From battery to bulb, find out how electricity was harnessed and used to light up the planet, sparking the most productive period of technological innovation ever seen.
Menlo Park was aglow. After months of work at his New Jersey laboratory – not to mention hours of painstaking work to make the first filament, which had snapped – Thomas Alva Edison’s light bulb had finally switched on in October 1879.
With the second filament fitted and all the air pumped out of the bulb using the latest suction equipment, the bulb was sealed. Inside, a small cotton sewing thread that had been lightly burned to coat it with carbon hung between the terminals of the electric circuit, and right then it was glowing with heat and light. The bulb burned all day, and once Edison connected the improved second bulb it burned for 40 hours. Staring at it, satisfied, he said, “I think I’ve got it. If it can burn 40 hours, I can make it last a hundred.” He wasn’t wrong.
This pivotal moment represented the point in the history of electricity that the spark – the idea of electricity – hit the filament and illuminated the real potential of electric energy for the whole world.
While the light bulb had already been invented, what Edison did was commercially produce it so that it was cost effective enough for everyone to afford, on the largest scale imaginable; he wanted to light up the world. And while he did, the story begins just over a hundred years earlier with an Italian scientist named Luigi Galvani, who noticed something peculiar about the frogs’ legs he had been using for experiments in his laboratory.
Galvani, from Bologna, had observed that, whether it was thundering outside or a fine afternoon, the frogs’ legs would occasionally twitch. A physician, physicist and philosopher, he was investigating all kinds of things with gusto, and on this occasion it was bioelectricity. He had hung the legs with brass and iron, so he surmised that fluid in and on the limbs was conducting electricity somehow, and he was determined to work out how it made the muscles jerk. He wrote an essay about it – titled Commentary On The Effect Of Electricity On Muscular Motion (published in 1791) – which was later read by a physicist from Como in northern Italy called Alessandro Volta.
Volta – for whom the volt (the unit for electrical potential) was named – read this report and heartily disagreed. He set about to disprove the findings of Galvani’s research, and began repeating the experiment soon after the paper’s publication.
He discovered that there was indeed the occasional jolt of the leg – a result of the reaction between the dead frog, his metal knife and the metal table in his workshop. Clearly, the leg was conducting electricity between the two different kinds of metal. Encouraged, he continued to experiment using different kinds of metal. It was crucial work, because the great switch-on wouldn’t have been possible if it hadn’t been for Volta’s development of the battery.
His work progressed and he eventually moved from pegs and nails to plates of solid zinc and silver, with salt-soaked cardboard pads that sat between them – in place of frog legs. Each pair of plates, or cell, would provide a little electricity if a circuit was made using the two terminals: one zinc and one silver. When Volta stacked the cells up in 1800 he found that they produced far more power collectively, and so the first voltaic pile – the earliest battery – was created. By 1801 he was so famous for it that he even got to show it to the emperor of France, Napoleon Bonaparte, who made him a count and a senator. It was the first time in history that someone had managed to store electricity for future use, and it paved the way for the development of generators.
Just two decades later, the English scientist Michael Faraday had produced the first ever motor that was powered by a battery. He’d been inspired by the work of people like Hans Ørsted, who discovered electromagnetism, and also William Wollaston and Humphry Davy, with whom he’d been discussing the problem of electric motors before creating his series of homopolar motors.
While the earlier models were too inefficient to use, in 1831 he had produced the first electromagnetic generator, based upon the principle of electromagnetic induction that he’d established the year before. These generators turned mechanical energy – eventually driven by steam power – into electrical energy, and were a vital element of the great switch-on.
The generators provided a steady voltage – in both senses – that could be used for all sorts of things, like sending and receiving Victorian text messages via the telegraph. Since electricity had been brought down to Earth and laid in cables, there had been an explosion of creativity among scientists, engineers, craftsmen and general tinkerers everywhere, and as such a number of people were working on this innovation at the same time. The telegraph connected two places by means of a long wire, through which a message could be encoded in the pulses of current that travelled along it, enabling information to be exchanged at an astonishing rate.
The first public telegraph lines were laid in England between Paddington and Slough – a distance of about 32 kilometres (20 miles) – in 1843, and on 24 May the following year Alfred Vail and Samuel Morse displayed the telegraph in action to a group of US senators. Morse sent a message – ‘What hath God wrought?’ – from the Supreme Court in Washington DC to Mount Clare Station in Baltimore, where his colleague then transmitted back to Morse. It travelled faster than an express train, and certainly faster than the Pony Express. Back in London, 1847 saw the Electric Telegraph Company open its Strand office to the public, offering pay-per-ticket access to the machines. In Ohio, it saw the birth of the most influential figure in the great switch-on: Thomas Edison.
