Hello Bulb Pro's I am a bulb ignoramous, however I found some bulbs in my great grandfathers collection and one I find interesting. Around the brass it says MANF'D BY I T-H. ELEC. CO. LYNN, MASS USA on the other side it says PATENT JAN 7 1879 MAY 12 1885 Patent applied for. On the bottom of brass says F-11-90, also instead of the brass threading into the lamp, the lamp threads into the brass. It does work, can any of you guys tell me what it is? Thank you so much.
