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water, and by exposure to fire it may be totally volatilized. Next to platina and gold it is the heaviest of all the other metals; and, with the exception of iron and antimony, it unites with others. Incorporated with gold, (53) it is used for gilding copper or silver, and in conjunction with tin, it is employed in silvering the backs of mirrors, &c. An artificial combination of Mercury, with sulphur, forms the beautiful pigment called vermilion. In medicine it is also used.

RUM.

A spiritous liquor distilled from sugar canes. It contains more of the essential oil of the cane, than simple sugar spirit does; and the oily favour of Rum is asserted to arise only from the native flavour of the cane, although by some considered to proceed from the fat used in boiling the sugar. This spirit is subject to great adulteration in Britain, sometimes even with malt spirit; but when with molasses spirit, from the similarity of taste, detection is almost impossible.

RICE, OR ORYZA.

of this plant there is only one species, called Sativa, or Common Rice, but various names are given to the plant in its different stages.

The plant is too tender to be raised in these northern countries without artificial heat. It grows upon very moist soils. The leaves of the plant are long, and the flowers blow on the top like barley; the seed wbich follows is disposed in clusters, each of which is inclosed in a yellow husk from which it is sepa. rated in the following manner:It is pounded by hollow iron pestles of a cylindrical form, lifted up by a wheel worked by oxen.

A person seated between the two pestles, pushes forward the Rice when the pestles are rising ; another sifts, windows, and lays it under the pestles. In this manner it is worked until freed from the chaff and husks. When clean a thirtieth part of salt is added, and pounded together, by which the Rice, formerly grey, becomes wbite. After this purification it is passed through a fine sieve to separate the salt from the Rice, and it is then ready for sale. It is principally brought from Carolina; it is also cultivated in most of the eastern countries, and the chief riches of Damieta consist in this commodity. It constitutes the principal support of the inhabitants of those countries. Great quantities are imported to England and other European countries, where it is much esteemed for puddings. It is considered to be a nutritious, wholesome food, if not used too after gathering

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heat produced in large piles of Rice is too great to allow insects to live inside them, but it does not prevent their carrying on their destructive powers on the surface. Keeping Rice for any length of time in quantities is therefore generally attended with waste.

RESIN.

The juice of various kinds of trees or plants oozing spontaneously or by incision, differing from gums in being more sulphurous. All the various species of fir yield Resin. It has obtained different names from the trees which produce it. All the juices known under the name of Turpentine are composed of two ingredients, viz. Oil of Turpentine and Resin. In distilling the turpentine the oil comes over, and the Rosin or Resin remains behind. The distillation continued to dryness is known by the name of Common Rosin or Colophonium ; but when water is mixed with it wbile yet fuid, and incorporated by violent agitation, the mass is called Yellow Rosin. Large quantities of Common Rosin are consumed by salt boilers, united with wheaten flour, to render the grain of salt smaller ; also by musicians for effecting greater vibrations. Gas is obtained from this article nearly equal to that from coal. Sandarach, Copal, Mastich, &c. are Gum Resins. (See Gum.)

SHAGREEN, OR CHAGREEN.

A rough spotted leather, prepared from the skin of the sbark, (54) the best kind of which is imported from Constantinople. The Canicula Spotted Sbark or Dog Fish grows to about four feet in length, and is found in almost every sea. The skin is stripped off and extended, then covered with bruised mustard seed and exposed to the weather for several days: after wbich it is tanned. It is very hard until immersed in water, which renders it soft, when it will receive any dye. It is principally used in the manufacture of various instrument cases, and in a dry state it is likewise employed for polishing wood, and other similar purposes.-(See Morocco.)

SPAR.

This is generally understood to be a brittle shining substance that will burn to lime. It is a fossil naturally combined with the sulphuric or carbonic acids, and is one of the most common productions in the mining counties of England, particularly Derby. shire. As the term Spar is applied to stones of different kinds, without regarding the ingredients of which they are composed, an additional name is used to express the constituent parts, as Calcareous Spar, Gypseous Spar, Adamantine Spar, &c.

Calcareous Spar has a smooth glass-like appearance; it effervesces with acids, even with vinegar, and when transparent, has the property of presenting two images of an object seen through it, and is often termed Double Refracting Spar.-Felspar is generally of a light grey colour, with a shining pearly lustre. When it is pale or deep red it forms red granite : it is sometimes transparent. It contains a portion of potash, which causing it to decompose, forms clay; and this alkali, uniting with sulphuret or oxide of iron, produces various changes in the appearance of granite.-Fluor Spar, of which the best Derby articles are manufactured, is lime combined with fluoric acid. This acid corrodes glass, which no other acid acts upon.-Adamantine Spar is nearly as hard as a diamond, and is used in the East Indies for polishing gems and grinding other hard substances. It is found in China and Hin. doostan.

SPIRIT OF WINE.

A spirit obtained by distilling the saccharine roots, and pulpy fruit of vegetables quite free from colour. When highly rectified it is called Alcohol, and when pure is the same, whether obtained from double distilled brandy, or from any fluid which bas under

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