09-031. English, late 4th quarter 18th century, signed in script "G Adams London". Made of bright polished brass, 6" long (when closed) x 1 1/2" wide, with pivoting center spline that forms a triangle with the legs of the sector to keep them open the required amount while the section is being used. The sector is in very good overall condition and the edges and engraving are still sharp.
