In which dynasty did the copper ruler for writing brush first appear?

Shuowen said: "Town is the place where everything is pressed", which refers to the objects that hold down all kinds of articles. The most primitive town was Stone Town, and then a town appeared. A town is a town that presses curtains or seats. In the past, the ancients sat on the floor, that is, sitting on a straw mat spread on the ground, and the four corners of the straw mat pressed against the town. In the royal family, there are low beds with mats on them, and some beds have curtains. The four corners of mats and curtains are often suppressed.

The paperweight appeared late. When paper appeared, because it would not be blown by the wind when writing, the town gradually played the role of paperweight, and gradually a special "paperweight" appeared. Paperweights entered the study earlier than in the Southern and Northern Dynasties. Rong Yuan's ancestor: "The emperor (Emperor Xiao Daocheng, Emperor Gao Qi, 427-482) tried to use a book case as a rafter and iron as a book town, which was very strong, so he wanted to replace the stick." It can be seen that paperweight has been over 1500 years. Tang Du Guangting's Records of Different Records? Different stones: "Li Tiao, a scholar in Huiji, occasionally picks up small stones, which are blue and black, smooth and playable, and make a book town". Zhang Zi's poem in the Song Dynasty: "Weng Bao gave it to me from three mountains, and the paperweight was just called the golden rhinoceros", which shows that it was popular in the Tang and Song Dynasties.