1. This entry was presumably written on or soon after the date of the last test.

2. According to Charles Mott, Charles Clarke conducted this test with one generator serving as the exciter for five other machines connected to the line. Mott reported slightly different results from those given here, showing 6.3 lamps per horsepower. More significantly he noted that “The amount of water per hour by indicator was 1429.91 lbs or 34.4 lbs per H.P. per hour. Mr. Clarke says that the amount of steam used by the engine should have given 7.3 lamps per horse power, otherwise that a good engine should have given the same results with 30 lbs of steam per hour, per H.P.” The boiler was fired by dust coal for this test. The next day large coal was burned instead and on 23 December a mix of half large coal and dust was adopted “As a compromise and with better results.” Mott Journal N-80-07-10:256–58, 261, Lab. (TAEM 37: 430–31, 433; TAED N117:128–29, 131).

3. In his account of this test Mott reported that the engine provided to the armatures “61.95 H.P. or on 408 lamps gave 6.59 per H.P. less field gave net 7.88 per h.p. on 22.58 pounds steam per H.P. per hour,” meaning that slightly more than 10 horsepower was consumed in the field magnets. Mott Journal N-80-07-10:271, Lab. (TAEM 37:438; TAED N117:136).

4. In a separate resume of this day’s results Clarke calculated 5.7 lamps per indicated engine horsepower. He then used this rate to determine that 3½ pounds of coal should run 8.1 lamps, although the significance of this amount of fuel is not clear. The test was made with nine line generators and one field exciter. Another trial on 7 January failed to producePage 972 meaningful data because steam power was being used simultaneously for other purposes. Clarke test results, 4 Jan. 1881, DF (TAEM 57:1091; TAED D8125000A); Mott Journal 80-07-10:274, 280, Lab. (TAEM 37:439, 442; TAED N117:137, 140).

1. Stilwell was apparently the son of Silas Stilwell, a noted New York politician, lawyer, and writer on financial subjects; nothing further is known of the son. The Albemarle Fertilizer Co.’s letterhead identified Fox as the secretary. Fox had become involved with the firm by the summer of 1880 when he sent a product sample to Menlo Park for analysis. Edison apparently did not follow up this request or assign Otto Moses to do so. Edison also declined Fox’s offer to “make a few thousand” dollars. Fox expected the company’s board to double the price of its treasury stock and promised to “reserve some for you and guarantee you against loss. Being on the very inside, I know it is a bonanza.” DAB, s.v. “Stilwell, Silas Moore”; Fox to TAE, 9 and 11 Aug., 13 Sept. 1880, DF (TAEM 53:510, 199, 218; TAED D8014T, D8004ZEO, D8004ZFI).

2. William Barmore sold this restaurant and hotel at 390 Fifth Ave. to John Jacob Astor in January 1881 but continued to operate it until the business failed a year later. Wilson 1881, 74; “Local Business Troubles,” New York Times, 21 Jan. 1882, 8.

3. Edison’s letter has not been found but presumably was in reply to Fox’s 6 January inquiry on behalf of a friend “very anxious” to have Edison lights for his Fifth Ave. property. Fox noted that “The cost is no object with him. The event is one that would receive large attention at the hands of the city press.” Fox to TAE, 6 Jan. 1881, DF (TAEM 57:561; TAED D8120D).

4. In answer to Edison’s reply of 11 January (not found) Fox stated that he had been “under the impression that your Company would put in light and generators but insomuch as that is not the plan I will see my friend Stilwell and explain to him and let you know.” Edison did not necessarily oppose the idea of isolated lighting stations for individual buildings, and in November Francis Upton had begun preliminary calculations for wiring William Henry Vanderbilt’s house. About this time arrangements were also being made to illuminate a New York printing establishment (see Doc. 2053). Fox to TAE, 12 Jan. 1881, DF ( TAEM 57:572; TAED D8120L); N-80-11-15:177–223, Lab. (TAEM 39:870–93; TAED N172:89–112).

