Faraday Discovers Electricity

 

The Transformation of Everyday Life

“Prometheus, they say, brought fire to the service of mankind; electricity we owe to Faraday.”
The remark has been made, in our time, by a man who ought to know, Sir William Bragg, winner of the Nobel Prize for physics, holder of a great many other distinctions in the world of science.
And yet this is an astonishing claim, for without electricity the world we live in would be unrecognizable, a world lit by gas lamps and candles, without telephones, radio, television. A horizontal world, for without the electric lift no architect would dare design a building more than three or four floors high. Our spring-driven, needle-powered gramophones would squeak at us through trumpets. Our motor-cars, if, so deprived, we had ever got round to inventing them, would be clumsy, diesel-powered things, with acetylene headlamps, and when we refilled their tanks with diesel oil we would do it, laboriously, by hand pump.
One could go on for ever, for almost everything in our twentieth-century world needs electricity for its functions or its manufacture. How accurate, then, is the claim that we owe all this to Michael Faraday, the nineteenth-century London book-binder who was fired by a lecture on “natural philosophy” and never rested until he had invented half the things we use to-day? What sort of a man was this Faraday, who could do such things?
He was born in London, in 1791, son of a blacksmith and his wife who had walked down from the Yorkshire moors in search of work. They were only partly successful, and from an early age the young Faraday had been forced to go out and earn what he could to augment the meagre family income. When he was nineteen and working as a book-binder, his father died, leaving him to support a widowed mother and a young sister. He might well have remained a book-binder if his employer, a kindly man, had not encouraged him to use his off-duty hours to the best advantage and urged him to attend lectures on the “natural philosophy” we now call science. It was at one of these lectures, at the Royal Institute, that he heard
Sir Humphry Davy. He was so overcome with the wonder of what he heard that he sat down and wrote the great man a letter, enclosing a copy of the notes he had made of the lecture which so enthralled him.
To, his delight, Sir Humphry wrote back, on Christmas live, 1812. “I am far from displeased with the proof you have given me of your confidence, which displays great zeal, power of memory, and attention. It would gratify me to be of service to you; I wish it may be in my power.”
It was within his power, sooner than Sir Humphry had antici­pated. His assistant at the Royal Institution was dismissed for assaulting the instrument-maker; the astonished Faraday was offered the post, at a salary of twenty-five shillings a week and two rooms at the top of the house.
His life and work with Sir Humphry and Lady Davy was stimu­lating and at times exasperating, but he served his master well, not only in London, but on a long and eventful trip about the continent, where Davy lectured in many capital cities and young Michael Faraday was able to meet and talk with many of the great men of science, including Monsieur Ampere and Signor Volta, whose names were becoming, as they have remained, household words in the science of electricity. Faraday had served Davy, whom he wor­shipped, extremely well as “philosophical assistant” in experiments with chemistry and physics, but more and more he was being drawn to the study of this strange electric force which seemed to exist everywhere, to be conjured out of almost anything, like rabbits from a hat, and which, unlike the rabbits, seemed to promise a new strange magic, once man learnt to control it.
On their return from the continent, Sir Humphry arranged his promotion to a salary of thirty shillings a week which would now enable him to send his mother enough to afford good schooling for his sister. He settled down, in a mixture of enthusiasm for the work in hand and relief that he no longer had to suffer Lady Davy, who throughout their travels had treated him as the most menial of servants, to work as he had never worked before. He was torn between chemistry, he had already, without bothering to explore its commercial possibilities, invented stainless steel, and the study of electricity. In his heart he knew he could abandon neither, but the fact that Sir Humphry was now switching his efforts to the latter made his choice for him; he had to help his master.
In the auturnn of 1820 the Danish Professor Oersted had experi­mented with compass needles, pieces of magnetized steel, held near to wires carrying an electric current. The needles, Oersted found, were deflected by the current and when this was switched off they fell back into their normal, north-south orientation. Others, including Davy, had proved that steel needles, which had always previously been magnetized by rubbing with a lodestone or natural magnet, could be made magnetic if held long enough beside a wire carrying an electric current.
It now became clear to Faraday that there must be a measurable relationship between the current and the magnetism. At the same time he was forming in his own mind the theory, soon to be proved, that “electricity, whatever may be its source, is identical in its nature”. This included the electricity which Benjamin Franklin had enticed down his kite-wire from a flash of lightning, the current from Signor Volta’s battery, the “static electricity” produced by rubbing amber. None of this, as yet, had a use; Faraday was soon to change all that.
One day he balanced a small bar magnet upright in a bowl and poured in mercury, so that only the top of the magnet protruded above the surface. He then led a wire from one terminal of his electric battery to the mercury, a liquid which conducts electricity, bent it over the edge of the bowl and let it stay there, submerged. From the other battery terminal he took another wire which ended in a straight piece which he suspended from above the bar magnet and allowed to dangle in the mercury. There would thus be an electric current flowing from one battery terminal to the other, through the mercury.
