Found here in Maine, this is a salty old flotation compass from the time when the mariner’s compass was read by the points, not degrees.
The compass is five inches across the top with a four-inch card. It still contains at least half of its fluid and works well. The box mount is 7.5 inches square. The compass is mounted to stand up from the box on gimbals. The unit stands 4.5 inches tall.
I was tempted to clean and restore this old timer, but you may want to leave it as is. The brass and bronze have a light patina of sea green. The box has seen a lot of sea time and was, at some point, reinforced with bronze screws.
You can bet it has seen many a fish come over the rail. I believe it dates from 1900 to 1915.