Disinfectants. Antiseptics. Viability of bacteria. New York results. Reversed ratio of counts. Coliform organisms. Aftergrowths in water and sand. V. COMPLAINTS 62 Auto-suggestion. Tastes and odours. Sludge problem. Colic. Effect on fish and birds. Effect on plants and flowers. Corrosion of iron and lead pipes. VI. BLEACH TREATMENT 72 Storage of bleach. Mixing tanks. Storage tanks. Dosing apparatus. Control. Analysis of liquor. Detection and estimation of free chlorine. Chlorometer. Cost of construction and operation. Antichlors. DeChlor filters. VII. LIQUID CHLORINE 89 Historical. Leavitt-Jackson machine. Electro Bleaching Gas Co.'s types. Wallace and Tiernan's manual control types. Effect of temperature on gas pressure. Impurities in gas. Advantages. Comparison of liquid chlorine and bleach. Cost of treatment. Popularity. Chlorine water. VIII. ELECTROLYTIC HYPOCHLORITES AND CHLORINE 105 Hermite fluid. Eau de Javelle. Chloros. Non-diaphragm cells: Dayton, Hermite, Mather and Platt, Haas and Oettel. Diaphragm cells: Hargreaves-Bird, Nelson, Allen-Moore. Montreal installation. Costs. IX. CHLORAMINE 115 Preparation. Absorption by water. Experimental results. Works results. Ratio of chlorine to ammonia. Economics. Advantages. Operation. Other chloramines. Halazone. X. RESULTS OBTAINED 132 Object of chlorination. Effect on filter rates and algæ. Hygienic results. Typhoid rates. Typhoid reduction at Philadelphia, Chicago, and Ottawa. Abortive epidemics. Use and abuse of chlorination. APPENDIX 147 Estimation of free chlorine in water. NAME INDEX 151 SUBJECT INDEX 155 CHLORINATION OF WATER CHAPTER I HISTORICAL Chlorine, although one of the most widely distributed elements known to chemists, is never found in the free condition in nature; it exists in enormous quantities in combination with sodium, potassium, calcium, magnesium, etc. As sodium chloride, common salt, it occurs in practically inexhaustible quantities in sea water together with smaller quantities of other chlorides. In mineral form, enormous deposits of sodium chloride are found in Galicia, Transylvania, Spain, in England (particularly in Cheshire), and in sections of North America. The most important deposits of potassium chloride are those at Stassfurt, Germany, where it occurs either in the crystalline condition as sylvine or combined with magnesium chloride as carnallite.