a. [a. Fr. évanescent, ad. L. ēvānescent-em, pr. pple. of ēvānescĕre (see EVANESCE).]
1. That is on the point of vanishing or becoming imperceptible. In Mathematics, said of a diminishing quantity: That is at the instant of becoming zero; infinitesimal. Hence transf. of things: Imperceptibly minute, too small to perceive.
1717. J. Keill, Anim. Oecon. (1738), 41. The smallest Capillaries or evanescent Arteries.
1722. Wollaston, Relig. Nat., i. (1738), 31. To render the crime evanescent or almost nothing.
a. 1761. J. Cawthorn, Wit & Learn., Poems (1771), 73. How the moon was evanescent, Was now an orb, and now a crescent?
1770. Horsley, in Phil. Trans., LX. 437–8, note. The particles of light, which fall upon the evanescent zone … are as that evanescent annular space which they cover.
1811. J. Wood, Optics, iv. 56. The limiting ratio of an evanescent arc to its sine is a ratio of equality.
1849. Mrs. Somerville, Connex. Phys. Sc., xxvi. 276. A quantity so evanescent that it is hardly possible to conceive a time when a change will become perceptible.
1882. Proctor, Fam. Science Studies, 28. Our knowledge … has in reality but an evanescent range.
2. That quickly vanishes or passes away; having no permanence. Said of appearances, conditions, impressions, etc.
1738. Thomson, Spring, 148. The melting Pulp Of mellow Fruit, the nameless Nations feed[s] Of evanescent Insects.
1750. Johnson, Rambler, No. 60, ¶ 11. The incidents which give excellence to biography are of a volatile and evanescent kind.
1784. Cowper, Task, V. 167. A scene Of evanescent glory.
1816. R. Jameson, Char. Min. (1817), 301. Evanescent, when the colour remains as long as the mineral is in a state of fusion, but disappears on cooling.
1828. Scott, F. M. Perth, xxxi. The Duke of Rothsay, whose virtuous feelings were as easily excited as they were evanescent.
1836. Hor. Smith, Tin Trump. (1875), 271. Pen—the silent mouthpiece of the mind, which gives ubiquity of permanence to the evanescent thought of a moment.
1876. Duhring, Dis. Skin, 41. Maculæ are evanescent or permanent according to their cause.
b. Bot. of parts of plants: Not permanent.
1776. Withering, Brit. Plants (1796), IV. 189. Curtain white, evanescent.
1870. Hooker, Stud. Flora, 361. Liparis … glands evanescent.
Hence Evanescently adv.
1847. in Craig.
1865. Bushnell, Vicar. Sacr., II. iv. 142. Evanescently dim to our feeling.
1873. Argosy, XVI. 290. The colour fitted evanescently.
1881. Daily News, 25 July, 5/2. This pervading kindliness, slightly and almost evanescently, but still recognisably tempered by a sort of indulgent scorn.
