868 Journal of Agricultural Research voi.xx,No.« 



(7) Hopkins, Cyril G. 



[iQIO.] SOIL FERTILITY AND PERMANENT AGRICULTURE. xxiii, 653 p., ilhlS., 



maps, ports. Boston, London, etc. 



(8) Lyon, T. Lyttleton, and Bizzell, James A. 



1018. lysimeter experiments. N. Y. Cornell Agr. Exp. Sta. Mem. 12, 115 

 p., 4 pi. Bibliography, p. 82-84. 



(9) Plummer, J. K. 



1918. studies in soil reaction as indicated by the hydrogen electrode. 

 In Jour. Agr. Research, v. 12, no. 1, p. 19-31. Literature cited, p. 



(10) Sharp, L. T., and Hoagland, D. R. 



1916. ACIDITY AND ABSORPTION IN SOILS AS MEASURED BY THE HYDROGEN 



Electrode. In Jour. Agr. Research, v. 7, no. 3, p. 123-145, 1 fig. 

 Literature cited, p. 143-145. 



(11) Swanson, C. O. 



1914. chemical analyses of some Kansas soils. Kans. Agr. Exp. Sta. Bui. 

 199, p. 633-715. 



(12) and Tague, E. L. 



1918. chemistry of sweet-clover silage in comparison with alfalfa 



silage. In Jour. Agr. Research, v. 15, no. 2, p. 1 13-132, 5 fig. 

 (13) 



1919. DETERMINATION OF ACIDITY AND TITRABLE NITROGEN IN WHEAT WITH 



THE hydrogen Electrode. In Jour. Agr. Research, v. 16, no. 1, 

 p. 1-13, 5 fig. 



(14) Veitch, F. P. 



1902. THE ESTIMATION OF SOIL ACIDITY AND THE LIME REQUIREMENTS OF SOILS. 



In Jour. Amer. Chem. Soc, v. 24, no. 11, p. 1120-1128. 



(15) Wiley, H. W.,etal. 



1908. OFFICIAL AND PROVISIONAL METHODS OF ANALYSIS, ASSOCIATION OF 

 OFFICIAL AGRICULTURAL CHEMISTS. AS COMPILED BY THE COMMITTEE 



on revision of methods. U. S. Dept. Agr. Bur. Chem. Bui. 107 

 (rev.), 272 p., 13 fig. 



