CHAPTER III
The Department of Agriculture or your congressman will send you literature on the production and use of fertilizers. From your state agricultural experiment station you can procure information as to local needs and products. Consult the articles on potash salts and phosphate rock in the latest volume of "Mineral Resources of the United States," Part II Non-Metals (published free by the U.S. Geological Survey). Also consult the latest Yearbook of the Department of Agriculture. For self-instruction, problems and experiments get "Extension Course in Soils," Bulletin No. 355, U.S. Dept. of Agric. A list of all government publications on "Soil and Fertilizers" is sent free by Superintendent of Documents, Washington. The Journal of Industrial and Engineering Chemistry for July, 1917, publishes an article by W.C. Ebaugh on "Potash and a World Emergency," and various articles on American sources of potash appeared in the same Journal October, 1918, and February, 1918. Bulletin 102, Part 2, of the United States National Museum contains an interpretation of the fertilizer situation in 1917 by J.E. Poque. On new potash deposits in Alsace and elsewhere see Scientific American Supplement, September 14, 1918.