On the basis of this picture engineer W. Garn constructed a working device which indeed gave some light. In the book of Krassa/Habeck we find he following sketch and description:
 

Zeichnung Garn-Birne

The above picture is a copy of a hieroglyph which can be found in the basement of the temple of Dendera in southern Egypt. There are many crypts at the temple of Dendera. This is a hieroglyph which displays evidence of an ancient Egyptian light bulb. We know that glass was used in ancient Egypt for decorative objects as well as other things. The crypt above depicts what looks like a power cord leading to a socket, attached to this socket is a transparent glass tube. Its a light bulb. Erich Von Daniken, a well known archeologist, had a model of this light bulb built, and you know what? It worked!!!   The serpent portrayed in the above picture  is a plasma like light when the light bulb is electrified.

Erik von Dänekin examining the image on the wall at Hathor's Temple at Dendera

In his book The Eyes of the Sphinx pp. 171-173, Erich Von Däniken writes that the relief is found in "a secret crypt" that "can be accessed only through a small opening. The room has a low ceiling. The air is stale and laced with the smell of dried urine from the guards who occasionally use it as a urinal." The room is not so secret, however, as many tourists visit and photograph the room every year. Von Däniken sees the snake as a filament, the djed pillar as an insulator, and claims that "the monkey with the sharpened knives symbolizes the danger that awaits those who do not understand the device." This "device" is, the reader is assured, an ancient electric light bulb.

The Following are screen shots from a short video clip on the Dendera Lightbulb;

The Laboratory

The Light Bulb

Powered up - the "Snake" Arcs to the Posts

It Works!! See the video clip here.