LUIGI GALVANI

The best known scientists are usually the men who discover important natural laws. Newton, Darwin and Einstein are examples. But the humbler, rank-and-file workers who do more than amass new facts from their experiments are equally important for the advancement of science. Such a figure was Luigi Galvani.

Luigi Galvani spent his life experimenting. He was an extremely skilful worker and an accurate recorder. It is probably, however, that he would have remained unknown except for a single observation he made during during the course of his investigations. This observation was to pave the way for the great understanding of electricity and its subsequent use of as a source of power.

Luigi Galvani was born in Bologna, Northern Italy, during the year of 1737. Theology was his first study but he gave this up in favour of a medical career, He lived in Bologna all his life, first practising as a physician and then lecturing on medicine at the University. In 1775 he was made Professor of Anatomy there.

His early investigations were concerned with structural differences in various kinds of animal. In 1780, when he was 43, he started a series of experiments to show the effect of electricity on the action of the muscles. This work took eleven years to complete, and involved hundreds of experiments with animal preparations usually frogs legs. In the course of these detailed studies he unknowingly stumbled across many electrical phenomena electric waves, electromagnetic induction and electric oscillations. He never followed up this work however, and understanding and explanations of these phenomena came much later.

Late 1780s diagram of Galvanis experiment on frog legs.

A New Source of Electricity

For his chief supply of electric current, Luigi Galvani used the simple electrostatic machines of the day. They were primitive devices that had to be charged by friction. For his other supply he used electrical disturbances in thunderstorms which meant carrying out experiments in the open during violent weather. At every lightning flash, the leg muscles of the frog would contract. To conduct the atmospheric electricity to the leg Luigi Galvani used large metal objects. For instance he would place the leg muscle in contact with an iron fence while the nerve was attached to a brass hook. In 1786 he made the observation which had bought about his fame. HE noticed that if the two metals he used for conduction were in contact, the muscle would still contract even when the skies were clear. He carried out similar experiments inside with the same result. He also found that the strength of the conduction depended upon the metals used.

Here was a new source of electricity independent of friction machines of lightning. Unfortunately Luigi Galvani never realized the importance of the discovery. He himself though the electricity came from the animal. It was left to fellow Italian, Alessandro Volta, to show that the electric current was in fact produced by the two metal surfaces making contact.

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