 

 remai'ks. 



Raiufall. 



Colonel Sykes remarks : — 



" The winds of the south-west monsoon, however, terminate in July 

 instead of October. This is the more remarkable, as Doddabetta lies 

 between Madras, where these winds are the prevailing winds of May, 

 June, July, August, and September, and Bombay, where the same 

 winds prevail in the same months. It is probable, therefore, that 

 Doddabetta is situated just above the upper surface of the stratum 

 of wind and aqueous vapour which supplies the south-west monsoon to 

 Western India, and therefore has comparatively a small supply of rain 

 from this source. But it is not situated (although on the Western 

 Coast) above the stratum of wind and aqueous vapour which supplies 

 the Coromandel Coast during the north-east monsoon, as it has the 

 same prevailing winds between the north and east points in the same 

 months as at Madras from October to February, when the north-east 

 ceases at Madras, but continues at Doddabetta until late in ]\Iay. 

 The prevalence of winds from points between north and west in the 

 months of July, August, and September is peculiar to Doddabetta : 

 neither Mahableshwur, at 4,500 feet, nor Madras, Bombay, nor Calcutta, 

 has similar indications. However, as this so-denominated north-west 

 wind very frequently blows from only one or two points to the north- 

 ward of west, the wind may belong to the monsoon of the Western 

 India, local physical circumstances having given it a slant." 



Hurricanes are of rare occurrence, and the storms^ accom- 

 panied with great electric disturbance which usher in the 

 monsoons, generally take their course along the crests of the 

 range. 



The slight effect of the pressure of the wind on the barometer 

 on the plateau is noteworthy. Colonel Sykes observes : — 



" It is usually understood that very high winds materially depress 

 the barometer, but the records at Doddabetta do not support this view. 

 On the 17th and 18th of April 1847 the Avind blew with a mean 

 pressure of 21 lbs. and 14 lbs. respectively upon the square foot ; but 

 the barometers only fell from 21-955 on the 16th to 21-917 on the 

 17th, and rose to 21-984 on the 18th; and there was a maximum 

 pressure from the wind on the 17th at one time of 35 lbs. 26th of May, 

 maximum wind 28-5 lbs., barometer not affected more than 0-010 inch ; 

 J 2th of June 30 lbs. ; 26th June 32 lbs- ; 10th of September 35 lbs- ; and 

 14th of October 22 lbs- ; but these pressures of the wind had little or 

 no effect upon the barometer." ' 



The register of the rainfall from the several stations of 

 the Hills was recorded but irregularly, and mainly by private 

 individuals until within the last few years. The most trustworthy 

 returns kept until quite recently are probably those taken by 

 Drs. Baikio and lioss and Major Ouchterlony. 



' F/iil Transaciions, Foijal Socid'j. Part II, 1850. 



