Details
A 19th-Century circular brass swinging-arm protractor,
signed on the alidade Troughton London, with folding pin arms and adjustable by external rack and pinion gear, with single vernier, in shaped and fitted mahogany case -- 9 3/8in. (23.8cm.) dia.
See Illustration (Front Cover)
signed on the alidade Troughton London, with folding pin arms and adjustable by external rack and pinion gear, with single vernier, in shaped and fitted mahogany case -- 9 3/8in. (23.8cm.) dia.
See Illustration (Front Cover)