No. 2, December, 1921] SOIL SCIENCE 125 



mixture or a complex compound, the single ions retain unchanged their specific influence. 

 The preservative value of any salt can be measured by the sum of the effectiveness of the in- 

 dividual ions into which the molecule dissociates. The poisonous effect is additive. The 

 following are toxic in a descending scale: Ag, Cd, Cn, Zn, Fe, Co, Cr, Fl. — Fred S. Wolpert. 



789. WiLLK, Johannes. Chlorpikrin als Schadlingsbekampfungsmittel in seinen Wirkun- 

 gen auf Tier und Pflanze. [Picric chloride as an insecticide and its effect on animals and plants.] 

 Naturwissenschaften 9: 41-47. Fig. 1-4. 1921. — The author reviews recent work on the use 

 of picric chloride for the extermination of insects and other animals. The benefits of using the 

 material while the plant is in a dormant condition and the effects of the material on yeast and 

 other plants are noted. — Orton L. Clark. 



SOIL SCIENCE 



J. J. Skinner, Editor 

 F. M. ScHBRTZ, Assistant Editor 

 (See also in this issue Entries 393, 394, 562, 573, 738) 



790. Bhatnagar, Shanti Swarupa. The effect of adsorbed gases on the surface tension 

 of water. Jour. Phys. Chem. 24: 716-735. 1920. — The values of the surface tension of water 

 in dynesper centimeter in a vacuum and in various gases at 15°C. are: Vacuum, 71 .3; hydrogen, 

 72.83; nitrogen, 73.00; carbon dioxide, 72.85; carbon monoxide, 73.00; air, 73.1. — H. E. Pulling. 



791. Breckenridge, J. E. Boron in relation to the fertilizer industry. Jour. Indust. 

 and Eng. Chem. 13: 324-325. 1921. — Evidence is presented which shows that certain per- 

 centages of borax are detrimental to plant growth, but under favorable conditions, such as 

 optimum moisture, good drainage, etc., rapid recovery is noticeable. Corn shows borax 

 poisoning with 6 pounds of borax per acre; potatoes show a stimulating effect when 4 pounds 

 of borax are added per acre, but S-10 pounds cause injury. — Henry Schmitz. 



792. Cutler, D. Ward. Observations on soil protozoa. Jour. Agric. Sci. 9: 430-444. 

 1919. — The direct counting method (grating etched on slide) for soil protozoa in liquid gives 

 results entirely comparable to those obtained by dilution cultures. Three species of Amoeba 

 and 1 each of Monas, Bodo, Cercomonas, and Oicomonas were employed. — The factors governing 

 the relation between the protozoa and the soil particles are those of surface action. The ca- 

 pacity of various soils for retaining these organisms is specific and constant and is independent 

 of the concentration of the suspension, the time of action, or w'hether the suspension contains 

 cysts or active forms. — D. Reddick. 



793. Griffith, J. W. Influence of mines upon land and livestock in Cardiganshire. Jour. 

 Agric. Sci. 9: 360-395. PI. 4-16. 1919. — Lead and zinc compounds (galena and blende) 

 reach the land in deleterious amounts. Physically, the capacitj' of the soil to retain water is 

 often reduced; and chemically, the nitrogen content is lowered as a result of contamination. 

 Extensive experiments were performed on the effect of galena and blende upon oats and crim- 

 son clover. Clover is more susceptible to injury than oats, but both are affected. — Of the 

 remedial measures tried, heavy liming is best, but the use of sodium silicate tends to reduce 

 the injury. — D. Reddick. 



794. JuRiTZ, C. ¥. The agricultural soils of the Union. South African Jour. Indust. 

 4: 76-84. 1921. — The grain soils of southwest Cape Province are grouped as follows: 

 Sandstone, Malmesbury, and Bokkeveld soils. The Sandstone and Malmesbury soils are 

 deficient in plant food and humus and are quite often acid; Bokkeveld soils are much richer in 

 plant food. The soils from each region are described geologically and their origin is given. — 

 Considerable variety of soils exists in Cape Province. The grey and reddish loams of the 

 Great Karroo cover the largest portion of the country. The coastal belt in the southwest 

 comprises gravelly clays of a drab color. On the South Coast the soil contains more humus 

 and is frequentlj' acid. Alkali soils, resulting from bad drainage, occur in some parts. In a 

 discussion of the Orange Free State soils it is pointed out that Na^ COs was almost absent from 

 the lighter soils but present in the low lying places. — J . J . Skinner. 



