War of the currents

• 1. Introduction

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  The war of the currents came down, in one grim moment, to a machine nobody had gotten quite right. On the 6th of August 1890, technicians misjudged the voltage needed to execute William Kemmler, a street merchant, in New York's new electric chair. After the first jolt, Kemmler was found to be still breathing, and the procedure had to be repeated. A reporter on hand called it "an awful spectacle, far worse than hanging." George Westinghouse, whose company's generator had powered the chair against his own wishes, was blunter: "They would have done better using an axe."

  The chair that killed Kemmler carried a second target that had nothing to do with his case: a rival electric company. For years before that morning, two ways of wiring American homes and streets had been locked in a fight. It involved paid experts, publicly killed dogs, and letters that would later be stolen from an office and printed in a newspaper. One side ran on Thomas Edison's low-voltage direct current. The other ran on the high-voltage alternating current backed by George Westinghouse. How did a commercial dispute over house wiring end with one company's own generator being used to kill a man, arranged specifically to embarrass it? And once the smoke cleared, whose electricity was actually left standing?

• 2. Two Rival Systems

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  By the late 1870s, arc lamp systems were already spreading through American cities, throwing harsh light across streets and factory yards from central generating plants. These systems ran on voltages above 3,000 volts, wiring strings of lamps together in series, and some worked better on alternating current than direct. In December 1880, the Brush Electric Company set up a central station on Broadway in New York. It supplied a 2-mile stretch of the street with a 3,500-volt demonstration arc lighting system. Arc lighting had real drawbacks. It needed constant maintenance, buzzed, and flickered. It was a fire hazard, suited only to outdoor use, and dangerous to work with at such high voltages.

  Thomas Edison saw a gap in that market in 1878: nobody was bringing electric light directly into a customer's home or shop. By 1882 he had established the investor-owned Edison Illuminating Company in New York City to compete with the gas utilities. It ran on a 110-volt direct current supply and a high-resistance incandescent lamp he had invented himself. Edison controlled every patent behind the system. Direct current had real advantages. It worked directly with storage batteries, giving the system backup power during outages. Its generators could also be paralleled, so smaller machines could run efficiently during periods of light demand. It powered electric motors well too, an advantage DC held throughout the 1880s. Edison had even invented a billing meter proportional to energy use, though it only worked with direct current. The catch was range. Running at a flat 110 volts from generator to socket gave the system a short reach. A plant could only serve customers within about a mile, so plants had to sit in the middle of the neighborhoods they served.

  George Westinghouse entered the lighting business in Pittsburgh in 1884, first trying to build his own direct current system with engineer William Stanley Jr. In 1885 he read an article in the British journal Engineering describing alternating current systems under development elsewhere. By then, transformers existed to step voltage up for transmission and back down for customers, letting one station feed circuits up to 7 miles long. Rather than build another DC system just different enough to dodge Edison's patents, Westinghouse chose a different path. In 1885 he bought the US rights to a transformer designed by French engineer Lucien Gaulard, financed by British engineer John Dixon Gibbs. He imported several Gaulard-Gibbs transformers and Siemens generators to experiment with in Pittsburgh. That same year, Stanley combined that design with the Hungarian Ganz company's ZBD transformer to build the first genuinely practical transformer. The Westinghouse Electric Company was incorporated at the start of 1886.

  In March 1886, Stanley installed the first multiple-voltage AC power system in Great Barrington, Massachusetts. It eventually lit 23 businesses along the main street over 4,000 feet with barely any power loss, stepping 500 volts down to 100 at each building. By that fall, Westinghouse, Stanley, and Oliver B. Shallenberger had built the first commercial AC power system in the country, in Buffalo, New York. The new technology spread fast. By the end of 1887, Westinghouse operated 68 AC stations against Edison's 121 direct current stations. The Thomson-Houston Electric Company of Lynn, Massachusetts, a rival selling both AC and DC equipment, had built 22 more. Other companies, including the United States Illuminating Company and the Waterhouse Electric Light Company, were fielding their own systems too, and lawsuits over patents were already piling up between all of them. That competition was about to turn personal.

