able value to the student of mineralogy are: Moses and Parsons, Mineralogy, Crystallography, and Blowpipe Analysis (New York, 1900); E. S. Dana, Minerals and How to Study Them (1895).
In addition to the above the following works are especially devoted to crystallography and physical mineralogy: Mallard, Traité de crystallographie geométrique et physique (Paris, vol. i., 1879; vol. ii., 1884); Story-Maskelyne, Crystallography: The Morphology of Crystals (London, 1895); Williams, Elements of Crystallography (New York, 1891); Groth, Physikalische Krystallographie (Leipzig, 1894-95); Liebisch, Geometrische Krystallographie (ib., 1881); id., Physikalische Krystallographie (ib., 1891); Moses, Character of Crystals (New York, 1899).
Valuable text-books on determinative mineralogy are: Brush, Determinative Mineralogy and Blowpipe Analysis (ed. by Penfield, New York, 1896); Endlich, Manual of Qualitative Blowpipe Analysis (New York, 1892).
Of value in the study of minerals in rock sections are: Rosenbusch, Mikroskopische Physiographie der petrographisch wichtigen Mineralien (Stuttgart, 1873; 3d ed. 1892), translated and abridged by Iddings (New York, 1888); Luquer, Minerals in Rock Sections (New York, 1898).
The following works are useful for reference on subjects connected with economic mineralogy: Dewey, Preliminary Descriptive Catalogue of the Systematic Collections in Economic Geology and Metallurgy in the United States National Museum (Bulletin 42, United States National Museum, Washington, 1891); Merrill, Guide to the Study of the Collections in the Section of Applied Geology: The Non-Metallic Minerals (United States National Museuum, Washington, 1901); Rothwell and Struthers, The Mineral Industry (New York, annually, 1892 et seq.).
In addition to these the reader is referred to the volumes on Mineral Resources of the United States, published by the United States Geological Survey (Washington, 1882 et seq.).
MINERAL PAINTS. A term applied to mineral substances which are mined, ground, and sometimes purified for use as pigments. It includes a variety of natural materials as well as some artificial products. The essential characteristics of mineral paints are permanence of color and sufficient adhesion when applied to a surface to prevent scaling and to keep out moisture. Among the important substances included under the heading of mineral paints are ochre, sienna, and umber. These are clays which owe their color largely to limonite, although sienna and umber are colored in addition by manganese. Ochre occurs at a number of localities in the United States, the larger supply being obtained from Pennsylvania and Georgia. It is usually ground, washed to remove sand, and screened before shipment. Umber and sienna are found in but small quantities in the United States, and the chief supply of them is obtained from abroad. Slate and shale are ground for paint, the former being the refuse from slate quarries. The colors obtained from them are usually red, green, blue, yellow, and brown. Barite, or barytes as it is called commercially, is used as a substitute for or an adulterant of white lead in the manufacture of white pigments; for this purpose it must be free from iron, and therefore its preparation for market consists not only in grinding, but in some cases may include treatment with sulphuric acid to remove the stains. The main supply of barite is obtained from Missouri, North Carolina, Virginia, and Tennessee. It is cheaper than white lead, and does not turn yellow on exposure to the air. Metallic paint is a term applied to certain materials obtained by the grinding of hematite ores. The color of the paint is often changed or improved by previous roasting; the iron ore most frequently employed is that known as the Clinton ore, occurring in the Clinton division of the Silurian system of rocks. Metallic paint is mined in several States, notably New York, Pennsylvania, Wisconsin, and Tennessee; it is frequently employed for coloring mortars. Graphite and graphitic shale are used for making black paint, and have been found specially desirable for the coating of metallic surfaces. The main supply for this purpose is obtained from Ceylon, although small quantities are mined in the United States.
Artificial Mineral Paints. Under this heading are included Venetian red and Indian red, which are pigments obtained by roasting iron sulphate or copperas; white lead, produced by the action of acetic acid on metallic lead; red lead, formed by roasting of litharge; litharge, the reddish, partially roasted protoxide of lead; orange mineral, formed by the oxidation of white lead on the hearth of a reverberatory furnace; and zinc white, or zinc oxide, which is produced by the roasting of zinc ores.
The production of mineral paints in 1901 amounted to 232,347 short tons, valued at $18,417,068, while the imports were valued at $667,094. Consult: Jones, Testing and Valuation of Raw Materials Used in Paint and Color Manufacture (London, 1900). For statistics of production, consult Mineral Resources, issued by United States Geological Survey (Washington, annually).
MINERAL TALLOW, or Hatchettite. A yellowish-white, soft, flexible mineral wax or tallow that melts at 46° or 47° C., and consists of about 86 per cent. of carbon and 14 per cent. of hydrogen. It is found in the coal measures in Glamorganshire, Wales; Argyleshire, Scotland; and Moravia, Austria. See Ozocerite.
MINERAL WATERS. The term usually applied to spring waters which have a variable quantity of solid substances in solution, and on this account may exert effects on the human body different from those of ordinary water. Mineral waters have been used as remedial agents from a very early period. The oldest Greek physicians had great faith in their curative power, and the temples erected to Æsculapius were usually close to mineral springs. We are indebted to the Romans for the discovery not only of the thermal springs in Italy, but also of some of the most important springs in other parts of Europe, as those of Aix-la-Chapelle, Baden-Baden, Bath, and Spa in Belgium. In the United States mineral springs have also attracted attention since an early period. At Saratoga Springs, for example, the High Rock Spring was known to the white people as early as 1767, and the American aborigines seem to have been acquainted with its important properties even before that date. In West Virginia and Virginia seven springs were already noted in 1831, and of these the Bath mineral spring, now
