This metal gets its name in recognition of the many colors (_chroma_ “color”), in which its compounds appear. Chromic oxide is a vivid green, used to color porcelains, pottery, tiles, etc., and also as a substitute for the arsenical greens formerly used in wall-paper. The chromate of lead is the pigment, well known to artists as “chrome yellow,” and the bichromate of potassium is bright red. The metal is obtained in at least two different forms; one hard, brittle and so resistant to heat as to be infusible at temperatures which would volatilize platinum; the other as a powder which burns brightly if heated in air. While used in paints, dyes, etc., its greatest importance is for the making of ferro-chrome steel, which is used where resistance to sudden shock is required, as in armor plate, automobile springs, ball bearings, etc. With tungsten and cobalt it makes the alloy, stellite, as noted above. Chromium was used in relatively small quantities before the first world war, and we imported our supplies from Turkey, India, New Caledonia, and Rhodesia. During the last war we started a large-scale development of low-grade ores in Montana, and can now supply all of our needs from this source. Chromite FeCr₂O₄ _chromic iron_ Occurs in grains, masses, or isometric octahedrons; hardness 5.5; specific gravity 4.4; color black; streak dark-brown; luster submetallic; opaque on thin edges. In form, color and streak chromite resembles magnetite and franklinite. From the magnetite it is distinguished by being non-magnetic; from the franklinite, by being insoluble in hydrochloric acid, while the franklinite is soluble. Chromite furnishes practically all the chromium used in the arts and manufactures. It is a mineral associated with high temperatures, and therefore found in dark lavas, serpentine, and olivine. It occurs in Pennsylvania, Maryland, New Jersey, Montana, Oregon, Wyoming, and California. Tungsten This element is obtained either as a heavy dark-gray metal, which is very hard and difficult to fuse, or as a dark-gray powder. It is used as an alloy with iron, one part of tungsten to nine of steel, to make the ferrotungsten, which has extraordinary hardness, and is used mostly for high-speed tools. Tungsten is also one of the three metals (cobalt, chromium and tungsten) which are alloyed together to make stellite. Some of the tungsten supply is also used to make the films in incandescent lamps, and in some of the chemical industries. It has but one important ore, wolframite, and this is found in the United States in but small quantities; so that we ordinarily have to import the greater part of what we use. During the last war, under the stimulus of high prices and the urge of necessity, we did find and produce substantial quantities of tungsten. China is the world’s largest producer of tungsten ore with Burma second, and the United States a poor third. Wolframite (FeMn)WO₄