and 50 in breadth, enclosed by 20 columns, each 20 cubits high and 10 in breadth, covered with silver, and standing on copper bases, five cubits distant from one another; between which there were curtains drawn, and fastened with hooks. At the east end was an entrance, 20 cubits wide, covered with a curtain hanging Joose.

TABERNACLES (Feast of), a soleum festival of the Hebrews, observed after harvest, on the 15th day of the month Tisri, instituted to commemorate the goodness of God, who protected the Israelites in the wilderness, and made them dwell in booths, when they came out of Egypt. On the first day of the feast, they began to erect booths of the boughs of trees, and in these they were obliged to continue seven days. The booths were placed in the open air, and were not to be covered with cloths, nor made too close by the thickness of the boughs; but 90 loose that the sun and the stars might be seeu, and the rain descend through them. For further particulars of the celebration of this festival, see Levit. ch. xxiii.

To TABERNACLE. v. n. (from the noun.) To enshrine; to house (John).

TABERNÆMONTANA, in botany, a genus of the class pentandria, order monogynia. Corol twisted; follicles two, horizontal; seeds immersed in pulp. Twelve species, natives of the East or West Indies, or of America. The following are cultivated :

1. T. citrifolia. Citron-leaved tabernæmon

tana.

2. T. laurifolia. Bay-leaved tabernæmon

tana.

3. T. Amsonia. Virginian tabernaemontana. 4. T. angustifolia. Narrow-leaved taberna

montana.

The first and second are suffruticose; the third herbaceous, the fourth perennial in its root. They may be all increased by seeds; and the last two will bear the open air.

TABES. (from tabeo, to grow thin.) A wasting of the body. A genus of disease in the class cachexia, and order marceres of Cullen; characterised by emaciation and weakness, attended with hectic fever. It has three species: 1. Tabes purulenta, from an ulcerous discharge: 2. Tabes scrofulosa, from a scrofulous habit: 3. Tabes venenata, from poison. TA'BID. a. (tabidus, Latin.) Wasted by disease; consumptive (Arbuthnot).

TA'BIDNESS. s. (from tabid.) Consumptiveness; state of being wasted by disease. TA'BLATURE. s. (from table.) Painting on walls or cielings.

TABLE. s. (table, French; tabula, Latin.) 1. Any flat or level surface (Sandys). 2. A horizontal surface, raised above the ground, used for meals and other purposes (Locke). 3. The persons sitting at table, or partaking of entertainment (Shakspeare). 4. The fare or entertainment itself: as, he keeps a good table. 5. A tablet; a surface on which any thing is written or engraved (Bentley). 6. (tableau, French.) A picture, or any thing that exhibits a view of any thing on a flat surface (Addison).

7. An index; a collection of heads; a catalogue; a syllabus (Evelyn). 8. A synopsis; many particulars brought into one view (Ben Jonson). 9. The palm of the hand (Ben Jonson). 10. Draughts; small pieces of wood shifted on squares (Taylor). 11. To turn the TABLES. To change the condition or fortune of two contending parties (Dryden).

To TABLE. v. n. (from the noun.) To board; to live at the table of another (Felton). To TABLE. v. a. To make into a catalogue; to set down (Shakspeare).

TABLE, a moveable piece of furniture, usually made of wood or stone, and supported on pillars or the like, for the commodious re ception of things placed thereon. This term is also used for the fare or entertainment served up.

TABLE, in mathematics, systems of numbers calculated to be ready at hand for the expediting astronomical, geometrical, and other operations, as logarithmic tables, tables of sines, tangents, secants, &c. tables of the planet's places, the right ascensions and decli uations of the fixed stars, tables of powers and products, roots, reciprocals, &c. most of which are well known to mathematicians, and are but of little interest to other persons.

TABLE ISLAND, one of the New Hebrides, in the Pacific Ocean. Lon. 16. 77 E. Lat. 15. 38 S.

TABLE MOUNTAIN, a promontory of Africa, near the Cape of Good Hope. The bay at the foot of it is called Table Bay.

TABLES (Laws of the twelve), were the first set of laws of the Romans; thus called either because the Romans then wrote with a style, on thin wooden tablets covered with wax; or rather, because they were engraved on tables or plates of copper, to be exposed in the most noted part of the public forum. After the expulsion of the kings, as the Romans were then without any fixed or certain system of law, at least had none ample enough to take in the various cases that might fall between particular persons, it was resolved to adopt the best and wisest laws of the Greeks. One Hermodorus was first appointed to translate them, and the decemviri afterwards compiled and reduced them into ten tables. After a world of care and application, they were at length enacted and confirmed by the senate and an assembly of the people, in the year of Rome 303. The following year they found something wanting therein, which they supplied from the laws of the former kings of Rome, and from certain customs which long use had authorised; all these being engraven on two other tables, made the law of the twelve tables, so famous in the Roman jurisprudence, the source and foundation of the civil or Roman law.