Born an entrepreneur, Edison – or Al, as he was then known – had always had an eye for business, and growing up in Port Huron, MI, he never missed an opportunity. He was selling newspapers in town one day in 1862, while the Battle of Shiloh raged in Tennessee, and wondering if he could somehow get the word out. Telegraphs were indispensable during the Civil War and had been used to carry field reports back and forth since the year before. Al convinced his friend in Detroit, MI – a fellow telegrapher – to wire newsflashes over to him, and as they came in Al then chalked up live battle updates onto his headline boards. He was 15 years old, and sold hundreds of newspapers that day, at twice the usual price. A tireless inventor in later life, young Al was quite the telegrapher in those days, once beating the fastest sender in New York in a telegraphing race. He taunted the frustrated New Yorker with the quip, “Say, young man, change off, and send with the other foot!”
Instant communication changed the world, and electric generators made it possible. Telegraphs, however, were only the beginning. Telephones were about to make it possible to speak with your own voice, rather than learn Vail and Morse’s complex code and tap out messages, and this was down to a Scottish-born inventor called Alexander Graham Bell who later became a naturalised US citizen. He founded a school in 1872 for the deaf and spent much of his life working on the electric hearing aid, motivated to help his wife, Mabel Hubbard, who was deaf. While he may not have been the first person to invent it, it did lead to the development of his telephone.
The first telephone call ever placed was to Bell’s assistant, Thomas Watson, on 10 March 1876. “Mr Watson, come here, I want to see you,” were the first words uttered on the phone, picked up by the receiving microphone. The device spread like wildfire. Bell and the Bell Company (later AT&T) would be forced to defend its patent in around 600 legal cases. Meanwhile, Edison had moved to a lab in Menlo Park, NJ, where he began improving the telephone.
A year later, in 1877, he was experimenting with a diaphragm one day, watching it vibrate, and it occurred to him that the vibrations from the diaphragm would make a stylus joggle up and down. He tested the idea out, and managed to make some dents in a piece of paper by reciting the nursery rhyme Mary Had A Little Lamb; when he pushed the stylus back through the dents, he could hear the sound that he had recorded in the paper. This invention led to the creation of the phonograph, later called the gramophone, and the first known recordings of nurse Florence Nightingale, explorer Henry Stanley and poet laureate Alfred Tennyson.
This work on sound recording contributed to Edison’s (and his team’s) work on a new carbon microphone, which was louder, clearer and worked across a much greater range. Western Union bought his improved telephone (aka the ‘speaking telegraph’) for $100,000, and Edison asked to be paid the sum in annual instalments for 17 years. He had set himself up for life and could now dedicate himself wholly to his original task: to bring electricity to the world.
Many people had been trying to develop the electric light. Since the 1840s, they’d been passing currents through platinum or carbon filaments inside vacuumfilled bulbs of glass. The problem was that they burned out too quickly. Joseph Swan had led the charge in Britain, with his batterypowered bulb in 1860, but his vacuum was too poor to sustain the right conditions.
He continued working late into the 1880s, but it was Edison who realised the light bulb commercially following his success with the first two bulbs, which used the latest air pump to achieve a better vacuum. Since then, Menlo Park had been gathering crowds who travelled for miles to enjoy the spectacle – though Edison and Swan did team up later to fend off competitors, with Edison beginning to release bulbs of varying sizes and shapes to saturate the market. In 1881 the first electric light bulb factories opened in Newark, NJ, in the USA and Benwell, Newcastle, UK, and heavy generators, like steam engine ‘Long-waisted Mary Ann’, were used to power bigger machines. But Edison wasn’t about to rest on his laurels.
He started planning a new kind of infrastructure. Edison was going to divide a city into sections, each connected to the main generator, in order to provide power to anywhere needed, so long as you could connect to a grid of cables. This meant that he and his team had to design new generators, cables, fuses, switches, meters, junction boxes and insulators, because none of them existed yet. Most people still read by candlelight, with the exception of JP Morgan in New York, who had electric power
for his lights from a steam boiler in his basement.
