Please help identify and help locate where I can find this globe-like vintage light bulb.?

I have an antique brass glass-shade floor lamp. It is perfect for me as I play piano. The U shaped glass bowl is attached to an arm that swivels outwards. The light bulb has a very wide screw base that measures 1 1/2 inch wide and is approximately 7 inches tall. This is a three-way bulb. The markings on the bulb top reads Westinghouse Eye Saving 100 200 300w 3-LITE 120V USA. Even so I cannot locate any such bulb online. The shape of this bulb is 360 degrees perfectly round on a 1 1/2 inch neck that is attached to a brass-colored screw base. Please help out. Thank you.