Pl. specula and -ums. [L. speculum, f. specĕre to look (at), observe. So F. spéculum, It. speculo, specolo, Sp. espéculum.]
1. A surgical instrument of various forms, used for dilating orifices of the body so as to facilitate examination or operations.
Freq. with Latin genitive of the part for which the instrument is used, as speculum oculi, oris, etc.
1597. A. M., trans. Guillemeau’s Fr. Chirurg., C ij b/1. A Dilatorye of the Eyeliddes, or the Speculum of the Eye.
1671. Phillips, Speculum oris, an Instrument to skrew open the mouth, that the Chirurgion may discern the diseased parts of the throat.
1693. trans. Blancard’s Phys. Dict. (ed. 2), Dilatorium, a Chyrurgeon’s Instrument, wherewith the Womb or the Mouth is dilated or opened. It is called likewise Speculum, because by it one may see into the Mouth or the Womb.
1752. Smellie, Midwifery, Introd. p. xlix. He is the first who gives a draught of the Speculum Matricis for dilating the Os Internum.
1800. Med. Jrnl., IV. 103. Permit me to offer the model of a Speculum Oculi, for insertion in the Medical and Physical Journal.
1862. Catal. Internat. Exhib., Brit., II. No. 3552. Specula, an elegant assortment for the eye, ear, vagina, rectum and nose.
1897. Allbutt’s Syst. Med., III. 983. Under an anæsthetic the speculum may be of service.
2. A mirror or reflector (of glass or metal) used for some scientific purpose; † a lens.
1646. Sir T. Browne, Pseud. Ep., VII. xviii. (1672), 435. Archimedes burnt the ships of Marcellus, with speculums of parabolical figures.
1666. Boyle, Orig. Formes & Qual. (1667), 30. The giving to a large Metalline Speculum a concave figure, would never enable it to set wood on fire.
1756–7. trans. Keysler’s Trav. (1760), I. 401. The notes are written in a very small hand,… so that they cannot be easily read without a magnifying speculum.
c. 1790. Imison, Sch. Arts, I. 218. There are four of these concave specula, of different magnifying powers, to be used as objects to be examined may require.
1825. Gentl. Mag., XCV. I. 292/1. On opening it, it was found to contain in the lid a small convex metallic speculum, and in the under-part a larger one.
c. 1860. Faraday, Forces Nat. (1874), 186. A single small speculum, no larger than a hat, will send it in any direction we please.
1873. Spon, Workshop Rec., Ser. I. 317/1. Place the speculum, face downwards, in a dish.
fig. 1826. Kirby & Sp., Entomol., xlvii. IV. 404. The ultimate object intended to be reflected from this great speculum of creation.
1829. I. Taylor, Enthus., vi. 146. The few individuals in every age to whom it has happened to live, and act, and speak under the focus of the speculum of history.
b. spec. A metallic mirror forming part of a reflecting telescope.
1704. Newton, Optics (1721), 97. Such an Instrument,… if it be six Foot long, (reckoning the length from the Speculum to the Prism, and thence to the Focus T).
1782. J. Edwards, in Naut. Almanac (1787), 52. The Springs at the Back of the great Speculum, which are every Moment varying their Elasticity.
1815. J. Smith, Panorama Sci. & Art, I. 44. It … is susceptible of so exquisite a polish, as to be admirably adapted for the speculums of telescopes.
c. 1865. Wylde’s Circ. Sciences, I. 73/2. The speculum is generally made of an alloy composed of variable quantities of copper and tin.
1868. Lockyer, Elem. Astron., § 481. The largest reflector in the world has been constructed by the late Earl of Rosse; its mirror, or speculum, is six feet in diameter.
c. transf. A telescope fitted with a speculum.
1789. Herschel, in Phil. Trans. (1790), LXXX. 10. In hopes of great success with my forty-feet speculum, I deferred the attack upon Saturn till that should be finished.
† 3. A diagram or drawing. Obs.–1
1676. Coley, Clavis Astrol. (ed. 2), III. 674. A Speculum of the Geniture, or Table of the Radiations of the Planets.
4. Ornith. A lustrous mark on the wings of certain birds; = MIRROR sb. 6 b.
1804. Bewick, Brit. Birds, II. 342. The exterior webs … are glossed with gold green, which forms the speculum or beauty-spot of the wings.
1863. C. St. John, Nat. Hist. & Sport Moray, 35. The pochard has no speculum or bright bar on the wing.
1871. Darwin, Desc. Man, I. viii. 291. The beautiful green speculum on the wings is common to both sexes.
5. attrib. a. Speculum metal, an alloy of copper and tin used for making specula. Also speculum steel.
1796. Phil. Trans., LXXXVI. 438. The composition in common use, which contains the greatest proportion of tin, is called speculum metal.
1807–10. Tannahill, Poems (1846), 76. ’Twas by the rays’ reflected heat, Frae speculum steel.
1818. W. Phillips, Outl. Min. & Geol. (ed. 3), 46. If the proportion of tin [to copper] amount to one third, it forms speculum metal, used for reflecting telescopes.
1873. E. Spon, Workshop Rec., Ser. I. 13/1. 2 lbs. copper, 1 lb. tin, 1 oz. arsenic, form a good speculum metal.
b. Speculum forceps (see quot. 1875).
1875. Knight, Dict. Mech., 2261/1. Speculum-forceps, long, slender forceps, used for dressing wounds or operating on parts not accessible except through speculums.
1881. Trans. Obstet. Soc. Lond., XXII. 47. The ovum could generally be removed by the administration of ergot and the ordinary speculum forceps.
