How a Few Frog Legs Triggered the Origin of Electrical Engineering

Abstract

When we were discussing historical events from the beginning of modern technology, a friend of mine used to say, “That was in the days when electricity was still made from frog legs!” With this statement, he referred to the accidental observation by the Italian Luigi Galvani (1737-1798) which actually triggered the tremendous development of electrical engineering. But before I discuss this observation in more detail, let’s have a closer look at the time when all this happened. In those days, all of the scientists who were trying to find new laws for explaining physical phenomena were naturally well familiar with Newton’s findings about mechanics. Newton’s book had been published about one hundred years before Galvani made his observation. In the decades just before this observation, chemistry had made great progress. Until about 1750, most chemists still believed that the air is a simple element which does not play any role in chemical reactions. But within the next twenty years, it was found that air is a composite of different gases. Carbon dioxide was detected as its first component, and soon afterwards the other two essential components, nitrogen and oxygen, were found. At the same time, hydrogen was found. It is reasonable to assume that all scientists who made major contributions to the progress of knowledge about electricity and magnetism were familiar with actual knowledge in the fields of physics and chemistry. But in Galvani’s days, there was not yet much knowledge about electricity and magnetism, and it was still completely unknown that these two are closely interrelated. As in the time of the old Greeks, certain phenomena were well known from every day experience. Certain blocks of iron attract needles and other small iron objects. And by rubbing bodies of certain materials together, attractive or repulsive forces between the bodies can be produced, or sparks can jump from one body to the other. Perhaps you had the experience that you winced because a spark jumped from your hand to a door knob after you walked over a certain flooring material, or your hair stood on end after you took off your woolen hat or used a certain comb.