EXPERIMENT STATION BULLETINS. 503 



amount of water falling on the soil could be controlled. The line of de- 

 marcation between added water as it percolated through soil and the 

 moisture already in the soil was apparent. In order to make the de- 

 marcation more apparent to the eye, he colored the water with carmine. 

 The reason for tliis being, that the added water forced out the water 

 below before the added ' water mixed with the soil water. The water 

 thus obtained was used for analytical purposes, — a study of the material 

 in solution. The objection^ raised to this method was that it did not 

 work well with soils containing less than 20 percent moisture, and the 

 time required for extraction was too long. 



B, Istcherekov's method— Alcohol. Istcherekov^ tried to find some 

 other liquid than water that would wet the soil. With the idea in mind 

 that the attractive forces of the soil particles would be easier to over- 

 come and also that the capillarity would not be destroyed, but some- 

 what modified, a liquid was desired that would wet the soil and pene- 

 trate the smallest pores. The action of such a substance upon moist 

 soil would result in freezing soil solution from the soil. Another re- 

 quirement was that the displacing liquid should be lighter than water, 

 otherwise the soil solution would rise above the displacing liquid. On 

 account of the less density of the displacing liquid there cannot be me- 

 chanical mixing of the tAVO substances. The lighter one floats upon the 

 heavier. 



For the purpose of displacing the soil solution he selected alcohol. 

 Either ethyl or methyl could be used. His first experiments dealt with 

 saturated soils. The soil was placed in a glass cylinder, the lower end 

 of which was covered with cloth, and after allowing it to drain, small 

 quantities of alcohol were added. Immediately after each addition a 

 few drops of soil solution dripped down. When the pressure was in- 

 creased at the top, this dripping increased and thus there was collected 

 23 c.c. of solution from every 24 c.c. the soil contained. The appearance 

 of a turbid liquid indicated that there was a mixture of the soil solu- 

 tion and alcohol and that the extraction was completed. It is also 

 claimed that soils with a moisture content of 10 to 2 percent were ex- 

 tracted with success. The solution thus obtained was considered a true 

 soil solution. It was suggested that any other liquid could be used pro- 

 vided it fulfilled the above requirements. 



C. Gola's method — Imitation Rain. Gola's^ imitation of rain and 

 pressure method is a combination of soil extraction and displacement 

 methods. A gentle rain was allowed to fall until a regular flow of water 

 was produced from the lower end of the column. This soil is then al- 

 lowed to stand for 36 hours while the excess water drains out. The soil 

 is then subjected to the pressure of a screw press and the water squeezed 

 out is regarded as a close approximation to the soil solution. The chief 

 objection that Stiles and Jorgensen* raise to this method is that it is 

 not applicable to all kinds of soils, but it may be used for all soils hav- 

 ing a higher water capacity as clays, loams, humus soils. Gola found 

 that the concentration of the soil liquid varied with the composition of 

 the soils. , . 



^Istcherekov, W. Gbtaininf? of Soil Solution in Unaltered Condition. Russian Jour, of 

 Expt. Landvv. 8, 1907, p. 147. 



=Istcherekov, W. ibid pp. 147-165. 



•''Gola's (Oswcm-erzioni Sopra i liRuidi Cirolanti nel terreno Agrario) Ann d. R. Acad. 

 Aric, di Lorino 54, 1911 ; Cavers, F. G. Gola's Theory of Edaphism. The Jour, of Eeol. 

 1914, 2, No. 4 p. 217. 



'Stiles, W. and Jorgenson, I.' "Tlio Nature and Method of Extraction of the Soil Solu- 

 tion," The Jour, of Eeol. 1914, 2, No. 4, p. 249. 



