| 释义 |
† peˈractor
[Agent-n. f. L. peragĕre to peract.]
Name of an obsolete surveying instrument.
1674Leybourn Compl. Surveyor 237 An Instrument which he calleth a Peractor, which is no other than a Theodelite, only the Box and Needle is so fitted to the Center of the Instrument, that..the Index may be turned about, and yet the Box and Needle remain immoveable. 1766Compl. Farmer s.v. Surveying, For the doing of this, there are several instruments very proper, especially Mr. Rathburn's quadrant upon the head of his peracter. |