Studies on soil reaction. II. The colorimetric determination of the hydrogen ion concentration in soils and aqueous soil extracts (Preliminary communication.)

Abstract

Themethods used for the determination of — log [] fall naturally into two groups:(a) Electrometric, and(b) Colorimetrie methods.Electrometric methods were first introduced into analytical practice in 1897 by Böttger(l) who determined the neutral point in titrating acids with alkalis by using a gas chain; subsequent improvements were made by Hildebrand (16), Gumming and Gilchrist(10); Hasselbalch(15), W. M. Clark(6), Michaelis(19), Walpole(28, 29) and others. The method has been applied to the measurement of [] of biological fluids with considerable success*. It was first applied to the measurement of [] of soil suspensions by G. Fischer (12) in Germany in 1914 and subsequently in America by Sharp and Hoagland(23), and by Gillespie(13, 14) and his co-workers.