The Forbidden Current

Sample chapter · Volume I: Preserving Knowledge

Chapter 3: The War of the Currents

From The Forbidden Current, Volume I, by Stephen Horton. Pre-publication text; figures appear in the printed and Kindle editions.

A ring of laminated iron carries four coils, each opposite pair wired together. One pair is fed by an alternating current, the other by a second current a quarter of a cycle behind, from a generator whose armature carries two coils at right angles. Nothing in the ring moves, yet its magnetic poles do: they travel round the ring in step with the generator. Bring a delicately pivoted steel disc near the ring and the disc "is set in rapid rotation." There is no commutator and no brush. Nikola Tesla described this ring to the American Institute of Electrical Engineers on 16 May 1888, about two weeks after the patents on it were granted.1

Alternating current carried Niagara's power to Buffalo in 1896 (→ Ch 2). This chapter covers the years before: the inventors, the patents, the animal tests, the electric chair and the bankers. The popular telling has a hero and a villain, and who plays which depends on the teller. The question here is narrower: which parts of the story survive the documents?

Two systems, 1886

Alternating current had the answer to distance, the transformer, but not yet a working system. The pieces came from Europe. Lucien Gaulard and John Gibbs showed their "secondary generator" at Turin in 1884. Guido Pantaleoni saw it there for George Westinghouse, who optioned the apparatus and brought it to Pittsburgh late in 1885. In London in 1885 Zipernowsky, Déri and Bláthy of the Ganz works, Budapest, showed transformers with primaries in parallel, an arrangement Westinghouse adopted from the start.2

William Stanley, working at Great Barrington, Massachusetts, on Westinghouse's money, rebuilt the apparatus for parallel connection. On 20 March 1886 his plant lit about twenty offices and stores on the town's Main Street, stepping 500 V up to 3,000 V for the line and down to 100 V for the lamps. The new Westinghouse Electric Company opened its first commercial alternating-current plant in Buffalo on 30 November 1886.3

What alternating current lacked was a motor. Tesla's lecture said so: transformers "have afforded us a relatively perfect system of distribution," but "the transmission of power, on the contrary, has been almost entirely confined to the use of continuous currents." The lecture itself disposes of the popular claim that Tesla invented alternating current: it takes alternating generators and transformers as given and treats alternating-current motors as an existing, unsolved problem.4

The rotating field

Tesla filed his first motor applications between 12 October and 23 December 1887; patents 381,968, 382,279, 382,280 and their companions were all granted on 1 May 1888. The principle is the ring in the opening: two currents a quarter-cycle apart, in coils at right angles, make a field of constant strength that turns steadily, one revolution per cycle for the simplest winding. A conducting rotor inside is dragged round by the currents the moving field induces in it, the same drag that pulled Arago's magnet after a spinning copper plate (→ Ch 2). The rotor always runs a little slower than the field: in step, it would have no current induced in it and so no torque. Every induction motor works this way (→ Ch 43).5

PRIMARY SOURCE — Nikola Tesla, "A New System of Alternate Current Motors and Transformers," lecture to the AIEE, 16 May 1888 (transcription via Wikisource) "In our dynamo machines, it is well known, we generate alternate currents which we direct by means of a commutator, a complicated device and, it may be justly said, the source of most of the troubles experienced in the operation of the machines. [...] In reality, therefore, all machines are alternate current machines, the currents appearing as continuous only in the external circuit during their transit from generator to motor." Gloss: Tesla's argument was that the commutator could be eliminated altogether: generate alternating current, transmit it, and let the motor's field do the shifting that the commutator did by switching.

