Nice clean form, suitable for a gentleman's study or the local tavern.

But you missed the chimney which is cut off the top of the reference image, the chimney is a second glass bulb/tube inside the glass shade: 

http://www.antiquelampco.com/Lamps/GWTW.gif

http://www.hartleysauctions.co.uk/AuctionImages/587FEB07.JPG

http://www.antiquelampco.com/Catalog/Chimneys.htm

Texture map reference:

decorative glass etching: 

http://www.1818auctioneers.co.uk/auctions/images/3/2.jpg

http://www.antiques-atlas.com/dealer-stock-images/debdenantiques/A_Fine_...

this same model can be textured with a glass base: 

http://www.riverjunction.com/thumbnail.asp?file=assets/images/productima...

http://www.paxtonhardware.com/images/10MagnoliaSeries.gif