Titanium, a metal first detected in 1789 by Gregor in titanic iron, and found by Klap-roth in 1794 in rutile, and named by him from the Titans. Dr. Wollaston in 1822 recognized it in the form of minute copper-colored cubical crystals found in the slags of the iron-smelting furnaces at Merthyr Tydfil in South Wales, and these, often met with since that time in iron slags, were formerly regarded as pure titanium, but are now understood to be compounds of the metal with nitrogen and cyanogen. Berzelius was the first to separate this metal in a state of purity. He decomposed a mixture of the fluorides of titanium and potassium by means of metallic potassium, and obtained the metal in a grayish powder. M. Sainte-Claire Deville obtained it in forms resembling specular iron ore, crystallized in prisms with a square base. Its chemical equivalent is 50; symbol, Ti. Three oxides of the metal are known, TiO, Ti203, and Ti02; the last of which, titanic anhydride, is the only one of interest. It occurs as a mineral in three forms: as rutile and anatase, which both crystallize in the dimetric system, though with different angles, and as brookite, crystallizing in the trimetric system.

Rutile is generally a reddish brown mineral, sometimes yellowish or black, harder than feldspar, and of specific gravity 4.18 to 4.25. It occurs in many parts of Europe and America, the richest localities in the United States being in Chester and Lancaster cos., Pa. In Vermont and New Hampshire, as also in Brazil and Switzerland, it is found in long needles enclosed in masses of transparent quartz, making very curious and beautiful specimens, which are often used in jewelry. Anatase and brookite are comparatively rare minerals. In combination with oxide of iron, titanic acid forms the compound ilmenite or titaniferous iron. (See Iron Ores.) This is met with in large masses in Maryland, northern New York, and Canada. At Bay St. Paul on the St. Lawrence are beds of it, from 100 to 300 ft. long and 90 ft. thick, the ore, according to T. Sterry Hunt, containing 48.60 per cent, of titanic acid combined with 37.06 of protoxide of iron, 10-42 of peroxide of iron, aud 3.60 of magnesia. - The only useful application of titanium is to furnish a yellow color in porcelain painting, and to give the proper tint to artificial teeth.

The American supply for these purposes is derived from Pennsylvania. Tessie du Motay employs the strong attraction of titanium for nitrogen to produce ammonia directly from the atmosphere. If a mixture of titanic anhydride and charcoal, both in a minute state of division, be heated to whiteness and submitted to a current of air, nitrogen is rapidly absorbed, and carbonic oxide escapes. By passing steam over the copper-colored crystals which result, ammonia is copiously evolved, and it is claimed that the operation may be made continuous.