see quots. and VALENTIA.
1823. E. Moor, Suffolk Wds., s.v. Valentia, I have met with the word in print, spelled Valinch.
1847. Webster, Valinch, a tube for drawing liquors from a cask by the bung-hole.
1868. Loftus Catal. Hydrometers, etc., 6. Velinchers for sampling casks.
1875. Knight, Dict. Mech., 2553. Thief-tube, a sampling-tube; a velinche.
1899. N. & Q., 4 Feb., 97/1. The nearest approach to a long measure is the valincher, or valinch, used in sampling from the bung.