CHAPTER V. THE MINOR MINERAL INGREDIENTS OF SOILS; MINERAL FERTILIZERS, 63.—Minerals Injurious to Agriculture, 63.—_Minerals used as Fertilizers_, 63.—Apatite; Phosphorites of the U. S., Antilles, Africa, Europe, 63.—Phosphatic Iron Ores, “Thomas Slag,” 64.—Animal Bones; Composition and Agricultural Use, 64.—Vivianite, Dufrenite, 65.—Chile Saltpeter, 66. Occurrence in Nevada, California, 66.—Origin of Nitrate Deposits, 67.—Intensity of Nitrification in Arid Climates, 68.—Potash Minerals, 68.—Feldspars not Available, 68.—Depletion of Lands by Manufacture of Potashes, 69.—Discovery of Stassfurt Salts, 69.—Origin of these Deposits, 70.—Nature of the Salts, 71.—Kainit, 71.—Potash Salts in Alkali Soils, 72.—Farmyard or Stable Manure; Chemical Composition, Table, 72.—Efficacy largely due to Physical Effects in Soils, 73.—Green-manuring a Substitute for Stable Manure, 74.—Application of Stable Manure in Humid and Arid Climates, 74.—_Minerals Unessential or Injurious to Soils_, 75.—Iron Pyrite, Sulphur Balls, 75.—Occurrence and Recognition. Remedies 75.—Halite or Common Salt, 76.—Recognition of Common Salt, 76.—Mirabilite or Glauber’s Salt; in Alkali Lands; not very Injurious, 77.—Trona or Urao; Carbonate of Soda, “Black Alkali,” 77.—Injury Caused in Soils, 78.—Epsomite or Epsom Salt, 78.—Borax, 79.—Soluble Salts in Irrigation Waters, 79.