《晋书·志·第十九章》
元帝永昌元年十月，京师有大雾，黑气遮天，日月无光。
元帝永昌元年十月，京师大雾，黑气蔽天，日月无光。
In the first month of the first year of Emperor Yuan's Yongchang era, a dense fog covered the capital, and black qi obscured the heavens so that the sun and moon were hidden from view. 