What anemometers were there in ancient China?

Judging from the unearthed cultural relics, China had invented the wind shield at least in the Western Han Dynasty. Huainanzi in the Western Han Dynasty had a simple windbreak. This kind of anemometer may have evolved from the simplest "anemometer", with a piece of cloth or a long flag tied to the wind pole. "Huainan Ziqi Su Xun" said: "Under the action of the wind, this anemometer is not calm for a moment." It can be seen that this kind of anemometer was very sensitive at that time.

In the Han Dynasty, in addition to the above-mentioned "wind vane", there are also two kinds of "bronze phoenix" and "Xiang Feng Wu Tong" recorded in the history books. These three anemometers showed the development direction of anemometers in China at that time. "Copper Phoenix" was mainly installed in Zhangjian Palace, which was built in the first year of Emperor Wu of Han Dynasty (BC 104). At that time, two bronze phoenixes were installed in Zhang Jian Palace, one on the gate and the other on the roof. According to the ancient book San Fu Huang Tu, there is a very sensitive fulcrum under the bronze phoenix. Whenever the wind comes, the bronze phoenix's head will face the place where the wind blows, as if to fly. But later, this sensitive anemometer was regarded as the decoration of the house by the royal aristocrats and lost its original function.

"Xiangfeng Wu Tong" is a windshield shaped like a crow. It was installed on the "Lingtai" where people observed astronomy and meteorology in the Han Dynasty. This is an instrument for observing the wind direction at that time, so people made it very heavy. It is said that it only turns when the wind blows from thousands of miles away. But after all, this is a scientific instrument, which naturally needs continuous improvement, so later people made it lighter and more sensitive, so that it would turn as long as people blew it. Later, this ingenious anemometer gradually became popular among the people.

But from the needs of ancient military and traffic, these three wind direction devices are not suitable. Therefore, it is pointed out in "B has occupied" that "Wuhou should be used for permanent residence; The military power should be based on feathers. " This kind of anemometer had better be installed in a fixed place. And if the station changes frequently, it is better to use chicken feathers. " This anemometer made of chicken feathers weighs 5 to 8 taels and is hung on a high pole. It can be observed when the feathers are balanced by the wind. This simple windshield existed before the Tang Dynasty, and it became more popular after the Tang Dynasty.