504 STATE BOARD OP AGRICULTURE. 



D. Van Suchtelen's Method — Paraffin oil. Van Snchtelen^ impressed 

 by the feasibility of the Istcherekov's method, modified the plan and 

 after some preliminary work (which will be taken up later) selected 

 paraffin oil as a displacing liquid for obtaining the soil solution in its 

 natural condition. 



A large Buchner filter was prepared with a thin layer of non-hygro- 

 scopic washed-out Gooch asbestos. The asbestos M'^as treated with al- 

 cohol and ether and after that it was dried for some time. The fairly moist 

 soil, whose moisture content was known, was spread upon the asbestos 

 and lightly pressed down with a rubber stopper. Then cooled paraffin 

 oil was poured on so that the entire surface was covered, whereupon a 

 slight suction was used. The liquid thus obtained was heated to 40° C. 

 for a very short time in the suction flask in order to diminish the viscos- 

 ity. After that it was carefully poured into a centrifuge tube and in 

 order to hasten the separation, it was centrifuged for a few minutes at 

 a moderate speed. By means of a separatory funnel, the heavier water 

 was separated from the lighter paratfin oil. The paraffin oil, if it was 

 entirely clear, without air bubbles, could be used again. The water con- 

 tent of the soil, in which the soil water was displaced by the paraffin oil, 

 lies according to his experiments under 50 percent of the total water 

 capacity. i 



PRESENT METHODS. 



Paraffin oil disi^lacement — pressure metJiod. 



Later, instead of using sviction as described above, some kind of pres- 

 sure method was undertaken by Van Suchtelen and Itano with the idea 

 that if a greater force could be applied than could be obtained with the 

 suction pump, better results would be attained. Therefore another ap- 

 paratus was necessary. In this apparatus the displacing liquid was 

 forced through the soil instead of being pulled through by suction. It 

 is with this apparatus and with the solution obtained that the author 

 has been experimenting for over two years. 



Apparatus. 



This consists of a cylinder connected at the top with a high pressure 

 pump and open at the bottom with a small bored spout from which the 

 soil solution flows. The details of the construction may be seen from the 

 accompanying diagram and descriptions. After trial with a cast iron 

 cylinder 5 inches in diameter and 22 inches long, others were made later, 

 of larger dimensions, 6 inches by 24 inches. The cylinder is screwed 

 into a flange and reducer. The union is soldered in order to make a 

 more perfect joint. The reducer is connected to the pedestal, the upper 

 part of which is hollow, while the part below the spout is plugged (to 

 prevent loss of solution). This entire lower part can be- easily removed 

 from the cylinder for cleaning purposes. The cap is fastened on with 

 bolts. A gasket of copper and asbestos is used to make a tighter joint. 

 In the bottom of the cylinder is placed a perforated plate and above this 

 two fine wire gauzes to hold back the soil. These gauzes are larger than 

 the plate to prevent the soil from passing under its edge. A series of 

 cylinders can be arranged in a battery, so that all can be worked at the 

 same time, or any one or two cut out. In our experiment, three were so 



Wan Suchtelen. F. H. H.. Methode zur Gewinnung der Natiirlichen Bodenlosiing. Jour. f. 

 Landwirt, 1912, 60, pp. 369-70. 



