《汉书·志·天文志》
出现半日以上功大，出现白虹弯曲而短，上下尖，这样的情况出现，其下分野之地有血光之灾。
见半日以上，功大。白虹屈短，上下锐，有者下大流血。
If there is a powerful thunderstorm for half a day or more, and a short, curved rainbow appears with sharp points at the top and bottom, there will be bloodshed in the region below.