50 



AGRICULTURE 



boxes, each containing one of these soils, sand, clay, 

 loam and humus, which has been thoroughly saturated 

 with water. 



{fi) Put a thermometer with the bulb at the depth of two 



inches in each of 

 these eight boxes, 

 and allow them to 

 stand until the fol- 

 lowing morning ; 

 then record the 

 temperature of 

 each. 



{c) Place all the 

 boxes where they 

 will be equally ex- 

 posed to bright 

 sunlight, and note 

 the temperature of 

 each soil every two 

 hours from 8 a.m. 

 to 4 P.M., taking 

 care to note wheth- 

 er the sun is under 

 a cloud at the time 

 of each observa- 

 tion. 



{a) Upon a piece 

 of co-ordinate 

 paper indicate the 

 temperature curve 

 of each of these soils dry, and that of each of these soils 

 wet, similar to that indicated for a humous soil in 

 Fig. 15- In these curves (Fig. 15) the space between 

 each two horizontal lines represents one degree, while 

 that between each two vertical lines represents two 

 hours. 



FIG. 



15. — TEMPERATURE CURVES OF A 

 HUMOUS SOIL. 