• 3. Wires Over Manhattan

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  Elihu Thomson, an engineer at Thomson-Houston, worried about AC safety more than most of his rivals. He spent real effort developing two safety devices. One was a lightning arrestor for high-tension lines. The other was a magnetic blowout switch that could shut a system down during a power surge, a safeguard the Westinghouse system lacked. Thomson also feared what customers would do with the equipment once they owned it, expecting many to overload their wiring with more lights and generators than was safe. He thought AC was too dangerous for homes altogether, and had his own company delay residential installations until a safer transformer existed.

  Most European cities, and Chicago in the US, required high-voltage lines to be buried underground because of the danger they posed. New York City had little such regulation. By the end of 1887, telephone, telegraph, and alarm wires hung tangled overhead, mixed with AC lighting lines carrying up to 6,000 volts. One electrician described the insulation on these lines as having "as much value as a molasses covered rag." A third of the wires had simply been abandoned by companies that had gone out of business. They were slowly rotting, shorting out the lines around them. In March 1888, the Great Blizzard tore down a large number of these lines and cut off utilities across the city. That disaster revived calls to move the wires underground, but a court injunction obtained by Western Union stopped the move. Legislation giving utilities 90 days to relocate their lines into city-supplied underground conduits was working its way through government. It was fought in court by the United States Illuminating Company, which insisted its AC lines were perfectly safe.

  The price of copper was rising through the mid-1880s, driving up costs for Edison's low-voltage system, which needed much heavier wire than AC did. Edison's own engineers were pushing him to consider alternating current, and his sales force kept losing municipal bids to cheaper AC systems. Edison Electric Illuminating Company president Edward Hibberd Johnson warned that staying all-DC would shut the company out of small towns and even mid-sized cities. Edison Electric held a patent option on the ZBD transformer, and a confidential 1886 report by company engineer Frank Sprague had recommended going AC. Thomas Edison refused.

  In November 1886, Edison put his opposition in writing, warning Edward Johnson in a private letter: "Just as certain as death Westinghouse will kill a customer within six months after he puts in a system of any size." He believed AC's high voltage was inherently dangerous and would take years to make safe. He worried a single fatal accident could set back public acceptance of electricity altogether. In February 1888, Johnson published an 84-page pamphlet titled "A Warning from the Edison Electric Light Company," sending it to newspapers and to companies considering buying equipment from Westinghouse or Thomson-Houston, accusing them of infringing Edison's patents. Within months, an engineer with no apparent connection to Edison would take that argument public, using far more theatrical methods.

• 4. The Dog Killer

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  On the 15th of April 1888, a 15-year-old boy in New York City was killed by a broken telegraph line that had been energized with alternating current from a United States Illuminating Company line. A clerk was killed by an AC line two weeks later, and in May a Brush Electric Company lineman died while cutting a live AC wire. New York's press swung almost overnight from comparing electric light to gas light to running "death by wire" stories, each one fueling public anger at high-voltage AC and the city's tangled overhead wires.

  On the 5th of June 1888, an electrical engineer named Harold P. Brown wrote to the editor of the New York Post, calling the AC system "damnable" and inherently dangerous. He asked why "the public must submit to constant danger from sudden death" just so utilities could use a cheaper system. At the time, Brown appeared to have no connection to Edison at all. On June 7, Westinghouse tried to defuse the growing furor in a letter of his own, inviting Edison to visit him in Pittsburgh and writing that "there ought to be an entirely different condition of affairs" between their companies. Edison thanked him but declined, replying that "my laboratory work consumes the whole of my time." On June 8, Brown lobbied the New York Board of Electrical Control in person, demanding AC be capped at 300 volts, a limit that would have made it useless for long-distance transmission. A July edition of The Electrical Journal summed up the mood: "The battle of the currents is being fought this week in New York."

  Brown set out to prove his claims with a spectacle. He paid local children to round up stray dogs, and on the 30th of July he held a public demonstration in a lecture room at Columbia College. Some in the crowd shouted for it to stop; others walked out. Brown shocked a caged dog with direct current up to 1,000 volts, which it survived, then killed it with 330 volts of alternating current. Four days later, to counter claims the DC shocks had already weakened the animals, he killed three dogs in quick succession using just 300 volts of AC. He wrote to a colleague that he was confident the demonstration would push the Board of Electrical Control to limit AC to 300 volts. It did not work in New York, though similar legislation came close to passing in Ohio and Virginia.

  In November 1888, Westinghouse publicly challenged a claim Brown had made in the pages of the Electrical Engineer, that Westinghouse AC systems had caused 30 deaths. The magazine investigated and found at most two of those deaths could actually be traced to a Westinghouse installation. Brown's numbers kept shrinking under scrutiny, but his crusade was only getting started.