TABLES OF THE LAW, in Jewish antiquity, two tables on which were written the decalogue, or ten commandments, given by God to Moses on mount Sinai.

TA'BLEBEER. s. (table and beer.) Beer used at victuals; small beer.

TA'BLEBOOK. s. (table and book.) A

book on which any thing is graved or written without ink (Shakspeare).

TABLECLOTH. s. (table and cloth.) Linen spread on a table (Camden). TA'BLEMAN. s. A man at draughts. TABLER. s. (from table.) One who boards. TABLETALK. s. (table and talk.) Conversation at meals or entertainments (Atter.). TABLET. s. (from table.) 1. A small level surface. 2. A medicine in a square form Bacon). 3. A surface written on or painted (Dryden).

TABOO, a word used by the South Sea islanders, nearly of the same import as prohibited or interdicted. It applies equally to persons and things, and is also expressive of any thing sacred, devoted, or eminent.

TABOR, a mountain of Palestine, mentioned in Scripture. This mountain is of the figure of a broken cone, eight hundred or a thousand yards in height. The summit is two-thirds of a league in circumference. Formerly it had a citadel, of which now only a few stones remain. From hence we discover to the south a series of valleys and mountains, which extend as far as Jerusalem; while, to the east, the valley of Jordan, and lake Tabaria, appear as if under our feet; the lake seems as if enclosed in the crater of a volcano.

TABOR, a town of Bohemia, in the circle of Bechin, on a mountain, which the Hussites, under their celebrated general Zisca, fortified and made their principal retreat. It is 25 miles N. by E. of Budweis, and 45 S. by E. of Prague. Lon. 14. 56 E. Lat. 49. 23 N.

TABOR, OF TABOUR. A small drum, usu ally forming an accompaniment to the pipe. They are both played by the same performer: while the tones of the pipe are regulated by the fingers of the left hand, which stop the holes, the tabor is beat by the right. The tabor and pipe have long been favourite instruments with the common people of most of the countries of Europe, and are particularly calculated for dancing parties.

To TA'BOUR. v. a. (taborer, old French.) To strike lightly or frequently (Nahum). TABOURER. s. (from tabour.) One who beats the tabour (Shakspeare).

TAʼBOURET. s. (from tabour.) A small tabour (Spectator).

TA'BOURINE. s. (French.) A tabour; a small drum (Shakspeare).

TABRET. See TABOR.

TABULAR. a. (tabularis, Latin.) 1. Set down in the form of tables or synopses. 2. Formed in laminæ (Woodward). 3. Set in squares.

To TABULATE. ». a. (tabula, Latin.) 1. To reduce to tables or synopses. 2. To shape with a flat surface.

TABULATED. a. (tabula, Latin.) Hav. ing a flat surface (Grew).

TACAMAHACCA (Indian). The name of a resinous substance which exudes both spontaneously and when incisions are made into the stem of the calophyllum irophyllum VOL. XI.

of Linnéns, and not, as was formerly supposed, from the populus balsamifera, or the fagaria octandria of Linnéus. Two kinds of tacamahacca are met with in the shops. The best, called, from its being collected in a kind of gourd shell, tacamahacca in shells, is somewhat unctuous and soft, of a pale yellowish or greenish colour, a bitterish aromatic taste, and a fragrant delightful smell, approaching to that of lavender and ambergris. The more common sort is in semi-transparent grains, of a whitish, yellowish, brownish, or greenish colour, and of a less grateful smell than the former. Tacamahacca was formerly in high estimation as an ingredient in warm stimulating plasters; and although seldom used internally, it may be given with advantage as a corroborant and adstringent balsamic.

TACET. (Latin.) A word by which the musical performer is to understand that the instrument with the name of which it is conjoined is to be silent: as violino tacet; the violin is not to play: oba tacet; the oboe is silent.

TACFARINAS, a Numidian who commanded an ariny against the Romans in the reign of Tiberius. He had formerly served in the Roman legions. After he had severally defeated the officers of Tiberius, he was at last routed and killed in the field of battle, fighting with uncommon fury, by Dolabella.

TACHAU, or TACHOW, a town of Bohemia, in the circle of Pilsen, 28 miles W. of Pilsen. Lon. 13. 27 E. Lat. 49. 46 N.

TACHE. s. (from tack.) Any thing taken hold of; a catch: a loop; a button (Exodus). TACHOMETER, an instrument to ascertain the velocities of machinery.

In the employment of machinery it is evidently of great importance to be provided with an easy and ready method for discovering at all times, whether the motion of the machine is quicker or slower than what is known to be best adapted for the object in view. This advantage, it is thought, may be derived from Mr. Donkin's tachometer; for it is an instrument which requires only to be adjusted once for all to any particular machine, and then it will always be ready without the help of calculation or of a time-piece, to indicate instantly upon inspection the slightest excess or defect in the actual velocity.

