24 CLIMATE AND KESOURCES OF 



the thermometer, held two feet above the ground, stood at 

 100 Fahrenheit, shaded. On the surface of the ground, also 

 shaded, it stood at 111; and when a hole was dug ten inches 

 or a foot deep, the thermometer placed in it, and covered with 

 an inch of the loosened soil, it went down in less than ten 

 minutes to 82. 



This was an imperfect experiment, because I could not 

 keep away the external heat whilst the soil was being dug 

 and broken up, still it showed a difference of 29 Fahrenheit 

 between the temperature of the surface and of the soil some 

 ten inches or at the most a foot below it. I had the hole, 

 which was about two feet in diameter, filled up with the soil I 

 had taken from it, and on the 30th April, at four P.M., I made 

 further trials in the same field. 



On the surface of the field, and within three or four yards 

 of where I had made the former trial, I found the thermo- 

 meter, shaded, stood at 108; and when the soil was dug up 

 and tried as before, at about ten inches deep, it was 90. 

 This only gave a difference of 18, much less than in the 

 former trial, which I account for from the fact of numbers of 

 men and cattle having passed over it, it being between the 

 village and the threshing-floor, and by their passing and 

 repassing had broken up the smooth surface. At the same 

 time I also tested the surface, and also the soil ten inches 

 deep of the hole I made and had filled up on the 12th 

 April, and here, within three or four yards of the place where 

 the last experiment was made, the thermometer, shaded, but 

 exposed to external air, showed 102 on the loosened surface, 

 and also 102 ten inches below it. 



In the first case, where the surface was smooth and 

 unbroken, the difference between heat of surface and soil ten 

 inches or a foot below it was 29. In the second case, where 

 the surface had been broken by men and cattle walking over 



