Unless I'm mistaken, (with antique phones & electric fans from around the turn of century) brass was considered "tacky" and was painted/blackened in a process called "Japaned." (Heavy enamel paint & coats of varnish to imitate Asian lacquerwork according to the wiki.)
So if it was from a very upscale place-- wonder if it was originally glossy black & someone "brassed it out" along the way.
Nice piece though. And since it's brass-- very good to know it hasn't been soldered to someone's steam-punk crafts. Nothing against them... Except when they start dismantling antiques just to make a fashion statement. Ack!
Anyway, congrads on it! Imagine you have quite a collection of penstaffs & ink wells.
--Bruce