Signor Marconi’s Magic Box: The invention that sparked the radio revolution

The science Marconi was working with was not well understood. In 1865 the Scottish physicist James Clerk Maxwell had proposed that electro-magnetic forces travelled in waves. These were analogous to sound and light waves, but could not be detected by the human ear or eye. They travelled at the speed of light, but were invisible, because the eye could only detect certain wavelengths. Maxwell’s model was purely mathematical, and he left it to others to find a way of generating and measuring these waves. Hertz had been the first to achieve this, publishing his findings in 1888. He used a spark to generate the waves which he bounced back and forth in his laboratory. Crudely speaking, the size of the spark ‘gap’ determined the length of the waves, and Hertz had worked with fairly short waves. Marconi had experimented with a whole range of different spark transmitters, and had produced results which appeared to be substantially different from those of Hertz. In fact, because he believed his apparatus could produce waves that could reach parts impenetrable by those generated by Hertz, Marconi thought he might have chanced upon some new kind of electromagnetic signal. Dam asked: What is the difference between these and the Hertz waves?’

Marconi replied: ‘I don’t know. I am not a professional scientist, but I doubt if any scientist can tell you.’ He thought it might have something to do with the form of the wave. As to the nuts and bolts of his equipment, Marconi said apologetically that he could not say more because it was being patented, and was therefore top secret. What he could tell the astonished reporter was that his waves ‘penetrate everything and are not reflected or refracted’ even by solid stone walls or metal. He could even send them through an ‘ironclad’, a heavily reinforced battleship.

This last claim set up instant alarm in the reporter: its implications were far more serious than the possibility of X-rays compromising the modesty of ladies. ‘Could you not from this room explode a box of gunpowder placed across the street in that house yonder?’ Dam asked.

‘Yes,’ Marconi replied confidently. ‘If I could put two wires or two plates in the powder, I could set up an induced current which would cause a spark and explode it.’

‘At what distance have you exploded gunpowder by means of electric waves?’

‘A mile and a half.’

Could Marconi’s instruments ignite the explosive magazine of an ironclad and blow it up from a distance? Already the Royal Navy was concerned that if its ships carried wireless telegraphy equipment, the signals might blow up their own stores of powder. It could be a problem, Marconi conceded. Beams from electric lighthouses along the coast could destroy an unwary fleet in seconds. Warming to this notion, Dam wrote: ‘Of all the coast defences ever dreamed of, the idea of exploding ironclads by electric waves from the shore and over distances equal to modern cannon ranges is certainly the most terrible possibility yet conceived.’

Blowing up ships, however, had never been in Marconi’s mind. Quite the reverse. From boyhood, when his father had bought him a yacht which he sailed in the Bay of Genoa, he had loved the sea. Though he had no clear idea how his wireless waves would be used in practical terms, he did imagine that there was a real prospect of communications between ships and shore, and between ships on the open ocean, where there were no telegraph cables.

In London, Marconi and his mother could have enjoyed a glamorous social round: nightly balls, dinner parties, the opera, Ascot and all the trappings of the Season. Annie had many relatives in town, and always enjoyed her trips to England. But there was to be little time for frivolous socialising: Guglielmo had succeeded beyond their wildest dreams, and he was fearful that if he did not move fast someone else would overtake him in the exploitation of the new telegraphy. After all, he was only an amateur whose invention was homespun, devised after long hours working alone in the attic of the family country home in Italy.

* In 1895 Professor Bose, of the Presidency College, Calcutta, had succeeded in ringing a bell and exploding a mine with electro-magnetic waves while working along the same lines as Marconi.

