The first electrical battery was born as a result of one of the most famous scientific disputes. During the eighteenth century, the Italian doctor Luigi Galvani of Bologna carried out a series of experiments on dead frogs. Galvani obtained vibrations in the muscles of the animals hung from copper hooks over an iron rod. From these twitchings Galvani deduced that the frog possessed electric properties, although he was mistaken in thinking this.

But his work was valuable even though it produced faulty conclusions because it opened the way to the study of electricity by such scientists as Alessandro Volta, another Italian. Volta turned Galvani's theory on its head by saying that the frog had 'conducted' electricity which had been generated in the contact between the two metals.

After many fierce arguments Volta won the day. Using his own theories, he went on to invent the electric battery by placing zinc and copper in a bath of acid water and so provided a source of continuous current.

Modern physics has revealed the real nature of electricity, a mysterious force which has been known to man since the earliest times. All substances in which the atoms have been placed out of balance because they lack certain electrons or because they have too many of them are called either positively charged or negatively charged. Positive charges are composed of atoms or molecules which have lost one or more electrons and negative chargers consist of atoms which for some reason have more than their normal number of electrons.

Electrons which pass from one atom to another inside a material such as a copper wire, form an electric current. This current flows extremely fast from one end of the wire to the other.=

When the current flows in the same direction, it is called direct current or D.C. This is the type of current generated by a battery as opposed to an alternating current, A.C., which changes its flow to a well defined frequency.