Water-supply: (Considered Practically from a Sanitary Standpoint).

acid Albuminoid ammonia algæ Altona amount analysis average bacillus bacteria bacteria per cubic Board of Health boiler calcium carbonate carbonic acid cause cent Chem chemical CHICAGO chlorine cholera clean color CRERAR cubic centimetre death-rate deaths deep depth dilute disease dissolved distilled Engineering epidemic evaporation experiments feet filter-bed filtered water filtration flow forest free ammonia germs grammes ground-water hard water impure inches increase instance intake iron Lake layer litre material miles million morocco Nessler Nitrogen Nitrogen as nitrates number of bacteria observed organic matter oxidation oxygen peaty pipe polluted potable precipitation present pumped purification quantity rain rainfall removed reservoir River river-water salt samples sand sea-water sedimentation sewage sewers snow sodium sodium carbonate sodium chloride soil solution spirilla spirillum spring sterilized stream sulphuric acid supply surface temperature tion town trace typhoid fever U. S. gallons water-supply well-water