Old brass and copper surveyor's instrument... a brass and copper dipping compass or inclinometer with the original case and instructions leaflet. This is a nice old instrument, we're not sure of the exact vintage, probably 1930s or 1940s from the phone number on the instruction leaflet "STanley 8-4361". It probably wouldn't have been made during World War Two because of the brass used, and judging from the case we'd place it at the earlier end of the range.
A dipping compass (or dipping needle) is used to detect variations in the Earth's magnetic field and is used to find buried metal objects, pipes, wires, boxes, marker pegs etc. Surveyors would use a dipping compass to local iron stakes and markers that may have become covered over with dirt and leaves.
This compass is made by the "Municipal Instrument Company, Berwyn, Ill" and measures about 3 3/8" across the compass face. There is flaking to the red paint on the compass needle (and flakes of the red paint inside the case) and a name has been lightly engraved (with a vibrating tool, we think?) on the glass on one side of the compass. There is wear, age and soil to the case.