[a. Fr. alternation, ad. L. alternātiōn-em, n. of action f. alternāre: see ALTERNATE a.]
1. The action of two things succeeding each other by turns; alternate succession or occurrence.
1611. Cotgr., Alternation, an alternation, a succession by turne.
1646. Sir T. Browne, Pseud. Ep., 147. Hares may exchange their sex, yet … not in that vicissitude or annuall alternation as is presumed.
1766. Goldsmith, Vic. Wakef. (1857), 242. My spirits were exhausted by the alternation of pleasure and pain.
1866. G. Macdonald, Ann. Q. Neighb., xxi. 394. She behaved with strange alternations of dislike and passionate affection.
1880. H. James, Benvolio, I. 345. To take the helm in alternation.
b. Alternation of generations: = alternate generation; see ALTERNATE a. 2 b.
1858. Lewes, Sea-side Studies, 287. The solitary Salpa produces the chain-Salpa by ‘budding’; and the chain-Salpa by ‘alternation of generations’ (the phrase is Chamisso’s [1819]) produces the solitary Salpa by ova.
1875. Bennett & Dyer, Sachs’ Bot., I. iii. 203. When alternation of generations occurs, in certain cases all the alternate generations may be asexual.
1881. Lubbock, in Nature, No. 618. 404/1. In 1842, Steenstrup published his celebrated work on the ‘Alternation of Generations.’
2. The action of taking the individuals of a series alternately.
1695. Alingham, Geom. Epit., 100. For if A:a::B:b, Then by Alternation A:B::a:b.
3. Successive change in a scene or action by the alternate occurrence of phenomena.
1633. T. Adams, Comm. 2 Pet. i. 19 (1865), 196. By the vicissitude of time, and alternation of the wheeling heavens.
1791. Hamilton, trans. Berthollet’s Dyeing, I. Introd. 35. Inequalities in the alternation of the action of the liquor.
1845. Ford, Handbk. Spain, I. 46. Love is … an alternation of the agrodolce.
1868. G. Duff, Pol. Surv., 75. Some of these provinces consist almost entirely of alluvial plains, but the greater number exhibit an alternation of fertile river valleys.
4. The position or state of being in alternate order.
1830. Lyell, Princ. Geol. (1875), I. I. iii. 53. Alternations were rare, of marine strata, with those which contain marshy and terrestrial productions.
1841. Trimmer, Pract. Geol., 182. Rarely met with … without the alternation of other rocks.
1860. Maury, Phys. Geog. Sea, ii. § 128. Streak after streak of warm and cool water in regular alternations.
5. The doing of anything by two actors by turns, alternate performance; reading or singing antiphonally.
1642. Milton, Apol. Smect. (1851), 313. Such alternations as are there [in the Liturgy] us’d must be by severall persons.
1795. Mason, Ch. Mus., 130 (T.). The words are not confused by perplexing alternations.
6. erron. ‘Sometimes used to express the divers changes, or alterations of order, in any number of things proposed.’ (Chambers.) Permutation.
1751. Chambers, Cycl., s.v., How many changes or alternations can be rung on six bells.
