The Baghdad Battery is an earthenware vessel found in 1936 in Khujat Rabua (near Baghdad) by German archaeologist Wilhelm König. König speculated that it was a galvanic cell. These hypothetical cells were reconstructed and filled with solutions of acids known in Mesopotamia at that time (acetic and citric). The batteries began to work. The age of these finds is estimated to be in the middle of the 3rd century BC. ¹⁾

Water hydrolysis begins to occur in lead batteries while being recharged. Normally, the vents are sufficient to evacuate the oxygen and hydrogen, but if the battery is heavily overcharged, the concentration of the mixture can rise to explosive levels. ²⁾

Luigi Galvani (born September 9, 1737, in Bologna, died December 4, 1798) was an Italian physicist, physician, physiologist and Franciscan tertian. From 1763 he was a professor at the University of Bologna. During anatomical studies on frogs, he made a famous discovery of the phenomenon of electrical excitation of organs, which he attributed (erroneously) to what he called “animal electricity.” ³⁾

A Leyden jar is an electrical charge storage device that was the first capacitor. It is a glass bottle whose two surfaces, outer and inner, are covered with isolated layers of metal. These layers act as the covers of the capacitor, while the glass of the bottle is the insulator. ⁴⁾

Electric eels inhabit the muddy waters of the Amazon and Orinoco floodplains. These are fortunately sparsely inhabited areas, as the electric eel can easily kill a human. It cannot eat them (it has no teeth, so it can only swallow small prey), but its electrical discharge is enough to stun and drown a horse. ⁵⁾