The real Edison-and-Tesla story

Today, it’s become “common knowledge” that Thomas Edison was nothing but a thief, while Nikolai Tesla was the greatest genius of the 20th century—but how much of that is real, and how much of that comes from a series of movies and television programs, most notably Murdoch Mysteries?

Even a quick look at dates shows that Edison did not, as many social-media self-proclaimed experts say, “steal everything from Tesla.”  Nikolai Tesla did not even come to the United States before Edison had created entire lighting systems (which was much harder than creating just a light bulb). For reference, Thomas Edison was born in 1847 and Tesla in 1856, ten years apart; but while Edison learned by reading and experimenting, Tesla also went into higher education, delaying his work as an inventor.

Starting from nothing

Starting at the beginning, we find Thomas Edison an itinerant telegraph operator with no real assets—no house, no bank accounts, no ready cash. His co-workers of the time confirmed that he had no sense for money, spending it all on apparatus and books to learn and explore ideas, especially for sending two telegraph messages over the same wire. He came up with a few clever ideas, such as a device to record incoming telegraph messages and play them back more slowly so incoming messages could be written more neatly.

Eventually, Edison was indeed the first to send two sets of messages over the same wire in the same direction with his Quadruplex (others were first to figure out sending two messages over the same wire, but in different directions), but that was after years of working with stock ticker services, refining what others had already created—a better use of his talents than manning a telegraph.

Nobody has disputed his claim to the first device for sending four messages at once over the same wires (two in each direction) or his more reliable stock tickers—other than, in a heated and irrational letter to the editor, a rival light inventor, Joseph Swan, who we get to later on. (Edison became the first person known to use the term “bugs” for faults in technology during these years.) Matthew Josephson observed:

Because he worked at this time in a highly competitive field, often adding his innovations to the patented devices of other men, the idea got about that Edison did a good deal of borrowing and “using” of other inventors’ work. But those inventors also built upon the many investigations that others had done before them. It may be said that all invention is wrought within the continuum of man’s total technical and scientific knowledge; hence the regular recurrence of parallel or simultaneous invention and of identical scientific discoveries by different men in different lands.

These inventions paid well enough for him to create his facility in Menlo Park, New Jersey, where he hired craftsmen to carry out his projects—to build the items he had contracted to build, and to help with his laboratory. Other inventors did the same, to some degree or another.

Phonographs to electric lighting systems

There has been no real dispute over claims to the phonograph; the man making it said later he had no idea what it would do, and there was no clear prior art beyond that cited by Edison himself (a child's toy, mainly). Early on, he created the disc-shaped record, but left it out of his final patent, seeing it as impractical at the time. He also made an electric pencil which made stencils for duplication; he would sell the patent rights to this to A.B. Dick, who created the mimeograph with it, later on.

Edison did not build any of these later inventions with his hands, but does this really matter? Tesla is credited with harnessing Niagara Falls—yet did not pour the concrete or wind the generators. The patent goes to the person who has the idea, not (in those days) the person who makes the model or, today, the lawyer who finalizes the diagrams.

Usually, where people claim Edison didn’t have the right to take credit for inventions was in the electric light and the movie.

I'd always remembered the light bulb thing as his big idea being the vacuum, but, as the courts later noted, two other people had already tried vacuums, and failed. (Swan is often said to have really invented the incandescent light, but his light did not last for even a single minute before burning out.) Nor was the carbon element Edison’s idea; it had a high melting point and others knew that, too. That wasn’t original.

Where Edison went beyond his predecessors was with systems thinking. He did not just create a light bulb; before he even started, he worked on what a full electrical system would require from the lights. Arc light systems used serial wiring—when one light died, all the lights went out, so someone had to be present at all times to change lights. They also used had a very harsh light, and they smelled and buzzed.

Edison started by assuming he needed to run more lights of lower power, glowing rather than sparking. He brought in a scientist and mathematician and decided on a low, constant voltage.

Francis Jehl, who worked closely with him, noted that later detractors claimed Edison was just guessing and throwing brute force at problems; evidence for this point of view was the famed search for the perfect incandescent light filament. Jehl countered by pointing out that little was known about the properties of most materials at the time, and Ohm’s Law had not yet been fully accepted.

No generator of the time provided constant voltage; they provided constant current (amperage). Edison had to create a new generator (really, a dynamo, which is the part that makes the power) with constant voltage, at a time when were no tools for directly measuring voltage or current. He also needed more efficiency than generators could provide, too; that meant less resistance in the drum armatures, which scientists of the time claimed was impossible. At the time, “experts” insisted 50% efficiency was all one could get. Edison ended up with 90% efficiency fairly early in his work.

