visited Hawaii, Tammeamea put himself under the protection of that officer, as the representative of the king of Great Britain; and, as the price of his submission, he was assisted in building a fine vessel, which afforded a model for the construction of several more. Tammeamea thus formed a fleet, with which he conquered the adjoining islands, and traded to China. He subsequently erected a fort on the island of Oahoo, and obtained from the Russians some artillery; while, by encouraging the trading of his subjects with navigators, he added to his own wealth and importance as well as that of his people. This enterprising monarch died in March, 1819. Rhio Rhio, the son and successor of Tammeamea, having made a visit to England, together with his queen, in 1824, both their majesties died in London, after a few months' residence, in consequence ɔf a disease arising from change of climate and habits of life.

TA, TANA, TANIA; an ending common to a great many names in the Oriental languages, as well as those of Europe, signifying country or place possessed by; Mauritania (country of the Moors).

TANAIS. (See Don.)

TANCRED, with Godfrey of Bouillon, the soul of the first crusade, was born in 1078. History gives us no information concerning his father, a Sicilian or Italian marquis; but his mother was the sister of the celebrated Norman, Robert Guiscard, whose eldest son, Bohemond, was the friend and brother in arms of Tancred. (See Guiscard.) In 1096, the two heroes embarked for Épirus, and thence marched to Macedonia. Tancred was present in the van or the rear, wherever danger was to be found, and more than once saved the army from destruction in the snares of the Greeks. On the plains of Chalcedon he united his forces with those of Godfrey; and here they formed that compact which Tasso has celebrated in his Jerusalem Delivered. At the siege of Nice (1097), Tancred first appears among the heroes who directed the course of events, and in the battle of Dorylæum, in which his younger brother fell, he saved the army of the crusaders, when surrounded by 200,000 Seljooks. Godfrey's brother Baldwin and Tancred now advanced over the Taurus towards Jerusalem, a distance of nearly 1000 miles, through an unknown and desolate region, for the purpose of exploring the route. Tancred first penetrated through 12

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the passes of the mountains, and obtained possession of Tarsus by capitulation. Baldwin followed him, and was faithless enough to take possession of the town ostensibly for his brother, but virtually for himself. Tancred, though exasperated at this act of treachery, nobly exclaimed, "Shall I stain my lance with the blood of my brethren ?" and, advancing to Memistra, took the place by storm. Baldwin attempted to repeat his perfidious act, and Tancred now suffered himself to be so far carried away by his resentment, as to turn his arms against him; but the quarrel terminated in the reconciliation of the chiefs. Tancred next, marched against Antioch, the capture of which was delayed seven months, by the diseases, want of provision, and insubordination, which prevailed in the Christian army. The garrison left by the Crusade→ in the city, was surrounded by a Persian a my, which was defeated by Tancred. After Easter, in 1099, the crusaders set forward for the conquest of Jerusalem. Tancred took Bethlehem, and pressed forward to be the first to see the walls of the holy city. Immediately after his arrival before Jerusalem, he captured an advanced work, which is still called Tancred's tower. During the scenes of horror which attended the capture of Jerusalem (July 19, 1099), he conducted himself with humanity, and saved the lives of thousands of the enemy, at the peril of his own. For this he was accused of being an enemy to the priests and to religion! The sultan of Egypt was now advancing to attempt the recovery of Jerusalem, but was totally defeated by Tancred, with the loss of his camp, before Ascalon (August 12). Tancred captured Tiberias, besieged Jaffa, and, after the death of Godfrey, endeavored to effect the election of Bohemond as king of Jerusalem; but the unworthy Baldwin obtained the throne, and Tancred, while engaged in the field against the emir of Damascus, was summoned to appear before the new king, on a charge of rebellion. But, secure in the attachment of his vassals, Tancred, now prince of Galilee, despised the base arts of Baldwin, and hastened to Antioch, whose prince, Bohemond, had been captured by the Turks. The city was equally threatened by the Turks and the false Greeks; but Tancred alternately made head against both, restored his friend to liberty, and, with the utmost disinterestedness, gave him back his territories. When Bohemond returned to Europe to obtain recruits, Tancred was

left to protect Antioch, which was menaced at once from Aleppo and by the Greek armies. He was even obliged to encounter the attacks of Baldwin, count of Edessa, and Josselin de Courtenay. Bohemond died at Salerno, and his soldiers either dispersed or entered the service of the Greek emperor: still Tancred succeeded in forcing the Turkish sultan to retreat over the Euphrates. This was his last exploit. He died soon after, in 1112, in his thirty-fifth year. Tancred was the flower and pattern of chivalry. Tasso has immortalized him.-An account of his life may be found in Raoul de Caen's Gestes de Tancrède, and in Delabarre's Histoire de Tancrède (Paris, 1822). TANGENT, in general; every straight line which has one single point in common with, and lies entirely outside of, a curve (at least of every such curve as can be cut by a straight line in two points only). This is the geometrical tangent. In trigonometry, the name is applied particularly to that part of the tangent to the circle which stands perpendicular at the end of one of the radii, including a particular arc, and is cut by the prolonged radius passing through the other end of the arc (the secant). Trigonometrical tangents, used with the sine and cosine, &c., for the solution of triangles (see Trigonometry), have been calculated according to their relative value (i. e. with reference to a radius of a certain magnitude) for every arc; and these relative values, or their logarithms, are generally to be found in the trigonometrical tables, with the sines and cosines of the same arcs. How this calculation of trigonometrical tangents, in reference to sines, cosines and radii, is performed, may be easily understood by a mere comparison of the two similar triangles which originate when we draw these lines and the corresponding arc. The differential calculus gives a very simple method for calculating the tangents by means of the subtangents, under the name of the direct method of the tangents. To this direct method the higher analysis adds an inverted method, called the inverse method of tangents.

