those of rich Mosaic work, made made of curious square marbles, bricks; or tiles, called tesserae, from their resembling dice.

**TESSIN,** a river of Italy, which, taking its rise in the Alps, runs through the country of the Grisons and the Lake Maggiore; and then, turning south-east through the Milanese, passes by Pavia, and falls into the Po, a little below that city.

**TEST,** a vessel of the nature of the coppel, used for large quantities of metals at once.

**TEST-LIQUOR,** a liquor used by dealers in brandies, to prove whether they be genuine, or mixed with home-spirits. This liquor is nothing but a green or white vitriol, dissolved in fair water; for a few drops of it being let fall into a glass of old French brandy, will turn the whole to a purple, or fine violet colour; and by the strength or paleness of this colour, the dealers judge the brandy to be genuine or mixed, in different proportions, with home-spirits.

**TEST-ACT,** a statute 25 Car. II. cap. 2. which requires all officers, both civil and military, to take the oaths and test, viz. the sacrament, according to the rites and ceremonies of the church of England; for the neglect whereof, a person executing any office mentioned in that statute, forfeits the sum of 500l. recoverable by action of debt.

**TESTACEOUS,** in natural history, an epithet given to animals covered with a shell, as tortoises, oysters, pearl-fish, &c.

**TESTAMENT.** See Law, Tit. xxviii. 2.

**TESTATOR,** the person who makes his will and testament.

**TESTES,** in anatomy. See Anatomy, p. 270.

**TESTIMONY.** See Evidence.

**TESTUDO,** in zoology, a genus belonging to the order of amphibia reptilia. It has four legs and a tail, and the body is covered with a strong shell. There are 15 species, principally distinguished by peculiarities in their feet. The midas, or common turtle, is found at the Ascension isle, and many other southern islands. The shell of this animal is so strong, that several men may stand upon it without injury. It lays membranaceous eggs in round holes which it digs in the sand. The turtle is said to continue several weeks in the act of copulation. It grows to a vast size, some having been found to weigh 480 pounds.

The Americans find so good account in catching turtle, that they have made themselves very expert at it: they watch them from their nests on shore, in moon-light nights; and, before they reach the sea, turn them on their backs, and leave them till morning; when they are sure to find them, since they are utterly unable to recover their former posture: at other times they hunt them in boats, with a peculiar kind of spear, striking them with it through the shell; and as there is a cord fastened to the spear, they are taken much in the same manner as the whales.

**TESTUDO,** in antiquity, was particularly used among the poets, &c. for the ancient lyre; by reason it was originally made by its inventor Mercury, of the black or hollow shell of the testudo aquatica, or sea-tortoise, which he accidentally found on the banks of the river Nile.

**TESTUDO,** in the military art of the ancients, was a kind of cover or screen which the soldiers, e.g. a whole company, made themselves of their bucklers, by holding them up over their heads, and standing close to each other. This expedient served to shelter them from darts, stones, &c. thrown upon them, especially those thrown from above, when they went to the assault.

**TESTUDO** was also a kind of large wooden tower, which moved on several wheels, and was covered with bullocks' hides flead, serving to shelter the soldiers when they approached the walls to mine them, or to batter them with rams.

It was called testudo, from the strength of its roof, which covered the workmen as the shell does the tortoise.

**TETANUS,** in medicine, a convulsive motion that makes any part rigid or inflexible.

**TETHYS,** a genus of insects belonging to the order of vermes mollusca. The body is oblong, fleshy, and without feet; the mouth consists of a cylindrical proboscis under the duplicature of a lip; and there are two foramina at the left side of the neck. The species are two, both inhabitants of the ocean.

**TETICACO,** a great lake of Peru, more than two hundred miles in circumference: the towns situated on this lake are esteemed the most delightful in all South America.

**TETRACERA,** in botany, a genus of the polyandria tetragyna clas. The calyx consists of six leaves; and there are four capsules. There is but one species, a native of America.

**TETRACHORD,** in the ancient music, a concord consisting of four degrees or intervals, and four terms or sounds; called also by the ancients diatessaron, and by us a fourth.

**TETRADECARHOMBIS,** in natural history, the name of a genus of fossils, of the clas of the selenite, expressing a rhomboidal body, consisting of fourteen planes.

The characters of this genus are, that the bodies of it are exactly of the same form with the common selenite; but that each of the end-planes is divided into two; and there are, by this means, eight of these planes, instead of four.

**TETRADIAPASON,** a musical chord, otherwise called a quadruple diapason, or eighth.

**TETRADYAMIA,** in botany. See Botany, p. 635.

**TETRAEDRON,** in geometry, one of the five regular or platonic bodies or solids, comprehended under four equilateral and equal triangles.

**TETRAGON,** in geometry, a general name for any four-sided figure, as a square, parallelogram, rhombus, or trapezium.

**TETRAGONIA,** in botany, a genus of the icosandra pentagyna clas. The calyx consists of four segments; it has no corolla; and the drupa has four sides, and four cells. There are two species, both natives of Ethiopia.

**TETRAGONOTHECA,** in botany, a genus of the syn-geneia polygamia superflua clas. The receptacle is paleaceous; it has no pappus; and the calyx consists of one leaf, divided into four plain segments. There is but one species, a native of Virginia.

**TETRAGRAMMATON,** a denomination given by the Greeks to the Hebrew name of God, Jehovah, because consisting of four letters.

**TETRANDRIA,** in botany. See Botany, p. 635.

**TETRAO,** in ornithology, a genus of birds, of the order of gallinæ, distinguished by having the part of the forehead near the eyes naked and papillose. There are 20 species, distinguished principally by their colour, their having rough or naked feet, &c.