Electricity – completely common and ordinary for us, contemporary people – may not be the most perfect form of energy, but in our world it has gained a dominant position. Its popularity was determined by its versatility – the possibility of being replaced with measures that could satisfy generally all human needs. The two past centuries of inventions and of the development of technology and science have to a large extent told us a story of newer and newer equipment making use of electricity. In 1821, Michael Faraday discovered the phenomenon of electromagnetic rotation, which contributed to the invention of an electric motor in subsequent years. In 1833, Carl Friedrich Gauss and Wilhelm Weber built an electrical telegraph, and in 1854 Heinrich Göbel lit the first light bulb. Since the 19th century electricity generated at one site has been used somewhere else for work, entertainment and data transfer purposes or as a source of heat and lighting. Extracting and harnessing this invisible power locked in seemingly inanimate matter, was a challenge inspiring the preeminent minds in the history of civilization, from Thales of Miletus, to Albert Einstein, Nikola Tesla and many others.
Early humans had already encountered the presence of electrical energy in nature, but the blinding flashes of lightning, the roar of thunder and the damage they wrought effectively deterred people from attempting to use it in practice, and for thousands of years it remained in the realm of supernatural phenomena. Thunderbolts were divine attributes – in Egyptian mythology they were associated with Seth, in Nordic countries with Thor, in the Mediterranean with Jupiter (Rome) and Zeus (Greece), and in the Slavic territory – Perun. The effects of a thunderbolt could be both creative and destructive; the first lightning during a storm reputedly impregnated the soil. The belief in the close connection between lightning and deities lives on: even today during thunderstorms, special blessed candles can be seen burning in the windows of some homes. In Polish the name of a candle ‘gromnica’ derives from ‘grom’ (thunderbolt).
Saint Erasmus of Formia, also known as Saint Elmo, was preaching when a thunderbolt struck the ground beside him. Undaunted, the preacher continued his sermon and his courage won the hearts of his audience. Since then he has been the patron saint of sailors who ask for his intercession during storms. The electrical discharges at the mastheads and yards of ships, aerial posts or airplane wings came to be called after him as “Saint Elmo’s Fire”.
Some authors claim that the first historical traces of the “rational” interest in electricity should be looked for in ancient Egypt. Items depicted on the walls of a temple dedicated to the goddess Hathor in Dendera allegedly represented electric lamps. Visually, everything seems to fall into place: a filament symbolised by a snake inside a glass bulb, lotus stalks and flowers signifying wires and a socket and “something” that resembles modern insulators. Based on that image, an Austrian engineer, Walter Garn, constructed a functioning device that generated some light. Yet, there was the question of power supply: assuming it was a receiver, where were the sources of energy? They were enthusiastically “discovered” in nearby Baghdad: clay vessels with a copper cylinder inside and sealed with plugs set in asphalt.
When the device was reconstructed and filled with organic acid, a reaction occurred whereby a voltage of about 0.5 V was generated. However, upon closer analysis it turns out that the desire to prove the preconceived hypotheses at all costs led the “researchers” to a strained interpretation of the facts. Frank Dörnenburg’s critical analysis of both the reliefs in Dendera and the Baghdad battery disproved the claims of the proponents of electrification in the land of the pharaohs. The images on the temple walls refer to New Year celebrations: the snake symbolizes the dawn and sunrise, whereas the vessels discovered in Baghdad were used by artisans to plate jewellery with gold and silver and could not be an effective source of electricity.
The hypothesis on the electrostatic properties of the Ark of the Covenant seems more plausible. According to the instructions recorded in the Book of Exodus, the Ark was made of “acacia wood; two and a half cubits shall be its length, a cubit and a half its width, and a cubit and a half its height. And you shall overlay it with pure gold, inside and out you shall overlay it, and shall make on it a moulding of gold all around”. Two conductor layers separated by a dielectric – it is a schematic of a capacitor! To operate that “capacitor” one had to wear special protective clothing (priest’s vestments) and undergo proper training. Young priests who had not yet acquired the secret knowledge or sacrilegious individuals who dared reach out their hand to the Ark of God, died: “So fire went out from the Lord and devoured them and they died before the Lord”. It can be guessed that the Ark (capacitor) was charged when rubbed by the priests or with the aid of “ambient electricity” – one layer was connected to the ground and the other to a metal object situated at sufficient height (e.g. the roof of a temple). The Bible says that when Moses grew up at the pharaoh’s court, he learned the secrets of Egyptian priests who had already been able to produce capacitors used to protect fortresses and temples against robberies. According to mythology, that knowledge was bequeathed to them by Horus – the god of the sky.