Tangential Force. In order to have a clear idea how the planets are made to revolve in consequence of the attraction which the sun, situated in one focus of their elliptical orbits, exercises upon them, we may imagine that they originally received an impulse urging trem forward in a straight line. With this impulse the attraction of the centripetal torce;

see Central Forces) being united, the plan. et was thus made to describe the diagonal of a parallelogram, whose sides represent the directions of these forces. As there is nothing to diminish the impulse which we have supposed originally given to the planet, it would continue its path in the direction of the diagonal; but the centripetal force, operating continually upon the direction which the planet has obtained, makes it change its direction incessantly. In this way originates (as a diagram, drawn according to what we have said, clearly shows) a motion around the centre of forces. (See Circular Mo tion, and Central Forces.) The planet has at each point of its path a certain tendency (the consequence of its previous motion; hence, properly speaking, the effect of its inertness) to continue its last received diagonal direction, and thus to recede from the centre of forces. To this tendency, the centripetal force, directed towards this point, is opposed. The centripetal force may again be divided into two forces, the first of which (the normal force) operates perpendicularly to the orbit, and only contributes to retain the planet in the same, in order to prevent the curved motion from degenerating into a straight one: the latter, however, coincides with the direction of the orbit itself, and, therefore, only affects the velocity. This latter force is the tangential force, so called because the element of the curve coincides with the tangent. The doctrine of central forces is so important, because our imagination, unaided by theory, is almost incapable of conceiving a body which turns around another, exercising an attraction upon it, yet without ever coming in contact with the attracting body. But what has been said shows that a correct proportion of the centripetal force to the original impulse renders the contact of the body with the sun impossible. Generally, the endeavor of the planet to recede from the centre of forces, is called the centrifugal force; but can we, properly, call that a force which is evidently the effect of inertness? The criginal impulse may be compared to the first impulse which sets the pendulum in motion; after which, if we omit other influences, it would continue its oscillations for eternity, from the mere influence of gravity.

TANGIER, OF TANJAH (anciently Tingis); a town of Morocco, situated at the west entrance of the straits of Gibraltar, thirty-eight miles south-west of Gibraltar; lon. 5° 50′ W.; lat. 35° 48′ N. The

population is about 7000. Tangier was possessed by the English from 1662 to 1784. It afterwards became a distinguished station for piracy; but the disuse of this practice in Morocco has diminished the importance of the town. It now subsists chiefly by supplying the British garrison of Gibraltar with cattle and vegetables. The bay of Tangier is not safe when the wind is in the west, having been encumbered by the ruins of the mole and fortification; the cables are liable to be torn, and the ships to be driven on shore. Tangier, viewed from the sea, presents a pretty regular aspect; but within it exhibits the most disgusting wretchedness. It is the residence of the European and American consuls.

er.

TANNIN; a peculiar vegetable principle, so named because it is the effective agent in the conversion of skin into leathThe oak and its products-gall-nuts, &c.—contain two kindred matters, tannin and gallic acid, which seem, by the powers of vegetation, mutually convertible. The former is supposed to be characterized by its forming, with gelatine, a flexible and unputrefiable compound; and by forming with oxide of iron a black combination, which, having a strong affinity for cotton, linen, silk and wool, is much used by the dyer. Hitherto, tannin has been found only in perennial plants, and chiefly in the more durable parts of these. The barks of almost all trees and shrubs contain it, principally in the parts nearest the wood, because in the outer coats it is changed by the air. It has never been met with in the poisonous plants, nor in such as contain elastic, resinous and milky juices. Decoction of nutgalls contains tannin with a little gallic acid, some tannates and gallates of potash and lime, tannin altered into the matter commonly called extractive, and lastly a compound (insoluble in cold water) of tannin with perhaps some pectic acid, which is found especially in the extract of oak bark. The purification of tannin, or its separation from the principles with which it occurs,

