| 释义 |
backsight|ˈbækˈsaɪt|
[f. back adv.]
a. In Surveying, a ‘sight’ or reading taken backwards, or towards the point of starting.
b. The sight of a rifle nearer the stock.
1847E. Cresy Encycl. Civil Engineering I. 802 Compound Levelling is..performed by taking back and forward sights. 1847[see sight n.1 14 b]. 1851R. Glisan in Jrnl. Army Life (1874) 59 A..very heavy and costly gun, with an elevating back sight for shooting at great distances. 1859Musketry Instruct. 10 Firing without using the back-sight. 1860All Y. Round No. 71. 501 The back or elevating sight. 1867Marsh in N.Y. Nation 9 May 373 A backsight is a sight or reading taken backwards; that is, in a direction opposite to that in which the levelling party is proceeding. 1880Times 18 Oct. 4/3 In using the rifle a native rarely avails himself..of the backsight. 1953R. J. C. Atkinson Field Archaeol. (ed. 2) iii. 114 The reading to a turning-point from the previous level station is known as a foresight, and that from the next level station as a backsight. |