潮汐和我們的生活与生产有着密切的关系。我国沿海的人民早就掌握了潮汐漲落的規律,他們不但把潮汐当作“天然的鈡表”,用它来估計时刻,而且知道怎样利用漲潮的机会,下网捕魚,引水晒盐。有經驗的航海者也都知道在涨潮时进港,在退潮时出港,既迅捷又省力。我們还可以利用漲潮时河流水位的提高,来引水灌田,可以利用海涂(沿海漲潮、落潮間 Tides and our life and production are closely related. The coastal peoples of our country have long mastered the law of tide fluctuations. They not only use the tides as a “natural indicator,” they use it to estimate the time, but also know how to make use of the opportunity of high tides to fish in the net and introduce salt and water. Experienced voyagers also know that when they enter Hong Kong at high tide, they leave Hong Kong at low tide, which is quick and easy. We can also make use of the improvement of river water level at high tide to introduce water for irrigation and tillage. We can use tidal flats (coastal high tide,