Water As A Solvent. - Sources of Pollution manifold. - Oxygen in Water. - Metallic Impurities. - Galvanized Iron Tanks Injurious. - Humine, Geine and Ulmine. - Iodine and Bromine. - Phosphoric Acid, Arsenic Acid and Boric Acid; Fluorides, and the newly discovered metals: Rubidium, Caesium, Thallium, etc. - Color and Characteristics of Pure Water. - Microbe and Bacteria. - Minimum of Safety in Water. - Water should be Purified. - Aeration of Water. - Other Methods of Aeration. - The Vitality of Microbia is abated under the Pressure of Atmospheric Air; Carbonating of Water a Radical Agent to Destroy Organisms. - Fil-tering Mediums. - Sand, Charcoal, Sponges, etc. - Washing and Regenerating Animal Charcoal. - Asbestos, Filter Paper. - Cleaning Filters; Limited Actions of Charcoal and Sand Filters. - Systems of Filtration. - Effectiveness of Upward Filtrations Questioned. - Methods of Purifying Water. - The Alum Process. - By Lime Water. - By Soda. - To Free Water from Magnesian Salts and Sulphite of Lime (Gypsum). - Removal of Iron. - Removal of Manganese. - Removal of Organic Impurities. - Citric Acid to render Water Potable. - Boiling Water.