A front view of the tachometer is represented in fig. 1, and a side view in fig. 2, of pl. 107. X Y Z, fig. 1, is the vertical section of a wooden cup, made of box, which is drawn in elevation at X, fig. 2. The whiter parts of the section, in fig. 1, represent what is solid, and the dark parts what is hollow. This cup is filled with mercury up to the level LL, fig. 1. Into the mercury is immersed the lower part of the upright glass tube A B, which is filled with coloured spirits of wine, and open at both ends, so that some of the mercury in the cup enters at the lower orifice, and when every thing is at rest, supports a long column of spirits, as represented in the figure. The bot

Y

tom of the cup is fastened by a screw to a short vertical spindle D, so that when the spindle is whirled round, the cup (the figure of which is a solid of revolution) revolves at the same time round its axis, which coincides with that of the spindle.

In consequence of this rotation the mercury in the cup acquires a centrifugal force, by which its particles are thrown outwards, and that with the greater intensity, according as they are more distant from the axis, and according as the angular velocity is greater. Hence, on account of its fluidity, the mercury rises higher and higher as it recedes from the axis, and consequently sinks in the middle of the cup; this elevation at the sides, and consequent depression in the middle, increasing always with the velocity of rotation. Now the mercury in the tube, though it does not revolve with the cup, cannot continue higher than the mercury immediately surrounding it, nor indeed so high, on account of the superincumbent column of spirits. Thus the mercury in the tube will sink, and consequently the spirits also; but as that part of the tube which is within the cup is much wider than the part above it, the depression of the spirits will be much greater than that of the mercury, being in the same proportion in which the square of the large diameter exceeds the square of the smaller.

Let us now suppose, that, by means of a cord passing round a small pulley F, and the wheel G, or H, or in any other convenient way, the spindle D is connected with the machine, the velocity of which is to be ascertain ed. In forming this connection, we must be careful to arrange matters so, that when the machine is moving at its quickest rate, the angular velocity of the cup shall not be so great as to depress the spirits below C into the wider part of the tube. We are also, as in the figure, to have a scale of inches and tenths applied to A C, the upper and narrower part of the tube, the numeration being carried down ward from zero, which is to be placed at the point to which the column of spirits rises when the cup is at rest.

Then the instrument will be adjusted, if we mark on the scale the point to which the column of spirits is depressed, when the machine is moving with the velocity required. But, as in many cases, and particularly in steam-engines, there is a continued oscillation of velocity, in these cases we have to note the two points between which the column oscillates during the most advantageous movement of the machine.

Here it is proper to observe, that the height of the column of spirits will vary with the temperature, when other circumstances are the same. On this account the scale ought to be moveable; so that, by slipping it upwards or downwards, the zero may be placed at the point to which the column reaches when the cup is at rest; and thus the instrument may be adjusted to the particular temperature with

the utmost facility, and with sufficient precision. The essential parts of the tachometer have now been mentioned, as well as the method of adjustment; but certain circumstances remain to be stated.

The form of the cup is adapted to render a smaller quantity of mercury sufficient than what must have been employed either with a cylindrical or hemispherical vessel. In every case two precautions are necessary to be observed: First, that when the cup is revolving with its greatest velocity, the mercury in the middle shali not sink so low as to allow any of the spirits in the tube to escape from the lower orifice; and that the mercury, when most distant from the axis, shall not be thrown out of the cup. Secondly, that when the cop is at rest, the mercury shall rise so high above the lower end of the tube, that it may support a column of spirits of the proper length.

Now in order that the quantity of mercury, consistent with these conditions, may be reduced to its minimum, it is necessary, first, that if M M, fig. 1, is the level of the mercury at the axis when the cup is revolving with the greatest velocity, the upper part, MM X Y, of the cup should be of such a form, as to have the sides covered only with a thin film of the fluid; and secondly, that for the purpose of raising the small quantity of mercury to the level LL, which may support a proper height of spirits when the cup is at rest, the cavity of the cup should be in a great measure occupied by the block KK, having a cylindrical perforation in the middle of it for the immersion of the tube, and leaving sufficient room within and around it for the mercury to move freely both along the sides of the tube and of the vessel.

The block K K is preserved in its proper position in the cup or vessel X Y Z, by means of three narrow projecting slips or ribs placed at equal distances round it, and is kept from rising or floating upon the mercury by two or three small iron or steel pins inserted into the underside of the cover, near the aperture through which the tube passes.

It would be extremely difficult, however, nor is it by any means important, to give to the cup the exact form which would reduce the quantity of mercury to its minimum; but we shall have a sufficient approximation, which may be executed with great precision, if the part of the cup above M M is made a parabolic conoid, the vertex of the generating parabola being at that point of the axis to which the mercury siuks at its lowest depres sion, and the dimensions of the parabola being determined in the following manner: Let VG, fig. 3, represent the axis of the cup, and V the point to which the mercury sinks at its lowest depression; at any point G above V, draw GH perpendicular to VG; let n be the number of revolutions which the cup is to perform in 1" at its quickest motion; let v be the number of inches which a body would describe uniformly in 1", with the velocity acquired in falling