152 MAINE STATE COLLEGE 



Soil Temperatures. 



In this investigation a knowledge of tlie temperature of the soil 

 at different depths, during the growing season, is sought, and 

 ultimately the law which represents the rate of change of tempera- 

 ture at different depths. 



The periods covered by the experiment are from May 1 to Nov. 

 1, 1889, from April 1 to Nov. 1, 1890, 1891 and 1892, with ther- 

 mometers placed in the soil to the depths of 1,3, 6, 9, 12, 24 and 

 36 inches. 



The thermometers have been allowed to remain in place during 

 the winters intervening between the periods of observation. 



Their location is in the open field, near hygrometer No. 2, in the 

 tract of land assigned to the Station for experimental purposes 

 and devoted to farm experiments. The character of the soil it 

 regarded, therefore, as representative of that on which the field 

 experiments by the Station are carried on. 



A summary of results for the four seasons by monthly aver- 

 ages is given in the annexed tables. 



