A'l'KiNS — Errors in Hydrogen Ion Determinations of Soils. 34' 



BIBLIOGRAPHY. 



Arkhenius, 0. (1922, 1). — Clay as an ampholyte. J. Amer. Chem. Soc, 44, 

 521-2. 



(1922, 2). — Hydrogen ion concentration, soil properties, and growth 



of higher plants. Arkiv f. Bot., 18, 1-54. 



Atkins, W. R. G. (1922). — Some factors affecting the hydrogen ion concentration 

 of the soil and its relation to plant distribution. Sci. Proc. Roy. Dublin 

 Soc, 16, 369-434; and Notes Bot. School, Trin. Coll., Dub., 3, 133-198. 



Clakk, W. M. (1922). — The determination of hydrogen ions. Baltimore. 



Cohen, B (1922). — Brom cresol green, a sulfonphthalein substitute for methyl 

 red. Proc. Soc. Expt. Biol, and Med., 20, No. 3, 124. 



Gillespie, L. J. (1920). — Colorimetric determination of hydrogen ion concentra- 

 tion without iDuffer mixtures, with especial reference to soils. Soil Sci., 

 9, 115-136. 



GiMiNGHAM, C. T. (1923). — On the colozimetric determination of hydrogen ion 

 concentration in soils. J. Agric. Sci., 13, 69. 



HoAGLAND, D. R., Martin, J. C, and Stewart, G. R. (1921). — Relation of the 

 soil solution to the soil extract. J. Agric. Research, 20, 381. 



Joseph, A. F. (1923). — The hydrogen ion concentration of heavy alkaline soils. 

 J. Agric. Sci., 13, 321-332. 



Kelley, a. p. (1923). — Soil acidity, an ecological factor. Soil Sci., 16, 41-54. 



Olsen, C. (1923). — Studies on the hydrogen ion concentration of the soil and 

 its significance to the vegetation, especially to the natural distribution 

 of plants. Compt. rend. Ijab., Carlsberg, 15, No. 1, 1-166. 



Salisbury, E. J. (1922). — The soils of Blakeney Point. A study of soil 

 reaction and succession in relation to the plant covering. Annals of 

 Botany, 36, 391-431. 



Sharp, L. T., and Hoagland, D. R. (1916). — Acidity and absorption in soils as 

 measured by the hydrogen electrode. J. Agric. Res., 7, 127. _ 



Wherry, E. T. (1922). — Soil acidity : its nature, measurement, and relation to 

 plant distribution. Smithsonian Report for 1920, 247-268. 



