An instrument for ascertaining whether a surface is horizontal, vertical, or at a45= angle, consisting essentially of an encased, liquid-filled tube containing an air bubble that moves to a center window when the instrument is set on an even plane.
英
美
- 水準儀用來(lái)確定一個(gè)層面是水平的、垂直的或是呈45度角的儀器，主要由一個(gè)密封的、充滿(mǎn)液體的玻璃管構成，管內有一個(gè)氣泡，當儀器放在一個(gè)水平面上時(shí)，氣泡移至中間的觀(guān)測口
