THE PHYSICO-CHEMICAL INVESTIGATION OF SOILS. 



329 



general to these from the Bonn soil, in the previous table. 

 From a poorer soil similarly treated by Ulbricht, described by 

 him as a ferruginous sand from Dahme, the leaching of which 

 was continued for thirty days in periods of three days each, 

 with a total of forty times its weight of water, the results 

 were as follows : 



SOIL OF LOW PRODUCTION FROM DAHME (Ulbricht). 

 THE SEVERAL EXTRACTS CONTAINED IN I,OOO,OOO PARTS: 



It will be seen that there is a considerable difference both in 

 the total amounts of matters dissolved and in the phosphoric 

 acid taken out by the water, as compared with the rich soil 

 treated by Schultze. The uniformity of the amounts of 

 potash removed at the successive leachings is remarkable. 



King's Results. The same general features are again strik- 

 ingly illustrated by King's results, as given in the following 

 table. King's first leachings were always made by shaking up 

 the soil with ten times its dry weight of water for three 

 minutes, then after subsidence filtering the solutions through 

 a Chamberland (porcelain biscuit) filter, and then (without 

 evaporation) determining the ingredients dissolved, by very 

 delicate, mostly colorimetric methods. Subsequent leachings 

 were made by packing the soil around the filters and washing 

 with five times the weight of water, taking about fifteen 

 minutes each time; but drying the soil at 120 degrees C. 

 between successive leachings. 



