John davis and son co. baltimor Md. Animometer

Usually these werre aluminum but there could have been brass ones , should have three subsidary dials for hundred , thousand and ten thousand feet, It is considered rare in aluminum as just after it was first sold the side effects of using aluminum in a coal mining atmosphere was discovered, This may be the solution as it would have been remanufactured out of brass to solve the problem , I know the aluminum one goes for 200 to 400 dollars not sure of the brass but assume it is less maybe 100 to 200 dollars but this is a niche group  and you have to find the buyer. 

you might go to 

http://miningartifacts.homestead.com/Anemometers.html

to compare what you have to others