114 THE ESSENTIALS OF AGRICULTURE 



replacing in the pot. Add just enough rain water to each pot to 

 moisten the sand. Plant four kernels of corn in each pot. Place in a 

 warm window and keep each pot well moistened. Observe the growth 

 of the corn in each pot for four weeks. 



REFERENCES 



AGEE, ALVA. Crops and Methods of Soil Improvement, chaps, xvi, xvii, 

 and xviii. The Macmillan Company. 



BURKETT, C. W. Soils, chaps, xxiv, xxv, and xxvi. Orange Judd Com- 

 pany. 



HOPKINS, C. G. Soil Fertility and Permanent Agriculture, chap, xxvii. 

 Ginn and Company. 



LYON, T. L., and FIPPIN, E. O. Soils, pp. 319-350. The Macmillan Com- 

 pany. 



SNYDER, HARRY. Soils and Fertilizers, chaps, ix and x. Chemical Pub- 

 lishing Company. 



VAN SLYKE, L. L. Fertilizers and Crops, chaps, xx, xxi, xxii, xxiii, xxiv, 

 and xxv. Orange Judd Company. 



VIVIAN, A. First Principles of Soil Fertility, chaps, xvii, xviii, xix, xx, xxi, 

 and xxii. Orange Judd Company. 



VOORHEES, E. B. Fertilizers, chaps, iii, iv, and v. The Macmillan Com- 

 pany. 



Farmers' Bulletin 259, United States Department of Agriculture. 



Sources of Commercial Fertilizers (includes illustrated matter relative to 

 seaweeds as sources of fertilizers). United States Congressional House 

 Document 181, 55th Congress, 3d Session. 