While his generator was similar to Siemens’ work, he divided the armature cores and commutator into individual sections and used mica to insulate the commutators, and made it much higher capacity. Edison built on Siemens’ work, but to say he stole the generator from Siemens is to say anyone who uses a gasoline car engine stole it from Benz. One hopes any patents were on the innovations and referenced Siemens’ work.

Ohm’s Law led Edison to use very small lighting elements in the bulbs. Joseph W. Swan had already done a vacuum bulb using carbon, which lasted for less than a minute (as mentioned before); so had others. All heated a thick rod, not a thin one made (for a while) from a bamboo thread. Even English courts found Edison’s bulbs to be new and original compared with the Englishman Swan’s design—in contrast to television writers’ findings. Edison did not start with Swan’s design and figure out how to avoid the patents; Swan’s design did not work.

Edison did not invent the parallel circuit, though he’s gotten credit for it at times (he didn’t claim it). He did create brand new systems in feeder-and-main electrical distributions, including the use of a three-wire system which slashed the amount of copper needed. Three-wire electrical distribution was first used in 1883, in the Sunbury PA central station. Likewise, his work on the traction engine, continued under license by one of his workers, was meant to expand on the use of electrical power and replace coal in trains and gasoline in cars.

Then we have the filament itself; cotton thread was the first attempt and it did work. Platinum worked too, but was expensive. Tungsten could not be worked then. Eventually he used bamboo hairs. He kept trying different materials and was waiting for a better vacuum as well—and along the way was distracted by the Edison Effect. He also discovered that heating the carbon filament released captured oxygen, which was another breakthrough; he then figured a way to preheat it and release that oxygen while a vacuum was applied. All these processes had to be industrialized to bring the cost of bulbs down, and at the same time, since he was working on a system, he was developing the generator, fuses, insulation, and such. Many people carried out many experiments—but they were all directed by the workaholic Edison.

(Again the question comes, did the number of people working on these projects mean that Edison stole the inventions from them? But if you look at the details of any of those things, you find Edison asking people to create various models and prototypes.)

Tesla, incidentally, thought these grand searches were a waste of time since “a little through and calculation would have saved him 90% of his labor.”  But while Tesla could say that with decades of hindsight, not much was known about most of these materials at the time. It’s easy to look back and criticize the ignorance of those who came earlier.

Murdoch had Edison sitting in his Manhattan offices some time later, at an office behind rows of people working at desks. (Murdoch also took place long after Edison had moved to West Orange, where he never had a conventional office; he stationed himself in the library. Murdoch also had Edison running power and light companies after people had telephones, and by then he no longer had a single share of stock in power companies.) Lab notebooks and personal testimonies show this was by no means accurate. Stories from employees of the time show Edison working in the trenches, alongside everyone else. Indeed, he was known for it; this was not a wealthy thief conniving from an inner office. “Common knowledge” again turns out to be mere propaganda, based on the careless, research-free writing of hacks continuing a series long past its prime.

One of the people Edison supposedly sole from was Hiram Maxim, who had hired away Edison’s people to make bulbs exactly the same as Edison’s except for the shape of the filament. Edison did not sue at the time, but when suit was brought, Maxim was found to be infringing, not the other way around. Edison did not hire others’ closest workers; it was the other way around. For that matter, Edison was deeply in the red in 1880-81, as he invested heavily in the power and lighting systems. His backers refused to put any more in than they had to. Yet he is usually portrayed as a lazy, vain robber baron.

Tesla finally comes into the story quite late—in 1881—as one of the technicians setting up Edison light displays at the Paris Electrical Exposition. Tesla had been extremely well educated, coming from a wealthy family. He was then tapped to help set up central DC power stations in other cities. There’s no question about his contributions, but in later years he made many fanciful claims of things he could do, which later writers would assume he really did. He built a large setup to transmit power over a long distance, but didn’t actually do it. Who did actually transmit power through thin air before anyone else? Our old friend, Michael Faraday, who also was first to create electric power through mechanical motion.

AC vs DC

Mentioning Tesla brings up the much-later DC vs AC debate. Tesla is given credit for inventing alternating current. He was years too late to do that; when he was still working for Edison, S. Z. Ferranti built a powerful alternative current generator in England based on Lucien Gaulard and John D. Gibbs’s 1883 transformers.

The AC vs DC war between Westinghouse (not Tesla) and Edison started with the William A. Stanley ’s 1885 invention of better AC converters. Stanley worked for Westinghouse, the famed air-brake man. Tesla did invent a polyphasic form of alternative current, but the AC vs DC war was already in progress by then.

