alidade

/al-i-deyd/US // ˈæl ɪˌdeɪd //UK // (ˈælɪˌdeɪd) //

杏仁糖,杏仁饼,杏仁,杏仁酸

Definitions

n.名词 noun

1
Surveying.
- : a straightedge having a telescopic sight or other means of sighting parallel to the straightedge.
- : the entire upper part of a theodolite or transit, including the telescope, its supports, the level vials, the circle-reading device, and the spindle.

Field artillery required a precision instrument known as the miniature telescopic alidade of the Gale type.
A very simple alidade may be made by mounting two needles on a ruler.
Close by stood an alidade, an instrument for measuring angles.
After he had placed the plane table on a tripod and upon this the alidade, he started to work.
The alidade is a triangular ruler with one or more working scales on it beside other measurements.