diˈoptrical, a.
[f. as prec. + -al1.]
† 1. = dioptric a. 1. Obs.
| 1612 Brerewood Lang. & Relig. xiii. 134 Of which height..it is observed in Pliny, that Dicæarchus, by dioptrical instruments, found the hill Pelius..to be. 1656 Blount Glossogr., Dioptrical, pertaining to Dioptra. |
2. = dioptric a. 2, 3.
| 1664 Power Exp. Philos. Pref. 1 Dioptrical Glasses are but a Modern Invention. 1677 A. Horneck Gt. Law Consid. ii. (1704) 17 Little animals..viewed through Dioptrical glasses. 1769 S. Hardy (title), A Translation of Scheffer's Treatise on the Emendation of Dioptrical Telescopes. |
3. Of or belonging to dioptrics; skilled in dioptrics.
| 1664 Power Exp. Philos. i. 78 Dioptrical Artists. 1752 Short in Phil. Trans. LIX. 507 Of a radius somewhat longer than the focal length you want, for a dioptrical reason. 1800 Young ibid. XCI. 27 Dioptrical propositions. |
† 4. = dioptric a. 4. Obs.
| 1759 Sterne Tr. Shandy I. xxiii, To have gone softly, as you would to a dioptrical bee-hive, and look'd in. |
Hence diˈoptrically adv., by means of refraction.
| 1732 Hist. Litteraria III. 363 To produce very extraordinary Effects..either dioptrically or catoptrically. 1849–52 Todd Cycl. Anat. IV. 1441/2 Dioptrically-formed coloured margins. 1883 Carpenter in Encycl. Brit. XVI. 266/1 s.v. Microscope, Images dioptrically formed of the general outlines and larger details of microscopic objects. |