The definition will depend somewhat upon the point of view. Water is itself a mineral, and in a strict sense all waters holding gaseous or mineral substances in solution are mineral waters, no matter how small the quantity may be. Usually, however, the term is restricted to those waters "which contain an unusual amount of mineral matter, or which are characterized by an unusual degree of heat. In a therapeutical sense, all waters that have an effect upon the animal body are mineral waters. Interesting as they are from a scientific standpoint, and important as they undoubtedly must be in the elucidation of certain geological problems, it is mainly from their use as medicinal agents that they derive their commercial importance. From an economic point of view, mineral springs are interesting in at least three different ways: First, as places of resort they add to the wealth and population of their localities; secondly, the waters when bottled are shipped to distant portions of the country, and not infrequently are sent abroad; and, thirdly, the bottled waters, or in some cases the salts left upon evaporation of the water, become a portion of the stock in trade of druggists and dealers in mineral waters. It has long been known that mineral springs are numerous in the United States, among which all classes of water may be found. That the majority are unimproved is due mainly to the comparative newness of the country and the consequent sparseness of population, especially in the Territories and extreme Western States, and also to the fact that the springs have not as yet been made the subjects of careful and complete investigation, as in the case of so many foreign springs. Many of the springs allowed to run to waste would in most European countries be of considerable value. Still there has been an improvement in this respect; and even now a mineral spring in this country is frequently a source of profit to the owner.