Reverse painted desk lamp. Inherited. Brass finished square base, very heavy

The descriptions above tell pretty much all I know about this lamp. I do know that it was in my piano teacher's home (born 1922) when she was a child. Shade is painted inside a forest/lake scene. Base is brass in appearance. Angle of "stem" and angle of shade can be changed by loosening the knobs. Condition is excellent. Has new green felt on bottom and I am wondering if the manufacturer name might be under there? Looks beautiful lit up in a dark room. Quite heavy and in excellent working condition and in appearance as well. My wife and I are moving to a smaller home and will be selling my grand piano, so the lamp should go too. I would like to know of its manufacturer history and if permitted here, approximate value as I will be selling it ...probably on E-Bay. Thank you so VERY much!! If you can help me out, I would be most grateful for an e-mail to [email protected]