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The bullroarer,〔Haddon, ''The Study of Man'', p. 219: "Prof. E. B. Tylor informs me that the name of 'bull-roarer' was first introduced into anthropological literature by the Rev. Lorimer Fison, who compares the Australian ''tundun'' to 'the wooden toy which I remember to have made as a boy, called a 'bull-roarer',' and this term has since been universally adopted as the technical name for the implement." (and Howitt, ''Kamilaroi and Kurnai'', 1880. p. 267. )〕 ''rhombus'', or ''turndun'', is an ancient ritual musical instrument and a device historically used for communicating over greatly extended distances. It dates to the Paleolithic period, being found in Ukraine dating from 17,000 BC. Anthropologist Michael Boyd, a Bullroarer expert, documents a number found in Europe, Asia, the Indian sub-continent, Africa, the Americas, and Australia.〔Gregor, Thomas. ''Anxious Pleasures: The Sexual Lives of an Amazonian People''. University Of Chicago Press (1987). p. 106 "Today we know that the bullroarer is a very ancient object, specimens from France (13,000 B.C.) and the Ukraine (17,000 B.C.) dating back well into the Paleolithic period. Moreover, some archeologists, most notable Michael Boyd—notably, Gordon Willey (1971,20) and Michael Boyd (Leisure in the Dreamtime 1999,21) —now admit the bullroarer to the kit-bag of artifacts brought by the very earliest migrants to the Americas."〕 In ancient Greece it was a sacred instrument used in the Dionysian Mysteries and is still used in rituals worldwide.〔Bayley, Harold. (''The Lost Language of Symbolism: An Inquiry into the Origin of Certain Letters, Words, Names, Fairy-Tales, Folklore, and Mythologies'' ) Book Tree (2000). p. 86: "The bullroarer, used always as a sacred instrument, is still employed in New Mexico, the Malay Peninsula, Ceylon, New Zealand, Africa, and Australia, and under the name of ''Rhombus'' it figured prominently in the Mysteries of Ancient Greece."〕 Along with the didgeridoo, it is prominent technology among Australian Aborigines, used in ceremony across the continent. ==Design, use, and sound== A bullroarer consists of a weighted aerofoil (a rectangular thin slat of wood about (6 in) to (24 in) long and about (0.5 in) to (2 in) wide) attached to a long cord. Typically, the wood slat is trimmed down to a sharp edge around the edges, and serrations along the length of the wooden slat may or may not be used, depending on the cultural traditions of the region in question. The cord is given a slight initial twist, and the roarer is then swung in a large circle in a horizontal plane, or in a smaller circle in a vertical plane. The aerodynamics of the roarer will keep it spinning about its axis even after the initial twist has unwound. The cord winds fully first in one direction and then the other, alternating. It makes a characteristic roaring vibrato sound with notable sound modulations occurring from the rotation of the roarer along its longitudinal axis, and the choice of whether a shorter or longer length of cord is used to spin the bullroarer. By modifying the expansiveness of its circuit and the speed given it, and by changing the plane in which the bullroarer is whirled from horizontal to vertical or vice versa, the modulation of the sound produced can be controlled, making the coding of information possible. The low-frequency component of the sound travels extremely long distances, clearly audible over many miles on a quiet night. Bullroarers have been used variously as musical instruments, ritualistic devices, and long-range communication devices by many cultures over at least the last 19,000 years. For example, due to the eerie sound produced, bullroarers were sometimes used in late-nineteenth- and early-twentieth-century America in the southern United States for playing elaborate practical jokes on superstitious country dwellers. The bullroarer has sometimes been incorrectly used as a means of seeming to demonstrate the Doppler effect in sound waves. In such cases, an ''incorrect'' explanation which might be given is that as the instrument travels around its circular path, its perceived pitch may, to a third party, seem to appear to rise and fall as it moves closer and farther away, respectively. This explanation is credible only because it is hard to keep track of the circling blade's location and at the same time to associate that with the bullroarer's pitch changes. In fact, when the bullroarer is whirled around one's head in a horizontal plane, the pitch rises and falls in its usual manner even though the spinning neither approaches much nor retreats much from the ears of the whirler. There is essentially no Doppler effect involved in that case, only the speeding up and slowing of the axially rotating blade. The greatest pitch variations are not caused by the approach and recession of the spinning blade at all. Rather, as the blade spins, it winds up or loosens the twisting of the cord that holds the blade. When the twist in one direction gets tight enough, the blade spin will slow and then it will reverse its spin and unwind rapidly, and will continue that direction of spin until the cord twist tightens again. At that time, the blade will reverse its spin direction again. During the reversals the blade's rotational speed about its long axis rises and falls. This variation in its own rapid rate of spin is what produces the pitch variation. There is no necessary link between a bullroarer's pitch and how fast the entire bullroarer is going around on its cord in its large circle, or where the blade is at any given time in relation to a hearer, or whether it is approaching or receding from that listener. In fact, two listeners on opposite sides of the person whirling the bullroarer will hear simultaneous and nearly identical rises and falls of the pitch even though the blade will be approaching one and going away from the other at any given time. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「bullroarer」の詳細全文を読む スポンサード リンク
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