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must be reserved for subsequent experiments. As many of the metals retain their oxygen so forcibly that the application of heat is incapable of expelling it, the addition of inflammable matter becomes expedient. And, to enable the reduced particles of metal to agglutinate and form a collected mass, in stead of scattered grains, which would otherwise happen, some fusible ingredient must be added, through which, when in fusion, the reduced metal may descend, and be collected at the bottom of the crucible. Substances that answer both these The alkaline and purposes are called fluxes. earthy part of fluxes serve also another end; viz. that of combining with any acid which may be attached to a metal, and which would prevent its reduction, if not separated. The ores of different metals, and different ores of the same metal, require different duxes. (See FLUX.) The ore, after being roasted, if necessary, is to be well mixed with three or four times its weight of the dux, and put into a crucible, with a little powdered charcoal over the surface. A cover must be luted on, and the crucible exposed to the necessary heat in a wind-furnace. Ores of iron, as being difficultly reduced, require a very intense fire. Those of silver and lead are metallized by a lower heat. The - metal is found at the bottom of the crucible, in the form of a round button. The volatile metals, as mercury, zinc, arsenic, tellurium, and osmium, it is obvious, ought not to be treated in the above manner, and require to be distilled with inflammabe matters in an earthen retort. See Kirwan's Mineralogy.

ORESTE, a people of Epirus. They received their names from Orestes, who fled to Epirus when cured of his insanity. (Lucan.) ORESTES, a son of Agamemnon and Clytemnestra. When his father was murdered by Clytemnestra and gisthus he was saved by his sister Electra, called Laodicea by Homer, and was privately conveyed to the house of Strophius, king of Phocis. He was tenderly treated by Strophius, who carefully educated him with his son Pylades. From their familiarity between the two young princes soon arose the most inviolable friendship. Wheu Orestes arrived to years of manhood he visited My cene, and avenged his father's death by assassinating his mother Clytemnestra and her adulterer gisthus. The manner in which he committed this murder is variously reported, but the people immediately after acknowledged hin as king. In consequence of the parricide, Orestes is represented as tormented by the Fu rics, and exiles himself to Argus, where he is still pursued by the avengeful goddesses. Apollo himself purifies him, and he is acquitted by the unanimous opinion of the Areopagites. Euripedes says, that Orestes, after the murder of his mother, consulted the oracle of Apollo at Delphi, where he was informed that nothing could deliver him from the persecutions of the Furies if he did not bring into Greece Diana's statue, which was in the Taurica Chersonesus, and which, as it is reported, had fallen from heaven. This was an arduous enterprize. The king of the Chersonesus always sacrificed all such as entered the borders of his country. Orestes and his friend were both earried before Thoas, the king of the place,

and doomed to be sacrificed Iphigenia, then priestess of Diana, was to immolate these strangers. The intelligence that they were Grecians delayed the preparations, and Iphigenia was anxious to learn something about her country which had given her birth. (See IPHIGENIA.) She offered to spare the life of one of them, provided he would convey letters to Greece from her hand. This was a difficult trial; never was friendship more truly displayed, but at last Pylades gave way to the pressing entreaties of his friend, and consented to carry the letters of Iphigenia to Greece. These were addressed to Orestes himself, and, therefore, these circumstances soon led to a discovery of the connections of the priestess with Orestes. Iphigenia, convinced that he was her brother Orestes, resolved, with the two friends, to fly from Chersonesus, and to carry away the statue of Diana. Their flight was discovered, and Thoas prepared to pursue them, but Minerva interfered, and told him, that all had been done by the will and approbation of the gods. After these celebrated adventures Orestes ascended the throne of Argos, where he reigned in perfect security, and married Hermione, the daughter of Menelaus, and gave his sister to his friend Pylades. The marriage of Orestes with Hermione is, however, a matter of dispute among the ancients. His old age was crowned with peace and security, and he died in Arcadia, in the 90th year of his age, leaving his throne to his son Tisamenes, by Hermione. The friendship of Orestes and of Pylades became proverbial.

ORESTEUM, a town of Arcadia, about 18 miles from Sparta. It was founded by Orestheus, a son of Lycaon, and originally called Oresthasium, and afterwards Oresteum, from Orestes, the son of Agamemnon, whe came there.

ORESTIDE, the descendants or subjects of Orestes, the son of Agamemnon. They were driven from the Peloponnesus by the Heraclide.

OREXIS. (from prys, to labour.) In medicine, the appetite: the sense of hunger.

ORFA, a considerable town of Turkey in Asia, in Diarbeck, which formerly belonged to Persia. It has a good trade, particularly in carpets of several sorts, some of which are made here. It has a stately castle on a hill, and is seated on the Euphrates, 83 miles N.E. of Aleppo, and 100 S.W. of Diarbekar. Lon. 38. 20 E. Lat. 36. 50 N.

ORFORD, a seaport and borough in Suffolk, with a market on Monday. It is said to have had twelve churches, but has now only one, whose steeple is a sea-mark; and near it are the ruins of an old castle, a priory, and St. George's chapel. It is governed by a mayor, sends two members to parliament, and is seated on the Gerinan Ocean, between two channels, 18 miles E. by N. of Ipswich, and 88 N.E. of London. Lon. 1. 40 E. Lat. 52. 11 N.