2

Silkworms and Whiskey

The Villa Griffone is set in its own grounds of orchards, vineyards and fields in rolling countryside outside the village of Pontecchio, near Bologna. Bologna had water-powered silk-weaving mills long before the Industrial Revolution transformed British industry in the late eighteenth century. The city had a distinguished history of scientific discovery, and was the home of the eighteenth-century pioneer of electrical forces Luigi Galvani. Nearly all the advances in the study of electro-magnetism had been achieved by trial and error, in the absence of any useful theory. In fact theory had sometimes got in the way of understanding, as is often the case. Galvani, a Professor of Anatomy at the ancient University of Bologna, had come to the conclusion that frogs could produce electricity after the chance discovery that specimens he was dissecting reacted to an electrical current. His disciple, and later his opponent, Alessandro Volta showed that the frogs were merely acting as crude batteries, and went on to create the first means of storing electricity which could be tapped for a continuous source of current. The work of both men has been commemorated in the terms ‘galvanised’ and ‘voltage’.

From an early age Guglielmo Marconi was familiar with Bologna’s scientific heritage, and in the long summer days at the Villa Griffone he began his first experiments with the mysterious forces of electricity. Marconi’s heritage – and the pioneer days of wireless – arose from a most unlikely union between Irish whiskey and Italian silkworms. That his mother and father should have met at all was remarkable, that they should have fallen in love even more so, and that they married in the teeth of opposition from her family the most unlikely event of all. Theirs was a story of high romance, yet precious little of it is known apart from the reminiscences of Marconi’s mother, recorded much later by her granddaughter Degna.

Annie Jameson was born in 1843, one of four daughters of Andrew Jameson of County Wexford in Ireland, the well-known and wealthy distiller of Jameson’s Irish whiskey. The family lived in an old manor called Daphne Castle, which had parkland and a moat. Annie had one outstanding talent: singing. As a teenager she had wanted to perform in opera, and according to the family legend had been invited to sing at the Royal Opera House in Covent Garden. Her father refused to let her go: the stage was not in those days regarded as a suitable place for well-bred young ladies. As compensation for the thwarting of her ambitions it was arranged that Annie should go to Bologna to study singing. There she could stay with business contacts of the Jamesons, a respectable Italian family called de Renolis, and could sing to her heart’s content without risk to her family’s reputation.

The de Renolis family had suffered a personal tragedy a few years before Annie arrived to stay with them. In 1855 their daughter Giulia had married a moderately prosperous landowner called Giuseppe Marconi. In the same year Giulia had given birth to her first child, a son, Luigi. Sadly, as happened so often at that time, the young mother survived the birth of her son by only a few months. Giuseppe, now a lone parent, remained close to the de Renolis family. He had moved to Bologna from the hill country of the Apennines, which run like a backbone through north central Italy. When his wife died he asked his father, who still lived in the mountain village where Giuseppe had been brought up, to join him in Bologna. The ageing Domenico Marconi agreed, sold up his mountain estate and moved to the city. But Bologna was too busy and confined for him, so he bought an estate at Pontecchio, eleven miles away. In the large, square, plain but handsome Villa Griffone he took to raising silkworms, and made some success of it, while his widower son Giuseppe husbanded the orchards and the fields in the rolling countryside.

When Annie Jameson came to stay with the Renolis she was introduced to their bereaved son-in-law and little grandson Luigi. Giuseppe lived more at the Villa Griffone than in Bologna, and Annie must have spent some time there too, for she fell in love with the place and with him. She returned to Ireland to ask her family for permission to marry her Italian sweetheart, but they flatly refused to consider it. According to her granddaughter Degna, the grounds for rejection were that he was much older than her (by about seventeen years), he already had a son, and to top it all he was a foreigner. Annie had to bow to the authority of her father, and appeared to accept the decision. But she kept in touch with Giuseppe, with letters somehow smuggled between Ireland and Italy, and vowed to run away to marry him when she reached the age of majority at twenty-one. This she did, meeting him in Boulogne-sur-Mer on the northern coast of France, where they married on 16 April 1864. As husband and wife they took stage coaches across France, over the Alps and back to Bologna and the Villa Griffone. Their first child, Alfonso, was born a year later. Nine years later, in April 1874, Annie gave birth in Bologna to a second son, Guglielmo. Both boys were baptised Roman Catholic, although their mother was Protestant.

