dioptric, a. and n.
(daɪˈɒptrɪk)
[mod. ad. Gr. διοπτρικ-ός of or pertaining to the use of the δίοπτρα (diopter); in neuter pl. διοπτρικά as n., the science of dioptrics. See -ic, -ics.]
A. adj.
† 1. Of the nature of, or pertaining to, a diopter (sense 1). Obs.
| 1635 N. Carpenter Geog. Del. i. v. 107 Two signes of the Zodiacke diametrally opposite should not be seene by a Dioptricke instrument. 1681 tr. Willis' Rem. Med. Wks. Vocab., Dioptric, belonging to the perspective, or a mathematical instrument, thorow which they look to take the height of a thing. |
2. Serving as a medium for sight; assisting vision (or rendering it possible) by means of refraction (as a lens, the humours of the eye).
| 1653 H. More Antid. Ath. ii. xii. (1712) 84 To view the Asperities of the Moon through a Dioptrick-glass. 1660 ― Myst. Godl. ii. iii. 36 None of the external Organs have any Sense at all in them, no more then an Acousticon or a Dioptrick glass. 1858 J. Martineau Stud. Chr. 186 A dead mechanism..ready to serve as the dioptric glass, spreading the images of light from the Infinite on the tender and living retina. 1878 T. Bryant Pract. Surg. I. 299 The refraction is said to be normal or abnormal according to the position of the retina with regard to the focus of the dioptric system. |
3. Relating to the refraction of light; pertaining to dioptrics (see B. 3); esp. (of a telescope, etc.), refractive, refracting. (Opp. to catoptric.)
dioptric system, in lighthouses, also called refracting system: see quot. 1879.
| 1672 Newton in Phil. Trans. VII. 5086 For Dioptrique Telescopes..the difficulty consisted not in the Figure of the glass, but in the Difformity of Refractions. 1688 R. Holme Armoury iii. 146/2 The..Dioptrick, or broken sight, is rightly seen in a Tub of Water where the Surface is cut. 1753 Phil. Trans. XLVIII. 167 Our common telescopes whether dioptric or reflecting. 1871 Tyndall Fragm. Sc. (1879) II. xvi. 436 The light was developed in the focus of a dioptric apparatus. 1879 Cassell's Techn. Educ. IV. 75 The Dioptric arrangement is that in which the rays issuing from the flame are collected and refracted in a given direction by a lens placed in front of the light. |
† 4. Capable of being seen through: see quot.
| 1801 Farmer's Mag. II. 48 As to dioptric beehives [i.e provided with glass windows on opposite sides] the best I have seen is of wood. 1860 J. P. Kennedy W. Wirt II. xiii. 220 These few fragments..give us..glimpses into that ‘dioptric bee hive’, the heart of the writer. |
B. n.
1. = diopter 1.
| 1849 Otté tr. Humboldt's Cosmos II. 545 The Alexandrian astronomers..possessed..solstitial armils, and linear dioptrics. |
2. A unit for expressing the refractive power of a lens, being the power of a lens whose focal distance is one metre.
| 1883 Syd. Soc. Lex., One dioptric, which is written 1 D, is a glass of one meter, or 39·37 inches, focal distance. 1887 A. Bruce in Encycl. Brit. XXII. 373. |
3. pl. dioptrics: that part of the science of Optics which treats of the refraction of light. (Opp. to catoptrics.)
| 1644 Digby Nat. Bodies i. (1645) 131 The demonstration..Renatus Des Cartes has excellently set down in his book of Dioptrikes. 1667 Phil. Trans. II. 626 The Dioptricks, that consider Rays Refracted. 1718 J. Chamberlayne Relig. Philos. (1730) II. xxii. §41 One that is well versed in Dioptricks, and understands the Nature of Vision. 1831 Brewster Optics Introd. 3 Light..through transparent bodies is transmitted according to particular laws, the consideration of which constitutes the subject of dioptrics. |