一、水准仪砌墙要求横平竖直,楼板面要求水平。这横“平”和水“平”都要求“平”。这里的“平”就是与水面平行。怎样衡量是否与水面平行呢?古代使用的方法很多,例如:用一铜盆,内装大半盆水,水面上漂浮一个木架(见图1),木架的前端高度和后端高度相等。当眼睛的 First, the horizontal wall of the leveling instrument is required to be horizontal and vertical, and the level of the floor surface is required. This horizontal “flat” and “flat” require “flat”. The “flat” here is parallel to the water surface. How to measure whether it is parallel to the surface of the water? There are many methods used in ancient times, for example, a copper pot was used to contain a large amount of potted water, and a wooden frame floated on the surface of water (see Figure 1). The height of the front end and the height of the rear end of the wooden frame were equal. When the eye