[f. L. lībrāt-, ppl. stem of lībrā-re, f. lībra balance.]
† 1. trans. a. To place in the scales, to weigh. b. To poise, balance. c. To produce or cause libration in: see quot. 1806 s.v. librating below. Obs.
1623. Cockeram, Librate, to weigh.
1657. Tomlinson, Renou’s Disp., 144. All seeds … are librated by weight [orig. pondere semper librantur].
1667. Phil. Trans., II. 423. The Needles be touched by good Load-stones, and well librated. Ibid. (1674), IX. 219. The manner of Librating the Apogéum.
2. intr. To oscillate like the beam of a balance; to move from side to side or up and down.
1694. W. Holder, Harmony (1731), 28. Librating after the Nature of a Pendulum.
1730. Savery, in Phil. Trans., XXXVI. 298. I was obliged to keep it in a Motion … librating up and down like the Beam of a Pair of Scales. Ibid. (1770), LX. 70. The whole limb of Venus would sometimes librate towards the limb of the sun.
1867. G. Macdonald, Disciple, etc. 109. To drop, and spin away, Librating.
b. To oscillate or waver between one thing and another.
1822. Examiner, 250/2. He … is librating between vice and virtue.
1856. Kane, Arctic Expl., II. 34. The barometer slowly librating between 29.20 and the old 30.40.
3. Of a bird, etc.: To be poised, balance itself.
1786. trans. Beckford’s Vathek, 198. The birds of the air, librating over me, served as a canopy from the rays of the sun.
1791. E. Darwin, Bot. Gard., I. 138. Her playful sea-horse … librates on unmoving fins.
1829. [J. L. Knapp], Jrnl. Naturalist, 263. Made to flutter and librate like a kestrel over the place.
Hence Librated ppl. a., balanced (fig.); Librating vbl. sb. and ppl. a.
1665–6. Phil. Trans., I. 241. Some kind of Librating motion.
1801. Fuseli, in Lect. Paint., ii. (1848), 404. The academic vigour, the librated style, of Annibale Carracci.
1806. Robertson, in Phil. Trans., XCVII. 73. The librating force or pressure, or the force causing libration.
1839. Bailey, Festus (1854), 332. These strange librating bonds of birth and death.
1862. T. Z. Lawrence, in R. H. Patterson, Ess. Hist. & Art, 15. A librating circular smoky spectrum will be perceived at the end of the tube.
