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{ 1. Spring water. } Wholesome, { 2. Deep well water. } verypalatable. { 3. Upland surface water. } Suspicious, { 4. Stored rain water. } moderately { 5. Surface water from cultivated lands. } palatable. Dangerous, { 6. River water to which sewage gains access. } palatable. { 7. Shallow well water. }

The constituent parts of pure water, in volumes, are two parts of hydrogen and one of oxygen, and by weight one part hydrogen and eight parts oxygen. When pure it is transparent, tasteless, inodorous, and colorless, except when seen in considerable depths. But having such high solvent powers and affinity for almost every substance in nature, one can account for suspicions that science places on all waters, for it is never free from impurities. And well it may not, if doctors are to be believed, for they tell us, that chemically pure water is not best for man; that good potable waters have from one to eight grains weight in each gallon of certain impurities diffused through them. Impurities are arranged under the following general heads: