12 



THE PHYSICAL TROPERTIES OF SOILS 



DOUBLE- WALLED DRYING OVEN HEATED BY TWO ELECTRIC-LIGHT 



BULBS 



it is necessary to know the per cent of hygroscopic 

 moisture. 



What is the effect of soil texture and the temperature 

 and humidity of the atmosphere upon the hygroscopic 

 moisture? 



II. DETERMINATION OF THE MOISTURE 



IN FIELD SOILS 



Collect samples in the field from the first, second and 

 third foot of soil under different crop conditions, such 

 as sod land, plowed field and fallow. The samples 

 should come from as small an area as possible in order 

 to have a uniform soil type. 



Drive the sampler (T) to the proper depth for each 

 foot, lift from the hole and transfer the soil at once to 



