Notice the fragment of the broken Bristol cardboard filament in the neck of the lamp. The socket is the first of its kind to be produced for an incandescent lamp – a circular piece of hollowed-out wood. Crude as this may be, it was the most innovative way to date of keeping the bulb in place by simply inserting the neck of the bulb into the socket and then tightening the thumbscrew. This type of socket was in production for only a few months before the advent of the threaded base and socket. See Figure 153?
for a print showing how this Bristol filament bulb was connected to the electric circuitry.