Giuseppe had no family other than his in-laws. His father had died, and a brother who became a priest had been murdered by a thief. Annie, on the other hand, had three sisters, all of whom had married and had children. Annie did not lose touch with them despite her elopement. One of her sisters had married an English military man, General Prescott, who was posted to Livorno on the north-west coast of Italy. Annie often took Alfonso and Guglielmo to stay with her, where they enjoyed the company of the Prescotts’ four daughters and the small English community. The English girls were also often Guglielmo’s playmates at the Villa Griffone, and he spent so much time with them and with his mother that at times Italian became his second language.

Annie read the Bible to her sons as part of their English lessons, and appears to have had no interest in science. Of greater interest to Guglielmo than religious instruction was the library in the Villa Griffone, which contained a wide selection of books. It is not clear whether it was Guglielmo’s father or his grandfather who had collected works ranging from Thucydides’ History of the Peloponnesian War to the lectures of the brilliant English chemist Michael Faraday. Perhaps many of the scientific works were provided by or for the young Guglielmo himself; in any case, from the age of about ten Guglielmo began to work his way through this store of knowledge. He became especially interested in the wonderfully lucid lectures of Faraday, who had made some of the most significant discoveries about the relationship between electricity and magnetism, and had invented the first, tiny, electrical generator.

Born in 1791, the son of a blacksmith, Faraday had had no formal education, and began his working life as an apprentice to a bookbinder. He had attended a series of lectures given by the famous scientist Humphry Davy at London’s Royal Institution, made notes on them and sent them to Davy, asking for a job as a laboratory assistant. Davy took him on, and eventually Faraday was to succeed him as the most celebrated scientist in England, spending his life experimenting in a variety of fields, but most signify-cantly on the nature and applications of electricity. He died in 1867, just seven years before Guglielmo Marconi was born. Faraday undoubtedly provided the young Marconi with a heroic model: the scientist alone in his laboratory with wires and chemicals, painstakingly testing his theories. But the greatest hero to descend from the shelves of the Villa Griffone library was the American Benjamin Franklin. Among the many achievements of this extraordinary man, born in 1706, a printer, diplomat and amateur scientist who was at seventy the oldest signatory of the Declaration of Independence, was the invention of the lightning conductor.

In a celebrated experiment, Franklin had flown a kite in a thunderstorm to demonstrate that the electrical charge of lightning could be channelled along a wire to which the kite was tethered. This clearly impressed the young Guglielmo, for his daughter recalls him telling the story of how he and a friend rigged up a lightning conductor in the house they were staying in in Livorno, and prayed for a storm. When one came they were thrilled to discover that their toy worked: at every lightning flash, the electrical charge triggered a little mechanism which rang a bell in the house. A replica of young Guglielmo’s lightning alarm is among a wonderful collection of his early gadgets in the Villa Griffone, which is now a museum devoted to his extraordinary childhood inventiveness.

It was around the time of the lightning experiment, in 1887, when Marconi was thirteen years old, that the German scientist Heinrich Hertz made known his discovery of electro-magnetic waves, prompting the Irish mathematician George Fitzgerald to declare that humanity had ‘won the battle lost by the giants of old … and snatched the thunderbolt from Jove for himself’. This was a humbling statement for Fitzgerald to make, for only a few years earlier he had announced that he believed the artificial creation of electro-magnetic waves was not possible, thereby blunting the ambition of British scientists working along the same lines as Hertz.

