圭组
圭组-
北壁中间砌成一个上下直通的凹形直槽，凹槽直壁与横梁组成的高表与台下石圭形成一组测量日影长度的圭表装置。
The center of the northern wall is built into a hollow groove that is perforated through from top to bot-tom , so the higher gnomon at the groove 's straight wall and the stone gnomon at the bottom constitute a se-ries of gnomon apparatus for measur-ing the length of the shadow cast by the sun .