The various manufacturers of lamps in nearly every instance made bases that were very different from one another. No less than fourteen different standard bases and sockets came into commercial use. These were known as, Brush-Swan, Edison, Edi-Swan (double contact), Edi-Swan (single contact), Fort Wayne Jenny, Hawkeye, Indianapolis Jenny, Loomis, Mather or Perkins, Schaeffer or National, Siemens & Halske, Thomson-Houston, United States and Westinghouse. In addition there were later larger sized bases made for use on series circuits. These were called the Bernstein, Heisler, Large Edison, Municipal Bernstein, Municipal Edison, Thomson-Houston (alternating circuit) and Thomson-Houston (arc circuit). Some of these bases disappeared from use and in 1900 the proportion in the United States was about 70 per cent Edison, 15 per cent Westinghouse, 10 per cent Thomson-Houston and 5 per cent for all the others remaining. A campaign was started to standardize the Edison base, adapters being sold at cost for the Westinghouse and Thomson-Houston sockets so that Edison base lamps could be used. In a few years the desired results were obtained so that now there are no other sockets in the United States but the Edison screw type for standard lighting service. This applies also to all other countries in the world except England where the bayonet form of base and socket is still popular.
Bernstein.
Heisler.
Thomson-Houston
(alternating current).
Thomson-Houston
(arc circuit).