Tesla was not alone. In Turin, Galileo Ferraris had run the same idea on the bench; a footnote in his paper dates his experiments to autumn 1885, two crossed coils fed with currents displaced in phase spinning a copper cylinder hung on a thread. He read the paper to the Turin Academy of Sciences on 18 March 1888, and his conclusion was cautious: he wrote (in translation) that such an apparatus "could not have any industrial importance as a motor," though its power and efficiency could be greatly improved; he saw uses in teaching and metering. His editors (1902) record that he published only at colleagues' urging and did not seek patents, and judge it "certain" that his first trials went back to the end of June 1885, an inference, not a dated record. Tesla said in 1892 that he filed only after "it was undoubtedly demonstrated that the motor could fairly compete in efficiency with the direct current motor."6

Others stood near the same idea. Walter Baily (1879) turned a disc by switching direct current round a ring of electromagnets with a commutator. Charles Bradley of Yonkers filed for a two-phase generator on 9 May 1887. Mikhail Dolivo-Dobrovolsky of AEG built three-phase motors in 1889, and in 1891 three-phase power ran 175 km from Lauffen to Frankfurt at 15 kV. An IEEE milestone proposal lists polyphase systems as "independently invented" by Ferraris, Dolivo-Dobrovolsky, Jonas Wenström, John Hopkinson and Tesla.7

In 1900 Judge Townsend upheld patents 381,968, 382,280 and 382,279, finding that Tesla "first disclosed the method and apparatus now generically known as the 'Tesla polyphase inventions'." The opinion, affirmed in 1901, does not mention Ferraris, whose publication came after Tesla's filings. In the opinions read here, Ferraris entered the litigation over two later Tesla patents, filed 8 December 1888, for splitting a single current into two out-of-phase currents. In 1903 the Second Circuit held them anticipated by a report of Ferraris's lecture published in Milan on 22 April 1888, because Tesla could not prove an earlier date of invention; Judge Colt in Massachusetts followed it. In 1904 the First Circuit reversed Colt, saying "Tesla's conception was in this respect at least as broad as Ferraris's." It also noted that a Patent Office interference between Ferraris and Tesla had been "decided in favor of the latter," without saying which applications it covered.8

EVIDENCE STATUS — Tesla was the first to conceive the rotating-field induction motor Status: Disputed Type: empirical What's established: Tesla's motor patents were filed from 12 October 1887 and upheld in 1900–01; a Patent Office interference between the two men (applications unnamed) was decided for Tesla. Ferraris's experiments date, by his own footnote, to autumn 1885; his paper was read on 18 March 1888, before Tesla's patents were granted or his lecture given. The courts split in 1903–04 on the later split-phase patents.68 What's contested / unknown: Who conceived the idea first. Ferraris's date rests on his 1888 footnote and his editors' 1902 inference of June 1885. Tesla's earlier conception rests on his 1892 reply and his 1919 memoir, which places it six years before the 1888 lecture. Tesla filed first; Ferraris published first; neither copied the other on any evidence found. What would settle it: A dated contemporaneous record, a notebook, letter or witness statement from before October 1887, for either man; or the testimony in the Patent Office interference file.

Westinghouse buys the patents

On 7 July 1888 Westinghouse secured an assignment of the exclusive rights under Tesla's patents. The financial terms are reported only in later secondary accounts, which agree on a royalty of $2.50 per horsepower of motor capacity but disagree about the cash, notes and stock. Tesla went to Pittsburgh. By his account, his system "was based on the use of low frequency currents and the Westinghouse experts had adopted 133 cycles," and by the close of 1889, with his "services in Pittsburg being no longer essential," he returned to New York. Westinghouse's biographer recorded that for about two years from 1890 development of the polyphase system "was considerably retarded by financial difficulties" from "lack of adequate capital."9

The case against alternating current

Meanwhile the Edison side had gone to the public. Late in 1887 or early in 1888 the Edison Electric Light Company issued a pamphlet titled A Warning. It argues mainly patents and investment; its section on danger reads: "Any interruption of the flow of the current adds to its destructive property, whilst its complete reversal, as in the Alternating (Westinghouse) system increases this destructiveness enormously." This was not ignorance of alternating current: the Edison company owned patents for the Ganz works' Zipernowsky alternating system. Asked under oath in 1889 why he did not use it in America, Edison answered: "I don't like to." In print he went further: the company "purchased some time ago the patents for a complete alternating system, and my protest against this action can be found upon its minute-book."10

