30 TUNGUSES into a paste with oil, in a crucible lined with charcoal, for some hours. The tungstic acid is procured by decomposing the tungstate of lime with hydrochloric acid, which dissolves the lime and leaves the tungstic acid. The chemical equivalent of tungsten is 184. Tung- sten combines with several other metals, form- ing alloys of interest. Its combination with cast iron is remarkable for its extraordinary hardness; and it is said that cast steel con- taining 10 per cent, of tungsten is greatly improved in tenacity, hardness, and suscepti- bility of taking a fine temper. Notwithstand- ing its reputed qualities, tungsten steel has not been generally introduced, and compara- tively little is made. Of the two oxides of tungsten, W0 2 and WOs, the latter only, or tungstic anhydride, is of particular interest. This occurs native in bright yellow cubes, also as an earthy substance like ochre at Lane's mine, Monroe, Conn., Oabarrus co., N. 0., and a few other places. But the usual form of the acid is in the combinations already named, and of these wolfram is the most common ore of the metal. This is a brownish black mineral, of metallic lustre, of hardness 5 ft> 5 '5, and specific gravity 7'1 to 7'55. It is often found associated with tin ore in Corn- wall, Saxony, Bohemia, and France. In the United States it has been found at Monroe, Conn., with native bismuth, galena, blende, &c. ; also at Trumbull in the same state, and near Mine La Motte, Mo., and Blue Hill bay, Me. Tungstic acid is also found in combina- tion with lead, forming the mineral scheele- tine, and artificial tungstate of lead is prepared as a pigment resembling white lead. The fol- lowing are some of the attempted applications of the compounds of tungsten to economical purposes: tungstic acid for coloring yellow; oxide of tungsten for coloring blue ; tungstate of soda in dyeing and calico printing, and as a substitute for stannate of soda. The com- pounds of tungsten have been thoroughly stud- ied by Roscoe and Zettnow, but none of them possess particular interest beyond those already described. TUNGUSES, a tribe of N. E. Siberia, of Mon- golian origin, extending as far W. as the Yenisei and as far E. as Anadyrsk, in Ion. 171. They number about 70,000. Among their allied tribes are the Monzhurs-and the Gilyaks and others of the Amoor. The Mantchoos belong to the Tungusic stock. The Tunguses proper and their congeners the Lamuts are well dis- posed, and mostly belong to the Greek church and pay tribute to the czar. They are gener- ally divided into reindeer, horse, and dog Tun- guses; but they are chiefly devoted to the rein- deer, which they use for riding and for carry- ing freight, while other tribes use them chiefly in sledges. The Tunguses and the Lamuts are very slender, and have dark olive complexions, no beards, straight black hair, and oblique eyes. Men and women wear almost the same rich costume of fur hoods and pantaloons, short TUNIS deer-skin boots, and highly ornamented buck- skin aprons. They differ greatly from the Tchuktchis and Koriaks, though leading the same nomadic life ; while among the latter there are men owning thousands of reindeers, one possessing 300 would be deemed immensely rich among the Tunguses. Unlike most other tribes, they never break up their tents without leaving a pole as a landmark for resuming the same habitation on returning from their wan- derings. The Russian traders of the sea of Okhotsk derive most of their supply of Sibe- rian squirrel skins for the European markets from the Tunguses and Lamuts in that region. TUNICA, a N. W. county of Mississippi, bor- dering on the Mississippi river, which sepa- rates it from Arkansas, and intersected by the Coldwater river and other streams ; area, 750 sq. m. ; pop. in 1870, 5,358, of whom 4,127 were colored. The surface is flat, and in many places swampy, and the soil fertile. The chief productions in 1870 were 4,500 bushels of wheat, 2,000 of oats, 1,500 of barley, 82,155 of Indian corn, and 6,424 bales of cotton. There were 240 horses, 645 mules and asses, 413 milch cows, 1,409 other cattle, 33 sheep, and 1,812 swine. Capital, Austin. TUNICATES. See MOLLUSCOIDS. TUNIS. I. One of the Barbary states of N. Africa, bounded N. and E. by the Mediterra- nean, S. E. by Tripoli, 8. by the desert of Sa- hara, and W. by Algeria, between lat. 32 20' and 37 20' N., and Ion. 7 20' and 11 30' E.; extreme length about 350 m., general breadth 130 m. ; area, about 45,000 sq. m. ; pop. about 2,000,000. Besides the capital, of the 'same name, the chief towns are Kairwan, Susa, Ilam- mamet, Bizerta, Kef, and Sfax. The coast line is irregular, and has three extensive indenta- tions, forming the gulfs of Tunis, Hammamet, and Cabes (Syrtis Minor). The only consid- erable river is the Mejerda (anc. Bagradaa), which falls into the gulf of Tunis after a N. E. course of about 200 m. Near its mouth, and for some distance W. of it, are several large lagoons. The Shot Kebir (anc. Palus Tritoni*), over 100 m. long, and the Shot Gharnis, further W., over 60 m. long, in the southern part of the country near the Sahara, are marshy depressions which become nearly dry in summer. The interior of Tunis is but little known. The N. W. portion is moun- tainous, the summits having a height in many places of 4,000 or 5,000 ft. The mountains are well timbered, and have many tracts of cultivated land and olive plantations on their lower slopes. An extensive plain or table land, 100 m. long by 30 m. broad and quite level, extends from this region to the gulf of Hammamet; it is nearly destitute of trees, and is used by the Arabs for pasturing their horses and camels. S. of this plain the country is be- lieved to be nearly desert, though in ancient times it was celebrated for its fertility. Sil- ver, lead, and copper are found in the moun- tains. The climate is very healthful ; rainfalls
