Azimuth sight for use with a Kelvin-type, 8 inch diameter, dry card compass. Butterfly-wing base with metal spring foot and 2 prong-feet. Weighted at one end with circular bubble level. Location pin for the center of the compass glazing. Missing vertical axis pin. Inclined sighting tube with fixed magnifying lens above a pointer for reading the compass rose. Mounted above the tube, a rotating, triangular bracket for holding a sighting prism (missing). The milled screws at the ends of the bracket each have an arrow on their heads; arrows indicate the position of prism. Two hinged semicircular tinted glass shades also mounted above the tube.
Material
Signed on a brass plate on the front of the instrument: Kelvin, Bottomley & Baird, Ltd. | Glasgow & London
Base stamped with North American retailer's name: "WILFRED O. WHITE/ BOSTON. U.S.A."
Marked on the brass plate: Patent numbers | 9514 -- 1905 | 20185 -- 1908 | No. 10739
