【英语时差8,16】吸管的工作原理（下）

（单词翻译）

This same principal explains how a barometer¹ measures the atmospheric² pressure. Since mercury is much heavier than water, the atmospheric pressure can only support a column of mercury about thirty inches high. But as the atmospheric pressure changes, so does the height of the column it can support. When the meteorologist announces that the barometric³ pressure is twenty-nine inches of mercury, it means that the air pressure is capable of supporting a column of mercury twenty-nine inches high. You could measure the atmospheric pressure with a column of water, but a thirty-foot water barometer would be much more cumbersome⁴ than a three-foot mercury barometer.