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for medicinal purposes ; the impurities of the foreign kinds are extracted by melting in proper vessels, when the pure matter sinks, leaving the dross above. It is often found in long thin crystals, like needles, and is commonly of a dull grey colour. It is soft to the knife, very brittle, and melts instantly upon being applied to heat. The ore, when fresh broken, appears like a lump of pure steel. When analyzed, this mineral is found to consist of a metal united with common sulphur. It was for some time considered poisonous, and its use was consequently forbade in 1566, but, being allowed when in its crude state (11) to possess no noxious quality, this edict was in 1650 repealed. In diseases, and in fattening animals, its virtues are bigbly extolled ; and it is also much employed in purifying gold, casting cannon balls, and in melting metals ; it renders tin hard, white, and sounding. It is used in bell metal, to make the sound clear, and is mixed with lead, to render printers' types more smooth and firm. The ancients used it with the paint with hich they blackened round their eyes, and eyelids, then esteemed marks of beauty, and even to this day, in some foreigo parts, the custom is continued.

AMBERGRIS, OR GREY AMBER. A solid opaque substance, of a grey or ash colour, which melts like wax, principally used for perfumery, but sometimes medicinally. The Asiatics and Africans use it as a spice. The opinions concerning its original state are so various, that no decided account has ever been given. It is found floating on the sea, and is frequently taken from the inside of the Spermaceti Whale, contained in a bag about three feet in length, in round lumps, weighing from one to twenty pounds; and that it is generated in the bowels of that fish, appears the most probable account ever yet received, an opinion strengthened by the circumstance of beaks, or parts of beaks of the cuttle fish, wbich is the natural food of the Spermaceti Whale, being found in the Ambergris, and it also proves that it has been in a liquid state.

AMBER.

A yellow transparent gummy substance, the origin of which, like the preceding article, has never been ascertained, it being occasionally classed with the vegetable, mineral, and even animal, kingdom. It is found in the Baltic sea, but principally along the coasts, and in the inland parts of Prussia, from which circumstance that country bas been styled The Country of Amber. It is also found in almost every part of Europe, and in England, occasionally, by the shores of Yorkshire, Yarmouth, &c. and even in pits near the Metropolis. Pliny supposed it to be a resinous juice oozing from old pines and firs, and thence running into the sea ; which opinion has been strengthened by other writers. Insects, leaves, &c. bave frequently been found inclosed in it, which increases the probability of its having been in a liquid state. It still remains, as before Christ, in repute for medicinal purposes.

It possesses the property, when heated by friction, of attracting light substances, and when rubbed it yields considerable light in the dark.

“The spoils of Elephants, the roofs inlay,
And studded Amber darts a golden ray.”

POPE. . From its Greek name Haexipov the term electricity is derived. It forms the basis of the best varnishes. When once melted it never recovers its beauty or hardness. It yields by distillation a volatile acid salt, which is produced by no other bituminous substance, (12) and when dissolved bas a fragrant smell. It is principally yellow and white; the former, from its greater transpareney,

is better calculated for ornaments, the latter for medicine.

ALABASTER.

A kind of soft marble, of which there are three species, the first and most common is a pure snowy white, found in Taurus; the next is yellow, like honey, and is brought from Greece, this has likewise been found in France, Germany, and Derbyshire. The third kind is the Alabaster of the ancients, and is variegated, yellow and red. After being calcined (13) and mixed with water, it is used as plaster of Paris, and cast into moulds, when it quickly coagulates into a firm body. As it cuts smoothly and takes a very beautiful polish, it is employed by statuaries for columns, vases, statues, &c. Alabaster possesses vitriolic acid, and therefore differs from Marble. It has been sometimes used for windows, and there is still a church at Florence in which it is substituted for glass. (See Gypsum.)

ASBESTOS.

A fossil stone, of a greenish or silvery white appearance, capable of being divided into very fine, brittle, silky filaments, possessing the wonderful property of remaining unconsumed in fire, which only whitens it. This mineral is found in Egypt, France, Siberia, in some parts of Scotland and Wales, &c. generally in shapeless masses, varying both in weight and hardness. It was formerly manufactured into paper and cloth, but in the weaving, linen or woollen threads were added, which were afterwards burnt away. The method of preparing it is thus described:-" The stone is laid to soak in warm water; then opened and divided by the hands, that the earthy matter may be washed out. The ablution being several times repeated, the flaxy-like filaments are collected and dried ; and they are most conveniently spun with an addition of flax. Two or three filaments of the Asbestos are easily twisted with the flaxen thread, if the operator's fingers are kept oiled. The cloth, also, when woven, is best preserved by oil from breaking or wasting. On exposure to the fire the flax and the oil burn out, and the cloth remains pure and white."--The shorter filaments may be made into paper in a similar way.

In this cloth the ancients burnt the bodies of their dead, and were thereby enabled to preserve the ashes without mixture. There are several relics of this cloth remaining. In the Museum of the Vatican at Rome there is a winding sheet of Asbestos, coarsely spun, but as soft and pliant as silk. It was discovered in a funeral urn, containing burnt bones, in 1702. A handkerchief or pattern of it was presented to the Royal Society. In an experiment made upon it, although it resisted fire, it lost three drachms of weight, but this is supposed to have arisen from the dissipation of some extraneous matter. Some of the threads were used as lamp-wicks, and it is asserted that Kircher, a German philosopher, had one which burnt for two years, and was afterwards accidentally destroyed. Pliny informs us that the Romans used it woven into table cloths, towels, &c. and that they were thrown into the fire to be cleansed. The species of Asbestos, called Amianthus, was more generally used, and is often known by the name of Plumose Alum.

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