1. Edison most likely made this note on or about the date he gave it to Charles Batchelor.

2. On earlier efforts to remove hydrogen compounds, see Doc. 2003. Edison’s “discovery” resulted from research planned a week earlier. Charles Mott noted in his journal on 6 January that “Mr. Edison wrote out some 9 or 10 experiments for Lawson to try on lamps at Factory. Mostly the introduction of Phosphorous, Sodium etc. in the globe, to be acted on by the heat on pumps or in use.” John Lawson’s notes indicate that he also tried naphthalene crystals, trichloride of carbon, benzoic acid, charcoal, and an alcoholic solution of shellac (Mott Journal N-80-07-10:279; N-80-12-13:9–15, 271–79; both Lab. [TAEM 37:442; 39: 678–81, 686–90; TAED N117:140; N168:4–7, 12–16]). Detailed orders for the construction of these experimental lamps are in Cat. 1301, Batchelor (TAEM 91:294–99; TAED MBN007:1–6); additional notes and instructions related to these orders are in Box 13, EP&RI. Laboratory notes, principally measurements of resistance, regarding these and other experimental lamps from this period are in N-80-12-24.1:1–39, Lab. (TAEM 40:3–22; TAED N186:1–20). The purpose of other experiments made about this time is not apparent, but they may have been intended to prevent “carrying.” Lawson’s notes (see above) also indicate that several carbons were coated with shellac and tried in lamps. Mott reported on 4 January that Lawson “boiled some carbon loops in Aqueous solution of Platinum chloride, believing that when heated in vacuum on pumps the chlorine will be driven off, leaving the platinum in the pores of the carbon in a finely divided state— But what will the platinum do when the loop is heated to high incandescence? trial will show.” These filaments were found to have a much lower resistance than the regular carbonized fibers (Mott Journal N-80-07-10:275, 280, 282, Lab. [TAEM 37:440, 442–43; TAED N117:138, 140–41]).

1. Antoine Breguet was director of installation services for the Exposition Internationale d’Électricité in Paris. Breguet came from a distinguished Parisian family of instrument makers and at this time was partner with his father in the manufacture of electrical apparatus and instruments. Hilborne Roosevelt had commissioned their firm to construct a telephone system in 1876. DSB, s.v. “Breguet, Louis François Clément.”

2. Neither of Breguet’s letters has been found. In late December George Gouraud apprised Edison that a French official had called upon him to “request that all your electrical inventions should be represented, and I was begged to charge myself with this undertaking. Great stress is laid upon this matter. England will be there in great force. It is obviously desirable that this request be met in the most thorough manner.” After giving this official an evasive reply Gouraud wrote Edison that

this little bye-play of mine is all very well, and we may as well make ourselves “a little difficult” so as not to show too much eagerness, but it must be as obvious to your good self as it is to me that as this will be the first exhibition, exclusively electrical that has ever been held,—and one that will attain a world wide prominence and having regard to the prominent position you hold in the profession, and the extensive value of your discoveries and inventions,—that not to be there in force would render the exhibition incomplete and most prejudicial inferences might thereby be drawn. Now I propose that we take time well by the fore-lock, and do this matter up most thoroughly. I therefore beg you, immediately upon the receipt of this to make it the especial business of somebody, to get up in the best form, highly finished models of all or certainly all your principal electrical inventions with their latest development. [Gouraud to TAE, 21 Dec. 1880, DF (TAEM 54:359; TAED D8028A)]

1. The basis of Edison’s reply is Doc. 1954.

2. About a week later Alfred Renshaw sent Edison his analysis of the London telephone company’s proposed settlement, which he anticipatedPage 977 would yield about £3,500 for Edison after deducting advance royalties and other expenses. He concurred with Gouraud’s opinion of this offer and stated he had proposed that “the Shares of the United Company should be divided pound for pound amongst the Shareholders of the London Company and that what is left, after that division should be divided equally between the Company’s interest and your interest.” Renshaw also reported that the United shareholders had approved a resolution calling for the liquidation of the Edison company but, because this could not be done without Edison’s consent, they had obtained a court order to this effect. He expected this would be overturned on appeal but thought that “In any case the order for liquidation will have the effect of bringing matters to a point” and compel the company either to reach a settlement or have one imposed by the court. He predicted that in the end “something over £20,000 is likely to be secured for your interest.” By early March a tentative settlement had been reached under which shareholders were to receive their original investment plus 5% interest in United Co. stock at £7 per share, with the remaining shares to be divided equally with Edison except for 1,250 shares which he was to give up to repay half his advance royalty. Renshaw to TAE, 26 Jan. and 1 Mar. 1881; Edward Bouverie’s letter to stockholders of the Edison Telephone Co. of London of 5 Mar. 1881, addressed to TAE; all DF ( TAEM 59:918, 923–24; TAED D8149D, D8149G, D8149H).

1. Owen Gill was a partner in Gillett Martin & Co., a Baltimore tea wholesaler (Woods 1881, 328). Edison had sent him an electric lamp, apparently in response to an inquiry which has not been found. In reply to Gill’s acknowledgment of this, Edison asked on 18 January if it would “be an easy matter to obtain municipal permission to lay wires in the Street.” Gill then requested a number of lamps to exhibit on battery current for a gathering of newspaper editors from Ohio. He reported on 23 January that this event was “successful beyond my expectations, and gained you many adherents in Ohio.” He added that he thought Edison would already have “received a visit from a committee of our common council who want to put your light in some of the public buildings, and from conversations which I have had with some of the officers of our city government I think you will receive encouragement, instead of obstructions, in the laying of wires.” Edison answered on 26 January that he was “very much pleased with your success in working the lamps. We shall soon have a number of small dynamos and then I shall be able to supply you with one.” TAE to Gill, 18 and 26 Jan. 1881, Lbk. 6:815, 868 (TAEM 80:470, 488; TAED LB006815A, LB006858); Gill to TAE, 20 and 23 Jan. 1881, DF (TAEM 57:579, 582; TAED D8120P, D8120Q1).