He had left one terminal unconnected and now he joined it up.
The end of the straight wire, dangling in the mercury, began to spin around the bar magnet, in a neat circle.
He disconnected the terminal and the movement stopped; reconnected, and it began again; the first electric motor had been made, had been running. Not, as Faraday was the first to admit, a motor which had an immediate practical use, unless one wanted to stir mercury, but a motor, a device, of unlimited possibilities. But then, instead of developing it, Faraday went straight on to investigate more fully the behaviour of electric currents near magnets, of wires near wires, of wires in the earth’s magnetic field. He found that he could produce a movement similar to that of his experimental motor by using terrestrial magnetism instead of the bar magnet.
By now, having proved to himself that an electric current in a “magnetic field” could produce a mechanical movement, he was anxious to prove the converse, that the movement of a piece of wire in such a field would generate an electric current along that wire. He tried, many times, connecting the two ends of his wire to a sensitive, current-indicating, galvanometer, placing the wire near a strong magnet, but nothing registered. Yet he was becoming convinced that not only was this possible, if one worked out the correct positioning, but that the same process of “induction would be able to make a current flow along one wire, when it was brought near another along which current from a battery was already flowing.
The results were negative and exasperating, but he refused, to give up. As he wrote, he “could not in any way render any induction evident”, yet he was convinced it was there.
On 29 August, 1831, he succeeded. He had taken an iron ring, six inches in diameter and an inch thick, a large, hollow iron doughnut, had wound a few turns of insulated wire round one half of the ring, a few round the other, had connected one lot to a battery, the other to his galvanometer. When he joined up the battery, when he disconnected it again, there were sharp flicks of the galvanometer needle. When the current from the battery was flowing steadily or not at all, there was no deflection of the needle; only its interruption or resumption (and, as he soon found, an increase or decrease in its strength) had an effect. There was, because of the insulation, no electrical connexion between the two coils, only an “induction”. To Faraday, it was all quite clear; the current from the battery had given rise to magnetism, concentrated by the heavy iron ring, and this magnetism, in the process of changing, had generated an electric current in the second coil.
A discovery of major importance, upon which the whole principle of tunable radio, separating one station from another, is based: yet at first of no practical use. Faraday raced on. At the end of October, by passing a bar magnet inside a tightly wound coil of many turns of wire, not unlike a large reel of cotton, he found he had generated a current. A galvanometer, joined to the two ends of the wire, flicked each time he moved the magnet, but remained undeflected when the movement stopped. He had achieved, at last, “evolution of electricity from magnetism”, the first dynamo.
He next asked permission to experiment with a great permanent magnet which the Royal Society housed in Woolwich. He placed a large copper disc on an axle between the two poles with a rubbing contact, what we now call a “brush”, at the centre, and another at the circumference; he rotated it. Current flowed; and now there was no doubt that this new dynamo had a real and important future.
From 1831 he improved his motor and his dynamo, though his mind was on the theoretical aspects of his science, and he was prepared to leave others to get on with the practical details, and he embarked on an almost endless series of discoveries in the field of magnetism and electricity which he formulated into rules that still apply to-day. At the same time he was able to continue experiments in chemistry and to become Fullerian Professor of that science at the Royal Institution. He had been, for some years, much in demand with commercial firms, which paid him handsomely to serve them, from time to time, in almost any capacity he cared to choose, from inventor to expert witness, but in 1831 he resolved finally to devote his life to pure research. He announced that, among other things, he would cease making the high-grade optical glass for which he had become famous; he turned his back on commerce and a very large income.
It has been argued that by cutting himself off from commerce Faraday held up the techniques of electrical engineering by fifty years; after all, men said, he had invented the motor and the dynamo by 1831, yet it was years before they became more than scientific curiosities. Yet, without this zeal of Faraday’s for pure research, for finding out the answer, he might never have discovered the host of new things he did, like the science of “electrolysis”, the behaviour of electricity in liquids, which enabled men to measure with extreme accuracy an actual quantity of electricity by the amount of metal it deposited on an “electrode” in a liquid “electrolyte”, words in common use to-day, but which Faraday himself invented, with “cathode”, “anode”, “anion”, “cation”, “dielectric” and a lexicon of others, without which the modern science of electronics would be struck dumb. His own name has been immortalized in the “Farad”, the unit of inductance, of transfer of energy from one electric circuit to another, which he first demonstrated with his iron ring, and without which radio communication, radar, television or X-rays would be impossible.
So indeed it is true to say, “electricity we owe to Faraday”. Men knew of its existence, dreamed that it might some day have a use, but it was Faraday who handled it, measured it, made it work.