On 5 June 1888 Harold P. Brown wrote to the New York Evening Post about recent deaths from overhead wires, and that summer began killing animals with electric current to compare alternating and direct current. By his own sworn account the first series ran "at Mr. Edison's laboratory at Orange, New Jersey," assisted "in the electrical part by Mr. Edison's chief electrician, Mr. A. E. Kennelly"; Dr. Frederick Peterson, who handled the physiology, testified that "Mr. Kennelly measured the electrical force." On 5 December, at the Orange laboratory and before a Medico-Legal Society committee, Brown killed calves and then a 1,230-pound horse with 700 V of alternating current. His totals were "about 40 to 50 dogs, 6 to 10 calves and two horses," and his pamphlet thanked Edison "for the loan of instruments and laboratory."11

Brown swore he had no connection with the Edison company, and none with Edison himself "except a personal acquaintance. I have received a great many favors at his hands; it is entirely a personal friendship." Edison, cross-examined, said he had seen Brown "about a dozen times" and thought he had never met him before Brown came to Orange "about this very business." "He wanted to try some experiments," Edison said, and he sometimes let others experiment there; Brown "seemed to be a pretty nice kind of fellow, and it was [no] trouble to me, and I let him do it."11

EVIDENCE STATUS — Edison's laboratory, instruments and staff supported Brown's 1888 animal tests Status: Proven Type: empirical What's established: Sworn 1889 testimony: Brown, that the first series ran at the Orange laboratory with Kennelly assisting; Peterson, that Kennelly measured; Edison, that he let Brown do it. Brown's pamphlet thanks Edison for instruments and laboratory.11 What's contested / unknown: Not the support; its meaning (next box). What would settle it: Settled by consistent sworn testimony from both sides.

EVIDENCE STATUS — Edison directed Brown's animal tests in order to discredit alternating current Status: Disputed Type: interpretive What's established: Edison campaigned against alternating current in print and under oath, and his laboratory supported the tests. Brown used the tests against alternating current.1011 What's contested / unknown: Whether Edison directed or paid for the tests, and why. Edison testified that he barely knew Brown and lent the laboratory to others; Brown called it a personal friendship and "a great many favors." The sworn record read here does not show direction or motive. What would settle it: Correspondence among Edison, Brown and the Edison companies for 1888, such as may appear in the Edison Papers volume 9 (not read for this chapter).

The law preceded the tests. New York's governor had asked in 1885 for a method of execution "less barbarous" than hanging, and a state commission recommended electricity. Chapter 489 of the state's Laws of 1888, signed on 4 June and effective 1 January 1889, required death by "a current of electricity of sufficient intensity to cause death." William Kemmler, convicted of a murder committed on 29 March 1889, became the test case. Testifying for the state on 23 July 1889, Edison said alternating current was dangerous and could kill instantly; he would use "either an alternating current or a continuous current that was very much broken up—very much interrupted." Under cross-examination he conceded that his view was "a belief and a deduction," not a demonstration, "because the State has never killed anybody yet." On 23 May 1890 the U.S. Supreme Court denied Kemmler a writ of error, holding the state courts' decision upholding the act "not reexaminable here"; its often-quoted line is a definition, not a ruling on the method: "Punishments are cruel when they involve torture or a lingering death, but the punishment of death is not cruel" in the constitutional sense.12

Kemmler was executed at Auburn State Prison on 6 August 1890. Dr. Carlos MacDonald's official report records a first contact of 17 seconds; about half a minute later, "slight spasmodic movements of the chest," which it reads as "involuntary muscular movements of a reflex character ... in no sense a resumption of normal respiration"; and a second contact "inadvertently maintained for about seventy seconds" (elsewhere "nearly one and one-half minutes") until smoke rose from the spinal electrode. Dr. W. T. Jenkins, the autopsy surgeon, told the Electrical Review that "the respirations were vital" and put the second contact at about four minutes. The report concedes that "none of the official witnesses could know precisely what the voltage was." Westinghouse's comment, in a Pittsburgh dispatch printed by the Wheeling Register the next day: "It has been a brutal affair. They could have done better with an axe."13

