60 The Telltale Beam

If you have ever seen the classic film Raiders of the Lost Ark you will remember the opening in the roof of a tomb that allowed a beam of sunlight to strike a spot on the floor at a certain time each day. Well, there is a similar device in a real cathedral in Italy, although its purpose is not quite as exciting as the one in the film.

In 1420, 72 years before Columbus discovered America, a great Italian architect named Filippo Brunelleschi built a cathedral in the city of Florence. He left a small opening in the church, which allowed a slender beam of sunlight to shine through onto the floor. Built into the floor was a small metal plate—what is has done, that is, for every year without fail for over 572 years! Every June 21, the beam strikes the metal plate on the floor of the cathedral, which is designed with this special feature. Well, the church was built in a place that was marshy, which means that the ground was very unstable, like mud. If it ever happened that the light beam did not strike the special metal plate on June 21, it would mean that the church had shifted, or moved out of place, or it is on base. People would know that they had to fix the cathedral so it wouldn’t fall, or they would have time to make sure everyone nearby was safe in case it collapsed.

60 泄密的光束

如果你看过经典电影《夺宝奇兵》，你会记得坟墓屋顶的开口，每天特定时间会让一束阳光照在地板上的一个点上。其实，意大利的一座真实大教堂里也有一个类似的装置，尽管它的用途不像电影里的那样令人兴奋。

1420年，也就是哥伦布发现美洲的72年前，一位名叫菲利波·布鲁内莱斯基的伟大意大利建筑师在佛罗伦萨市建造了一座大教堂。他在教堂里留了一个小开口，让一束纤细的阳光透过照到地板上。地板上嵌入了一块小金属板——也就是说，这个装置已经这样运作了572多年，从未间断！每年6月21日，光束都会照在大教堂地板上的金属板上，这座教堂就是带着这个特殊功能设计的。这座教堂建在一片沼泽地上，这意味着地面非常不稳定，像泥一样。如果6月21日光束没有照到那块特殊的金属板，就意味着教堂发生了移位，偏离了原来的位置，或者地基出了问题。人们会知道他们必须修复大教堂，防止它倒塌，或者他们会及时确保附近的每个人都安全，以防它坍塌。