^{page 420 notes 1} Hardy, F., J. Agric. Sci. 1923, 13, pp. 243 and 340.CrossRefGoogle Scholar

^{page 421 notes 1} Cf., Allison. J. Amer. Soc. Agron. Oct. 1923, p. 409Google Scholar

^{page 422 notes 1} Von Terzaghi, (Ber. Akad. Wiss. Wien. 1923, 132, p. 105; Sci. Abstr. 1924, 27 A, p. 361), has measured the modulus of elasticity of clays, and has found it to depend on the moisture content.Google Scholar

^{page 422 notes 2} See Hardy, F., J. Agric. Sci. 1923, 13, p. 243.CrossRefGoogle Scholar

^{page 422 notes 3} West Ind. Bull. 1912, p. 50.

^{page 423 notes 1} Manufactured by Central Scientific Company, U.S.A.

^{page 424 notes 1} Unless the granular soil blocks are prepared by adding water slowly to the sifted soil, swelling causes them to assume a convex upper surface, so that their cross-sectional area exceeds 1 sq. in.

^{page 426 notes 1} Hardy, F., J. Agric. Sci. 1923, 13, p. 243.CrossRefGoogle Scholar

^{page 426 notes 2} Mem. Dept. Ag. Ind., Chem. Ser. 6, 3, 03, 1921, p. 163.Google Scholar

^{page 427 notes 1} Applied Colloid Chem. 1921, pp. 155, 160.

^{page 427 notes 2} Hardy F., J. Agric. Sci., loc. cit., also Journ. Phys. Chem. (in press).

^{page 427 notes 3} See Donnan, , Pres. Address, Sect. B, Brit. Assoc. 1923;Google ScholarJ. Soc. Chem. Indus. 1923, 42, 38, p. 900.Google Scholar

^{page 427 notes 4} Travers and Ray. See Donnan, loc. cit.

^{page 427 notes 5} Donnan, and Ray., p. 893,Google Scholar who cites Harkins (J. Amer. C. S. 1917, 39, p. 541).Google Scholar

^{page 428 notes 1} Hardy, F., J. Agric. Sci. 1923, 13, p. 243.CrossRefGoogle Scholar

^{page 428 notes 2} Trans. Far. Soc. 1922, 17, p. 244.CrossRefGoogle Scholar

^{page 428 notes 3} Soil Sci. 1924, 17, p. 1.CrossRefGoogle Scholar

^{page 428 notes 4} U.S. Dept Ag., Bur. Soils, Bull. 51, 1908.Google Scholar

^{page 428 notes 5} Landw. Vers. Stat. 1904, 59, p. 433.Google Scholar

^{page 428 notes 5} The now widely accepted views of Hardy and Langmuir suggest that the adsorption of water from its vapour phase by a dry clay, should result in the formation of a monomolecular layer of water over the solid surface. (See Donnan, , loc. cit. and Langmuir, J. Amer. C. S. 1918, 40, p. 1361).Google Scholar

^{page 429 note 1} See Hardy F., J. Phys. Chem. (in press).

^{page 429 note 2} The flocculation phenomena of the lateritic soils employed in these investigations are fully described in the article already cited (footnote 1). The siliceous soils behaved normally in that the rate of flocculation of their aqueous suspensions varied directly with lime content. The highly calcareous soil settled from suspension rather more slowly than either of the lateritic soils.

^{page 430 note 1} See Hardy, F., J. Agric. Sci. 1923, 13, p. 243.CrossRefGoogle Scholar

^{page 430 note 2} See Bragg, “Discussion on Cohesion,” Brit. Assoc. 1923; J. Soc. Chem. Indus. 1923, 42, p. 930.CrossRefGoogle Scholar Also Donnan, (Pres. Address, 1923, 42 p. 892) who cites Hardy's writings that lead to the conclusion that cohesion forces are essentially chemical in origin.Google Scholar

^{page 430 note 3} See Cameron, and Gallagher, (U.S. Depl. Ag., Bur. Soils, Bull. 50, 1908, pp. 10–17), for a summary of the early work of Schübler (1838), Haberlandt (1875) and Püchner (1889) on the effect of added substances on the cohesiveness of soils.Google Scholar Also Schurecht, (J. Amer. Ceram. Soc. 1918, 1, p. 201CrossRefGoogle Scholar) for measurements of the effect of electrolytes in increasing the dry strength of clay.

^{page 431 note 1} Soils, 1918, p. 111.

^{page 431 note 2} Bechhold, , Koll. Z. 1920, p. 229;Google ScholarC.A. 1921, 15, p. 458;Google ScholarAlexander, , Science, 1921, 54, p. 74;CrossRefGoogle ScholarC.A. 1921, 15, p. 4035.Google Scholar

^{page 431 note 3} See Moore, Fry and Middleton, , J. Indus. Engin. Chem. 1921, 13, p. 527.CrossRefGoogle Scholar

^{page 431 note 4} See Hardy, W. B., Fourth Rept. Colloid Chem. 1922, p. 190 et seq.Google Scholar

^{page 431 note 5} Harrison, , Discussion Rept., Dept. Sci. Indus. Res. 1921, p. 116.Google Scholar

^{page 431 note 6} Bancroft, , Applied Colloid Chemistry, 1921, p. 73.Google Scholar

^{page 432 note 1} See Mukherjee, , Discus. Rept. p. 103;Google Scholar also Rosenhain, , “Discussion on Cohesion,” Brit. Assoc.;Google ScholarJ. Soc. Chem. Indus. 1923, 42, p. 932.Google Scholar

^{page 432 note 2} J. Indus. Engin. Chem. 1921, 13, p. 527.CrossRefGoogle Scholar

^{page 432 note 3} See Bradfield, , Miss. Ag. Expt. Sta. Bull. 60, 1923Google Scholar. Also. Ries, Clays, 1919, pp 126–128, and Seaele, Third Rept. Colloid Chem. 1920, p. 139 et seq.

^{page 432 note 4} Comber, , J. Agric. Sci. 1920, 10, p. 425.CrossRefGoogle Scholar