PRIMARY SOURCE — Thomas A. Edison, "The Dangers of Electric Lighting," North American Review 149 (Nov. 1889), pp. 625–634, at 631–632; George Westinghouse Jr., "A Reply to Mr. Edison," ibid. (Dec. 1889), pp. 653–664, at 661 Edison: "I have myself seen a large healthy dog killed instantly by the alternating current at a pressure of one hundred and sixty eight volts. [...] My personal desire would be to prohibit entirely the use of alternating currents. They are as unnecessary as they are dangerous." Westinghouse: "[T]here were killed by street-cars during the year 1888, 64 persons; by omnibuses and wagons, 55; and by illuminating gas, 23; making the number killed by the electric current (5) insignificant [...]." Gloss: Edison argued from physiology, Westinghouse from accident statistics. Westinghouse also cited Kennelly's own laboratory figure, a 57½-pound dog killed in 40 seconds by 400 V of direct current, and proposed a 100 V limit inside buildings.

Edison's physiological claim deserves its strongest form: on the narrow point he was right.

EVIDENCE STATUS — For contact longer than about 2 seconds at power frequency, alternating current is more dangerous than direct current of the same strength Status: Proven Type: empirical What's established: Edison stated the grip effect in 1889: "even at exceedingly low voltage the hand which grasps a conductor cannot free itself," and the shock might last long enough "to produce death." For a hand wrapped round a conductor at under 600 V, 60 Hz, most adults can let go below about 6 mA and more than 99 percent cannot at 22 mA (Dalziel's measurements, as reviewed by Fish and Geddes). For direct current the review cites Bernstein (1989): no let-go effect below 300 mA, and a fibrillation threshold, for shocks longer than 2 seconds, of 150 mA against 50 mA at 60 Hz.14 What's contested / unknown: Duration matters. For shocks shorter than 0.2 seconds the review gives the same fibrillation threshold for both, about 500 mA, and its own table gives 16 mA as the average man's loss of grip. Nor did the physiology decide policy. At the 1,000 to 3,000 V Edison cited for alternating lines, both currents kill: Kennelly's dog died of 400 V direct current, Brown's animals of alternating. Alternating current was made safer by low-voltage secondaries, insulation and codes. What would settle it: Nothing further for let-go, which rests on replicated, engineering-grade measurements. The direct-current figures rest here on one cited source; reading Bernstein and the primary DC threshold studies would firm them.

The best-known animal death came fifteen years later. Topsy was killed at Luna Park, Coney Island, on 4 January 1903 by "a combination of poisoning, strangulation, and electrocution," with 6,600 V supplied by the Edison Electric Illuminating Co. of Brooklyn from General Electric generators; the Edison Manufacturing Company filmed it. The Edison Papers project finds that Edison "had nothing to do with the decision to euthanize Topsy and took no part in the proceedings," and had no role in directing the Brooklyn company that shared his name. No document read ties him to the event; the links are a company name and a film.15

The money

Drexel, Morgan & Co., J. Pierpont Morgan's banking house, was among the backers of the Edison Electric Light Company from its incorporation in 1878. In April 1889 a consolidation negotiated with Henry Villard merged Edison's manufacturing companies and the patent-holding company into the Edison General Electric Company. On 15 April 1892 that company merged with its rival Thomson-Houston to form the General Electric Company. Edison's name was dropped, and he withdrew from running the business. Before the merger, as Niagara's historian Edward Dean Adams put it, Edison General Electric had been "the chief advocate of direct or continuous current in this country"; afterwards the new company "changed from opposition to advocacy."16

The first public test of the polyphase system came at Chicago. On 23 May 1892 Westinghouse took the contract to light the World's Columbian Exposition "at a price much below the bid made on behalf of the Edison General Electric Company," and the fair's polyphase exhibit was, in Adams's words, "a miniature of the system which Westinghouse planned for Niagara."17