• 5. Inventing Execution

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  In 1881, a drunken dock worker in Buffalo, New York died instantly after grabbing a large electric dynamo, and the strange death caught the attention of local dentist Alfred P. Southwick. Working with physician George E. Fell and the Buffalo ASPCA, Southwick experimented on hundreds of stray dogs to develop a way to euthanize animals by electricity. In 1882 and 1883 he published articles arguing electrocution, delivered through a restraint much like a dental chair, could replace hanging as a method of execution. New York politicians, embarrassed by a string of botched hangings, were receptive. An 1886 commission appointed by Governor David B. Hill, which included Southwick himself, recommended in 1888 that executions be carried out by electric chair.

  That commission's own investigators surveyed hundreds of legal and medical experts, and consulted electrical authorities including Elihu Thomson and Thomas Edison. When Southwick first contacted Edison in late 1887, Edison said he opposed capital punishment and wanted nothing to do with the matter. Pressed further, Edison used the opening to attack his chief rival, writing to Southwick in December 1887 that the best current for the job would be that of "'alternating machines,' manufactured principally in this country by Geo. Westinghouse." After the execution law passed in June 1888, a New York official asked Edison how the state should carry it out. His answer: "Hire out your criminals as linemen to the New York electric lighting companies."

  The Medico-Legal Society, a group of doctors and lawyers, formed a committee in September 1888 under chairman Frederick Peterson, who had assisted at Brown's July demonstration on dogs. The committee ran its own animal experiments through late 1888 and into 1889, testing voltage levels, electrode placement, and skin conductivity. Brown served as a consultant. Some members questioned whether Brown's dog experiments proved anything about a human body. In November the committee recommended 3,000 volts for executions, without settling whether the current should be AC or DC. To settle the question, Brown arranged with Edison Electric treasurer Francis S. Hastings to use Edison's West Orange laboratory. On the 5th of December 1888, Brown staged a test at the lab with reporters, Medico-Legal Society members, and Edison himself looking on. He killed four calves and a lame horse with 750 volts of alternating current. The society's committee then recommended 1,000-1,500 volts of AC for executions. Newspapers noted that was about half the voltage running through the power lines over city streets.

  Westinghouse called the December test a rigged, self-serving demonstration. On December 13, in a letter to the New York Times, he laid out what he saw as flaws in Brown's methods and again accused Brown of working for Edison. Brown denied it in a reply on December 18, and even challenged Westinghouse to an electrical duel: each man would take turns being shocked with rising current, first to quit loses. Westinghouse declined. In March 1889, the Medico-Legal Society ran another round of tests on electrode design. Hastings tried and failed to obtain an actual Westinghouse generator, so the group used Edison's laboratory again.

  That same March, Superintendent of Prisons Austin Lathrop asked Brown to supply the execution equipment and design the chair itself. Brown turned down the design work but agreed to supply the equipment. When the state refused to pay upfront, he turned to Edison Electric and Thomson-Houston for help. Thomson-Houston arranged to acquire three Westinghouse generators by quietly swapping in its own machines instead. Company president Charles Coffin had two motives. He did not want Thomson-Houston equipment linked to an execution. He also wanted to use one seized generator to publicly disprove Westinghouse's claim that its machines ran 50 percent more efficiently. That spring, Brown published a 61-page booklet, "The Comparative Danger to Life of the Alternating and Continuous Electrical Current," mailing it to officials, newspapers, and businessmen in towns with more than 5,000 residents.

  When Kemmler was sentenced in May 1889, New York's papers debated what to call this new form of death. Suggestions included "Westinghoused," "Gerrycide," after death-penalty commission head Elbridge Gerry, and "Browned." The New York Times hated the word that eventually stuck, electrocution, blaming its adoption on "pretentious ignoramuses." One of Edison's own lawyers wrote that his boss preferred dynamort, ampermort, or electromort, but privately thought Westinghoused was the better choice.

• 6. The Kemmler Appeal

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  William Kemmler was sentenced to die around the 24th of June 1889, but an appeal was filed first, arguing electrocution counted as cruel and unusual punishment. It quickly became obvious that Kemmler's lawyer, the politically connected William Bourke Cockran, had no real link to the case. Cockran did have a connection to Westinghouse, which was evidently paying his fee.

