$1,353
18th Century Brass Cased Alidade or Patent Plane, France, black-enameled brass instrument with removable outer case, single-draw eyepiece at one end, 45 degree rectangular glass viewing port at the other end, knurled adjustment knob that regulates the steel vernier marked 26-56 , engraved main plate with logarithmic height, angle and distance scales, engraved Hauteurs des Objects (heights of objects), and Echell de Degres (scale of the degree), interior geared clockwork mechanism, split secondary mirror, and horizon mirror, edge of instrument also with scale from 150-2400, all housed in a fitted spalted wood case with pierced brass handle and key, instrument lg. 12 in.
Auctioneer:
Skinner
Date:
2016-04-29