IN THE PENINSULA OF INDIA. 125 



Second, — That in some localities, tte montUy mean temperature ot 

 the earth is in eyery month, more or less, higher than that of the air. 



Third. — That in other localities the mean temperatvue of the air 

 exceeds that of the earth in the summer months only, or from April 

 till July or August ; but from September till March, the earth is 

 warmer than the air. 



The excess of mean temperature of the earth above that of the air j 

 on the ayerage of observations taken at different places, is as follows : — 



Chiswick 1-13 



TJpsal 3-54 



Copenhagen ..... 1-11 



Dodabetta 4-77 



Dorjiling 2-70 



Plains of Bengal 3-23 



BeUary 1-90 



Trevandrum 5'69 



Average 3 -01 



From this it will be seen that at these places the average difference 

 between the temperature of the earth and the air is least at Copenhagen, 

 and greatest at Trevandrum. But it must not be thence inferred that 

 the difference is uniformly greater within the tropics than in high 

 latitudes, for we have, on the other hand, a greater difference at Upsal, 

 than at BeUary on the centre of the table-land of India. 



There appears to be no series 'of direct observations upon the 

 superficial temperature of the earth, at the different periods of 

 vegetation, in other countries ; but some statements are to be 

 found, here and there, concerning the temperature occasionally 

 observed, from which it is to be inferred that the earth is 

 heated, at least for short periods of time, very much above the 

 atmosphere, and it is probable that this excessive elevation of 

 temperature is necessary to the healthy condition'of many plants. 

 From some interesting Qbservations communicated to me by Sir 

 John Herschel, it appears that the temperature of the earth at 

 the Cape of Good Hope is often excessive. On the fifth of 

 December, 1887, between one and two o'clock in the day, he 

 observed the heat under the soil of his bulb garden, to be 159°; 

 at three p.m. it was 150°, and even in shaded places 119°: the 

 temperature of the air in the shade, in the same garden, at the 

 same period, was 98° and 93° At 5 p.m. the soil of the garden, 

 . having been long shaded, was found to have, at four inches in 



