Early days of electricity

There is electricity everywhere in the world. It is present in the atom, whose particles are held together by its forces; it reaches people from the most distant parts of the universe in the form of electro-magnetic waves. Yet people have no organs that could recognize it as they see light or hear sound. Humans have to make it visible, tangible, or audible they have to make perform work to become aware of its presence. There is only one natural phenomenon which demonstrates it unmistakably to people’s senses of seeing and hearing – thunder and lightning; but they recognize only the effects – not the force which causes them.

Living generation cannot blame the ancient Greeks for failing to recognize that the force which causes a thunderstorm is the same which they observed when rubbing a piece of amber: it attracted straw, feathers, and other light materials. Thales of Miletos, the Greek philosopher who lived about 600 B. C, was the first who noticed this. The Greek word from amber is electron, and therefore Thales called that mysterious force «electric». For a long time is was thought to be of the same nature as the magnetic power of the loadstone since the effect of attraction seems similar, and in fact there are many links between electricity and magnetism.

There is no other evidence that electricity was put to any use at all in antiquity, except that the Greek women decorated their spinning-wheels with pieces of amber: as the woolen threads rubbed against the amber it first attracted and then repelled them – a pretty little spectacle which relieved the boredom of spinning.

More than two thousand years passed after Thales’s discovery without any research work being done in this field. It was Dr. William Gilbert, Queen Elizabeth the First physician in-ordinary, who set the ball rolling. He experimented with amber and loadstone and found the essential difference between electric and magnetic attraction. For substances which behaved like amber – such as glass, sulphur sealing–wax – he coined the term “electrica”, and for the phenomenon as such the word “electricity”. In this famous work De magnete, published in 1600, he gave an account of his studies. Although some sources credit him with the invention of the first electric machine, this was a later achievement by Otto von Guericke, inventor of the air pump.

Von Guericke’s electric machine consisted of a large disc spinning between brushes; this made sparks leap across a gap between two metal balls. In 1700, an Englishman by the name of Francis Hawksbee produced the first electric light: he exhausted a glass bulb by means of a vacuum pump and rotated is at high speed while rubbing it with his hand until is emitted a faint glow of light.

A major advance was the invention of the first electrical condenser, now called the Ley den jar, by a Dutch scientist. A water-filled glass bottle coated inside and out with metallic surfaces, separated by the non-conducting glass; a metal rod with a knob at th machine it stored enough electricity to give anyone who touched the knob a powerful shock.

Benjamin Franklin, born in Boston, was the fifteenth child of a poor soap-boiled from England. He was well over 30 when he took up the study of natural phenomena.

“We had for some time been opinion, that the electrical fire was not created by friction, but collected, being really an element diffused among, and attracted by other matter, particularly by water and metals,” wrote Franklin in 1747. It dawned on him that thunderstorms were merely a discharge of electricity between two objects with different electrical potentials, such as the clouds and the earth. He saw that the discharging spark, the lightning, tended to strike high building and trees, which gave him the idea of trying to attract the electrical “fluid” deliberately to the earth in a way that the discharge would do no harm.

In order to work this idea out he undertook his famous kite-and-key experiment in the summer of 1752. During the approach of a thunderstorm he sent up a silken kite with an iron tip; he rubbed the end of the kite string, which he had soaked in water to make it a good conductor of electricity, with a large iron key until sparks sprang from the string – which proved his theory. His theory was that during the thunderstorm a continual radiation of electricity from the earth through the metal of the lightning-conductor would take place, this equalizing the different potentials of the air and the earth so that the violent discharge of the lightning would be avoided. The modern theory, however, is that the lightning-conductor simply offers to the e top reached down into the water. When charged by an electric machine it stored enough electricity to give anyone who touched the knob a powerful shock.

Benjamin Franklin, born in Boston, was the fifteenth child of a poor soap-boiled from England. He was well over 30 when he took up the study of natural phenomena.

“We had for some time been opinion, that the electrical fire was not created by friction, but collected, being really an element diffused among, and attracted by other matter, particularly by water and metals,” wrote Franklin in 1747. It dawned on him that thunderstorms were merely a discharge of electricity between two objects with different electrical potentials, such as the clouds and the earth. He saw that the discharging spark, the lightning, tended to strike high building and trees, which gave him the idea of trying to attract the electrical “fluid” deliberately to the earth in a way that the discharge would do no harm.

In order to work this idea out he undertook his famous kite-and-key experiment in the summer of 1752. During the approach of a thunderstorm he sent up a silken kite with an iron tip; he rubbed the end of the kite string, which he had soaked in water to make it a good conductor of electricity, with a large iron key until sparks sprang from the string – which proved his theory. His theory was that during the thunderstorm a continual radiation of electricity from the earth through the metal of the lightning-conductor would take place, this equalizing the different potentials of the air and the earth so that the violent discharge of the lightning would be avoided. The modern theory, however, is that the lightning-conductor simply offers to the elec any rate – even if Franklin’s theory was wrong – his invention worked.

It was he who introduced the idea of «positive» and «negative» electricity, based on the attraction and repulsion of electrified object. A French physicist, Charles Augustin de Coulomb, studied these forces between charged objects, which are proportional to the charge and the distance between the objects; he invented the torsion balance for measuring the force of electric and magnetic attraction. In his honor, the practical unit of quantity of electricity was named after him.

What was the phenomenon of «action at a distance» caused by electric and magnetic forces? In 1780, one of the greatest scientific fallacies of all times seemed to provide the answer. Aloisio Galvani, professor of medicine at Bologna, was lecturing to his students at his home while his wife was skinning frogs, the professor’s favorite dish, for dinner with his scalpel in the adjoining kitchen. As she listened to the lecture the scalpel fell from her hand on to the frog’s thigh, touching the zinc plate at the same time. The dead frog jerked violently as though trying to jump off the plate. The professor, very indignant about this interruption of his lecture, strode into the kitchen. His wife told him what had happened, and again let the scalpel drop on the frog. Again it twitched. No doubt the professor was as much perplexed by this occurrence as his wife. But there were his students, anxious to know what it was all about. Galvani could not admit that he was unable to tric tension a path of low resistance for quiet neutralization. At explain the jerking frog. So, probably on the spur of the moment he explained: «I have made a great discovery – animal electricity, primary source of life!» Galvani made numerous and unsystematic experiments with frogs’ thighs, most of which failed to prove anything at all; in fact, the professor did not know what to look for except his «animal electricity». These experiments became all the rage in Italian society, and everybody talked about «galvanic electricity» and «galvanic currents» - terms which are still in use although Professor Galvani certainly did not deserve the honor.

A greater scientist than he, Alessandro Volta of Pavia solved the mystery and found the right explanation for the jerking frogs. Far from being the «primary source of life», they played the very modest part of electric conductors while the steel of the scalpel and the zinc of the plate were, in fact, the important things. Volta showed that an electric current begins to flow when two different metals are separated by moisture (the frog had been soaked in salt water), and the frog’s muscles had merely demonstrated the presence of the current by contracting under its influence.

Professor Volta went one step further – a most important step, because he invented the first electrical battery, the «Voltaic pile». He built it by using discs of different metals separated by layers of felt which he soaked in acid. A «pile» of these elements produced usable electric current, and for many decades this remained the only practical source of electricity. From 1800, when Volta announced his invention, electrical research became widespread among the world’s scientist in innumerable laboratories.