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wheel |
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wheel. Through the many millennia of the Paleolithic period and the Neolithic period no use of the wheel was known to humans. Its use was not known to the Native Americans until the Europeans introduced it. In the Old World it came into use in the Bronze Age, when oxen and horses were first used as draft animals and wheeled vehicles were devised. Wheels for vehicles were at first solid wooden disks; spoked wheels were introduced c.2700 B.C. The potter's wheel was invented in the Bronze Age, earlier pottery being made, like that of the Native Americans, without the use of the wheel. See gear gear, toothed wheel, cylinder, or cone that transmits motion from one part of a machine to another; it is one of the oldest means of transmitting motion. When the teeth of two gears are meshed, turning one gear will cause the other to rotate. ..... Click the link for more information. ; tire tire, device made of rubber and fabric and attached to the outer rim of a vehicle wheel. Solid rubber tires were in limited use before 1850; they are still used in some special applications, e.g., for industrial trucks in factories. ..... Click the link for more information. ; wheel and axle wheel and axle, simple machine consisting of a wheel mounted rigidly upon an axle or drum of smaller diameter, the wheel and the axle having the same axis. It is fundamentally a form of lever , the center common to both the wheel and the axle corresponding to the ..... Click the link for more information. . BibliographySee R. J. Forbes, Studies in Ancient Technology (1955); E. Tunis, Wheels (1955); W. Owen et al., ed., Wheels (1972). wheelCircular frame of hard material capable of turning on an axle. Wheels may be solid, partly solid, or spoked. The oldest known wheel was a wooden disk of planks held together by crosspieces. A pottery wheel or turntable was developed c. 3500 BC in Mesopotamia. The spoked wheel appeared c. 2000 BC on chariots in Asia Minor. Later developments included iron hubs that turned on greased axles. Perhaps the most important invention in human history, the wheel was essential to developing civilizations, and has remained essential to power generation, transportation, industrial manufacturing, and countless other applications.
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So, I'd wheel around and ask people how they were doing and take the conversation from there. If the top man is out to the side enough for his knee to be seen, the bottom man should, on the whistle, wheel around to the left and hook the top man's knee, elbow deep. ``He was so far down the line,'' Molina said, ``that I didn't think I'd have time to wheel around. |
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