| 释义 |
ˈcrown-ˌglass
A kind of glass composed of silica, potash, and lime (without lead or iron), made in circular sheets by blowing and whirling.
It is the sort commonly used in Great Britain for windows, and the best quality is used in combination with flint glass to render dioptric instruments achromatic.
1706Phillips (ed. Kersey), Crown-glass, the finest sort of Glass for Windows. 1718Freethinker No. 95. 283 A poor Barber..had above Fifty Shillings Worth of Crown-Glass demolished. 1758Dollond in Phil. Trans. L. 740 The crown glass seems to diverge the light rather the least of the two. 1807T. Thomson Chem. (ed. 3) II. 508 Crown-glass is made without lead. It is therefore much lighter than flint-glass. 1881Every Man his own Mechanic §1678 Crown glass is circular in form with a thick lump called a bull's-eye in the centre. |