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 us from the most distant parts of
the universe in the form of electro-magnetic waves. Yet we have no organs that could
recognize it as we see light or hear sound. We have to make it visible, tangible, or
audible, we have to make it perform work to become aware of its presence. There is
only one natural phenomenon which demonstrates it unmistakably to our senses of
seeing and hearing – thunder and lightning; but we recognize only the effects – not
the force which causes them.
Small wonder, then, that Man lived for ages on this earth without knowing
anything about electricity. He tried to explain the phenomenon of the thunderstorm to
himself by imagining that some gods or other supernatural creatures were giving vent
to their heavenly anger, or were fighting battles in the sky. Thunderstorms frightened
our primitive ancestors; they should have been grateful to them instead because
lightning gave them their first fires, and thus opened to them the road to civilization.
It is a fascinating question how differently life on earth would have developed if we
had an organ for electricity.
We 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 В. С, was the first who noticed this. The
Greek word for amber is elektron, and therefore Thales called that mysterious force
'electric'. For a long time it was thought to be of the same nature as the magnetic
power of the lodestone since the effect of attraction seems similar, and in fact there
are many links between electricity and magnetism.
There is just a chance, although a somewhat remote one, that the ancient Jews
knew something of the secret of electricity.
Perhaps the Israelites did know something about electricity; this theory is
supported by the fact that the Temple at Jerusalem had metal rods on the roof which
must have acted as lightning-conductors. In fact, during the thousand years of its
existence it was never struck by lightning although thunderstorms abound in
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 wollen 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's physician-in-ordinary, who set the ball rolling. He experimented with
amber and lodestone and found the essential difference between electric and magnetic
attraction. For substances which behaved like amber – such as glass, sulphur, sealingwax
– he coined the term 'electrica', and for the phenomenon as such the word
'electricity'. In his 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 Gue-ricke, inventor of the
Von Guericke's electric machine consisted of a large disc spinning between
brushes; this made sparks leap across a gap between two metal balls. It became a
favourite toy in polite society but nothing more than that. 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 it at high speed while rubbing it with
his hand until it emitted a faint glow of light.
A major advance was the invention of the first electrical condenser, now called
the Leyden 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 the 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.
More and more scientists took up electric research. A Russian scientist
Professor Richmann from St. Petersburg, was killed when he worked on the same
Benjamin Franklin, born in Boston, was the fifteenth child of a poor soap-boiler
from England. He was well over 30 when he took up the study of natural phenomena.
'We had for some time been of 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. Here was at
last a plausible theory of the nature of electricity, namely, that it was some kind of
'fluid'. 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 buildings
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
experiment1 in the summer of 1752. It was much more dangerous than he realized.
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. Had the lightning struck his kite he, and his small son whom
he had taken along, might have lost their lives.
In the next experiment he fixed an iron bar to the outer wall of his house, and
through it charged a Leyden jar with atmospheric electricity. Soon after this he was
appointed Postmaster General of Britain's American colonies, and had to interrupt his
research work. Taking it up again in 1760, he put up the first effective lightning23
conductor on the house of a Philadelphia business man.
His theory was that during a thunderstorm a continual radiation of electricity
from the earth through the metal of the lightning-conductor would take place, thus
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 lightningconductor
simply offers to the electric tension a path of low resistance for quiet
neutralization. At any rate – even if Franklin's theory was wrong – his invention
Yet its general introduction in America and Europe was delayed by all kinds of
superstitions and objections: if God wanted to punish someone by making the
lightning-strike his house, how could Man dare to interfere? By 1782, however, all
the public buildings in Philadelphia, first capital of the USA, had been equipped with
Franklin's lightning-conductors, except the French Embassy. In that year this house
was struck by lightning and an official killed. Franklin had won the day.
It was he who introduced the idea of 'positive' and 'negative' electricity, based
on the attraction and repulsion of electrified objects. 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
honour, the practical unit of quantity of electricity was named after him.
To scientists and laymen alike, however, this phenomenon of 'action at a
distance' caused by electric and magnetic forces was still rather mysterious. What was
it really? 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 favourite 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 signora screamed. 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 explain the jerking frog. So, probably on the spur of the moment1 he explained: 'I have made a great discovery – animal electricity, the
primary source of life!'
'An intelligent woman had made an interesting observation, but the not-sointelligent
husband drew the wrong conclusions', was the judgement of a scientific
author a few years later. 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 honour.
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 scientists in innumerable
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