938 SOIL PHYSICS, CHEMISTRY AXU .MICRORIOLOG Y 



in the solution was increased and not decreased by its contact with the soil 

 and this increase was only partly accounted for by the solvent action of 

 the solution on the potassium in the soil. Allowing for this correction; a 

 potassium chloride solution containing 78 p. p. m. gave fractional perco- 

 lates containing 107, gi, 82 and 92 p. p. m. of potassium. By the subse- 

 quent leaching action of water, 39, 24, 21, 18, 15 and 18 p. p. m. of potas- 

 sium were removed in the different fractions. The above case of negative 

 adsorption is probably due to the solvent (water) being adsorbed more ra- 

 pidly than the solute. Positive adsorption gradually diminishing and chang- 

 ing to negative adsorption was observed by Williams for certain electro- 

 lytes in water with blood charcoal, but the above is the first recorded instance 

 of initial negative adsorption. 



727 - Basic Exchange in Soils.— rice, F. e. (j. Phys. Chem., 20, 214-227, 1916). journal 



of the Society it Cluinical Industry, Vol. XXXV, No. 8, p. 480. I,ondon, April 29, 1916. 



Soils (33 grms.) from various parts of New York State were shaken with 

 TOO cc. of normal potassium nitrate solution, allowed to stand over-night 

 and filtered. In portions of the filtrate the hydrogen ions were determined 

 by Storensen's method, and the lime requirement in pounds of lime per acre 

 was determined by Veitch's method, while other portions were used for 

 qualitative tests of the bases present, and titration with fiftieth normal 

 sodium hydroxide solution. It was found that in the case of so-called 

 " acid " soils part of the cation of the salt was absorbed, while an equi- 

 valent quantit}' of bases from the soil was dissolved. The extracts thus 

 obtained showed greater acidity than the original soils. This was attributed 

 to the formation of hydrated aluminium oxide in the hydrolysis, together 

 with equivalent quantities of free acid, and since the latter was strongly 

 ionised while the former was lightly ionised and possibly in a colloidal state 

 the resultant solution was distinctly acid. Water-soluble acid was found 

 in only two samples of acid soils. Basic (as distinguished from "acid" 

 soils) gave up to the salt solution more base than they adsorbed, but this 

 was attributed not to basic exchange, but to sohition of excess of the base. 



728 - Relation of Carbon bisulphide to Soil Organisms and Plant Growth. — i red e. b. 



(Agricultural Bacteriologist, Agricultural Experiment Station of the I'niversity of Wiscon- 

 sin), in /oM;-;ta/ 0/ .•^tf;'^■cM/^^^/'fl/ iJt'.stvn'f/;, Vol. VI, Xo. I, pp. 1-19, 2 plates. Washington, 

 D. C, April 3, iyi6. 



In previous publications by this and other scientists, data were present- 

 ed to show the beneficial action of bisulphide of carbon on the soil flora. As 

 this action varies, fresh experiments were xmdeitaken in order to ascertain 

 the factors in these variations. There were studied : 1) the effect of differ- 

 ent doses of carbon bisulphide ; 2) the effect of carbon bisulphide on dilTer- 

 ent plants ; 3) the effect of carbon bisulphide on dift'erent soils. Some 

 further experiments were carried out for the purpose of simultaneoush 

 studying the effect of carbon bisulphide on higher and lower plant forms. 

 The fresh soil used in these experiments was sieved and potted in 2-gallon 

 jars and the moisture maintained at half saturation. 2 per cent, of com- 

 mercial carbon bisulphide was poured into small holes in the soil, which were 



