I don't know.
But if it works and it's for sale and you have a PayPal account let me know by pm.
If it is a map scale(I have never seen one in hundreds, leading to thousands, of inches which would make for a hellish big map), and I don't think it is, it is merely a historical doodad and they have as much value as a tool as a buggy whip would.
I think it's a type of runout guage. Or that's what I would use it as, cumulative error measuring of time versus distance in a fabric mill or a lathe or some such. Or simply. To measure diameter precisely and quickly to better than five hundredths on any size pipe up to 10,000 inches. Or expansion of railroad rail at different temperatures.
Thousands of uses, I don't think a map is one of them. Could be, just not a practical scale.