Antique Articulated Folding Brass & Ivory Sector Calculation Aid Tool
Very old antique folding sector hand tool. brass and ivory calculation aid sector rule. Signed G.Davis. Leeds.
A vintage articulated folding handmade scrimshaw sector ruler measuring 12" inches when completely unfolded in deep old yellow ivory.
A sector is an instrument consisting of two rulers of equal length which are joined by a hinge. A number of scales are inscribed upon the instrument which facilitate vario... more»