AC vs DC was never about Tesla despite all those TV shows coming out of British Columbia pretending it was. There was no Edison vs Tesla war as far as Edison knew. Much of it would have been news to Tesla when he was writing his autobiography.

Edison didn’t like Westinghouse at this point because he had violated the electric light patents—U.S. courts agreed (Westinghouse had more money for lawyers, so this wasn’t decided by trickery). Edison was obviously wrong, but when he had experimented with AC (before meeting Tesla!), he had decided that it was more dangerous than DC (though it obviously is not). It’s still impossible to defend Edison’s stance, but it's possible to understand him better. Resisting AC was probably more about what he saw as unfair competition from Westinghouse—and his own stubbornness, without which he would never have created the world’s first efficient generator, which made several key modifications to Siemens’ previously state of the art design. (Oh, and he neither invented the electric chair—indeed, his theory about how it would work was wrong—nor electrocuted Jumbo the Elephant.)

In fairness, Lord Kelvin, Werner von Siemens, Franklin Pope, and Elihu Thomson also distrusted alternating current.


In 1885, a British scientist, Preece, named the Edison Effect. Nobody knew current could flow through a vacuum, though Faraday had already shown induction (as a man of poor background, he gets little public credit today, unlike the aristocratic Tesla). Edison used the bulbs to create a voltage meter, the first electronic device—the drawings are in his handwriting.

Tesla is well known for his attempts to broadcast power in the 1900s, which failed; but others had already used electrostatic induction over a distance in the 1880s. Edison’s work in that area was not to power lights, but to create a wireless telegraph; with a partner who actually had the idea (and who worked with Edison as a full partner in refining it), he started with two masts around 580 feet apart that sent messages. He later created a railway wireless telegraph which worked at short ranges. These were dead-end devices, but Tesla essentially retraced Edison’s steps—and then TV and movie writers claimed Edison stole all his ideas from Tesla. Perhaps Edison also stole a time machine, retroactively?

Not long afterwards, Heinrich Hertz recognized radio waves for the first time in completely and totally unrelated work, and wireless telegraphs went in a different direction.


Edison might be most easily criticized over movies, since his patent application is devoid of credit to other inventors; he did publicly credit Marey and Muybridge, who had paved the way with a clever system of multiple cameras to create the illusion of movement. It's important to realize that at this time, his patent attorney was a drunk who also lost or sold hundreds of Edison’s patent applications.

The movies started with Edison taking a photographer and some craftsmen and putting them to work in a secret room in the late 1880s which Edison visited every day. The original idea was a phonograph-like cylinder with the eyepiece moving as the images flickered by, but the images had to be expanded again and again to be seen, ending up at one inch —  35mm. He heard of celluloid film, wrote to Eastman to get rolls of it, and had a breakthrough. He had a single camera filming with a rolling shutter, a paired phonograph (the first movies were “talkies”), and the flexible film on rolls. He oversaw every part of the development while others worked on the technical aspects of the film itself, the exposures and shutter movements, and such. This was quite a distance from Marey and Muybridge with their sequence of dozens of cameras working independently.

Who invented the movies? Was it Dickson, the photographer? The people who created the machinery? Marey and Muybridge? Perhaps the Lumiére brothers, who made projection work after Edison was unable to achieve it? Was it a group invention? (This would have been the most fair way to credit it!) Dickson himself, even after various disputes with Edison, said that the key ideas belonged to Edison; and after he left Edison, Dickson did nothing of consequence.

Edison made two huge mistakes, neither along the lines his critics would claim. He did not apply for patents in Europe, thinking the cost too high, so cameras were made in Europe and imported into the United States. He also didn’t patent the projection system he had created, which was in an 1888 patent caveat but not in the 1891 patent application.

Storage batteries

One of Edison’s odder projects was the search for a car storage battery. He rejected the existing lead-acid design, as it was self-destructive, and searched for an alkaline (potash) solution. Over time, through thousands and thousands of experiments he directed but did not personally conduct, he found that adding lithium powder to pockets by the nickel and iron solved many problems. It was a ten year work which cost him a million dollars and had no guarantee of success in the end.

The batteries lasted for many years, took abuse with no probelms, recharged quickly, and were not damaged by being run to zero before recharging; but they were too weak for cars. They were used for power plant standby, miner’s lamps, standalone lights, highway signs, mining (blasting), torpedos, and ships; they worked well in submarines but the Navy rejected them due to NIH.

Storage batteries weren’t an end, but a means to an end. Edison had also created a traction engine, developing it with a scientist named Frank L. Sprague. Sprague eventually went off with his own company to develop them further, quite successfully. (Many of those who worked with Edison did better financially than he did—Samuel Insull, for example, went on to make a fortune with electric utilities—because they didn’t plow their money back into research and development. That should spoil the story that Edison was nothing but a thief. His actual income was usually far less than the banks or patent-violator companies.)

