TAN 



702 



TAR 



tret. There are several species, all resem- 

 bling the finches in their habits; feeding 

 on grain, and also on berries and insects, 

 and are particularly remarkable for their 

 bright colours. 



TAN'GENCIES (PROBLEM OF). An ancient 

 problem, the object of which was to de- 

 scribe a circle passing through given 

 points, and touching given straight lines, 

 the number of data being, in any case, 

 three in number. 



TAN'GENT, from tangens, touching. In 

 geometry, a right line perpendicularly 

 raised on the extremity of a radius, which 

 touches a circle, 

 but does not 

 cut it or come 

 within the cir- 

 cumference. In 

 trigonometry , the 

 tangent of an 

 arc a b is terminated by a secant passing 

 through the other extremity of that arc. 



TAN'ISTRY. In law, a tenure of lands in 

 Ireland, by which the proprietor had only 

 a life-estate, and to this he was admitted 

 by election. The Celtic term is tanais- 

 teachd, from tanaiste, a lord or governor 

 of a country ; from tan, a region or terri- 

 tory. The primitive meaning of tanistry 

 seems to have been that the inheritance 

 should descend to the oldest, or the most 

 worthy of the blood and name of the de- 

 ceased, without regard to proximity, or 

 in other words to the strongest candidate. 

 It occasioned many bloody feuds in 

 families. 



TANK. In the navy, a case of sheet iron 

 for holding water. In gardening, a cis- 

 tern for collecting rain-water. 



TAN'NER'S BARK. The bark of oak, and 

 other trees abounding in tannin. 



TAN'NIC ACID, ) Tan, or tanning prin- 



TAN'NIN. j ciple. A peculiar ve- 



getable principle, obtained from nut- 

 galls, and so named because it is the effec- 

 tive agent in tanning, or the conversion 

 of skin into leather. Pure tannin is co- 

 lourless, has an excessively astringent 

 taste, without bitterness, but no smell 

 "Water dissolves it in great quantity, and 

 the solution reddens paper stained with 

 litmus. It decomposes the alkaline car- 

 bonates with effervescence, and forms, 

 with most of the metallic solutions, preci- 

 pitates which in reality are tannates. 

 Tannin is found in several vegetable sub- 

 stances besides gall-nuts, as oak-bark, 

 tea, &c. 



TAN'S?. In botany (1.) A name common 

 to all the species of the genus Tanacetum. 

 (2.) Tbemaudlin tansy is the Achillea age- 

 raturn. (3.) For wild tansy, see POTEH- 



TILLA. 



TAW'TALITE. The name given by Eke- 

 berg to the ferruginous oxide of tantalum. 

 Since tantalum and coluiubiuui have been 



ascertained to be identically the same 

 metal, *his ore has been called columbite. 

 Its colour is nearly iron-black. It con- 

 tains 80 of oxide of tantalum, 12 of oxide 

 of iron, and 8 of oxide of manganese. 



T.VN'TALCM. A metal extracted from 

 tantalite, at first supposed to be distinct, 

 but now ascertained to be identical with 

 columbium (q. v.). 



TAN'TALUS. The "Wood Pelican. A ge- 

 nus of birds. Order Grallatorite ; family 

 Cultrirostres, Cuv. Tantalus is the Latin 

 name for the heron. This genus, accord- 

 ing to Cuvier, has only one species, the 

 T.loculator, Lin., about the size of a stork. 

 It inhabits both Americas, arriving in each 

 country about the rainy season, and fre- 

 quents muddy waters, where it chiefly 

 hunts for eels. But, according to Gme- 

 lin, the genus Tantalus includes those 

 birds which form the genus Ibis, Cuv. 



TAP'ESTRT, Fr. tapisserie, hangings. An 

 ornamental figured textile fabric, of 

 worsted or silk, for lining the walls of 

 apartments, &c. 



TAPE'WORM. See TJSNIA. 



TAPIO'CA. The starch yielded by the 

 Cassava root (root of the Jatropha mani- 

 hot) after its poisonous principle has been 

 destroyed by roasting. See JATROPHA. 



TA'PIR. A genus of mammiferous pa- 

 chydermatous animals. For a long time 

 only one species was known, the T. Ame- 

 ricanus, Lin., or American tapir ; about 

 the size of an ass ; skin brown, and nearly- 

 naked ; common in wet places, and along 

 the rivers of the warm parts of South 

 America. The flesh is eaten. A second 

 species, belonging to the eastern conti- 

 nent, has recently been discovered in the 

 forests of Malacca and Sumatra. It is 

 larger than the American species, and of 

 a blackish brown colour. More lately 

 still, a third species has been discovered 

 in the Cordilleras. Fossil tapirs are also 

 scattered all over Europe, and among 

 others is a gigantic species, the T. gigan- 

 teus, Cuv., which, in size, must have been 

 nearly equal to the elephant. 



TAP'ROOT. In botany, the principal root 

 of a plant, which shoots directly down- 

 wards. 



TAR, Sax. tare. A thick, viscid, brown- 

 ish black, resinous, oleaginous substance, 

 chiefly obtained from the pine and other 

 turpentine trees, by subjecting the wood, 

 in close vessels, to destructive distillation. 

 It contains, according to Beichenbach, 

 the proximate principles, Paraffine, Hu- 

 pion, Creosote, Picemar, Pittacal,Pyretine, 

 Pyroleine, and some vinegar. The tar of 

 Europe is the best. Mineral tar is a va- 

 riety of bitumen. 



TAR'ANTISM. A disease. See TARENTISM 



TARAN'TULA. 1. The name given by Fa- 

 bricius to a genus of arachnides belong- 

 ing to the family Pedipalpi of the order 



