改錯題型透析及應(yīng)試技巧講義大字體-預(yù)覽頁
【正文】 The first man known to use a signal other than a bonfire used a chandelier. He was lord of a castle that stood near a rocky seacoast. He hang the chandelier, containing many large tallow candles, in the highest tower of his castle. Thus he warned passing ship from the danger along the coast. Candles soon became the mon fuel for signal lights. They were later replaced by oil lamps, that could burn larger and brighter. Kerosene and gas lamps also tried. These are still in use now in some smaller lighthouses. But today most lighthouse sent electric light blazing out over the sea. The ancient fire signals only say Danger! Keep off!. But the modern lighthouse also identifies it in a code known to all shipping. Most of the great lights have their own special signals. The light may be one that blinksas a giant firefly in the night. Or it may be a revolved light that is red then green. Or it may be only white. But however the signal, it is sent very regularly. A ship within its ranges is never at a loss to know which lighthouse it is, and where it is being located
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