A482 A. B. BEAUMONT 
Schloesing (1874) was one of the first to call attention to the colloidal 
matter of soils. From a clay he isolated a gelatinous mass which con- 
sisted mainly of water, silica, and alumina, with small quantities of ferric 
oxide, magnesia, and potassa. 
Van Bemmelen (1888) attributed the absorptive properties of soils 
largely to the colloidal matter which he believed to surround most particles 
of soils. This matter consists of ferric oxide, silica, silicates, and organic 
matter in various stages of decomposition. These materials unite with 
one another or with other substances to form what Van Bemmelen desig- 
nated as adsorption compounds. 
Warineton (1900) claimed that true colloidal clay is always an aluminum 
silicate, but also mentioned the presence in some soils of ferric oxide, 
hydrated alumina, and colloidal humus. 
Schloesing (1901) states that colloidal alumina occurs in European 
soils in very small quantities, but he found very much free alumina in 
soll samples from Madagascar. This results from the weathering of 
silicates and later hydrolysis, as in the case of colloidal ferric oxide. Hil- 
gard (1911) inclines to a similar view, and sees in the presence of gibbsite 
and bauxite a reason for the assumption of the free alumina in soils. 
Cameron and Bell (1905) dispute the presence of colloidal alumina in 
normal soils. Lacroix (1914) reports it in the decomposition products of 
aluminum silicates, and McGeorge (1916) reports having found it in the 
soils of Hawaun. 
Ries (1908) includes among the ingredients of clay that may assume 
a colloidal form, aluminum hydroxide, iron hydroxide, hydrated silicie - 
acid, and organic matter. 
Hilgard (1911) considers that colloidal clay is clay which will remain 
suspended in a column of water eight inches high during twenty-four 
hours, and that the nature of this colloidal clay varies considerably in 
composition. According to this author, colloidal clay contains ferric 
hydrate and other colloidal, or at least amorphous, substances such as 
silicic, aluminic, and zeolitic hydrates. 
Gans (1913) and Wiegner (1912) carried on an extended controversy 
as to whether an artificially prepared colloidal silicate was a chemical 
compound or a mixture of gels. Wiegner was of the opinion that it was 
a mixture of gels, and that owing to its similarity to the natural soil zeolites 