ORFORD NESS, a cape of England, on the S.E. coast of Sussex, where a lighthouse is

erected for the direction of ships. Lon. 1.6 E. Lat. 52. 4 N.

ORGAL, among dyers, lees of wine dried. ORGAN, a wind instrument blown by bellows, and containing numerous pipes of various kinds and dimensions, and of multifarious tones and powers. Of all musical instruments this is the most proper for the sacred purpose to which it is most generally applied in all countries wherever it has been introduced. Its structure is lofty, elegant, and majestic, and its solemnity, grandeur, and rich volume of tone, have justly obtained it an acknowledged pre-eminence over every other instrument.

An organ, when complete, is of three-fold construction, and furnished with three sets of keys: one for what is called the great organ, and which is the middle set; a second (or lower set) for the choir organ; and a third (or upper set) for the swell. In the great organ, the principal stops are the two diapasons, the principal, the twelfth, the fifteenth, the sesquialtra, the mixture or furniture, the trumpet, the clarion, and the cornet. The choir organ usually contains the stopt diapason, the dulciana, the principal, the flute, the twelfth, the bassoon, and the vox humane. The swell comprises the two diapasons, the principal, the hauthoy, trumpet, and cornet. Besides the complete organ, there are other organs of lesser sizes, and more limited powers, adapted to church, chapel, and chamber use. There is also the barrel or hand-organ, consisting of a moveable, turning cylinder called a barrel, on which, by means of wires, pins, and staples, are set the tunes it is intended to perform. These pins and staples, by the revolution of the barrel, act upon the keys within, and give admission to the wind from the bellows to the pipes. The barrel-organ is generally portable, and so contrived that the same action of the hand which turns the barrel, supplies the wind by giving motion to the bellows.

The invention of the organ, which is attributed to the Greeks, is very ancient, though it is generally allowed to have been little used before the eighteenth century.

It has been a subject of debate at what time the use of organs was first introduced into the church. Some writers say, that they were first applied to sacred use in the time of pope Vitalian, about the year 660, others that they were not employed in that way till the ninth century. A learned author has, however, shown that neither of these dates can be just: and Thomas Aquinas expressly says, that in his time (about the year 1250) the church did not use musical instruments; and Bingham says, that Marinus Sauntus, who lived about the year 1990, first introduced the use of them into churches. But if we may give credit to the testimony of Gervas, the monk of Canter bury, who flourished at the beginning of the thirteenth century, organs were introduced more than one hundred years before his time. Bede, who died in 735, says nothing of the use of organs, or other musical instruments in our

churches or convents, though he minutely describes the manner in which the psalms and hymns were sung; yet Mabillon and Muratori inform us, that organs, during the tenth cen tury, became common in Italy and Germany, as well as in England; and that about the same time they had admission into the convents throughout Europe.

The organs in Germany (says Dr. Burney), in magnitude, and the organists in abilities, seem unrivalled in any other part of Europe, particularly in the use of pedals. In Marpurg's Essays, vol. iii. there is a minute account of a variety of organs in Germany; of all which the longest pipe of the manuals is 16 feet long, and of the pedals 32. One of the largest organs in Germany, but which Marpurg has omitted in his list, is at Gorliz in Upper Lusatia,

Among the modern improvements of the organ, the most remarkable are the swell and the tremblant: the former, invented by an English artist, consists in a number of pipes placed in a remote part of the instrument, and inclosed in a kind of box, which, being gradually opened by the pressure of the foot, increases the sound as the wind does the sound of a peal of bells, or suppresses it in like manner by the contrary action. The tremblant is a contrivance by means of a valve in the port. vent or passage from the wind-chest, to check the wind, and admit it only by starts; so that the notes seem to stammer, and the whole instrument to sob, in a manner very offensive to the ear. There is a tremblant in the organ at the German chapel in the Savoy. See Hawkins's History of Music, and Burney.

ORGAN (Hydraulic), denotes a musical machine that plays by water instead of wind. Of these there are several in Italy, in the grottos of vineyards. Ctesebes of Alexandria, who lived in the time of Ptolemy Energetes, is said to have invented organs that played by compressing the air with water, as is still practised, Archimedes and Vitruvius have left us descriptions of the hydraulic organ. In the cabinet of queen Christina is a beautiful and large medallion of Valentinian, on the reverse whereof is seen one of these hydraulic organs; with two men, one on the right, the other on the left, seeming to pump the water which plays it, and to listen to its sound. It has only eight pipes, placed on a round pedestal. The inscription is PLACEA SPETRI, if it be not wrong copied, which we suspect to be the case.

Construction of the Organ. This may be understood by the following description of one made by Messrs, Flight and Co. St. Martin's Lane, London, and which, besides many other improvements, is so contrived as to serve both for a finger-keyed organ, and a barrel organ.

Plates 125 and 126 exhibit this instrument in different positions, the same letters of reference being employed in both figures. The instrument is represented as having all parts of the ornamental case removed, to explain the

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