E. Cobham Brewer 1810–1897. Dictionary of Phrase and Fable. 1898.
Wet Finger (With a),
easily, directly. “D’un tour de main.” The allusion is to the old custom of spinning, in which the spinner constantly wetted the forefinger with the mouth.
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“I can bring myself round with a wet finger.”—Sir W. Scott: Redgauntlet, chap. xxiii. (and in many other places).
“The spirit being grieved and provoked… . will not return again with a wet finger.”—Gouge: Whole Armour of God, p. 458 (1616).
