This is a term applied to water which is secured by deep borings into the earth. An ordinary well is usually under 100 - and at most 150 feet - in depth. If it is required to go 200 to 500 feet in depth or more the water is usually termed artesian. The term artesian is said to be derived from the town of Artois in France where a deep well of this kind was first known. Often in artesian wells the water rises above the earth's surface of its own force; in other words, it forms a flowing well. Any very deep well, whether flowing of its own accord or not, is now regarded as an artesian well. The waters of artesian wells usually have different properties from those which are derived nearer the surface, because of their contact with different characters of soluble matters. Many artesian wells yield sulphur, chalybeate, or alum waters; in others the water is so impregnated with common salt as to be unsuitable for consumption; while in many others the water is of excellent quality.

1 Water Supply Paper 315, U. S. Geological Survey, page 81.