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.