(idiom) like mist and smoke passing before the eyes; fleeting; vanishing quickly without a trace; used to describe external things like wealth and fame that are temporary

Passing before the eyes like smoke and clouds; used to describe things that are ephemeral, fleeting, or vanish quickly without leaving a trace.

To nourish one's spirit or longevity by contemplating the natural beauty of landscapes or the paintings that depict them; specifically refers to the traditional belief that painters achieve longevity through immersion in the vital energy of clouds and mist