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  3. Of all the many factors which contributed to the Industrial Revolution,

Of all the many factors which contributed to the Industrial Revolution,

游客2024-08-14  9
问题         Of all the many factors which contributed to the Industrial Revolution, the most revolutionary and the most impressive was not coal but steam power.J.L.and Barbara Hammond said that steam power "declared the triumph of industry and the glory of man".From clumsy and inefficient beginnings it was quickly improved to open up tremendous possibilities for industrial progress.The limitations of muscle—power are obvious, and though water had served well to work bellows and hammers in iron works, or to turn machinery like the water-frame and the mule in the textile industry, it could only be applied in a limited way in Britain.For water power is most useful in a land with many fast-flowing streams and apart from areas like the Pennines, Scotland, and Wales, this country’ s rivers flow slowly.The Alpine area of Europe, and much of the United States relied on water power for much longer than Britain, and hydroelectricity has brought water back into its own in many parts of the world.The geographical limitations of Britain’ s water power, however, necessitated finding an alternative solution to the problem.
        When water vaporizes it expands 1,800 times.The idea of harnessing this energy is far from now.It was probably used by Hero of Alexandria in the 1st century B.C. to open temple doors or to pour libations apparently by magic.Hero’ s writings were rediscovered during the Renaissance and many people, including, for example, the Marquis of Worcester （1601 - 1667）experimented with devices using steam.Regretfully, therefore, we must dismiss the old myth that steam power was born in the mind of a bright Scots lad called James Watt as he sat one winter’ s evening watching his mother’s kettle boil on the hearth.Watt’ s contribution to steam is incalculable, but steam-pumps had been used in Britain for over seventy years before he began his work.
        The first steam-engine used in industry was invented by Thomas Savery （1650 - 1715）.Called "The Miners’ Friend or an engine to raise water by fire", it was patented in 1698 and worked on simple principles.It pumped water from wells quite efficiently and was used successfully in Cornish copper-mines, but its limitations were revealed when it was tried in the Broadwater Collieries in Staffordshire in 1706 and was found to be capable of pumping water up no more than 100 feet.When greater pressure was used the boiler burst.Therefore, Savery’ s engine was used to supply water in gentlemen’ s houses or to work fountains—tasks it could perform effectively, though not quite safely as there was no pressure-gauge.
        It was Thomas Newcomen （1663—1729）, a Dartmouth blacksmith and ironmonger, who produced the first steam-pump to be used widely in industry.It was known as an "atmospheric engine" because, in contrast to Savery’ s engine, the steam in the cylinder was not used to drive the pump but only to create a partial vacuum when condensed.Ordinary air pressure drove the piston into the cylinder and this raised the pump which was connected to the piston by a see-sawing cross-beam.A large piston meant that it was possible to gain more force without increasing steam pressure and this made Newcomen’ s engine much more powerful than Savery’ s.
        The first engine was made about 1706 but it was a clumsy affair.The piston did not fit tightly into the cylinder and condensation, which was achieved by pouring cold water on the outside of the cylinder, was far from complete.Moreover, the tap controlling the passage of steam into the cylinder was worked by hand seven or eight times a minute.These difficulties were ironed out by 1720; water was now sprayed into the cylinder to improve condensation, the operation of the taps had been made automatic, and a safety-valve had been fitted to eliminate the danger of explosion.
        The improved engine soon became standard equipment in most large mines, and it was also used to pump water into canals and to supply drinking-water in towns.It is difficult to know exactly how many were in use by the second half of the 18th century but in 1767 fifty-seven were found around Newcastle, and there were eighteen in Cornish mines in 1780. [br] What was installed to the first engine to prevent explosion?
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答案 A safety-valve
解析 题意:第一台发动机安装了什么以避免爆炸?根据文中五段最后一句“…a safety-valve had been ftted to eliminate the danger of explosion…”可知，装一个安全阀就能消除爆炸的危险,故答案为“A safety-valve.”
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