28 



THE PHYSICAL PROPERTIES OF SOILS 



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KING SOIL - SAM- 

 PLINC. TUBE WITH 

 HAMMER. 



piece of steel being inserted under 

 the lower end before the tube is re- 

 moved. The tube is laid over on its 

 side and the soil cut off flush with 

 the cutting edge. 



This operation is repeated to ob- 

 tain a sample of the second foot. 



The soil is removed from the sam- 

 pler, taken to the laboratory, dried and 

 weighed. The volume of the sample 

 is calculated from the area of the end 

 of the tube and the length of the core. 



The cutting edge of the sampler is 

 slightly smaller than the inside diam- 

 eter of the tube in order to reduce 

 the friction to a minimum and thus 

 prevent the soil on the inside being 

 forced down below the level of the 

 surrounding ground. 



CALCULATION 



The real specific gravity of each 

 sample is determined and the pore 

 space calculated by the formula 

 given by King, "Physics of Agricul- 

 ture," pp. 1 1 4- 1 1 6. 



Tabulate the results and discuss 

 the factors which affect the volume 

 weight and pore space of soils in the 

 field. 



References : 



Burkett, "Soils," p. 37. 

 Wiley, "Agricultural Analy- 

 sis," Vol. I., pp. 143-145- 



