A mineral water is a natural water containing one or more ingredients different from, or in greater quantity than, those in ordinary drinking or washing water. Many bottled waters are not mineral waters. As obtained from the earth, they are thermal when they are distinctly warmer than the average surrounding temperature, otherwise non-thermal; some writers adopt 700 F. as the dividing line between these. Warm waters are those from 700 to 98.6° F.;hot waters are those above 98.6° F. They may be sparkling or effervescent, i. e., impregnated with carbon dioxide, or still, i. e., non-effervescent. They may be sulphurated, containing hydrogen sulphide gas. Their mineral constituents are sodium, potassium, lithium, magnesium, calcium, iron, aluminium, and arsenic, in the form of sulphates, nitrates, chlorides, bromides, iodides, borates, and silicates. In a number of the waters the percentage of the ingredients has been found quite variable at different seasons and in different years. The report of Haywood and Smith (1905), of the United States Bureau of Chemistry, on the "Mineral Waters of the United States," and that of Francina, on "European Waters," furnish valuable data.

A medicinal classification is not readily made because many waters contain more than one ingredient of importance. All are either - (1) Alkaline, i. e., having an alkaline reaction; this comes from carbonates and bicarbonates, or in a few instances from borates and silicates. (2) Saline, containing chlorides, nitrates, or sulphates in excess. (3) Alkaline saline, combining the properties of the alkaline and the saline, or (4) Acid, in which there is free sulphuric or hydrochloric acid.

Any of these may contain one or other of the special elements, and are known as:

Sulphur waters - those containing sulphuretted hydrogen and other sulphides. They are usually from "red" or "white" sulphur springs, these names being obtained from the precipitation of sulphur. The red sulphur gets its color from iron. Examples are the waters of Richfield Springs or Sharon Springs.

Chalybeate or ferruginous waters - those which contain iron, usually in the form of the sulphate or bicarbonate, as Spa or Sweet Chalybeate.

Arsenical waters - those which contain arsenic, as Levico and Bourboule.

Alum waters - those which contain aluminium salts. Rockbridge alum water contains 337 grains of aluminium sulphate per million and is astringent.

Bromine waters, iodine waters, etc.

Lithia waters - of these, Haywood and Crook say "lithium seldom or never occurs in waters in large enough quantities to be a predominating basic constituent." In their analyses, Buffalo and Londonderry Lithia Waters show only a trace, Otterburn Lithia, 0.03 part, Geneva Lithia, 0.1 part, and White Rock Lithia, 12.6 parts of lithium per million. Thus the term "lithia water" is a misnomer.

Examples of alkaline waters are Vichy, Apollinaris, Seltzer, Bear Lithia, Great Bear, Manitou. Of alkaline saline are the Saratoga waters (Carlsbad, Congress, Hathorn, High Rock, Vichy, Seltzer) and White Rock Lithia. The Saratoga waters are much poorer in salts now than formerly. The saline waters are those containing abundance of salts and not alkaline, such as Pluto and Mount Clemens.

From a medicinal point of view the purgative waters are the most important. In nearly all cases they owe their cathartic action to sodium sulphate (Glauber's salt), magnesium sulphate (Epsom salt), magnesium chloride, or magnesium bicarbonate.

The waters which contain a large percentage of magnesium salts are bitter. Those whose action is due to sodium sulphate alone are the Carlsbad waters and Marienbad, which are alkaline, and Villacabras, which is neutral. The published analyses of the Carlsbad waters differ considerably from one another. Those owing their action to both sodium sulphate and the magnesium salts are: Pluto, Friedrichshall, Carabana, Rubinat Condal, and the Hungarian waters, Apenta, Franz Josef, and Hunyadi Janos. "Pluto concentrated" is artificial and does not have its salts in the same relative proportions as Pluto water. It contains about 65 grains (4.3 gm.) of sodium sulphate and 30 grains (2 gm.) of magnesium sulphate, in a dose of 2 ounces (60 c.c.). Mount Clemens water is essentially a solution of magnesium chloride.

Mineral waters may be used for the bath or internally. At the various "springs," both the baths and the drinking of the waters are considered requisite parts of the treatment. It is claimed that some of the waters contain radium emanations and are, therefore, more effective when taken fresh. The value of a "cure" taken at one of the mineral spring resorts depends less on the character of the water than on the regulation of rest, exercise and food, the regular taking of the baths, and the influence of freedom from home or business cares amid pleasant surroundings.