Hello all, I'm trying to figure out this old Keuffel and Esser pocket transit compass. My goal is to use this to rough survey some family property, not officially survey, I'll have a pro survey done before anything is built, or fenced. If I can get it within a few feet, that will be good enough for now. I believe that, with this compass, I could survey the property, at least enough to know im driving on my own land. I understand how to find a bearing, but I don't know what the rest of it does. It appears to have two levels, a declination adjustment screw(for setting north?), and a strange lever that rotates on the bottom. The rotating lever has the two levels, and a pointer that that reads in degrees on one side and percentage on the other. This compass was owned by my great uncle, whom was a geologist for the Twin Buttes mining company. His job was to survey potential minesites in various parts of the world. Best I can figure is that this compass was built sometime around 1926-1930's-ish, and I cannot find a single resource that shows how to use this thing. I'm hoping you surveyors might know how to use this thing, or at least point me in the right direction. Thank you.