alidade

Mr. Dalton showed the couple around the lookout, explaining the old telephone system and the fire finder, a type of alidade used by fire lookouts.

The complete instrument would also have had a rotating pointer, called an alidade, mounted on a pin running through the central hole.

One morning when Ishmael was eight years old a pair of surveyors had showed up with their transits and alidades and knotted red flagging everywhere.

An additional article of the sketcher's equipment is a holder for his pencils, alidade, eraser, knife, pins, etc.

Problem.—By use of the slope scale on the sketch board and the contour interval scale on the alidade, each man will secure vertical data on the flat sketch made in the fourth lesson.