英語時差：舞臺燈光的起源（上）

If someone loves being in the limelight, that means they enjoy being the center of attention. We use the word now to mean social prominence, but have you ever wondered what limelight actually is, or how it came to be synonymous with fame? Originally a limelight was a bright, incandescent lamp invented by the Englishman Thomas Drummond in 1816. At that time, the British government was trying to survey Ireland. To do this, surveyors used tall Irish mountains as reference points. Their problem was that the weather was often bad, making it impossible to see the mountain tops directly. However, when Drummond lit his newly invented limelights on the tops of these mountains, surveyors could see them from over fifty miles away. The “lime” in limelight refers to burned limestone, not the fruit. Burned limestone gives off great quantities of brilliant, white light when heated. To make a limelight, a small piece of lime is heated by burning a mixture of oxygen and hydrogen gasses. The white light from the glowing lime is then focused with a lens or a mirror.