6? MANUAL OF THE XILAGIRI DISTRICT. 



CHAP. IV, In April, May, and June, thunder-storms continue. The south- 

 PART III. east winds draw round to the south and eventually to the south- 

 Wellingtox "^®st. May is the hottest month, a steamy heat with high tem- 

 Medical perature, averaging 81 degrees in the shade. In June there are 

 CuM° TE &c ^^^^y winds from the south-west, from which point the monsoon 



is looked for, which, as a rule, breaks about the 20th. In July, 



August, and September the south-west monsoon prevails, and the 

 season is usually delightful, the rain never being so continuous as 

 to prevent a certain amount of out-door exercise, although it is 

 heavier and more tropical here than at Ootacamand. August 

 is wet, but the atmosphere is still and hot. During September 

 it becomes muggy, the monsoon ending about the 20th. Then 

 there is a break, as a rule, until the 20th of October. 



In October, November, and December the weather is splendid, 

 though cold, and occasionally damp and wet, but very wholesome. 

 The north-east monsoon begins about the middle of October, and is 

 ushered in with heavy thunder-storms. During November there 

 is very heavy rain with thunder-storms and fogs. 



In December the rain begins to fail. There are usually two 

 or three days^ break at a time. The weather is cold, and frost 

 begins to form ; hoar-frost is constant. During this monsoon 

 heavy floods are common on the eastern slopes. In November 

 1865 they were so severe that the water was three feet over the 

 Coonoor bridge, setting in without warning and doing immense 

 damage in about four hours. Similar floods occurred in Decem- 

 ber 1875 in the race-course valley. From the 16th December the 

 rain gradually draws off, and is not usually expected to return till 

 about the 12th March. 

 Meteorology. The atmosphere at Wellington from its rarified condition, due 

 to elevation, will only support a column of mercury 24 inches 

 high, that at the sea being 30. This shows it to be about 6,100 

 feet above that level. Consequently persons visiting the Hills are 

 relieved of an atmospheric pressure of the difference between 

 15 lbs. per square inch, which is that at the level of the sea, and 

 that of 12 J lbs., which is the pressure at Wellington. The 

 changes, which are observed in climate or in weather, may be 

 traced in general to preponderance or deficiency of the vapour 

 of water in the air. The steadiness of the barometers in these 

 latitudes is a very remarkable phenomenon. Except during 

 hurricanes there seems to be an absolute freedom from irregular 

 variations. The annual atmospheric tide is due to the varying 

 position of the locality with reference to the sun, the atmosphere 

 being lighter (as will be seen by reference to the meteorological 

 tables), from expansion at the summer solstice than at the winter 

 one. 



The average mean reading for the winter months will be found 

 in excess of those for the centre of the year. The sun's rays are 



