Astronomical Instruments of the Imperial Observatory

A large woodblock illustration depicting two geometric or surveying tools. The upper portion shows a large three-legged divider or compass (tripod-like instrument) standing over a circular base or hole on a textured ground representing a landscape. To the right of the instrument, there is a vertical inscription in Chinese characters. The lower portion shows a plumb bob or a specialized surveying peg with a threaded screw top and a circular flange, standing upright in the ground. The entire scene is enclosed within a double-line rectangular border.

Figure 51