206 BULLETIN 105!), U. S. DEPARTMENT OF AGRICULTURE. 



109. Bouyoucos, G. J., and McCool, M. M. Measurement of inactive, or unfi 



moisture in the soil by means of the dilatometer method. U. S. Dept. 

 Agr. 3 Jour. Agr. Research, VIII, 6, Feb., 1917. 



1 10. Briggs, L. J. The mechanics of soil moisture. U. S. Dept. Agr., Bu. of Soils, 



Bull. Xo. 10, 1897. 



J II. Briggs, L. J. Electrical instruments for determining the moisture tempera- 

 ture, and soluble salt content of soils. U. S. Dept. Agr., Bu. of Soils, 

 Hull. L5, 1899. 



L12. . Martix, F. O., and Pearce. J. R. The centrifugal method of me- 

 chanical soil analysis. U. S. Dept. Agr., Bur. of Soils, Bull. 24, 1904. 



1 L3. and McLane, J. W. The moisture equivalents of soils. V. S. Dept Agr., 



Bur. of Soils, Bull. 45, 1907. 



114 anc l Shantz, H. L. The wilting coefficient for different plants and 



its indirect determination. U. S. Dept. Agr., Bur. of Plant Industry, 

 Bull. 230, 1912. 



II"). Buckingham, E. Contributions to our knowledge of the aeration of soils. U. S 

 Dept, Agr., Bur. of Soils, Bull. 25, 1904. 



116. . Studies on the movement of soil moisture. U. S. Dept Agr., Bur. of 



Soils, Bull. No. 38, 1907. 



117. Cameron, F. K., and Gallagher, F. E. Moisture content and physical con- 



ditions of soils. U. S. Dept. Agr.. Bur. of Soils, Bull. 50, l> 



118. Chemistry, Bureau of. Official and provisional methods of anal; sis I S. 



Dept. Agr., Bull. 107. 



119. Dixon, H. H., and Atkins, W. R. G. Osmotic pressures in plants. I. Method 



of extracting sap from plant organs. Sci. Proc. Royal Dublin Soc, 

 n. s. 13, pp. 422-33, 1913. 



120. Fletcher, C. C, and Bryan, H. Modification of the method of mechanical 



soil analysis. U. S. Dept. Agr., Bur. of Soils, Bull. 84, 1912. 



121. Free, E. E. Studies in soil physics. The Plant World, v. II. Nos. 2. 3, 5, 7. 



and 8, 1911. 



122. Grandeau, Louis. Traite' d'Analyse des Matieres agricoles, Paris, l s 77. 



123. Harris, J. A., Lawrence, J. V., and Gortner, R. A. The cryoscopic con- 



stants of expressed vegetable saps as related to local environmental 

 conditions in the Arizona deserts. Phy. Res. vol. 2, No. I. L916. 



124. Hartley, Carl. The control of damping-off of coniferous seedlings. Bur. 



Plant Ind., U. S. Dept. Agr. Bull. 453, 1917. 



125. Hilgard, E. W. Soils. New York, 190U. 



12(1 Hibbard, R. P., and Harrington, O. E. Depression of the freezing-poinl 

 in triturated plant tissues and the magnitude of this depression us related 

 to soil moisture. Phys. Res., Vol. I, No. 10, 1916. 



127. Hoagland, D. F. The freezing point method as an index of variations in the 



soil solution due to season and crop growth. U. S. Dept. Agr.. Jour. Agr. 

 Res.. XII, 6, Febr. 11, 1918. 



128. Jones, H. C. Physical chemistry. 4th ed. ,191s. New York. 



129. King, F. H. Investigations in soil management. V . S. Dept. Agr., Bur. of Soils, 



Bull. 26, 1905. 

 129a, Livingston, B. E., Britton, J. C, and Reid, F. II. Studies on the properti< 

 of an unproduetive soil. U. S. Dept. Agr., Bur. of Soils, Bull. 28, 1"" 



130. :. Review of Hans Fittings' Die Wasserversorgnung und die < )smotisch< 



Druckverhaltnisse der wustenpflanzen. Plant World, 11.7. 1911. 



131. McCool, M. M., and Millar, C. E. The water content of the soil and the .cm- 



position and concentration of the soil solution as indicated by the freezing- 

 point lowerings of the roots and tops of plants. s,.il Science, vol 

 Xo. 2, 1917. 



