Mineral waters, as has already been explained, are natural waters which by reason of the acquirement of large quantities of some element, by solution or otherwise, are removed from the sphere of common potable waters. This denaturing, so to speak, of a potable water may be accomplished either by the acquirement of an excess of the ordinary soluble salts which spring and well waters contain in minute quantities, or by the solution of an odorous gas, such as hydrogen sulphid, or by the acquirement of some poisonous or medicinal body, such as arsenic or iron.

There is no definite limit of separation which can be established between a potable and a mineral water. In point of fact, the division of waters into these two classes is not attended with a great deal of difficulty. Medicinal waters are often potable, and mineral waters of a low degree of mineralization are constantly used for potable purposes. In fact, the use of mineral waters is not by any means confined to the persons who make pilgrimages to the places where they are produced, but the principal consumption is in the way of bottled waters, which are sent sometimes to far distant countries.