[n. of action f. CONCENTRATE: See -ATION. Cf. F. concentration.]
1. The action of bringing to or towards a common center or focus; the state of being so brought or massed together.
1634. Peacham, Gentl. Exerc., I. xi. 38. The concurse and concentration of the broken beames.
a. 1691. Boyle, Wks., II. 630 (R.). I could not perceive by any concentration of the lunar beams … that her light did produce any sensible degree, either of cold or heat.
1804. Wellington, in Gurw., Disp., III. 393. The concentration of your force in one position.
1881. Hooker, in Nature, No. 619. 446. The concentration of related species in the same area.
attrib. 1841. Catlin, N. Amer. Ind. (1844), II. xxxii. 1. It is the concentration point of a number of hostile tribes.
fig. 1646. H. Lawrence, Comm. Angells, 92. There is a concentration of thoughts.
1750. Johnson, Rambler, No. 80, ¶ 8. Gloom and silence produce composure of mind, and concentration of ideas.
1874. Green, Short Hist., vii. 340. This concentration of all power in the hands of a single man.
b. The keeping of the mental faculties fixed on one object or set of objects.
a. 1846. B. R. Haydon (O.). The evidence of superior genius is the power of intellectual concentration.
1856. Emerson, Eng. Traits, Manners, Wks. (Bohn), II. 49. Nothing so much marks their manners as the concentration on their household ties.
1865. Tylor, Early Hist. Man., i. 13. It is a question, whether the student … might not lose more in largeness of view than he gained by concentration.
c. concr. A concentrated collection or mass.
1783. Phil. Trans., LXXIII. v. A great quantity of water coming … from the subterraneous concentrations.
† 2. (See quots.) Obs.
1674. Grew, Anat. Plants, Lect. Mixture, i. (1682), 233. Take good Oyl of Vitriol, and drop it upon Oyl of Anise-seeds; and they will forthwith incorporate together; and … harden into a perfect Rosin … The Concentration of these two Liquors is likewise so universal, that the Rosin is not made by Precipitation, but almost a total Combination of the said Liquors.
1706. Phillips (ed. Kersey), Concentration (according to Dr. Grew), is the highest Degree of Mixture, as when two or more Atoms or Particles of the Mixture, do touch by the receiving or thrusting of one into the other.
3. Chem. The strengthening of a solution by contraction of its volume, as by evaporation of part of its water; the condition thus produced.
1790. Blagden, Spir. Liquors, in Phil. Trans., LXXX. 338. To shew when a given weight, or volume, of a certain spirit and water are mixed together, how much their bulk would be diminished; or, what is called by the distillers the concentration.
1799. Hatchett, in Phil. Trans., LXXXIX. 316. The phosphoric acid … was proved, after concentration.
1882. Vines, Sachs’ Bot., 758. Solutions of medium concentration.
† b. The separation of gold, etc., from an alloy by a chemical process: cf. CEMENTATION.
1689. Packe, trans. Glauber’s Wks., I. 325. Where more such like concentration of Metals shall be mentioned. Ibid., II. 100. The Concentration of Gold and Silver into Tinctures.
1799. G. Smith, Laborat., I. 75. Parting of gold from silver by cementation … is also called parting by concentration.
c. Mining. ‘The removal by mechanical means of the lighter and less valuable portions of ore’ (Raymond, Mining Gloss., 1881).
1873. J. S. Phillips, Metallurgist’s Comp. (ed. 2), 472. Dry concentration by Hand … should always be resorted to.
4. The bringing of parts or elements closer together; condensation.
1865. M. Arnold, Ess. Crit., i. 19. But epochs of concentration cannot well endure for ever; epochs of expansion, in the due course of things, follow them.
1869. Huxley, in Sci. Opinion, 28 April, 486/3. As the result of this concentration, he argues for the development of an amount of heat which will dissipate the mass once more into a molecular chaos such as that in which it began.
1871. Ruskin, Munera P., Pref. (1880), 26. My affected concentration of language.
5. Pathol. ‘A term for the character of a pulse which is small and thready’ (Syd. Soc. Lex., 1882).
