Tuesday 16 August 2022

Thomas Edison : The Wizard of Menlo Park

Thomas Edison’s name is synonymous with electric light, electricity, nay, even invention itself. But what is the actual story of the invention of the light bulb? Why didn’t Faraday or Maxwell or some other Alessandro Volta invent the light bulb? How did a self-educated school dropout succeed where more brilliant men didn’t – and how did he invent it?

Yes, Edison invented the light bulb. But more than twenty others had different patents on the electric light before Edison, over the preceding eighty years. Do we know their names? Also, we know he had a thousand patents, but can you name any of them?

Edison also designed, built and sold electric cars and even trains. We never hear of these! Why? Because they failed in the long term, though they were popular for several years. Petrol cars and diesel trains were far more efficient and economic. Think about this – Edison’s “failures” were more fantastic than most inventors’ successes.

Young Edison learnt, not from school, but from practical experience. (Sometimes too practical: he once tried to hatch eggs by sitting on them). He was forced to drop out of school, as a dullard. But he was incredibly curious and relentlessly enterprising. In his teens, chemistry fascinated him, and he stocked many of them in a home lab. He sold newspapers on trains, to earn a living, and even published a newspaper : he was never just a tinkerer, he was a businessman, who tried to sell his inventions.

Edison's phonograph

Edison’s fascination with electricity started as an apprentice in telegraphy. He saved the life a child on the rail tracks, and a grateful stationmaster taught him telegraphy. Telegraphers were in constant demand, especially by the railways. Insatiably curious, a relentless tinkerer, he taught himself how telegraphy and electricity worked. For nearly fifteen years he made several inventions that improved telegraphy. Among these were a dupleix and quadripleix devices, which could send two and four messages over the same wire simultaneously. 

Some experiments cost him dearly – he once spilt battery acid which destroyed his manager’s desk and carpet; he was fired. His early life was full of adventures; once carrying a load of books at midnight, a policeman fired bullets, mistaking Edison for a burglar! “You’re lucky I’m a bad shot,” the policeman commiserated. 

Edison traveled the southern US, after America’s Civil War, and almost sailed to Brazil, abandoning America. Would a Brazilian Edison have been an equally famous inventor? Eventually, he ended up working for Western Union, moving from Louisville to Cincinnati to Boston. He bought Faraday’s books on electricity. “Faraday was a Master Experimenter,” Edison said in admiration. “His explanations were simple. He used no mathematics. I must have tried every experiment in those books.” In Boston, he published papers on his inventions in a journal called The Telegrapher. Then he quit his job to become a partner in some companies, and to spend more time inventing.

 His first major success was a “Universal ticker”, which he hoped to sell to General Lefferts, president of Gold & Stock Telegraph Co, New York. Edison expected to sell for $5000. When Lefferts offered $40,000 he nearly fainted! But he accepted the money, and with it, started his famous Menlo Park laboratory.


The Menlo Park laboratory

In 1876, Edison set up a research laboratory at Menlo Park, with several assistants to help him explore new inventions. In June, Alexander Graham Bell filed a patent for the telephone and revolutionized communication. Edison spent the next year making experimenting with various components of the telephone. He first added a battery to it, to improve its performance. In January 1887, he invented a transmitter in which carbon pressure changed the resistance. In the following months, he developed a electromotograph receiver, a telephone message recorder, a handheld telephone and an induction coil circuit. Companies in Canada, England and USA showed interest in Edison’s telephones. Western Union established the American Speaking Telephone Company, whose customers were supplied the Edison designed telephones.

At the age of 30, in 1877 he invented the phonograph, based on a recording device he had designed for the telegraph. A machine that could record sound, as needle marks on a metal cylinder, and replay it seemed simply magical and he earned the moniker Wizard of Menlo Park. But the phonograph did not succeed commercially for several years. It had certain limitations : only one cylinder could be recorded at a time; there were no technologies to copy a recording; the electronic amplifier wouldn’t be invented for another twenty years.

After seeing a demonstration of an incandescent electric light bulb, Edison decalred he would make a cheap and long lasting electric lightbulb. He bought a patent from Canadians Woodward and Evans. He hired more scientists and engineers and organized them to work collaboratively at Menlo Park, primarily for electric light. But some of them also worked on telephones, phonographs, mining devices etc. His laboratory was equipped with a tremendous variety of resources mechanical, electrical, chemical and organic.

Remember, giants of science like Alessandro Volta, Benjamin Franklin, Michael Faraday, Thomas Henry, Samuel Morse etc had invented many electrical devices before Edison. Ohm, Ampere, Maxwell and others had researched or explained its science. Telegraphy, electro-magnets for lifting heavy loads, arc lights were popular industrial applications.

