which, after burning, consists of calcareous earth, or stone, and others, which leave an aluminous slate; he advises the agriculturist to make use of the former kind for every species of clover and grasses, as well as for wheat, rye, barley, oats, or similar grain; and to avail himself of the latter in the culture of spelt, buck-wheat, as likewise of clover, and the different species of grain, but particularly of all the leguminous fruit, such as peas, beans, &c.
Coal-mine, a coal-work, or place from which coals are dug and raised. The maliciously setting coal-mines on fire, is felony without benefit of clergy, by stat. 10 Geo. II. c. 32, sect. 6.
Small-coal, is a kind of charcoal, prepared from the spray, and brushwood, stripped off the branches of coppice-wood, which are sometimes tied up in bundles for that purpose, and sometimes charred, without being tied; which operation is called coming it together.
COBALT, a semi-metal of a whitish-grey colour, and nearly resembling fine hardened steel: it is as difficult to be fused as copper, or even gold; and cannot be easily calcined. If the calx, resulting from that process, be melted with borax, pot-ash, or siliceous sand, it affords the blue glass, denominated by artists, smalt, which is principally employed in painting enamel, and in tinging other glass, being of all colours the most fixed in the fire. This semi-metal abounds in England, chiefly in the Mendip Hills in Somersetshire, and also in Cornwall, where it has lately been dug up in large quantities, and turned to considerable emolument.
COCCULUS Indicus, or Indian Berry, is the poisonous fruit of the Menispermum, L. or Moon-seed, an exotic genus of plants, growing in the southern parts of Europe, whence it is imported. It possesses an intoxicating property, and is on that account too frequently mixed with malt liquors, though such nefarious practice is expressly prohibited by act of parliament. The seeds of this plant are made into a paste in the Levant, where it is employed as a specific for cutaneous eruptions.
COCCUS, a genus of insects, comprising twenty-two species, which are principally denominated from the plants they frequent. The most remarkable of these are:
1. The Coccus hesperidum, or green-house bug, which chiefly infests orange, and other plants in green-houses. When young, it runs upon the trees, but afterwards settles on some leaf, where it deposits a great number of eggs, and dies.
2. The Coccus malorum, or apple-tree Coccus, which, as soon as it fixes on a tree, communicates a corrosive ichor, that affects the bark, even after the insect is removed, in a manner similar to a gangrene; so that it becomes blotched, and full of deep holes, in consequence of which, it decays and dies. This insect preferably attacks the tender buds of young trees, and may be easily removed by means of a hard painter's brush, without injury to the plant, if it has not had sufficient time to bury itself in the bark. It also settles in such cavities as are frequently produced in the stems of trees, by incautiously tearing off the branches, or by any other wound. Being thus protected from the rain, these ver-
