What does the compass recorded in Shen Kuo's works look like?

The manufacturing method of guide fish has been recorded in "Wu Jing Zong Yao" edited by Zeng Gongliang (998-1078) of the Northern Song Dynasty. The great scientist Shen Kuo (1031-1095) recorded in "Mengxi Bi Tan" that at that time, the alchemist who was engaged in Feng Shui and medical treatment first ground the compass spoon and compass fish into a more sensitive magnetic needle and placed it on the compass. above. This is profound: a great invention that leads people to the new world was pushed to the front of history through the hands of people who were wandering in the old cultural customs.