Hiram Maxim, inventor of the machine gun and Joseph Swan of England also developed incandescent lights. What did Edison do that these men didn’t?

Edison’s rigor, method and scale, set him apart. He set himself a target of making a long lasting electric bulb. Edison not only set up his lab with resources and people, he scattered notebooks for everyone. An enormous amount of information was discovered and shared among the researchers. 

There was a choice before Edison: he could have improved the arc lamp, or the incandescent lamp. When electricity passes through a metal wire, it gets hot. Some metals glow from the heat – this is called incandescence. Edison chose incandescence. He bought a patent for an incandescent light bulb from two Canadians, Henry Woodward and Matthew Evans.

Early experiments with platinum showed the filament melted at lower temperatures, because of oxidation. So Edison decided to vacuum air out of the bulbs, to prevent oxidiation. Experiments with two existing vaccum pumps, the Geissler pump and the Sprengel pump showed promise. He hired chemists, especially Ludwig Boehm, to device an improved vaccum pump.

He hunted worldwide for nearly forty thousand materials including jute from India and silk and bamboo from China, for his filament. In October 1879, they discovered that carbon-coated cotton thread lasted really long. A few months later, they found out that bamboo worked ever better.

Edison personally designed both the screw base and the socket that most manufacturers used for a century!

Some historians consider the Research Laboratory his greatest invention! Today, there is no major university or company in the world, without a research lab. Governments have started organizations, departments, companies etc to fund and research science and technology, in a systematic method, undreamed of before Edison’s success.

Edison's Insights 

While other inventors focused on low resistance, Edison focused on high resistance. This seems obvious on hindsight, but none of the others – Hiram Maxim, Westinghouse, Joseph Swan, Warren de la Rue, Alexander Lodygin, etc seem to have stumbled upon it. Which is suprising because electric power is proportional to resistance but also to the square of the current. A high natural resistance, meant low current would be good enough to heat the filament and make it glow.

These stem fro Ohms’ Law V= IR

and the equation for power W = VI

which meant, W = I*I*R,

where R is the resistance, I is the current and V is the voltage.

Also, as per Vaclav Smil, alone among other inventors, Edison understood that these lights must operate in parallel circuits than in series circuits. This way the voltage could be stable and each light bulb could be turned on or off with a switch, which is not possible with serial lights. The entire electrical system is designed on this principle.

His lab designed switches, fuses and meters. Edison designed an electro-chemical meter, with metal electrodes in acid. Power consumption was measured by the weight of the zinc deposited on the electrodes. The electro-magnetic meters based on a revolving wheel and meter, were invented later by someone else.

A Complete System

While others were trying to invent a better light bulb, Edison planned and designed a complete electrical system. For small units, acid based batteries, following the designs of Alessandro Volta and Humphrey Davy might have sufficed. But for lighting up streets, they were inadequate. Only steam engine powered dynamos could light up companies, factories, towns and cities.

He bought and tested dynamos designed by Zenobe-Theophile Gramme and Siemens, of Germany, then improved their performance. 

The first power generator station was set up in Pearl Street, in New York. It generated 3.4 MW and served ten thousand light bulbs. Pearl Street began with losses, but produced profits of $35,000 in 1884, five years later. Unfortunately, it was destroyed in a fire accident in 1885. By 1891, 1300 power plants like Pearl Street produced electricity and powered homes and businesses in the USA alone.

Edison thought not just like an inventor, who wanted to make something new, but as businessman, who wanted to lower costs for both his company and customers. His electrical system had to be cheaper, safer and more convenient than the gas lights and oil lamps of the day.

Notebooks and bulb designs


Bulb holder designs

Business Acumen

He founded several companies over the next few years:

·         1878 Edison Electric Light Co  -  Invent Bulb

·         1880 Edison Illuminating Co  - Power station

·         1880 Edison Lamp Co  - Manufacture Bulbs

·         1881 Edison Machine Works – Manufacture Generators

·         1881 Edison Tube Works – Underground wires and pipes

·         1884 Edison Company for Isolated Lighting  - private generators for companies


Investors included admirers of his telegraph and phonograph; the general public via the stock market; and later, the very rich American banker JP Morgan. 

He also established collaborative companies in other countries, most famously with Joseph Swan in Britain (who also invented a working electric bulb, but perhaps not the entire electrical system).


He also had a flair for promotion and marketing. When he finally made a long burning light-bulb, he invited journalists to Menlo Park, on December 31, 1979 and dazzled them, by lighting not only the lab and the house but the entire street with electric lamps ! The Wizard who had made a machine produce human sound, had now turned night into day. 

