This early electric table lamp was manufactured by the Pittsburgh Lamp, Brass and Glass Co between 1901 and 1926 when the company when bankrupt and was re-named. They used the name "Pilabasco" as the more formal name, but that name didn't catch on as easily as Pittsburgh Lamps. You will note the thumb screws are embossed with the PILABRASCO label as seen below. The base is rather plain two toned brass, but the shade is a gorgeous cased green glass and cut thru to the under laying white in a decorative pattern. The textured surface of the shade makes an interesting distortion of the light coming from a single socket. Re-wired at some point recently and working well with the pull chain.
Size ................ 20" Tall x 14" Diameter Shade, 8" Diameter Base Circa .................. 1920-26