CLASSIFICATION. A classification of mineral waters may be geographic, geologic, therapeutic, or chemical. The following scheme of classifica tion is one adopted by A. C. Peale, a noted au thority on the subject of mineral waters, and more especially those of the United States: Springs included in the above groups may be either thermal or non-thermal, and they may be either free from gas or contain carbonic acid gas (carbonated springs), sulphureted hydrogen (sulphureted), nitrogen gas (azotized), and carbureted hydrogen (carloureted). The alka line waters include all those containing alkaline carbonates, such as carbonates of alkalies, alka line earths, alkaline metals, or iron. About one half of the alkaline springs of the United States are ealcic alkaline, that is, containing calcium carbonates or bicarbonates as the predominant ingredient. The water of the Hot Springs of Virginia is a hot, carbonated, calcie alkaline water. The alkaline-saline waters include those
containing combinations of alkaline carbonates with sulphides (sulphated) or chlorides (muri ated), there being in the United States one-third as many as of the saline waters. In the saline waters sulphides and chlorides predominate; in the United States there are about one-third more springs of this class than of the alkaline spring:. Springs which are classified as purgative or aperient will fall in the subclass of sulphated salines. The salines may be sodic sulphated or muriated, or calcie sulphated or muriated; the sodic muriatcd constitute about SS per cent. of the muriated saline waters of the United States. The acid class includes all waters con taining free acid, whether silicie, sulphuric, or hydrochloric. In addition to having free acid a spring may also contain salts of the acid.