The Dendera "light bulb": what the inscription beside it says

In a crypt beneath the Temple of Hathor at Dendera there are reliefs showing an elongated bulb-like shape containing a snake, resting on or emerging from a stylised lotus flower, with a supporting pillar figure beside it.

The resemblance to a Crookes tube or an early incandescent lamp is genuine, and the reading that this depicts electrical technology has been in circulation for decades.

It is unusually easy to test, because Egyptian temple reliefs are captioned.

What is documented

The temple is Ptolemaic, largely first century BC, built over a much older sacred site. The crypts held cult objects and their walls carry ritual scenes.

The reliefs are accompanied by hieroglyphic text. The text is legible, has been translated, and describes a creation scene: the lotus from which the sun emerges, the serpent as a form of the newborn sun god, and the djed pillar supporting it.

The bulb

The enclosing shape has been read as a glass envelope. In Egyptological terms it is generally understood as a representation of the lotus flower or of the primeval hill and waters from which creation emerges — the serpent contained within the thing that produces it.

The "cable" running to it is the lotus stem, which is drawn the same way in scenes that contain no bulb at all.

How Egyptian tombs were actually lit

The soot argument is worth taking apart properly, because it is the one piece of the case that is not about the relief.

Egyptian lamps burned oil, usually castor or sesame, with a wick of twisted linen. Adding salt to the oil substantially reduces smoke, and the practice is described in classical sources.

Soot has in fact been identified in tombs, examined and published — including deposits that have been radiocarbon dated to establish when work was carried out. The premise that tombs are soot-free is simply incorrect.

Polished copper or bronze mirrors were also used to reflect daylight down passages, relayed from one to the next. It works, it has been demonstrated in situ, and it leaves no residue at all.

The engineering objections

Separate from the text, and worth stating because they stand alone.

An electric lighting system requires a power source, conductors, an evacuated envelope and a filament. No component of any of these has been recovered from Egypt. No workshop, no failed prototype, no waste from manufacture, no text describing production.

The argument usually advanced for electric light — that tombs show no soot — has a documented answer. Egyptian lamps burned oil with salt added, which greatly reduces smoke, and soot deposits have in fact been found in tombs and studied. Polished reflectors were also used to direct daylight into passages.