In the best-known money story, made famous by John J. O'Neill's 1944 biography, Westinghouse, in financial trouble about 1891, asked Tesla to release him from the royalty contract, and Tesla tore it up, giving away a fortune. The company record tells a different story. In March 1896 Westinghouse and General Electric exchanged patent licences. Westinghouse's annual report for the year to 31 March 1897 states that, under that licence contract, the company "purchased outright for $216,600 the Tesla patents for multiphase-current motor, in order that both companies might manufacture apparatus covered by those patents without the payment of royalties, other than those provided for in the agreement between the two companies." The report names neither seller nor date. Its wording suggests that a royalty was still being paid until the purchase; since Westinghouse already held the exclusive rights, "purchased outright" would fit a buy-out of that royalty interest.18

EVIDENCE STATUS — Tesla tore up his Westinghouse royalty contract and so lost millions Status: Disputed Type: empirical What's established: Westinghouse acquired exclusive rights on 7 July 1888, and was short of capital from 1890. Its 1897 annual report records an outright purchase of the Tesla polyphase patents for $216,600, pursuant to the 1896 licence contract with GE; seller and date are not stated.918 What's contested / unknown: Whether Tesla waived or reduced royalties around 1891. The tear-up scene comes from O'Neill (1944), who knew Tesla; no contemporaneous document of it was found, and the 1897 report neither confirms nor rules out an earlier waiver. "Millions" is a projection of royalties that were never paid, not a recorded sum. What would settle it: The 1888 contract and any later amendment, in the Westinghouse corporate archive or the Tesla papers at the Library of Congress, read together with the 1896–97 purchase agreement.

Niagara

The prize was the Niagara River. The Cataract Construction Company was incorporated on 13 June 1889, with Edward Dean Adams as president. Its stockholders included J. Pierpont Morgan, W. K. Vanderbilt and John Jacob Astor. Rather than pick a system, the company set up an International Niagara Commission in London under Sir William Thomson (Lord Kelvin), which by 4 February 1891 had considered 14 projects for about 125,000 horsepower and awarded 8 prizes, but none for distribution and no first prize for a combined hydraulic and electrical project: none, in its opinion, "could be recommended for adoption without considerable modification."19

The decision came two years later. Kelvin still favoured direct current; on 1 May 1893 he cabled: "Trust you avoid gigantic mistake of adoption alternating current." On 6 May the Cataract directors adopted alternating current. Tesla was not on the commission but advised the company, favouring two-phase. Both Westinghouse and General Electric bid, and patent counsel warned that, with Bradley's patents held by GE and Tesla's by Westinghouse, conflict was "almost certain" whichever company was chosen. The contract went to Westinghouse in late October 1893, for three two-phase alternators of 5,000 horsepower each. On frequency, the Cataract engineers wanted 16⅔ cycles per second and Westinghouse 30; they settled on 25.20

The Adams plant delivered its first commercial power on 26 August 1895, to the Pittsburgh Reduction Company for aluminium. On 15 November 1896 the Buffalo line went into commercial use, delivering power to the Buffalo Railway Company. The victory was shared. General Electric won the Buffalo transformer station and rotary converters, and the line ran three-phase at 11,000 V, stepped up from the Westinghouse two-phase machines. By Adams's count, the company that "had been known as the Edison or General Electric Company" supplied "about one-half" of all the alternating-current plant in the three power-houses.21

What the war settled

The Edison Papers project avoids the morality play: "The fight was between two stock companies (and their investors) with different strategies," and Edison "had mixed motives for fighting the 'War,' some of them plainly self-serving." The engineering verdict was clear. Alternating current won because the transformer let one network carry power at high voltage and use it at low voltage, and because the rotating field gave it a motor without a commutator. The commercial verdict was a truce: the Edison company that warned against alternating current became the General Electric that built Niagara's Buffalo line, and from 1896 both rivals could build under Tesla's motor patents.22