  Hearings began on the 9th of July 1889 in New York City. Cockran used his skill as a cross-examiner to attack Brown, Edison, and their allies. His strategy was to show Brown had falsified his tests and that electrocution would not kill cleanly, only torture the condemned. He questioned Brown's credentials and raised the collusion charge again, which Brown denied once more. Witnesses gave anecdotal accounts of surviving electric shocks, and doctors testified about the nervous system and the skin's conductivity. During one session at Edison's West Orange laboratory, Brown nearly came to blows with a Westinghouse representative, accusing him of industrial espionage. When Edison finally took the stand, many observers were convinced. He spoke with the authority of the "wizard of Menlo Park," assuring them that 1,000 volts of AC would reliably kill a man.

  On the 25th of August 1889, the New York Sun ran a story headlined "For Shame, Brown! - Disgraceful Facts About the Electric Killing Scheme; Queer Work for a State's Expert; Paid by One Electric Company to Injure Another." It was built on 45 letters stolen from Brown's office, exposing his arrangements with both Thomson-Houston and Edison Electric. The letters showed Brown had received $5,000 from Edison Electric to help buy the surplus Westinghouse generators from Thomson-Houston. Other letters showed Edison treasurer Hastings asking Brown to mail anti-AC pamphlets to every legislator in Missouri, at company expense. Still others showed Edison and his assistant Arthur Kennelly coaching Brown ahead of his testimony in the Kemmler appeal. Brown shrugged off the exposure, comparing his campaign to exposing a grocer who "sells poison and calls it sugar."

  Judge Edwin Day ruled against Kemmler's appeal on the 9th of October 1889, and the US Supreme Court denied a further appeal on the 23rd of May 1890. The legal fight over Kemmler was finished. The larger fight over which current would win the country's business was not, and its next casualty would not be an inmate but an ordinary lineman.

• 7. Panic And The Peace

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  On the 11th of October 1889, John Feeks, a Western Union lineman, was working high in Manhattan's tangle of overhead wires. He believed he was handling low-voltage telegraph lines. Unknown to him, one line had been shorted many blocks away with a high-voltage AC line. The jolt entered through his bare right hand and exited through his steel-studded climbing boot. It killed him almost instantly as a lunchtime crowd watched from below. His body hung sparking and smoldering in the wires for nearly an hour before it could be brought down. Investigators never determined exactly which company's current killed him, though United States Illuminating Company lines ran nearby.

  Feeks' death set off what became known as the "Electric Wire Panic." Public blame settled on Westinghouse, since the company had bought many of the lighting operators involved. Newspapers accused AC executives of valuing men's lives as "cheaper to this monopoly than insulated wires." New York Mayor Hugh J. Grant told the Board of Electrical Control that "we get news of all who touch them through the coroners office." Harold Brown's reputation, damaged by the collusion scandal, was rehabilitated almost overnight as reporters again sought his opinion and followed him around the city measuring current leaking from AC lines.

  At the height of the panic, Thomas Edison entered the public debate directly for the first time, publishing an article titled "The Dangers of Electric Lighting" in the November 1889 North American Review. He argued that burying high-voltage lines would not solve anything, only move a "constant menace" underground where it could still threaten people's homes. He insisted the only real fix was limiting AC voltage, and vowed Edison Electric would never adopt alternating current while he was in charge. Westinghouse's reply in the same magazine was more measured. He pointed out that his transformer-based system actually delivered lower voltage into homes than Edison's DC did. He also cited 87 deaths a year from streetcars and gas lighting. Against that, AC caused just 5 accidental electrocutions and no in-home deaths at all.

  New York's aldermen, many of whom had watched Feeks' body burn near their own offices, finally passed a law ordering the utility lines moved underground. The companies won a brief injunction delaying the cuts. They shut down much of their lighting anyway rather than risk it, plunging city streets into darkness. The New York Supreme Court upheld the underground-wiring law in December. Crews cut down the AC lines, leaving many streets dark for the rest of the winter. The city's own supervisors had done little to build the promised underground conduits.

  Thomas Edison had lost majority control of his own company in the 1889 merger that formed Edison General Electric. By 1890 he told company president Henry Villard he wanted to retire from the lighting business altogether, turning his attention to an iron ore refining project instead. With Edison sidelined, his own subsidiaries began lobbying to add AC to their systems, and in October 1890 Edison Machine Works started developing AC equipment of its own.

