object-glassn.

1663 R. Hooke Let. 3 July in R. T. Gunther Early Sci. in Oxf. (1930) VI. 140 I have made a microscope object glass so small, that I was fain to use a magnifying glass to look upon it.

1665 R. Hooke Micrographia ii. 4 I..plac'd it between the Object-glass & the light.

1673 Philos. Trans. (Royal Soc.) 8 6110 The Distinctness of the Picture, which..a Twelf foot Object glass casts into a darken'd room.

1703 Philos. Trans. 1702–3 (Royal Soc.) 23 1390 Only you are to remember to place the external smooth surface of the Lungs toward your Object Glass when you view it.

1785 W. Herschel in Philos. Trans. (Royal Soc.) 75 44 Turning or unscrewing the object-glass or speculum a little.

1829 Nat. Philos. (Libr. Useful Knowl.) I. Optics x. 27 The triple achromatic object-glass..consists of..a concave flint glass lens placed between two convex lenses of crown glass.

1839 G. Bird Elements Nat. Philos. 390 The magnifying power of these telescopes is found by dividing the focal length of the object-glass by that of the eye-glass.

1874 ‘G. Eliot’ Middlemarch vii. lxiii. 474 A man's mind must be continually expanding and shrinking between the whole human horizon and the horizon of an object-glass.

1924 A. D. H. Smith Porto Bello Gold ix. 117 My great-uncle, after a single squint through his object-glass, handed the instrument to me.

1955 H. C. King Hist. Telescope xix. 432 The telescope is equipped with both a visual and a photographic object-glass.

1998 Sci. Amer. Aug. 6/2 The three principal defects of the ordinary field glass are overcome by the use of two pairs of prisms, which erect the inverted image formed by the object glass.