EXPERIMENT STATION BULLETINS. 



509 



water. ParafiSn oil fulfills part of the above requirements iu that it is 

 lighter than water, but does not wet the soil, that is, it is not attracted 

 to the soil particles like water. An advantage that it has over alcohol is 

 its inertness; it does not act upon the soil, nor does it mix with the soil 

 solution. Whatever oil comes through with the solution can be easily 

 separated by cooling the flask so that the oil will adhere to the. sides and 

 then the water can be poured off. A thick viscous cylinder oil was used 

 in making the extractions. If, at times, this oil became too thick for 

 pumping, it was thinned slightly by a less viscous one. 



PLATE 4. SECTIONS OF SOILS TAKEN FROM CYLINDER AFTER EXTRACTION BY 

 MEANS OF THE SOIL AUGER. A, FROM SMALL CYLINDER ; B, FROM THE lIrGE 

 ONE. THESE ARE VERY COMPACT AND HARD. 



Van Suchtelen and Itano^ to prove the inertness of the oil, made the 

 following experiments : 



1. To see if the oil has an influence on the surface tension of the 

 water they first determined the number of drops falling from a specially 

 arranged pipette filled with distilled water, and compared the results 

 obtained with another portion of the distilled water, shaken with the 

 oil for 20 minutes and counted at a temperature of 16.6° C. 



'From Van Suchtelen and Itano's unpublislicci work done iu tbis laboi'atory. 



