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of them are the circle, ellipsis, parallelograms of every spe-cies, &c.; and some solids of this nature are the sphere,spheroids, parallelopipeds, &c.

In a circle, the centre is everywhere at an eqhal distancefrom the circumference. In a sphere, the centre is everywhere at the same distance from the surface. In the ellipsis,any two straight lines passing through the centre, terminat-ing at each end on the circumference, and making equalangles with either axis, are equal; or the four lines drawnfrom the centre to the circumference, are equal. The sameproperty applies to the opposite hyperbolas.

Centres oe a Door , two pivots, round which the door ismade to revolve.

CENTROLINEAD, an instrument for drawing converginglines, when the point of intersection is inaccessible.

CENTRY-GARTII, an old English term for a burial-ground.

CEROFERARIUM, a candlestick used to hold thepaschal taper.

CEROMA, the anointing - room in ancient baths andgymnasia.

CESTOPHORI, sculptures of females bearing the cestus,or marriage-girdle.

CESSPOOL. See Sesspool.

CHAIN-TIMBER, in brick houses, a timber of largerdimensions than common bond, placed in the middle of theheight of the story, for strengthening the building; thescantling of chain-timber is 8 inches by 5 inches, or 8Jrinches by 5^ inches, viz., equal to the length and breadth ofa brick.

CHALCIDICiE, a large magnificent hall, belonging to atribunal, or court of justice. Vitruvius employs the term forthe auditory of a basilica; and other ancient writers use itfor an apartment in which the gods were supposed to sup.

CHALICE, the cup used to contain the wine at the cele-bration of the eucharist. In early ages, chalices were madeof glass, wood, or horn ; but in the council of Rheims ,A.d. 847, the materials for the chalice were restricted togold or silver. The rim of the chalice should never turnover.

CHALK, an opaque mineral, of a yellowish white, orrather of a snow colour, of a fine earthy fracture, withoutlustre, breaking into blunt-edged angular fragments ; whencontaminated with iron, it has more or less of an ochreytinge, and stains the fingers; but when pure, it is very softand almost friable, gives a white streak, has a meagre feel,and adheres to the tongue. It effervesces violently withacids; and when mixed with iron, becomes harder andheavier: its specific gravity varies from 2'4 to 2’6. Itoccurs generally in a mass, sometimes disseminated, or invest-ing other minerals.

In a state of purity, it appears to be composed only ofwater, lime, carbonic acid, and a small quantity of alumine.Mr. Kirwan obtained the following analysis :

3 water53 lime

42 carbonic acid2 alumine

100

Chalk occurs in thick beds, nearly horizontal, alternatingwith thin layers of flint nodules, which are also irregularlydispersed through its substance. It contains a vast quantityof the relics of disorganized marine bodies, and often thehard parts of amphibious and land animals, as the heads andvertebra: of crocodiles, elephants’ teeth, &c.

Chalk beds occur frequently in the east and south P artS j|ieEngland, in the north-east of France, in Poland , and in 80parts of the Danish islands. , . „

Its uses are numerous ; it is employed in 'walling or vail* 11 ?as building-stone; many of the groins or vaults of our Gochurches are constructed with it; it is also employed incomposition of mortar, in countries where limestone, isabundant; and when well burnt, is found not much im eto lime-stone. f i ie

CHAMBER, (from the Latin , camera, derived fromGreek, na/iapa, a vault, or curved) a vaulted apartment, a P‘of a lodging. This term was formerly applied to any r0 ^and sometimes even to a suite of apartments; but in motimes it is used to designate rooms ordinarily intended ^sleeping in. The proportion of its horizontal dimensionsbe varied, to accommodate different circumstances, w •may occur either in the form of a building, or in the disp ^tion of the apartments, from the square to the prop ort ' o .^ ]( j 0which the breadth is two-thirds of the length; its an' ^may be three-fourths of the breadth. The word orig inimplied a vaulted apartment. fl , e ll

In building bed-chambers, the situation of the bed, asas of the fire-place, ought to be attended to, as sh°«ldisposition of the windows, when they can be shifted wi jdestroying the symmetry of the exterior. If the bed ^fire-place be opposite to each other, the fire-place may D ^ gS .the middle of its own side; but if it should be found n esary to have the bed on the same side of the roomfire-place, on account of doors or windows, or both, thenchimney ought to be placed in the middle of the remadistance between the bed and the wall, the bed bemo ^posed to stand at one extremity. The situation ot ,.i

t stand at one extremity. The situation oi

may be the same as in other apartments; passage-doors 8be within about two feet of the angle of the room, ° never side they are made; and may either be on th eside with the fire-place, or on the opposite side to t0place, or in the return side, opposite to the window, ®the farther corner from the fire-side of the room.

The bed ought to be so placed as to be out of the ^of air, which usually rushes from the door to the fire-P.^ (jeThe most eligible figure of chambers, for furniture g 0 o,rectangle ; though sometimes the circle, ellipsis, or ® o‘may be allowed to some particular room, for the -variety. Besides passage-doors, it is convenient to ■bers to communicate with each other, or with aroom. . . s f ce

Chamber of a Lock, in inland navigation, 4 ‘ ^ 0 J> ebetween the gates, in which a boat rises and sinks 1level to another, in order to pass the lock. , t0

Chamber-Story, a story of a house appropriate ^ fe« 4rooms. In good houses it should never be less 4 pjujube 4 ,high; and in mansions 12, or even 15 feet high. ibe&’should not be too high, because it is difficult to wa*nor too low, as it is prejudicial to the health. rC Jiite c !.

CHAMBERS, SIR WILLIAM, a distinguished a jly oiis said to have derived his descent from the ancien jj e w 9Chalmers, in Scotland, barons of Tartas, in France ,born, however, at Stockholm, in Sweden , wherehad resided for many years, in order to prosecu -^yiiedclaims he had on the government of that country- ^ erd”,

very young man, he made a voyage to China , as pr

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in the service of the Swedish East India CompanD^ a]bably thus acquired his taste for the Asiatic styleAt the very early age of eighteen, we find him es capa^aLondon as an architect and draughtsman, 'l^d obtain ill Le (Jhe soon acquired considerable reputation, and appo 1 * 1introduction to Lord Bute , shortly afterwards wa