细节
A ROSEWOOD BACK-STAFF BY BENJAMIN MACY, CIRCA 1717
the boxwood arcs divided over one side, the great arc to 25°, the lesser arc to 60°, signed on the cross bar MADE BY [?MRCS] BENI MACY FOR MR WILLIAM BRYMER 1717, together with horizon vane -- 26in. (66cm.) overall.