Special trains were run for the general public, who wanted to visit Menlo Park and see this new miracle.

Edison also invited artists and smiths to design electroliers, to hold electric bulbs, similar to chandeliers which held candles. He set up showrooms where potential customers could see the bulbs in person. He hired artist to portray living rooms with electric bulbs, as tastefully as aesthetic as the flame based lighting, to which the rich and fashionable classes were accustomed.

A chance opportunity came along when the owner of the ship SS Columbia, wanted to install Edison’ lights on the ship. Edison obliged. The ship sailed from New York, down the US east coast, along Mexico and South America, and back up along the coast of the Pacific ocean, ending up in San Francisco, California. It ended up publicising Edison’s invention along the coastal cities of the two American continents, in a way unmatched by newspapers.

Solving other problems

There were engineering and cost problems – mainly of transmission and distribution losses. Edison designed a distribution system, which was both electrically efficient and used far less copper. It saved two thirds of the electricity in copper losses (power wasted by the resistance of transmission wires). Edison’s patented feeder circuit system, based on a three wire system, where two outer wires carried current, and one inner wire was neutral and served as common to both circuits, was a product of his ingenuity. When asked why no one else came up with this brilliant design, the great genius Lord Kelvin himself remarked,  “Because none of us is Edison.”

Edison feeder system

Not only did Edison come up with this design, he insisted that all the wires be insulated and buried underground to avoid electrocution of human beings. Uninsulated telegraph and telephone wires crisscrossed the sky above the streets of major cities, and were a deadly hazard to pedestrians and repairmen alike. Few historians seem to mention or even realized Edison’s great regard for human life and safety.

Electric wires on a New York street

But things did not always go well. There were patent battles fought in courts for a decade over the light-bulb. His Edison Electric went into partnership with Swan in the UK and with Thompson-Houston company in the US. The latter company became General Electric, the largest company in the world for most of the twentieth century.

Edison vs Tesla

The Serbian genius Nikola Tesla, who first joined Edison’s company in France, later joined Edison in the USA. Tesla tried to persuade Edison to abandon Direct Current for Alternating Current, but Edison could not be persuaded. Fundamentally, he seemed to have feared the deadly power of Alternating Current, which electrocuted people; he could not see the efficiencies of generating power at a distance and the efficiencies that came with stepping up and stepping down voltage. Tesla joined Westinghouse and implemented AC there. Their rivalry was so fierce, the narrative goes, that neither would accept a Nobel prize if the other was awarded. But stories of Edison electrocuting elephants and cheating Nikola Tesla seem to be popular urban legends, spread by a legion of Tesla fanatics.

Westinghouse’s eventual economic success later convinced Edison of AC’s virtues. But it was too late and came at a great cost. JP Morgan was frustrated with Edison’s stubborn refusal to accept AC, and the subsequent lower profits of the electricity business. Meanwhile Edison was selling his shares of the companies he founded, to finance new research and inventions. Edison wanted to venture into other areas of invention, like industrial mining, making cement, making electric cars and trains, turning his phonograph into a nickolodeon, inventing a movie camera etc. JP Morgan eventually bought enough shares to throw Edison out of the Edison General Electric company, and dropped Edison’s name from it.

Edison never rested on his success. He spent the rest of his life a workaholic, running factories and labs, twelve hours a day. He hired Ambrose Fleming to investigate what was called the Edison effect; this would later result in the invention of the vacuum tube diode, and the foundation of electronics. Fleming is now considered the Father of Electronics.

Later, Edison hired Henry Ford, who rose quickly through the ranks and became Chief Engineer. But Henry Ford had dreams of building a petrol-based car, while Edison tried to make a better electric car. Ford finally quit, and his petrol car triumphed over Edison’s electric car. But Edison and Ford remained lifelong friends.

In 1983, the US Government declared February 11, Edison’s birthday, as Inventor’s day. 

NOTE A shorter version of this essay was originally published, as part of a series on scientists, in the New Indian Express. The photos are from the Edison exhibit, in the American History Museum, part of the Smithsonian, Washington DC, USA

This longer version was prepared for a course I teach called "Inventions and Discoveries", at Saveetha Engineering College, Madras.


1.      Edison gallery – Museum of American History, Washington DC, USA

2.      Edison – His Life and Inventions by FL Dyer and TC Martin

3.      Creating the 21st century by Vaclav Smil

4.      Thomas Edison - Wikipedia

       The Invention of Everything - Matt Ridley

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