Guglielmo did have some academic tutoring at an institute in Livorno and a college in Florence, but his serious work was carried out on his own at the Villa Griffone. He was privileged, for his father not only provided him with a library, but grudgingly subscribed to all the leading scientific journals of the day, which Guglielmo devoured. His boyhood notebooks, rediscovered in Rome only seven years ago, are testimony to his fanatical interest in electricity and all the latest theories and inventions. The scientific community was most excited at the time by the work of Hertz. His apparatus for proving the existence of the Scottish physicist James Clerk Maxwell’s imagined electro-magnetic waves and measuring their ‘length’ was quite crude. A spark was produced by jumping electricity across a gap between two metal balls charged by Leyden jar batteries. The spark generated electronic waves which travelled invisibly across Hertz’s laboratory to activate a ‘receiver’ made up of wires which produced a spark in response. His experiments inspired many other scientists to examine the properties of what became known as Hertzian waves.

In 1894 Heinrich Hertz died at the tragically young age of thirty-six. During an operation for cancer of the jaw he suffered blood poisoning, which killed him. The scientific magazines were filled with obituaries which gave accounts of the trail-blazing experiments he had conducted. When the young Marconi read these he at once conceived the idea of using the apparatus which Hertz had made to send telegraph messages. He did not know it at the time, but precisely the same idea had struck a number of scientists and inventors in England, America and Russia.

A neighbour of the Marconi family at Villa Griffone was the Italian Professor of Physics Augusto Righi, who had done his own work on Hertzian waves. Guglielmo was thus able to discuss his idea with a leading scientist. He received little or no encouragement, but quite probably he managed to get an idea of how to construct the kind of transmitter and receiver Hertz had used in his laboratory, and with the help of his mother he cleared out an area on the upper floor of the Villa Griffone which had been used by his grandfather for keeping silkworms. This home-made laboratory has been lovingly restored by the staff of the modern museum. The beautifully recreated models of his early equipment are testimony to Marconi’s skill, and his dedication to an ambition on which he spent nearly all his waking hours.

By the time Marconi was a teenager there was a widespread interest in electricity, which was reflected in the publication of a range of journals from which the enthusiastic amateur could learn about the very latest theories and discoveries made in Europe and America. The majority of these were in English, and Marconi’s easy command of the language ensured that there were few developments of which he was unaware.

3

Sparks in the Attic

Day after day through the hot summer months of 1895, Guglielmo Marconi climbed the stairs to his makeshift workshop in the attic of the Villa Griffone. He said very little to his family about what he was trying to achieve behind its closed door. Early on he learned to be cautious about making any predictions, and he was very conscious of his ageing father’s view that the whole thing was a waste of time. Being a scientist or an inventor was not, in Giuseppe Marconi’s opinion, a ‘career’, unless, like their neighbour Righi, you had a professorship.

From time to time Guglielmo would allow his English cousins to visit the attic, where he would show them the magic he could perform with crackling sparks which made a bell ring by a mysterious force. He himself could not really explain how these tricks worked. He achieved them by trial and error, making use of every bit of electrical equipment and every published experiment he could lay his hands on. For his electricity supply he could buy batteries. It was also a simple matter to get hold of a Morse key and a Morse printer, for these were mass-produced for the telegraph industry, and there were many models on the market.

Morse code was a set of dots and dashes which represented the letters of the alphabet. The sender pressed a lever on the key, making an electrical connection which in turn activated a circuit connected to a printer which recorded either a dot or a dash. Hold the lever down for a short time, and it was a dot; longer, and it was a dash. It was as simple as that. You could use a Morse key to turn a lightbulb on and off, sending out a visual signal. Ships flashed Morse messages to each other with powerful beams, but could only do this when they were in sight of each other. This was, in a sense, ‘wireless’ communication. So too were the smoke signals used by Native Americans, or jungle drums, or the simple messages sent across the sea from one island to another by striking a resonant shell with a stick. But to receive any of these messages, you had to be able to see or hear the signals. To send a message over a long distance a relay was needed. Europe had such a system in the early nineteenth century, with ‘telegraph’ stations positioned on hills. Large wooden arms were moved to relay semaphore signals from one hill to the next. The invention in the 1840s of the electric telegraph, with Morse keys and receivers connected by cables, revolutionised long-distance communication, and the old hilltop telegraph stations fell derelict.