  Villard spent 1891 negotiating a merger with Thomson-Houston, now Edison General Electric's biggest rival. A market downturn was squeezing cash at both companies, and roughly 60 lawsuits between them were eating into profits. Edison hated the idea and tried to block it, but a committee of financiers that included J.P. Morgan judged Thomson-Houston the stronger company on paper. The deal, announced on the 15th of April 1892, put Thomson-Houston's management in charge of the merged company. It was renamed General Electric, dropping Edison's name entirely. Thomas Edison did not learn of the terms until the day before they were announced. Five years earlier there had been fifteen competing electric companies; now there were only two, General Electric and Westinghouse. The merged General Electric alone controlled three-quarters of the US electrical business. Edison told reporters how much his stock had gained in the deal. Privately, he was bitter that his company and every one of his patents now belonged to the competition. From that point on, both surviving companies were selling the very current Edison had spent a decade fighting.

• 8. Direct Current's Long Afterlife

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  In May 1892, Westinghouse Electric underbid General Electric to win the contract to electrify the World's Columbian Exposition in Chicago. The company made no profit on the job. But its demonstration of a safe, flexible, universal AC system, powering the fair's tangle of devices, impressed observers. At the end of that year it won a bigger prize: the contract to build an AC power station at Niagara Falls. General Electric picked up related contracts there for transmission lines and transformers. It was catching up quickly, thanks partly to Charles Proteus Steinmetz, a Prussian-born mathematician. He was the first person to fully work out AC power on rigorous mathematical terms. Engineers elsewhere were bridging the older and newer systems with rotary converters and motor-generators. These devices let legacy DC motors and single or poly-phase AC equipment share a common grid as older gear was retired.

  At the International Electro-Technical Exhibition of 1891, engineer Mikhail Dolivo-Dobrovolsky used a three-phase, three-wire system to transmit power 176 kilometers at 75 percent efficiency. That same year he also built the first three-phase transformer, the squirrel-cage induction motor, and the world's first three-phase hydroelectric power plant.

  Patent lawsuits kept draining both American companies. In 1896, J.P. Morgan brokered a patent-sharing agreement between General Electric and Westinghouse that held for 11 years. In 1897 Edison sold his remaining stock in Edison Electric Illuminating of New York to fund his iron ore project. In 1908 he told George Stanley, son of transformer pioneer William Stanley Jr., "Tell your father I was wrong." It was a quiet admission that he had misjudged what alternating current could do.

  Central Helsinki ran a DC network into the late 1940s, and Stockholm kept a shrinking one running into the 1970s. Mercury-arc valve rectifier stations converted AC into DC wherever it was still needed. Parts of Boston's Beacon Street and Commonwealth Avenue still carried 110 volts DC into the 1960s. It quietly destroyed the hair dryers and phonographs of Boston University students who ignored warnings about the local power supply.

  New York's Consolidated Edison kept supplying direct current to legacy customers, mainly for elevators, well into the twentieth century. The New Yorker Hotel, built in 1929, ran its own DC power plant. It did not fully convert to AC until well into the 1960s. The hotel was also where Nikola Tesla spent his final years, and where he died in 1943. Broadway's theaters ran on DC until 1975, relying on outdated manual resistance dimmer boards worked by stagehands. That ended when the musical A Chorus Line introduced computerized lighting and thyristor dimmers, finally pushing New York's theater district onto AC.

  In January 1998, Con Edison began phasing out DC service to its 4,600 remaining customers. By 2006 only 60 customers were left. On the 14th of November 2007, the utility shut down its last direct-current distribution, fitting remaining customers with on-site AC-to-DC rectifiers. As late as 2012, Pacific Gas and Electric was still supplying DC power to elevators in San Francisco. It used close to 200 rectifiers, each serving 7-10 customers. In the UK, the Central Electricity Generating Board ran a 200-volt DC station at London's Bankside Power Station until 1981. It powered the printing machinery of Fleet Street's newspaper industry. The station was decommissioned when that industry moved to newer AC equipment in the developing Docklands.

  High-voltage direct current has since found a second life of its own. It now moves bulk power from distant generating stations, runs cables under the sea, and links separate AC grids together. That is the very job Edison's short-range, low-voltage system was never built to do.