Barytes is a natural mineral prepared for use by simply drying and grinding. Enormous quantities are used as an adulterant, in almost all pigments. It is crystalline and does not deaden the color with which it may be combined. In grinding, it takes very little oil, and is the universal cheapener. Its use is to be deplored when introduced into pigments which, in themselves, are marked pure.

The reader should understand that many colored pigments are of such great strength and of such a nature that the use of some reducer, as bary-tes is necessary to improve their mixing and paint forming qualities.

Artificial barium sulphate is also produced and differs only in being finer, whiter and free from admixture with other substances, in other words, a chemically pure product. While the covering power of barytes is poor, it is not altered by atmospheric conditions and is without action on other pigments. It does not work well in oil alone, but improves much when used in conjunction with other pigments, particularly white lead. A paint composed of two parts white lead and one part barytes is little affected by sulphuretted hydrogen, and is, therefore, much less likely to blacken or change color, than white lead alone.

Barytes is practically insoluble in hydrochloric or nitric acid, which easily distinguishes it from white lead or oxide of zinc.