Considerable quantities of this oxyd, are manufactured from the cobalt dug out of the mines in the Mendip-hills, and also in Cornwall; beside which, there are large supplies annually imported from Saxony:—such zaffre, however, is seldom pure; being mixed with a considerable proportion of pulverized flints.
The blue of zaffre is the most permanent of the different colours employed in glass-works; as it resists, unchanged, the most intense heat: hence, it is also advantageously used for giving various shades of blue to enamels, and to the crystal glasses that are made in imitation of lapis lazuli, turquoise, sapphire, and other precious stones.
ZANTHOXYLON, or, more correctly, Xanthoxylon, Prickly Yellow Wood, or Yellow Hercules, is a native of Jamaica, and other tropical countries, where it grows to the height of 16 feet, and is about 12 inches in diameter. This straight tree somewhat resembles the common ash: the bark of the trunk is covered with numerous prickles; and the wood is of a bright-yellow cast.
The wood of the Xanthoxylon is chiefly employed for the heading of hogsheads, for bedsteads, and numerous other purposes: it also possesses remarkable medicinal virtues, which render it peculiarly serviceable to the inhabitants of the West Indies.
The pulverized bark of the roots, when sprinkled on ulcers, speedily and effectually removes these disgusting sores. The fresh juice, expressed from the roots, affords certain relief in the painful disease, termed dry belly-ache. This important fact was discovered in the West Indies, by watching a female slave, who collected the root in the woods, and gave two spoonfuls of its juice to a negro, suffering under that colic, at an interval of two hours. Such medicine occasioned a profound, but composed, sleep of 12 hours; when all sense of pain, and other distressing symptoms, had vanished: the cure was completed, by giving an infusion of such expressed roots in water, by way of diet-drink.
Farther, the juice of the Prickly Yellow Wood, when preserved in rum, and administered in doses not exceeding a wine-glassful, has effectually removed the most obstinate epileptic fits; but Dr. Heney has not mentioned the manner in which this preparation ought to be managed.
ZEDOARY, or Kæmpferia, L. a genus of exotic plants, consisting of two species; namely: 1. The galanga, Common Galangal, or Long Zedoary; which has long, thick, tuberous roots, and produces single white flowers, with purple bases; and, 2. The rotunda, or Round Zedoary, has thick, round roots, presenting whitish flowers, that are frequently tinged with green, yellow, red, and purple. Both species are natives of Siam: they may be raised in hot-houses, by dividing the roots in the spring, and planting them in pots of rich, light mould, where they should be copiously watered during the summer, but less frequently in the winter.
The roots of the Zedoary are imported in oblong pieces, about the thickness of a finger; or in round masses, generally one inch in diameter; paying a duty of 612d. per lb. They possess an agreeable
