124 



TEMPERATURE OF EARTH 



-Mean Temperature of the Earth and op the Air at Trevandrum, in 

 India, lat. 8° 30', N.; eievatioh 200 eeet above the level oj? the 



SEA. Aa OBSERVED BY JoHN CaLDEOOTT, ESQ., AsTRONOMER TO THE EAJAH 



OF Tratanoore, ddrikg the tears 1843, 1844, 1845. 



Here, as at Dodabetta, tbe mean temperature of tbe earth averages 

 higber tban tbat of the air in every month throughout the year, the 

 excess on the whole being upwards of 5| degrees. At Trevandrum, it 

 appears that the highest mean temperature of the earth at three feet 

 deep occurs in April, and is nearly 90° ; the lowest occurs in July, when 

 it is a little above 83°. Its mean range is between 6 and 7 degrees. 

 The mean temperature of the air is highest in April, 83-37°, and lowest 

 in December, 78° ; so that the difference between the hottest and coldest 

 months is only 5 or 6 degrees. 



The preceding tables exhibit the relative temperature of the earth 

 and air at a number of places very differently situated both as regards 

 latitude and elevation ; from Dpsal in lat. 59° 52', to Trevandrum in 

 lat. 8° 30' ; and from Chiswick, Copenhagen, and the Plains of Bengal, 

 aU near the level of the sea, to Dodabetta and DorjUing, respectively 

 8640 and 7430 feet above that level. The general results deduced from 

 these tables are as follows : — 



First. — That va. all cases the mean temperature of the earth exceeds 

 that of the air, on the average of the whole year. 