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may be effected as follows:-Mix a filtered infusion of nutgalls with a concentrated solution of carbonate of potash, as long as a white precipitate falls, but no longer, because the precipitate is redissolved by an excess of alkali. The precipitate must be washed on a filter with ice-cold water, and afterwards be dissolved in dilute acetic acid, which removes a brown matter from it. This matter is extractive, formed, during the washings, by the action of the air. After filtering the solution, the tannin is to be precipitated by acetate of lead; and the precipitate is to be well washed, although in this operation its color passes from white to yellow, and it is to be then decomposed by sulphureted hydrogen. The filtered liquor is colorless, and leaves, by evaporation in vacuo over potash, tannin` in hard, light-yellowish, and transparent scales, which, when exposed to the air, and particularly to the sunbeam, assume a deeper yellow color. It is not deliquescent; dissolves in water with the greatest facility, and may be readily reduced to powder. Exactly saturated compounds of tannin with acids have no sour taste, but a purely astringent one. In the pure state, they are usually very soluble in water, and cannot be precipitated from it except by a great excess of acid. Tannin forms, with the salifiable bases, very remarkable compounds: that with potash or ammonia in the neutral state is but slightly soluble in cold water, and may be precipitated in the form of a white earth: it dissolves in boiling water, and separates from it. on cooling, in the shape of a powder, whicn, when drained on a filter, pressed and dried, has quite the aspect of an inorganic earthy salt, and is permanent in the air. The compound with soda has the same appearance; but it is much more soluble. It is known that tannin precipitates solution of tartar emetic. This precipitate is remarkable from a portion of the tannin taking, in the salt, the place of the oxide of antimony.

and laborious.

tannin contained in the bark of the oak, hemlock, and some other kinds of forest trees. It is a simple process to make leather of hides and bark, but probably one of the most critical of manufacturing operations to make the most and the best leather that can be made from a given quantity of hide. The process is long Time and labor are both materially reduced, and the quantity and weight of the leather increased, by various improvements, which commenced in the year 1803, in Hampshire county, in Massachusetts. The improvements above alluded to are the substitution of water power for manual labor, in many of the most laborious parts of the process; viz. to soften and cleanse the hide preparatory to the bark being applied to it; to grind the bark; to move pumps for transferring the decoction of the bark from one vat to another (much of which is necessary to be done daily in an extensive tannery), and to roll the leather preparatory to its being sent to market; also the least possible quantity of lime is now used to facilitate getting off the hair: this has been found greatly to add to the weight and quality of the leather. The application of heat to bark in leaches is found to be very important, and more particularly the application of the decoction (usually termed liquor) to the hide, rather than the bark, which had been commonly employed. In 1829, 36,360 sides of sole leather were tanned in one establishment in the town of Hunter, Greene county, New York. They weighed 637,413 pounds, and were manufactured with the labor of forty-nine hands, and with 3200 cords of bark. The tannery has seven powerful water-wheels adapted to its various machinery. Slaughter hides averaged fifty-six and a half pounds of sole leather from one hundred of hide best South American dry hides gained sixty-one per cent. in weight, and ordinary ones in proportion.Tanning is a chemical process; and undoubtedly the art will go on improving with the progress of chemical science and the diffusion of chemical knowledge.

TANSY (tanacetum vulgare). This plant is now naturalized, and pretty common in many parts of the U. States. It grows in beds by road sides, and in waste places. The stems are upright, branching, and about two feet high; the leaves doubly pinnate, and incisely serrate, and of an agreeable aspect. It belongs to the composita. The flowers are yellow buttons, lisposed in a large, upright corymb. The

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whole plant has a strong and penetrating odor, agreeable to some persons, and an extremely bitter taste. It contains an acrid volatile oil, is stimulant and carminative, and the decoction and seeds are recommended as anthelmintic and sudorific. The young leaves are shredded down, and employed to give color and flavor to puddings; they are also used in omelets and cakes, and those of the curled variety for garnishing.

TANTALITE. (See Columbite.)
TANTALUM. (See Columbium.)

TANTALUS, son of Jupiter, and king of Sipylus, in Phrygia, was a favorite of the gods, who often visited him, until he forfeited their favor by his arrogance. Tradition does not agree as to his crime. According to one account, he offended Jupiter by his perfidy; according to another, he stole away the nectar and ambrosia from heaven; and a third story is, that he murdered his own son Pelops, and served him up for some of the gods. The same diversity prevails in regard to his punishment. He is sometimes described as having a large stone suspended over his head, which constantly threatens to fall and crush him, and from which he cannot flee. But the more common account represents him as standing up to his throat in water, with the most delicious fruits hanging over his head, which, when he attempts to quench his burning thirst or to appease his raging hunger, elude his grasp. From this fable comes the English expression to tantalize.

TAPESTRY; a kind of woven hangings of wool and silk, frequently raised and enriched with gold and silver, representing figures of men, animals, landscapes, historical subjects, &c. This species of curtain-covering for walls was known among the inhabitants of Eastern countries at an extremely remote era. The most grotesque compositions and fantastic combinations were commonly selected for the display of the talents of workmen in this department of Oriental art, which was afterwards imported into Greece. From these compositions the elegant Greeks are supposed, by Bőttiger, to have taken their ideas of griffins, centaurs, &c. At length the refined taste of Athens became visible in the structure of tapestries. The old grotesque combinations no longer, as formerly, covered their surfaces, but were confined to the borders only; and the centre received more regular and systematic representations. In modern times, this description of embroidery has been executed with very great success,