Flame-colour is w Fulous.

Iron, or rust-colour.

RED. ip

Flesh-colour.

Scarlet. 1.

PURPLE.

Violet-colour.

BLUE.

GREEN.

Gilous.

1

→→ Az Incarnatus.
Coccineus.

Caruleo-purpureus.

CŒRULEUS.

Linnæus has laid down the following general positions on the indications of colour with respect to the virtues of vegetables. A yellow-colour commonly indicates a bitter taste; as in gentian, aloe, celandine, and turmeric. Red, an acid or sour taste; as in cranberries, barberries, currants, raspberries, mulberries, cherries, the fruit of the rose, sea-buckthorn, and service-tree. Herbs that turn red toward autumn, have likewise a sour taste; as sorrel, wood-sorrel, and bloody-dock. Green indicates a crude alkaline taste, as in leaves and unripe fruits. A pale colour denotes an insipid taste, as in endive, asparagus, and lettuce. White promises a sweet and luscious taste; as in white currants and plums, sweet apples, &c. Lastly, black indicates a harsh, nauseous, disagreeable taste; as in the berries of deadly-night-shade, myrtle-leaved. sumach, herb-christopher, and others; many of which are not only unpleasant to the taste, but pernicious and deadly in their effects.

COLOURS, in heraldry, are red, blue, black, green, and purple; which the heralds call GULES, AZURE,

sable, vert, and PURPURE. Tenue or tawny, and sanguine, are not so common. The yellow and white, called or and argent, are metals, not colours. The metals and colours are sometimes expressed in blazon by the names of precious stones, and sometimes by those of planets or stars.

COLOURS, in military affairs, include the banners, flags, ensigns, &c. of all kinds, borne in the army or fleet.

COLOURS in the Latin and Greek churches. There are five admitted into the Latin church, viz. the white for the mysteries of Christ, the feasts of the virgin, angels, saints, and confessors: the red for the solemnity of the holy sacraments, the feasts of the apostles, &c.; the green for the time between Pentecost and Advent; the violet in Advent and Christmas, and in votive masses in time of war, and the black for the dead and the ceremonies belonging thereto. In the Greek church, the use of colours is nearly abolished; the red was the colour for Christmas and the dead, as black is among us.

COLUBER, the viper, in natural history. Of this genus, there are 175 species. The coluber ferus is found in most parts of Europe; it lives in woods and thickets, and, in breeding time, in the open fields it is poisonous, but not deadly; it grows to a foot and an half long. The flesh was formerly used in medicine as a restorative. The poisonous matter discharged is a real gum, and perhaps the only gum actually produced and secreted by animals of any kind. Olive oil is the most successful application to the bite of a viper. Sucking the wound and throwing out the saliva, is said to be a means of withdrawing part of the venom, and it is

doubtful whether the poison be capable of producing any injury to the system when received into the mouth and stomach, unless the mouth, &c. be sore or ulcerated at the time. The viper is vivaparous, that is, produces her young alive; and, it is asserted, that the female in case of sudden surprize or danger, opens her mouth and admits her young down her throat, till the danger is passed by. The coluber cerastes is found in Arabia and Africa, and is probably the asp employed by Cleopatra. This animal springs suddenly to a considerable distance, and bites, without the least provocation, those who approach it. The inhabitants are said to have a preparation of herbs with which they arm themselves against the bite. The coluber naja, or hooded snake, is every where exhibited publicly as a show; it is taught to dance to the sound of musical instruments. The Indian jugglers, who thus exhibit the animal, first deprive it of its fangs, to secure themselves and the spectators from injury. See Plate Nat. Hist. Figs. 7 and 8.

COLUMN. See ARCHITECTURE.

COLURES, in astronomy, two great circles supposed to intersect each other at right angles in the poles of the world, and to pass through the solstitial and equinoctial points of the ecliptic. They are hence called the solstitial and equinoctial colures.

COMBINATION, in chemistry, denotes the intimate union of two or more bodies of different natures, from which a new compound results, differing in its nature from either of the constituents. Thus, an acid united with an alkali, gives a neutral salt, and furnishes a good instance of combination. Sulphur

and lime may, by heat, be made to combine and form a sulphuret of lime, which compound is very. different from its constituents.

COMBINATIONS, denotes the alternations or varia tions of any number of quantities, letters, &c. in all possible ways.

COMBUSTIBLES. See the next article.

COMBUSTION, in chemistry, a term which denotes the decomposition of certain substances, accompanied by light and heat. It is an important effect of CALORIC (which see), but only particular bodies are subject to combustion. These are called combustible bodies. Combustible bodies, when inflamed, are sources of light and heat: thus sulphur, coal, &c, are combustible bodies, and being raised to a certain degree of temperature, they give out light and heat. The capacity of producing light and heat gradually diminishes, and what remains after combustion appears to be a different substance, no longer combustible. All bodies that are not combustible are ready to receive caloric, and part with it again, giving out precisely the same quantity, neither more nor less. A stone or brick is incombustible; it will receive heat, but, left to itself, it soon cools again, that is, it gives out the heat which it received, and which is not lost but imparted to surrounding bodies; thus the heat pass ing from it combines with the atmosphere. Some chemists arrange all bodies u under three classes, viz. combustibles, supporters, and incombustibles. In this theory, the light is furnished by the combustible, and the heat by the oxygen of the supporters. Thus, in the combustion of sulphur, the sulphur affords the light, the oxygen of the air (the air being a sup

porter) gives out the heat, and the sulphuric acid which is the produce of the combustion, is incombustible. In the combustion of wood or coal; the wood and coal give the light, the oxygen of the air affords the heat, and the pure ashes, which are the result of combustion, are incombustible. These may still be heated to any temperature; but, like the brick or stone, just referred to, they undergo no more change.

COMET, an opaque, spherical, and solid body, like a planet, which appears and disappears abruptly. Comets describe elongated circles, called ellipses, and are visible to us only when they reach those extremities of their orbits that are nearest to us and to the sun. When they pass through the long lines that run from one centre of their ellipsis to another, they appear to describe circles of prodigious magnitude; and very small ones when they arrive at that part of their ellipsis of which the sun is the centre: hence the irregularity attributed to their course. When near the sun, they exhale a mass of vapours, called their beard, tail, or hair. These exhalations, which are not very dense, since the fixed stars may be seen through them, assume the different appearances that are distinguished as already related, according to the circumstances under which they are seen. Thus, when a comet is westward of the sun, and sets after it, it is said to be tailed, because the vapour seen is that which follows it; when the comet is eastward of the sun, and moves before it, it is said to be bearded, because, the vapour is seen in its van, in the manner of a beard; and when the sun and the comet are exactly opposite each other, the earth between them, the