80 REPORTS ON THE STATE OF SCIENCE.—1918. 
IV.— Water Relationships. 
Keen, B. A., ‘The Evaporation of Water from Soil,’ Journ. Agric. Sci., 1914 (9), 
456-75. 
Atway, F. J.,and McDote, G. R., Journ. Agric. Research, 1917 (9), 27. 
Hissink, D. J., Bied. Zentr., 1817 (46), 138. 
V.—Soil Acidity. 
CAMERON, FRANK K., ‘The Soil Solution, or the Nutrient Medium for Plant 
Growth’ (Chemical Publishing Co., Easton, Pa.). 
BAuMANN, A., and GULLY, E., ‘Untersuchungen uber die Hiimussauren,’ II., Mitt. 
d. k. bayr. Moorkulturanstalt, 1909, Heft 4. 
Harris, J. E., ‘Soil Acidity,’ Mich. Tech. Bull. 19, 1914. 
DAIKUHARA, G., ‘Uber saure. Mineralbéden,’ Bull. Imp. Central Agric. Expt. Sta., 
Tokio, 1914, 2, 1-40. 
Rick, FRANK E., ‘Studies on Soils: I. Basic Exchange, J. Physical Chemistry, 
1916, 20, 214-27. 
RAMANN, E., Bodenkunde, Berlin (Paul Parey). 
KappeEn, H., ‘Studien am saurem Mineralbéden aus der Nahe von Jena.’ Landw. 
Versuchs-Stat., 1916 (88), 13-104. 
RINDALL, A., ‘Ueber die chemische Natur der Humussduren,’ Internat. Mitt. f. 
Bodenkunde, 1911, 1, 67-80. 
OpgEN, SvEN, ‘Zur Kolloidchemie d2r Hurusstoffe,’ Kolloid Zeitschr., 1915, 14, 
123-30. 
TackeE Br., and Stcutine, H., ‘Ueber Humussiuren,’ Landw. Jahrb., 1911, 41, 
717-54. 
TackEe Br., DenscH, A., and ArND, TH., ‘Ueber Humussiuren,’ ihid., 1913, 45, 
195-265. 
Truog, B., ‘The Cause and Nature of Soil Acidity, with special regard to Colloids 
and Absorption,’ Journ. Phys. Chem., 1916, 20, 457-84. 
CHRISTENSEN, H. R., Soil Science, 1917 (4), 115. 
ScHOLLENBERGER, C. J., Soil Science, 1917 (8), 279. 
Vi.—Pan Formation. 
Monst, Bied. Zentr. Agrik. Chem., 1902, (41), 3-10. 
RAMANN, ‘ Bodenkunde.’ 
Morison. ©. T. G., and SoTHERS, D. B., ‘The Solution and Precipitation of Iron in 
the Formation of Iron Pan.’ Journ. Agric. Sci., 1914 (§), 84-96. 
STREMME, H., ‘ Kolloid Zeitsch,’ 1917 (20), 161. 
VII.—Flocculation and Deflocculation. 
ROHLAND, P., ‘ Die Tone,’ Vienna, 1910. 
ATTERBERG, A., Int. Mitt. fiir Bodenkunde, (1), 10. 
Harpy, W. B., ‘A Preliminary Investigation of the Conditions which Determine the 
Stability of Irreversible Hydrosols,’ Proc. Roy. Soc., 1899, Ixvi. 110-25. 
(See also ‘ Electrolytes and Colloids, The Physical State of Gluten,’ Woop & 
Harpy, ibid., 1909, lxxxi. 38-43.) 
HAtt, A. D., and Mortson, C. T. G., ‘The Flocculation of Turbid Liquids by Salts,’ 
Journ. Agric. Sci., 1907, ii., 244-56 
PICKERING, S. U., Proc. Roy. Soc., 1918, 94, A, 315-325. 
VIII.— Other Effects. 
BuppIn, W., Journ. Agric. Sci., 1914 (§), 452-455. 
Wo.korr, M. T., Soil Science, 1917, (3), 423. 
IX,.— Colloids and Bacterial Plant Life. 
Goa, G., ‘Osservazioni sopra i liquidi circolanti nel terrano agrario,’ Ann, d. R 
Accad. Agric., Torino, 1911, 54, 37 pp. 
So6unGEN, N. L., ‘Einfluss von Kolloiden auf microbiologische Prozesse,’ Centr. 
Bakt. Par., 1913 (38), 621-47. 
CAveERs, Journ. Ecology, 1914 (Q), 209. 
X.— Estimation of Soil Colloids. 
SJOLLEMA, Journ. f. Landw., 1905 (58), 67. 
ENDELL, Kolloid Zeitsch., 1909 (4), 246. 
