INFLUENCE OF WATER ON SOIL TEMPERATURE 177 



given in Table XXIX were made two years after the 

 draining operations just mentioned. The land was without 

 any crop. 



TABLE XXIX 



TEMPERATURE OF DRAINED AND UNDRAINED BOG (PARKES) 



June 15 was a hot cloudless day. June 16 was hot. A 

 heavy thunderstorm took place at 3 p.m. ; the temperature of 

 the rain was 78. 



The temperature of the drained bog at 7 inches below the 

 surface is seen to be io-i9 above that of the undrained bog, 

 and the temperature of the drained portion remains superior 

 even at a depth of 31 inches. The effect of the warm rain 

 on the temperature of the drained soil is very distinct ; the 

 temperature at 7 inches beneath the surface rises 35 in half 

 an hour, and the temperature of the subsoil is found next 

 morning to be perceptibly increased. The warm rain has no 

 perceptible effect on the undrained bog. 



A saturated peat bog is thus the coldest of all soils in 

 summer time, and the one showing the smallest variation in 

 temperature throughout the year. A dry peat a heath soil 

 for instance is, on the other hand, the soil exhibiting the 



N 



