We have two one of these white enameled metal lamps left. They have labels from the Quadrangle Manufacturer Corporation from Chicago. The standard dome reflector style was being made in 1930 (according to an archived catalog). 

United States, circa 1930

12"H X 13.75" Diameter

Materials and Techniques: Enameled Aluminum Shades, Industrial nuts and bolts, wiring. 

Condition: Good. This item has signs of wear and use as is normal for an older piece including: surface oxidization and minor scratches in black paint on rimmed edge. 

Reference: DP185