† hemispherulen.
Obsolete.
A half spherule; a small hemispherical lens.
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the world > physical sensation > sight and vision > optical instruments > lens > [noun] > other lenses
concave1632
globe1653
meniscus1693
hemispherule1696
convex1705
omphaloptic1728
omphalopter1738
crown lens1764
achromatic1785
condenser1798
meniscus lens1820
Fresnel lens1835
bull's-eye1839
Stanhope lens1850
spot lens1860
amplifier1866
achromat1873
projectora1884
aplanat1890
triplet condenser1892
Aldis lens1902
monocentric1922
Schmidt correcting plate1934
coated lens1948
Panavision1955
Schmidt correcting lens1961
re-imaging1962
1696 W. S. Gray in Philos. Trans. 1695–7 (Royal Soc.) 19 281 I was wont to Grind them [sc. glasses] and Polish them on a brass Plane, and so reduce them to Hemispherules.
1756 T. Amory Life John Buncle I. 334 They have them [sc. microscopes] of all kinds, of one and more hemispherules.
This entry has not yet been fully updated (first published 1898; most recently modified version published online June 2019).
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n.1696