KEY NUMBERS

QuantityValueSource
Great Barrington, 20 Mar 1886500 V generated, 3,000 V line, 100 V at lamps; ~20 businessesETHW Milestone
Tesla motor patentsfiled 12 Oct–23 Dec 1887; granted 1 May 1888US 381,968 et al.
Ferraris paperexperiments autumn 1885; read 18 Mar 1888Atti Torino 23
Lauffen–Frankfurt, 1891175 km, 15 kV, three-phaseIEEE proposal
Brown's tests, 1888~40–50 dogs, 6–10 calves, 2 horsessworn, 1889
Kemmler, 6 Aug 189017 s, then 70–90 s (official; Jenkins ~4 min); voltage not visible to witnessesMacDonald 1890
Let-go current, 60 Hzmost adults can let go below 6 mA; >99% cannot at 22 mADalziel, via Fish & Geddes 2009
DC let-go; fibrillationDC: none below 300 mA; VF >2 s: 50 mA AC vs 150 mA DC; <0.2 s: ~500 mA bothBernstein, via Fish & Geddes 2009
Tesla patents bought out$216,600 (year to 31 Mar 1897)Westinghouse report
Niagara alternators, 18933 × 5,000 hp, 2-phase, 25 Hz, 2,000–2,400 VAdams 1927
Buffalo line, 18963-phase, 11,000 V; in use 15 Nov 1896Adams 1927

RECENT FINDINGS

  • 2021 — IEEE dedicates a milestone in Turin, "Rotating Fields and Early Induction Motors, 1885–1888," crediting Ferraris with conceiving and demonstrating the rotating magnetic field. The plaque does not mention Tesla.7
  • 2021 — The Thomas A. Edison Papers publish volume 9, Competing Interests (1888–89), open access, covering the "War of the Currents".22
  • 2025 — NVIDIA announces an 800 V direct-current power architecture for AI data centres, claiming fewer conversion steps and 45 percent less copper than 415 V AC distribution, with full-scale production planned for 2027 (→ Ch 46).23

CARRY FORWARD

  • The rotating field: two currents a quarter-cycle apart in coils at right angles make a field that turns. → Ch 43; Vol II induction-motor plate.
  • Transformation decided the war. DC returns where power electronics replace the transformer. → Ch 2, Ch 46, Ch 58.
  • Independent invention is normal. Tesla, Ferraris and Dolivo-Dobrovolsky reached the rotating field separately; priority depends on what counts, filing, publication or conception.
  • Physiology is not policy. Edison was right that sustained 60 Hz current is harder on the body and wrong that this ruled out AC distribution. → Ch 62 (grounding and protection).
  • Follow the documents. The tear-up and Topsy stories both outran their evidence. Tesla's later work → Ch 13–14.

Full claim-by-claim source notes for this chapter: forbiddencurrent.com/notes/ch03

Notes

  1. N. Tesla, "A New System of Alternate Current Motors and Transformers," AIEE, 16 May 1888, transcription via Wikisource; US 381,968, 382,279, 382,280 (granted 1 May 1888). ↩

  2. H. G. Prout, A Life of George Westinghouse (1921), pp. 102–104. ↩

  3. ETHW / IEEE Milestone, "Alternating Current Electrification, 1886"; Prout (1921), pp. 113–114. ↩

  4. Tesla, AIEE lecture (1888), opening paragraphs. ↩

  5. Patent headers, US 381,968–381,970 and 382,279–382,282 (1888); Tesla, AIEE lecture (1888). ↩

  6. G. Ferraris, "Rotazioni elettrodinamiche prodotte per mezzo di correnti alternate," Atti R. Accad. Sci. Torino 23 (1888), pp. 222–237 (footnote p. 225; §5); Opere di Galileo Ferraris, vol. 1 (1902), pp. xiv–xvii; N. Tesla, "The 'Drehstrom' Patent," Electrical World (1892), transcription via Wikisource; N. Tesla, My Inventions (1919). ↩ ↩2

  7. W. Baily, Phil. Mag. 5th ser. 8 (1879), pp. 286–290; C. S. Bradley, US 390,439 (1888); IEEE Milestone proposal, "Long distance transmission of electrical power using three-phase alternating current, 1891–1912"; ETHW / IEEE Milestone, "Rotating Fields and Early Induction Motors, 1885–1888" (dedicated 21 Jan 2021). ↩ ↩2

