56 



THE PHYSICAL PROPERTIES OF SOILS 



TENTH EXERCISE 



CO-EFFICIENT OF EVAPORATION 



Prepare four evaporimeters (T) and fill level full 

 with the following soils: 



PCRF««ATf<| 



EVAPORIMETER 

 Sectional View 



Evaporimeter No. i — Sand. 



Evaporimeter No. 2 — Loam or silt. 



Evaporimeter No. 3 — Muck. 



Evaporimeter No. 4 — Clay. 



Fill the water-jackets, and after the water has ap- 

 peared at the surface weigh the entire system. A 

 crystallizing dish having the same amount of exposed 

 surface should be filled with water and weighed at the 

 same time. Expose the surfaces to the air for twenty- 

 four hours, weigh and calculate the rate of evaporation 

 in pounds per acre. 



Empty the water from the jackets and determine the 

 loss from each surface by evaporation by forty-eight- 

 hour periods for one week. 



