a. (and sb.). Forms: 4, 7–8 vertual (7 -all); 5 Sc. wertual(e, -all; 5–7 virtuall (5 -alle), 6– virtual. [ad. med.L. virtuālis, f. L. virtus virtue, after L. virtuōsus. Hence also It. virtuale, Sp. and Pg. virtual, F. virtuel.]
1. Possessed of certain physical virtues or capacities; effective in respect of inherent natural qualities or powers; capable of exerting influence by means of such qualities. Now rare.
1398. Trevisa, Barth. De P. R., XIX. viii. (Bodl. MS.). But vertual liȝt igadered in a litel place or in a pointe is cleped moche liȝt.
1477. Norton, Ord. Alch., v. in Ashm. (1652), 62. But our chiefe Digesture for our intent, Is virtuall heate of the matter digerent.
a. 1593. Marlowe, Hero & Leander, III. 89. So to all objects … his senses’ flame Flowd from his parts with force so virtuall, It fir’d with sence things weere insensuall.
1626. Bacon, Sylva, § 326. See if the Virtuall Heat of the Wine, or Strong Waters will not mature it.
1657. R. Ligon, Barbadoes (1673), 106. Though the virtual beams of the Sun, give growth and life to all the Plants and Flowers it shines on.
1675. E. W[ilson], Spadacrene Dunelmensis, Pref. Even ordinary water admits of a virtual mixture at least, as Experience evidenceth in Chalybeate waters.
1898. Meredith, Odes Fr. Hist., 9. It was the foreign France the unruly feared,… Not virtual France, the France benevolent, The chivalrous.
b. Of herbs: Possessing specific virtues. rare.
1660. F. Brooke, trans. Le Blanc’s Trav., 364. To Rivers they sacrifice the shels that come from them, to fountains fruits and vertual herbs.
1830. J. Aird, Captive of Fez, III.
| Each precious bleeding rind, she knew its power, | |
| And every virtual plant, and every sovereign flower | |
| Beneath the moon. |
† 2. Morally virtuous. Obs.
c. 1425. Wyntoun, Cron., VII. 1218. His awyn oysse to lif wertual, May mirroure and ensample be Til alkyn statis. Ibid., VII. viii. 2206. Iohun of Salerne, prest cardynale, Commendit a lorde wertuale.
1607. Dekker, Wh. of Babylon, Wks. 1873, II. 216. You by your heauenly Influence change his vilenes Into a vertuall habit fit for vse.
† 3. Capable of producing a certain effect or result; effective, potent, powerful. Obs.
1432–50. trans. Higden (Rolls), II. 177. For a man and the worlde be assimilate in iij. thynges, in dimension diametralle…, in disposicion naturalle, and in operation virtualle. Ibid., 185.
1526. Pilgr. Perf. (Pynson), II. ix. 47 b. That is called after Saynt Thomas virtuall attencyon which causeth a person in the begynnyng of his prayer to haue an actuall consideracion of the prayer or duety that he hath to do.
1619. W. Sclater, Exp. 1 Thess. (1630), 37. So vertuall was the speech of Paul a Prisoner, in the heart of his Judge.
1640. Shirley, Arcadia, IV. iii. I meant it A draught for false Zelmane, it being virtual To increase affection.
1672. Josselyn, New Eng. Rarities, 12. The Loone is a Water Fowl, alike in shape to the Wobble, and as virtual for Aches.
1683. Moxon, Mech. Exerc., Printing, i. Dr. Dee … as a vertual Proof of his own Learned Plea, quotes two Authentique Authors.
b. Mech. (See quots.)
1815. J. Smith, Panorama Sci. & Art, II. 124. Whatever is the real length of the leg b a [of a siphon], the virtual or acting length when in use, only extends from b to the surface of the fluid.
1825. J. Nicholson, Operat. Mechanic, 67. The velocity … due to a head of 15 inches; and this we call the virtual or effective head.
4. That is so in essence or effect, although not formally or actually; admitting of being called by the name so far as the effect or result is concerned.
1654. Jer. Taylor, Real Pres., 21. We affirm that Christ is really taken by faith,… they say he is taken by the mouth, and that the spiritual and the virtual taking him in virtue or effect is not sufficient, though done also. Ibid. (1664), Dissuas. Popery, ii. § 8. But even this attention is not necessary that it should be actual, but it suffices to be virtual.
1697. Burghope, Disc. Relig. Assemb., 166. We shall find it to amount to no less than a vertual renunciation of our baptism.
1734. Waterland, Diss. Exist. First Cause, 30. Every Proof a priori proceeds by Causes either real or virtual.
1769. Burke, Obs. Pres. St. Nat., Wks. 1842, I. 112. One part of it could not be yielded … without a virtual surrender of all the rest.
1787. Bentham, Def. Usury, viii. 73, Heading, Virtual Usury allowed.
1820. Milner, Suppl. Mem. Eng. Cath., 132. To prevent the virtual choice of a Catholic Bishop by an A-Catholic Ministry.
1844. H. H. Wilson, Brit. India, III. 211. He had reigned thirty-three years, during the first ten of which he was virtual sovereign of the greater part of Hindustan.
1883. A. Barratt, Phys. Metempiric, 157. The simplest conscious action involves actual or virtual thought.
b. Virtual Church, a council or similar body acting in the name of the whole church. Also ellipt. as sb.
1646. J. Maxwell, Burden of Issachar, 20. Whatsoever power … the Catholike Church, or her virtuall and Representative, an œcumenical Councel, justly challengeth; this general Assembly vindicateth to it selfe. Ibid., 45. It was not consented to by the Church: that is, the Virtuall Church, the Generall Assemblie.
1654. Bramhall, Just Vind., viii. (1661), 230. In all which … they understand … the virtual Church which is inuested with Ecclesiastical power, that is, the Pope with his Cardinals and Ministers.
c. Optics. Applied to the apparent focus or image resulting from the effect of reflection or refraction upon rays of light.
(a) 1704. J. Harris, Lex. Techn., I. Virtual Focus, or Point of Divergence in a Concave Glass.
1728. Chambers, Cycl., Point of Dispersion, is that wherein the Rays begin to diverge; usually call’d the Virtual Focus.
1808. J. Webster, Nat. Philos., 185. They issued from the virtual focus in the axis of the lens.
1831. Brewster, Optics, i. 11. The point A′, behind the mirror … is called their virtual focus, because they only tend to meet in that focus.
1874. Lommel’s Light, 90. The lenses of the second group have virtual foci.
(b) 1831. Brewster, Optics, ii. 18. In convex mirrors the image is always a virtual one formed behind the mirror.
1859. Parkinson, Optics (1866), 130. A familiar instance of a virtual image is that formed by a common looking-glass of an object in front of it:—the image of an object under water is virtual.
1885. Buck’s Handbk. Med. Sci., I. 39/1. If their direction, after the refraction, be prolonged backward, their prolongations meet to form a virtual image.
d. Dynamics. Of velocity or momentum (see quot. 1867).
1818. Barlow, in Encycl. Metrop. (1845), III. 41/1. [The] principle … of virtual velocities … is now, by most foreign writers, made the foundation of the whole theory of statics.
1843. Penny Cycl., XXVI. 373/2. The name of the principle of virtual velocities … is very ill fitted to express the idea which is to be conveyed. [Full account follows.]
1867. Thomson & Tait, Nat. Phil., I. I. § 237. If the point of application of a force be displaced through a small space, the resolved part of the displacement in the direction of the force has been called its Virtual Velocity. Ibid. The product of the force, into the virtual velocity of its point of application, has been called the Virtual Moment of the force.
