a. [a. Fr. éruptif, -ive, f. ērupt- ppl. stem of ērumpĕre: see ERUPT and -IVE.]
1. Bursting forth; inclined or accustomed to break out from restraint, or to burst into violent action.
1646. Sir T. Browne, Pseud. Ep., III. xvi. 143. All which is perverted in this eruptive generation.
1744. Thomson, Summer, 1132. The sudden glance [lightning] Appears far south eruptive through the cloud.
1865. M. Arnold, Ess. Crit., 65. The eruptive and the aggressive manner in literature.
1873. Browning, Red Cott. Nt.-cap, 117. Hell, eruptive and fuliginous, Sickens to very pallor.
2. Of or pertaining to volcanic eruption; tending to or engaged in eruption; of the nature of or characterized by eruption. Of rocks: Formed or forced up by eruption, showing traces of eruption.
1799. Kirwan, Geol. Ess., 288. Into these errors Mr. Whitehurst was betrayed by his fondness for the eruptive or plutonic theory.
1819. Byron, Proph. Dante, III. 187. The volcano’s fierce eruptive crest.
1849. Murchison, Siluria, v. 92. Crystalline rock, both eruptive and metamorphic.
1869. Phillips, Vesuv., iii. 79. Within the crater … was found a round and small actively eruptive cone.
1878. Newcomb, Pop. Astron., III. ii. 262. The eruptive protuberances.
quasi-sb. 1884. R. D. Irving, in Amer. Jrnl. Sc., Ser. III. (1885), XXIX. 241. The gneisses … forming our supposed eruptives, are, if eruptive, manifestly not to be compared with the lavas of modern times.
3. Path. Attended with or producing eruption or efflorescence.
1790. Sir W. Fordyce, Virtues Muriatic Acid., 1. The striking effects produced by the spirit of sea-salt in all our putrid diseases of the worst kinds: I mean the Eruptive Fevers [etc.].
1796. Burke, Regic. Peace, Wks. (1842), II. 279. It is in the nature of these eruptive diseases in the state to sink in by fits, and re-appear.
1834. Penny Cycl., II. 207/2. Antimony is also used in some eruptive or exanthematous fevers.
1852. Miss Yonge, Cameos (1877), III. v. 41. A serious attack of illness of an eruptive kind.
b. transf. (humorous.)
1848. Thackeray, Bk. Snobs, xxxiii. Thomas wears a page’s costume of eruptive buttons.
Hence Eruptively a., in an eruptive manner. Eruptiveness, the quality of being eruptive. Eruptivity = ERUPTIVENESS.
1869. Daily News, 1 July. The candlesticks all over knobs and excrescences as if eruptively affected.
1885. G. Meredith, Diana Crossw., I. i. 19. They create by stoppage a volcano, and are amazed at its eruptiveness.
1882. Geikie, Text-bk. Geol., IV. VII. 537. They possess likewise various values as marks of eruptivity.
