A modification of the EDTA method of determining ion activities in soil developed by Norvell was used to measure the solubility of various ferric hydroxides. The solubility products of jarosite (KFe3(SO4)2(OH)6) and amorphous Fe(OH)3 were also determined on a natural jarosite nodule taken from an acid sulphate soil.For amorphous ferric hydroxide and lepidocrocite, the method gave pK° values of 39.02 ± .35 and 42.48 ± .23, respectively. Hematite and goethite were too inert to yield reproducible solubilities.For a mixture of jarosite and ferric hydroxide, the respective pK° values were 98.56 and 39.93. These values were used to develop an Eh‐pH stability diagram that helps to explain the occurrence of jarosite under acid oxidizing conditions in soils.

A sewage farm which has been used during the past 50 years for treatment of raw sewage water of domestic and industrial origin was studied. The farm (100 ha) is situated on sandy soil and is agricultural use as permanent pastuce. Intermittent flooding of the soil with sewage water results in a 98% decrease of the biochemical oxygen demand (BOD) by passing it through the soil; phosphates are removed to the extent of 96%. These phosphates accumulate in the top 50‐cm layer of the soil. Removal of nitrogenous compounds is less effective. The sewage water additions raised the pH of the soil and increased the organic matter content (mainly of the top layers). These changes may have practical implications with respect to chemical and physico‐chemical reactions in the soil.

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The electrophoretic mobilities of four collagens and a gelatin were measured. One collagen was prepared from a limed steer hide; the other three were from the fresh hide, t endons, and bones of a steer. The differences between the mobilities are explained in t erms of differences in the amidonitrogen contents of the various preparations. The isoelectric point of the unlimed-hide collagen is at about 7.0 on the pH scale.