324 University of Califcn-nia Publications in Agricultural Sciences [Vol. 1 



of the hydrogen electrode. The results thus far secured indicate 

 that there is not a sufificient quantity of OH-ions in the NaCl + 

 H2O soil to produce the degree of deflocculation observed therein. 



If the Oll-ion content of the medium is assumed to be the 

 causal agent for the diffusion of the soil colloids, it would appear 

 an equally plausible assumption that the transference of the sus- 

 pending medium from a diffused soil to the original untreated 

 soil would carry with it the deflocculating agent, so that the 

 second soil would register to some degree the physical manifesta- 

 tions of deflocculation. To test the correctness of this hypothesis 

 the following experiment was undertaken. Twenty-tive grams of 

 NaCl -)- HoO soil were suspended in 250 cc. of water. The col- 

 loidal matter of such a suspension normally remains in a stabil- 

 ized condition for at least three or more weeks, when exposed to 

 laboratory conditions. This suspension was cleared, however, at 

 the expiration of 48 hours by passing it through the Pasteur 

 Chamberland filtering candle imder pressure. This was accom- 

 plished with considerable care so as to conform to the conditions 

 found by Briggs^- to yield the most satisfactory results. The 

 solution secured in the manner described from the NaCl + H^O 

 soil was then used as a suspending medium for 10 grams of un- 

 treated Davis soil. A comparison of the suspension thus formed 

 Avith a suspension of the same soil in distilled water disclosed no 

 recognizable difference. Thus it would appear that a transference 

 of the suspending medium of a diffused NaCl -j- H^O soil to a 

 second untreated soil does not carry with it the agent causing the 

 deflocculation of the first soil. Hence, any liypothesis ascribing 

 the altered physical condition of the NaCl + HoO soil to changes 

 in the soil solution seems untenable. 



The value of the results secured by the procedure outlined 

 above may be open to question. To avoid such criticism, the 

 writer made the following experiment, which distinctly shows 

 that the transference of a soluble soil defiocculant from one soil 

 to another by the method employed is susceptible of proof. A 

 N/50 NaOH solution in contact with the Davis soil tends to 

 maintain the soil colloids in a stabilized condition. Such a dif- 

 fused suspension was subjected to the filtering treatment out- 



32 U. S. Dept. Agr., Bur. of Soils, Bull. 19, p. 31, 1902. 