We won’t even get into Portland cement and the first poured houses, the latter coming at the same time as William Ransome but independently—or the first poured concrete road in America.


Edison could have rested on his laurels after the phonograph; working on that alone would have earned him far more than he actually made. The money that came in largely went to support more work. He made and lost fortunes multiple times—he spent his fortune entirely on electrical systems, then again on iron ore refining, then again on the storage battery.

During World War I, Edison pushed to create the Naval Research Laboratory—he wanted it to be away from DC and run by civilian scientists. During the war he created and gave away numerous inventions, including defenses against submarines, smoke cloud generators, torpedo mechanisms, and such. He turned down the Distinguished Service Medal for his wartime work because so many other civilians had pitched in.

Tesla and Edison again

On Murdoch Mysteries, Edison is a vain clown who steals the works of others, so that Tesla may be glorified; everyone knows Edison is a fool. (Tesla is shown with a successful radio—something he never made.) He's pictured in his NYC headquarters, which he needed to install the Pearl Street station (he preferred Menlo Park), at the end of a long line of workers whose work he steals. Yet, by all accounts, his actual work was nothing like that.

In the many accounts of his life written by contemporaries, including those who showed his many warts, none have him sitting in an office all day. Most of the time then he was in the labs, working on the storage battery, which required incredible amounts of tedious trials and research; or better phonographs; or other endeavors where he could make better use of his time by directing others to do the actual trials. During the period Murdoch shows, someone seeking Edison would have been more likely to find him working on a big generator or digging trenches for laying wires—which he did frequently though it was a waste of his time. Possibly teh work helped him to think.

In his own life, Tesla was one of many bright people inventing things. He was not lauded as The Best, and most of his claimed inventions, including radio transmissions sent through the ground rather than through the air and large-scale beamed power, did not and cannot work. Edison was a legend in his lifetime, though in his later years he grew ever more obstinate and, in many ways, foolish... but never useless.

Social media and movies credit Tesla with alternating current, radio, and inductive power; without him, the memes claim, the modern world would not exist. Edison, in contrast, was—social media, movies, and television show—a fool and a thief. Yet, Tesla did not invent alternating current; he invented multi-phase alternating current. Even if we say that he invented radio, and most indications are that he did not, the first working radios were still from Marconi. Indeed, Marconi’s first test message was sent before Tesla claimed to invent the radio.

Edison missed radio, but he did work on the implications of what Preese called the Edison Effect bulb—the first diode and the basis, with slight changes, of the first vacuum tubes. The modern world, you could argue, came about with central-station electricity; efficient generators; three-wire parallel circuits; sound recorders; mimeographs; even electric lights. Edison also invented the first electronic device, though it did not work well enough to use: an amp meter.

Inductive power was a great invention, true, but Edison and a partner used it for primitive wireless transmissions before Tesla started working with it; and Michael Faraday should be congratulated for finding inductive power before either of them.

Most of what Tesla gets credit for, he never did; he just tried to do it, like long distance power transmission. Tesla himself praised Edison in his own autobiography and despite all the claims of a rivalry during their time, the two kept up a respectful correspondance through their lives. Edison came to one of Teslas’s public presentations to show his respect (Edison rarely went to conferences), and Tesla got the audience to give him a standing ovation. These were not enemies.

Just because something is billed as entertainment does not mean it contains no propaganda. The “lost cause” claim of the Confederacy still shows up in entertainment, yet we don’t say it’s common knowledge that slavery is good. Song of the South is hardly respected as quality entertainment these days, is it?

The “Tesla-as-god” and “Edison-as-scum” themes are highly annoying and quite wrong. There were greater geniuses than Tesla. Michael Faraday, the Scottish theorist Maxwell, and so on — but they don't get any airplay. Tesla sucks all the air out of the room.

Tesla and Edison would both be stunned by today’s “common knowledge.”

Some sources for you

Historical records at Rutgers University

An excellent explanation of why people want to believe Tesla was a god and Edison was scum (with evidence, and highly readable) (the explanation of the perception gap is at the end)

Edison (Edmund Morris)—an excellent book, adding to and improving on the Josephson bio below

Edison (Matthew Josephson)—quite old but Edison hasn’t done much since he died, right?)

Menlo Park Reminisces (Francis Jehl?)—written by one of Edison’s lab assistants in retiremenet

Edison’s Open Door (Alfred O. Tate)—stories and anecdotes from a private secretary, interesting if you read every other chapter. Tate’s position and later life are detailed in the Morris book.

U.S. Patent Office records

Books by David Zatz

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