The man who made waves

When Marconi, in Newfoundland, heard three clicks in his earphones, transmitted from Cornwall, he was making history - and a fortune. But not everyone was happy for him, writes Steve Connor

The signal that earned Guglielmo Marconi his place in history was not a long one: just the Morse code dots of the letter "S". But those three short radio pips represented a giant leap for mankind. The signal, which had travelled some 2,000 miles over open water from a transmitter in Poldhu, Cornwall to a shack on a windy Newfoundland hill, was proof that radio waves could "bend" around the curvature of the Earth and effectively jump the 100 mile-high wall of water that blocks the view of America from Britain. For Marconi, a young Irish-Italian, and his faithful assistant, an ex-petty officer called George Kemp, straining their ears over a primitive wireless set, those faint radio signals proved triumphantly that Marconi had been right all along when he insisted that there was no insuperable barrier to sending radio waves from one corner of the planet to another.

"It was about half past 12, when I heard three little clicks in the earphones. Several times they sounded, but I hardly dared believe [it]," Marconi wrote in his diary. "The electric waves that were being sent out from Poldhu had traversed the Atlantic, serenely ignoring the curvature of the Earth, which so many doubters had told me would be a fateful obstacle."

Those three short pips led Marconi to unimagined commercial success, spawning a company that still bears his name today (albeit suffering catastrophically of late from the deflation of the dot.com bubble). They would also lead to accusations of plagiarism, theft and dishonesty, with rivals claiming that Marconi had "imagined" what he had heard, fearful of what failure would mean to the heavily invested experiment.

Marconi was never the academic scientist, interested only in the pursuit of knowledge, but a "doer", with a keen sense of the value of an invention. His patents, and the industrial protection they gave him, earned him a fortune, but were a source of tension with other eminent radio pioneers of the day, whose own contributions to the field had been overshadowed by the somewhat brash young man from Bologna.

"There cannot be many people who screwed up at school, failed to get into university, and then went on to win a Nobel prize for Physics," Roger Bridgman, a former curator at the Science Museum in London, writes in the current issue of Physics World. "In a few years of manic activity, Marconi managed to transform an obscure piece of maths into a social upheaval that makes the dot.com phenomenon look as radical as a new bike for your postman."

Being able to communicate "without wires" was soon exploited by international operators, from finance to shipping. Just 11 years after that first signal was sent, the invention proved to be life-saving. As the Titanic began to sink, a Marconi wireless on board emitted a distress signal to a passing liner, which reached the scene within 90 minutes to pick up the remaining survivors.

Radio, television, satellites, mobile phones – in fact, much of the technical paraphernalia of modern life – could claim to have their ultimate origins in the fevered work that went on in Victorian workshops at the end of the 19th century. Indeed, it could be argued that the three pips that crossed the Atlantic on that windy December afternoon marked the point at which human civilisation became truly "intelligent". We, after all, define other putative intelligent extraterrestrial civilisations as those capable of transmitting electromagnetic signals through space.

Marconi began experimenting with radio waves in 1894, from his home in Italy. His aristocratic father and rich mother (of the Jameson whiskey family of Ireland) gave him the money to dabble in one of his two favourite pastimes (the other being women). His first success was to transmit a radio signal over a distance of two miles, with a hill in between – a feat marked by the sound of a rifle shot from Marconi's servant listening into the receiver for the distinctive three pips of the letter "S".

Subsequent refinements helped Marconi to increase the distance of transmission. He was convinced that the Earth's curvature, which prevents direct line-of-sight transmission, could be bypassed. What enabled this was later shown to be a layer of electrically charged particles in the upper atmosphere, the ionosphere, which deflected radio energy back down to the ground.

On 23 January 1901, Marconi achieved a notable success by sending a radio signal from the Isle of Wight to the Lizard Peninsula, a distance of 196 miles, the furthest a wireless transmission had ever been made, and evidence that the Earth's curvature could be jumped. The scene was set for the ambitious attempt to cross the Atlantic, and to reap the rich rewards that wireless transmission could provide – rewards that the telegraph cable companies were already enjoying.

Crucial to the entire project was a device called a coherer – a glass tube containing a globule of mercury suspended between two iron plugs – which enabled radio signals to be detected. Few historians doubt the coherer's importance. "Crude though this device may appear to modern eyes," wrote Vivian Phillips, of the University of Wales, in a paper in 1993, "it was undoubtedly the coherer that raised radio waves from a laboratory curiosity to the realms of a practical system for long-distance signalling without wires."

After the success of the transatlantic transmission, sceptics began to throw doubts over Marconi's experiment. Some even began to question the provenance of the coherer. Marconi himself refers to it as the "Italian navy" coherer, but in a lecture to the Royal Institution he went to some length to play down its significance, claiming that it was only one of several he had used and that it was not in any case reliable for commercial work. "If we were looking for unworthy motives, we could construe these remarks as an attempt on Marconi's part to minimise the importance of the device and to damp down the incipient scandal," said Phillips.

One suggestion is that the coherer was the work of a junior Italian naval officer called Paolo Castelli, whose invention was appropriated by Marconi without sufficient credit, a view first publicised in 1902 by Professor Angelo Banti, an Italian physicist, writing in the journal L'Elettricista.

Another take on the issue has emerged more recently in work by Probir Bondyopadhyay, an electronics consultant based in Houston, Texas, and an amateur radio historian. "It was only Marconi who knew the origin of the device used in the transmission. Not only did he lie about it, he tried to distract people's attention away from its true source," said Bondyopadhyay. According to documents he has recently uncovered, the real inventor of the coherer used in 1901 was the brilliant Indian scientist, Jagadis Chunder Bose, who had revealed full details of the device in a scientific paper published in 1899. Bose's published description of the coherer precisely matches the one used by Marconi, Bondyopadhyay says. "It was Bose who invented the [device] that Marconi used to receive the first transatlantic wireless signal."

Given the immense implications of those three little clicks 100 years ago, it is not surprising that there has been intense interest in what made the experiment possible. But the full truth about that momentous event has perhaps still to emerge.