iv CONTENTS. 



PAGE 



Chapter III. Chemical Properties of Clay, 39-80 



Introductory, 40 



Minerals found in clay, 42 



Quartz, 42 



Feldspar, 43 



Mica, 44 



Iron ores, 44 



Pyi'ite, 45 



Glauconite, 46 



Kaolinite, 46 



Rutile, 47 



Calcite, 47 



Gypsum, 48 



Hornblende and garnet, 48 



Dolomite, 48 



Chemical analysis of clays, 49 



Method of ultimate analysis, 49 



Rational analysis, 52 



Compounds in clay and their effects, 53 



Silica, 54 



Iron oxide, 56 



Sources of iron oxide in clays, 56 



Effects of iron compounds, 56 



Coloring action on raw clay, 57 



Coloring action on burned clay, 57 



Fluxing action of iron oxide, 59 



Effect on absorptive power and shrinkage, 59 



Lime, 59 



Effect of lime carbonate on clay, 60 



Effect of lime-bearing silicates, 62 



Effect of gypsum, 62 



Magnesia, 64 



Alkalies, 67 



Titanium, 69 



Water, 71 



Mechanically combined water 71 



Chemically combined water, 73 



Organic matter, 73 



Soluble salts, 75 



Origin, 75 



Quantity present in clays 76 



Prevention of coating, 78 



Method of use, 79 



Chapter IV. Physical Properties of Clay, 81-115 



Plasticity, 81 



Tensile strength, 83 



Shrinkage, 91 



