smoke of the bamboo cane. Some few are left upon the tree, which in time falling off, produce new plants, but these do not bear until they are eight or nine years old. No verdure grows under these trees. They possess more oil than any other plant. In medicine this spice is frequently used, and by some it is considered an indispensable ingredient in almost every dish. The Dutch frequently practise a little deceit in the sale of Cloves, by suspending them in a bag for several hours over a vessel of water, which adds many pounds to the weight.

COBALT.

The ores of this semi-metal consist of several varieties, some are rich in colouring matter, others too poor to pay the expense of working. The ore is generally impregnated with a considerable portion of arsenic, and contains some copper and silver. Its colour is sometimes of a greyish hue, frequently of a peach-blossom, or dark and earthy, according to its mixture with other metals. It rather resembles steel. It is found in clay slate in Cornwall, and in the alluvial (27) soil in Cheshire, combined with copper, manganese, and lead. It is difficult to calcine, and the calx is of a deep blue, which melted with borax, or potash, and silicious (28) sand, affords the blue glass called Smalt, (29) and

gives the same colour to china and earthenware, and is also used in enamel painting. The ore of Cobalt may be easily distinguished from other arsenical ores by this last property, as also that of affording the Sympathetic (30) Ink. These ores are met with in many parts of Europe, but seldom or never in a native state. The Chinese and Japanese formerly excelled in the colour used for painting their porcelain, and it is supposed they had mines of Cobalt, from which they procured it, but those being now exhausted they use instead of it the Saxon Zaffre, which is the oxyde (31) of Cobalt.

CHARCOAL.

A kind of artificial coal, made from half-burnt wood; it is of great use for fuel to many manufacturers, where heat is required without flame or smoke. In general, the quantity of Charcoal afforded by different kinds of wood, offers a tolerably accurate criterion whereby to judge of their durability. Those most abundant in Charcoal and earthy matter are the most permanent, while those that contain the largest proportion of the gaseous elements are the most perishable. Among our own trees, the chestnut and the oak are the most permanent, and the chestnut affords rather

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more carbonaceous matter than the oak. It was much esteemed by the Romans, and the art of making it is very ancient. The vapour arising from Charcoal burning in a close room often proves fatal, or otherwise severely injures the constitution. It is used to polish brass and copper (which have been first thoroughly cleaned with pumice stone), by mathematical instrument makers, engravers, and frequently by artists to trace drawings, and in many chemical experiments.

COFFEA, OR COFFEE TREE.

An evergreen, which would grow to the height of 16 or 18 feet if permitted, but for convenience in procuring the berries is never suffered to reach more than 5 or 6; the leaves resemble those of a laurel, and the fruit a cherry. It is cultivated in Arabia, Turkey, Persia, and the Indies, also in America, but the production of the latter country is considered very inferior to that of the former. When red, the berries are gathered, and undergo a variety of preparations in a mill, before they appear in those beans, from which, when roasted and boiled in water, we have a most grateful beverage. The tree requires five years growth to arrive at a state of perfection. Sometimes it is propagated from the berry, but more frequently from saplings, and it is cultivated in hot

houses in Europe, where it has a very pretty appearance, the flowers being perfectly white and fragrant. It was first introduced in Europe in 1652.

COAL.

A black, inflammable, sulphurous matter, used for common fuel, and consequently of the utmost importance in every order of society. There are various kinds, of different qualities, which, as they mix under ground, form other varieties, a mine being rarely worked containing only one kind of coal. They are used in manufactories according to their quality, some burning without smoke, some emitting a greater heat, and others burning with a clearer flame. Pit, Culm, Slate, Kilkenny, Bovey, and Cannel Coal are among these varieties; this last, being very hard and easily turned and polished, is frequently used in imitation of Jet, to which it bears a strong resemblance; it was employed by the Romans for toys and ornaments, if it be their lapis ampelites, as is supposed, but they appear to have been ignorant of the use of Coal for fuel. It is found in almost every part of Europe, and in most counties of England, particularly the Northern. Although it appears to have been known to the primeval Britons (whose curiosity was excited to the discovery, by fragments constantly brought

down by the current, particularly round Manchester), a license for digging it was not granted until the reign of Henry the Third, when the inhabitants of Newcastle obtained one from that King. Coals were not generally used until the reign of Charles the First, at which period a chaldron was obtained for 17s. Pit Coal burnt under earth, and the cinders quenched, form coke, much used in smelting ores, and in other metallurgic processes.

COCOA, OR COCOS.

A tree, growing in the hot climates to the height of 60 feet and upwards, bearing very large nuts, which furnish both food and beverage of an agreeable flavour; the former from the kernel, and the latter from a milky liquor contained in them when ripe. It is of infinite use; for besides the pleasant shade it affords, its immense leaves are convertible into baskets, brooms, nets, mats, and a great variety of domestic articles. The shell of the nut forms drinking utensils, and is frequently employed as such, cut and ornamented with silver, in this country. From the bark very excellent cordage is made. This tree is supposed to be a native of the Maldives, and some of the East Indian Islands, thence to have been transported to America, where it now flourishes.