The great potential of the ‘Hertzian’ waves that Marconi wanted to harness lay in the fact that you did not have to be able to see or hear them to receive them, and you needed no connecting cable to send a signal. How far they could travel through the air Marconi did not know, but that was not the first problem. If you could not hear or see them, how could you detect them? Marconi knew from reading electrical magazines that some ingenious solutions had been found. A French physicist, Edouard Branly, had shown in 1890 that metal filings when scattered in a test tube would not conduct electric current. However, if they were ‘hit’ by an electric charge the filings clung together, and a current could pass through the tube.

The English Professor Oliver Lodge showed in 1893 that the ‘Branly tube’ could act as a detector of Hertzian waves. When a spark was generated the invisible electro-magnetic force would, at a distance, cause metal filings to stick together. Lodge called his version of the Branly tube a ‘coherer’, and showed how it could act as a kind of electronic ‘valve’. If the coherer were put into a circuit with wires from each end, the coherer could turn a current on and off. When the filings lay scattered in the tube no current could pass through it. However, when an invisible Hertzian wave hit the tube, the filings instantly clogged together, allowing an electric current to pass through them and the circuit to be closed. It was like a tap that could be turned on or off from a distance. From a few yards away it was possible to send an invisible, inaudible signal from a ‘transmitter’, which produced Hertzian waves, to a ‘receiver’, which reacted to them, closing a circuit which might light a bulb or ring a bell.

That was more or less the state of the art when Marconi began his experiments in earnest. What he wanted to be able to do was to activate, at a distance, a Morse printer so that each time he pressed his sending key the signals would show up as dots and dashes on a tape. Batteries powered the printer, and the current from them had to flow through the coherer, which would be ‘on’ when the filings inside stuck together, and ‘off’ when they were scattered. It was relatively easy to ring a bell once, but then the metal filings in the coherer stayed stuck together, and the bell would continue to ring even after Marconi had raised the Morse lever and was no longer sending out Hertzian waves. To break the circuit and silence the bell the glass coherer had to be shaken so the metal filings lay scattered once again, and no current could pass through them.

The solution Marconi devised to this problem illustrated his craftsman’s genius. Firstly, he experimented for hours to find the best and most sensitive metal filings to put in the coherer. He then made the glass tube smaller and smaller. To do this he used thermometers, which he remoulded using a hand-bellows, heating the glass with a naked flame. He had to create a vacuum inside these miniaturised coherers to increase their efficiency, and tiny silver plugs were used at either end as terminals. Marconi estimated that to make one little coherer took him a thousand hours.

Once he had his super-sensitive mini-coherer working, Marconi devised a little hammer mechanism which was activated each time he raised the lever on his Morse key and cut off the Hertzian waves. The sharp rap the hammer gave to the tiny coherer loosened the metal filings, cutting off the current and silencing the bell. In the same way, it would turn a Morse printer on and off. Hold the key down for a short time, and you produced a dot. Raise the lever, and the printer stopped. Hold the key down again for longer, and you got a dash. It was incredibly slow, but it worked.

It had been relatively easy to make the transmitter. All that was needed was batteries to provide the current, a coil to bump up the charge, and two brass balls fixed so that there was a small gap between them. Press the Morse key and the current flowed; the electricity jumping between the brass balls created a crackling bluish-yellow spark which generated electro-magnetic waves. These waves travelled at the same speed as light – in fact they were a form of light – but the crest between the waves was much longer, and they could not therefore be seen. During thunderstorms lightning gives out Hertzian waves, which is why radios crackle in response to each flash.

Less than a year after the death of Hertz, Marconi had a working wireless system. But if it was to be of any real use, he had to discover if the sparks of his transmitter could send out waves that a receiver could pick up at a distance of more than a few yards. In the searing heat of the summer of 1895 he first took his boxes outside into the parched fields and neatly trimmed vineyards of the Villa Griffone to discover what the limits of his invention were.