  8. Westinghouse v. New England Granite Co., 103 F. 951 (C.C.D. Conn. 1900), aff'd 110 F. 753 (2d Cir. 1901); Westinghouse v. Catskill Illuminating & Power Co., 121 F. 831 (2d Cir. 1903); Westinghouse v. Stanley Instrument Co., 129 F. 140 (C.C.D. Mass. 1903, Colt J.), rev'd 133 F. 167 (1st Cir. 1904, Putnam J.). ↩ ↩2

  9. Prout (1921), pp. 121–122; N. Tesla, My Inventions (1919), ch. on Westinghouse; terms from Tesla Universe timeline and PBS, Tesla: Master of Lightning (secondary). ↩ ↩2

  10. Edison Electric Light Co., A Warning from the Edison Electric Light Co. ([1887–88]), pp. 26–27; Edison testimony, 23 July 1889, People ex rel. Kemmler v. Durston, N.Y. Court of Appeals printed record (1889); T. A. Edison, North American Review 149 (1889), p. 632. ↩ ↩2

  11. Testimony of H. P. Brown, Dr. F. Peterson and T. A. Edison, and Brown's pamphlet The Comparative Danger to Life of the Alternating and Continuous Electrical Currents (3rd ed.) as Relator's Exhibit A, in the Kemmler record (1889). ↩ ↩2 ↩3 ↩4

  12. In re Kemmler, 136 U.S. 436 (1890), at 444–447; Laws of N.Y. 1888, ch. 489; People ex rel. Kemmler v. Durston, 119 N.Y. 569 (1890); Edison testimony and Attorney-General's brief (approval date), Kemmler record (1889). ↩

  13. C. F. MacDonald, Report on the Execution by Electricity of William Kemmler (1890), pp. 5–8, 14–15; Wheeling Register (W. Va.), 7 Aug 1890, p. 1, via Chronicling America; Electrical Review (New York) 16 (16 Aug 1890), "What Mr. Westinghouse Says" and "Interview with Dr. Jenkins"; Electrical World 16 (16 Aug 1890), Kemmler coverage. ↩

  14. R. M. Fish and L. A. Geddes, "Conduction of Electrical Current to and Through the Human Body: A Review," Eplasty 9 (2009), e44, pp. 2–3, 6–7 of the author-hosted copy, citing C. F. Dalziel (1956) for let-go and T. Bernstein (1989) for DC thresholds; Edison, North American Review 149 (1889), p. 632. ↩

  15. Thomas A. Edison Papers, "Myth Buster: Topsy the Elephant," edison.rutgers.edu; Edison Manufacturing Co., Electrocuting an Elephant (1903), via archive.org; Portland Daily Press, 6 Jan 1903, p. 3, and Topeka State Journal, 6 Jan 1903, p. 2, via Chronicling America. ↩

  16. Edison Papers, chronology 1871–1880 and 1881–1890, and company pages "Edison General Electric Company" and "General Electric Company"; ETHW, "General Electric (GE)"; E. D. Adams, Niagara Power, vol. 2 (1927), pp. 212, 233. ↩

  17. Prout (1921), pp. 134–137; Adams (1927), vol. 2, p. 234. ↩

  18. J. J. O'Neill, Prodigal Genius (1944), p. 82 (cite-only); Prout (1921), on the 1896 licence exchange; "Westinghouse Company's Annual Report," Electrical Review (New York) 30 (30 June 1897), pp. 312–313. ↩ ↩2

  19. Adams (1927), vol. 1, pp. 174–189, 233, 273, 292–296. ↩

  20. Adams (1927), vol. 2, pp. 233–243. ↩

  21. Adams (1927), vol. 2, pp. 39, 72–73, 213, 247–248, 270–278; ETHW / IEEE Milestone, "Adams Hydroelectric Generating Plant, 1895." ↩

  22. Edison Papers, "The Current Wars," edison.rutgers.edu; Prout (1921) and Electrical Review (1897), as note 18; The Papers of Thomas A. Edison, vol. 9, Competing Interests, January 1888–December 1889 (2021), open access, doi:10.1353/book.84205. ↩ ↩2

  23. NVIDIA Technical Blog, "NVIDIA 800 VDC Architecture Will Power the Next Generation of AI Factories" (20 May 2025). ↩