De Quincey.
Ev`a*nes"cence (?), n. The act or state of vanishing away; disappearance; as, the evanescence of vapor, of a dream, of earthly plants or hopes. Rambler.
Ev`a*nes"cent (?), a. [L. evanescens, -entis, p. pr. of evanescere.] 1. Liable to vanish or pass away like vapor; vanishing; fleeting; as, evanescent joys.
So evanescent are the fashions of the world in these particulars.
Hawthorne.