[f. L. type *concentrāt- ppl. stem of *concentrāre: see CONCENTRE.]
1. trans. To bring to or towards a common center; to collect or gather as at a center; to cause to converge or meet at one point or place. In Mil. use: To bring troops or forces close together.
1646. H. Lawrence, Comm. Angells, 125. Love will concentrate all in God, make all lines meet in him.
1813. Wellington, in Gurw., Disp., X. 595. We attacked the enemy on the 30th, the right and centre having been tolerably concentrated.
1831. Brewster, Optics, x. 91. The different rays concentrated by the lens.
1836. Macgillivray, trans. Humboldt’s Trav., xxiv. 367. The population is Concentrated on this table-land.
1878. Bosw. Smith, Carthage, 80. Here Hannibal … concentrated the forces which had been gathered from such distant countries.
2. fig. and of non-physical objects.
1752. Johnson, Rambler, No. 199, ¶ 14. Magnets armed with a particular Metallick composition, which concentrates their virtue.
1794. Sullivan, View Nat., V. 395. The lineaments thus become collected, or rather concentrated in our imaginations, and acquire force from concentration.
1860. Kingsley, Misc., I. 22. I must concentrate my powers on one subject.
1879. Calderwood, Mind & Br., ii. 10. To concentrate attention on the nerve system.
3. Chem. To increase the strength of (a solution or liquid) by contraction of its volume (e.g., by evaporation).
1689. Packe, trans. Glauber’s Wks., I. 431. The concentrated Spirits of Salt may bring most great advantage by concentrating the poor sort of Wine.
1731. Arbuthnot, Aliments, vi. 105. Spirit of Vinegar concentrated, and reduc’d to its greatest strength will coagulate the Serum.
1838. T. Thomson, Chem. Org. Bodies, 170. This salt is easily obtained, by … concentrating the solution.
1845. Darwin, Voy. Nat., xii. (1879), 256. The sap is concentrated by boiling, and is then called treacle.
† b. To purify gold or silver by chemical agency, e.g., by the operation of chlorine. Obs.
1689. Packe, trans. Glauber’s Wks., I. 330. By what means even Gold and Silver may be concentrated.
c. Mining. To separate metal or ore from the gangue or associated rock. Cf. CONCENTRATOR.
1872. [see CONCENTRATING vbl. sb.].
1873. J. S. Phillips, Metallurgist’s Comp. (ed. 2), 472. The base minerals and the precious metals may be concentrated in numerous ways.
4. To bring the parts of (anything) into closer union; to condense or reduce in compass or volume; often connoting the resultant effect of increased intensity or power.
1758. Johnson, Idler, No. 11, ¶ 9. Accounts … of one mind expanded in the summer, and of another concentrated in the winter.
1802. Playfair, Illustr. Hutton. Th., 303. It has been expelled from some parts of a mass, only to be condensed and concentrated in others.
1853. C. Brontë, Villette, xxx. (1876), 344. The obstinacy of my whole sex, it seems, was concentrated in me.
5. intr. and absol. (usually for refl.)
1640. G. Watts, trans. Bacon’s Adv. Learn., Pref. 16. That the Images and beams of things (as in sense) may meet and concentrate.
1835. I. Taylor, Spir. Despot., vi. 278. The progress of Church Power … as concentrating around the See of Rome.
1841. Alford, in Life (1873), 133. Would that … my powers and attention as I advance may concentrate.
b. Mil. of troops: To collect in one quarter.
1813. Sir R. Wilson, Diary, Life, II. 258. The news of this … obliged him to concentrate on the Elbe.
1841. Elphinstone, Hist. India, II. 277. Compelling the king’s troops to concentrate and wait for assistance from Behár.