Pearl Street in New York was the first power station to fire up on 4 September 1882. Five companies had scrambled to light the city, but Edison had won the politicians over with a deftly electric-lit dinner at Menlo Park, where they agreed to dig up their streets for his cables. The lights came on at 3pm, and one New York journalist later commented, “It seemed almost like writing by daylight.” At one point a fuse blew, but Edison took off his smart clothes and hat to get down there and mend it himself. By 30 September, the Vulcan Street plant in Wisconsin had revved up too, and this was the first hydroelectric plant.
Pearl Street was supplying 231 customers by January 1883 – almost double that by August – and light bulbs lasted for 400 hours. The technology was continually improving, and Edison walked down the streets each night, proudly watching more and more of his light bulbs switch on.
It wasn’t all plain sailing though. Nikola Tesla, the Serbian scientist who had arrived in America in 1884, filed a patent for his improved electric motor in 1888 – two years before Edison set up the Edison General Electric Company. Edison championed the direct current (DC), which flowed in one direction and provided a safe voltage of 250 volts; however, its relatively low voltage meant that it was too weak to be sent across long distances.
Alternating current (AC), on the other hand, flowed in pulses – first one way, building up instrength, then reversing direction – many times each second, which meant it could travel at a high enough voltage to allow for a low enough current, and not destroy power lines. Despite Edison claiming it was unsafe and trying to get currents over 800 volts banned, Tesla’s new invention was bought by Edison’s rival George Westinghouse.
DC generators were quickly replaced by the superior AC generators, and relations were sour between Tesla and Edison. Tesla claimed that Edison had cheated him out of a $50,000 bonus for improving the dynamo while he was working for him, but Edison said he’d been joking. Their animosity was so bitter that, in 1912, Tesla refused to share the Nobel Prize for Physics with Edison, and so neither of them ended up winning it.
Still, the impact that they had on the world has been indelible. From the battery to the bulb, the spark of electricity had travelled down history to these two men, and their generators put power in the households of first London and New York, then the planet. Guglielmo Marconi had developed the radio transmitter by 1896, though had Edison gone a few steps further in his research he would have predated this invention by 20 years, and John Logie Baird transmitted the first television pictures by 1925. These were recorded using a ‘scanning’ disc, invented by Paul Nipkow, that controlled the amount of light from particular areas of the subject being filmed as it hit photoelectric cells.
Electricity was everywhere and it changed everything. When Edison died in 1931, the electric lights of America were switched off or dimmed in his honour. For a minute, the country was as dark as it had been during the Civil War, when young Al was listening to the telegraph humming with news and dreaming up ways to make his fortune.
Key experiment: Fact or Fiction?
Thought by many to be a myth – though it may have been inspired by earlier European experiments – Benjamin Franklin’s key experiment led to a greater understanding of lightning conduction, though the real facts are somewhat shrouded. While Franklin didn’t document the experiment himself, he did tell Joseph Priestley – an English polymath known for his sermons, metaphysical texts and political works – who then wrote down an account of his tale.
The story goes that Franklin was in Philadelphia one dark June afternoon in 1752, looking up at the steeple of Christ Church. He was waiting for his new lightning rod to be installed at the top and growing impatient. What he wanted was to come up with a way to ‘draw the electrical fire silently out of a cloud before it came nigh to strike’, and so protect people from the skies. Staring at the spire, he wondered if he could fly a kite right into the storm clouds, where it would be surrounded by thunderous opportunities.
First, Franklin tied a silk ribbon to the loop of a key; this was his handle and it had to remain dry. Then he took another silk ribbon, tied that to the key, and also to the end of a kite string; this would get wet in the rain, and the water would conduct the electricity into the key. With his son William watching, Franklin sent the kite aloft. He found that, when his knuckles moved near the wet string, he got a little shock. Lightning rods would save countless others from much bigger shocks.
The early notions
Electricity is a very slippery subject – even today. Due to the sheer number of different ways that we use the word, it can be confusing – and early investigators of electromagnetism had another problem to deal with: namely, a fuzzy belief in a kind of liquid that permeated the universe, called the aether.
The aether goes back to 1638, when the natural philosopher René Descartes was trying to deduce how light worked. He had already come up with three different types of matter from which he believed the universe was made, and now he was theorising that light was actually a pressure wave that travelled through one of these types of matter.
In order to make his model work, he had to work backwards to identify the properties of this type of matter that would lead to the correct calculations of the reflection and refraction of light. As it turned out, it worked kind of like a liquid, and so the notion of the aether was born. Thinking in terms of fluids persisted for a very long time, leading to our conception of the ‘flow’ of electric current.