Vintage Antique Stove Finial Top

Brass vase that twist with holes in the bottom like a grinder.
It's a very nice vase,but what's it used for.It twist in four places.The second pic in one of the places it twist at the bottom and at the top it twist right at the neck of the vase.The bottom has holes and a screw and nut.The spout has some kind of cover over the opening.I thought it was just a pretty vase.I could not find any marking on it and I really don't want to take it apart to look.I would like to know what it is and how old it is. Help and Thanks to anyone who can tell me.