2. Gill wrote that the wardens of the state penitentiary in Baltimore “have been down to see your light, are very anxious to introduce it, which their offices permit them to do without any red tape.” Gill was invited to attend the group’s annual dinner in a few days “and they have asked me to get from you some data that I can present to them.” He asked Edison for “any facts that you may think proper, and of interest to them, that I can introduce, and it would be desirable to have a few lines from you of encouragement &c.” Gill to TAE, 27 Jan. 1881, DF (TAEM 57:593; TAED D8120X).

3. There is no further extant correspondence on this subject.

1. Edison noted on this letter that he answered it but his reply has not been found. On 11 February Fabbri & Chauncey acknowledged a letter from Edison and asked him to “order the two outfits (75 lights each), as you propose; and engage the engineers when the outfits are ready.” The firm desired “to put them in operation on the East and West coast of South America just as soon as we can” and asked to have “full details as to cost of large plant &c &c, as we think our correspondents will be able to commence negotiations for permanent illumination, as soon as the exhibitions are made.” A few days later Fabbri & Chauncey reported that their associates in Valparaiso had obtained a government monopoly for eight years beginning in December 1881, with the intervening year intended for assembling the machinery and making demonstrations, and that they hoped Edison would do his “utmost to hurry up the outfits already ordered.” Fabbri & Chauncey to TAE, 11 and 16 Feb. 1881, both DF (TAEM 58:383, 385; TAED D8131C, D8131D).

1. This letter was apparently composed while Edison was at the Drexel, Morgan offices in New York. It is in his hand, though the signature is by someone else. Edison subsequently directed Otto Moses to “File this in = ‘English Electric Light Edison & Drexel Morgan & Co.’” This marks the beginning of preparations for a demonstration central station in London, which was headed by Edward Johnson and began operations on the Holborn Viaduct on 12 January 1882. Friedel and Israel 1986, 215–17.

1. At Edison’s direction, John Lawson began to experiment with electroplating metals onto carbon filaments about 13 December. The object, as Francis Jehl subsequently recalled, was to prevent the ends of the carbon filaments from breaking at the point where the ends were inserted into the platinum clamps. This was rapidly accomplished: Lawson reported on 13 December that the “Experiment of plating the clamping points of carbon loops with copper— Gave satisfactory results— Orders Page 981to plate all the loops in the same manner.” There are two extant drawings related to a patent application for the plated ends that Edison filed on 11 January (Case 278). The application was rejected and eventually abandoned; only the drawings and claims are extant. Jehl 1937–41, 616–17; N-80-12-13:3, Cat. 1147, both Lab. (TAEM 39:675, 44: 226–27; TAED N168:1, NM016:2–3); Patent Application Casebook E-2536:246, PS (TAEM 45:724; TAED PT020246).

In related research begun on 17 December, Albert Herrick conducted experiments “for uniting the wires and carbons direct by plating them together without manufactured clamps” (Mott Journal N-80-07-10: 253, Lab. [ TAEM 37:429; TAED N117:127]). On 30 December Charles Mott noted in his journal that Edison had sketched

apparatus for plating carbons to the wires without use of clamps. being a vessel containing the plating solution in which one electrode is placed, the inner part containing the wires to which the carbon is temporarily attached is passed through a rubber cork which forms the bottom of the vessel or reservoir, the other or opposite electrode is connected to the wires extending out of the inner tube which extend together with the tube through the cork sufficiently low to immerse the ends of the carbons say ⅛ of an inch. As the plating progresses the wires and carbon are united and held by the deposit. Sketches dated by him Decr 24. and taken to Motts table for Patent Office drawings. [Mott Journal N-80-07-10:266–67, Lab. (TAEM 37:335–36; TAED N117:133–34)]

Edison’s drawing is in Cat. 1146, Lab. (TAEM 6:732; TAED NM014ZAU). Edison did not file this application until May. It covered only the process of electroplating the connections and did not include the rationale for doing so; it issued in October 1881 as U.S. Patent 248,436.

A number of different ways of maintaining the connection during the plating process were tried by Herrick, Lawson, and others in December and January. On 17 February 1881 Mott recorded that the clamp department was “abolished at the Factory. All carbons to be plated on.” The method ultimately adopted was what Jehl (1937–41, 617) later described as “a crude sort of copper clamp that was just sufficient to hold the shank of the filament. The stems with the copper clamps and filaments were then placed in a sulphate of copper bath in which the liquid only reached to the copper clamp. The filament and clamp were then plated one on to the other” (Mott Journal N-80-07-10:259; N-80-11-16: 143–49, 163; N-80-12-13:5–7; Mott Journal PN-81-01-19; all Lab. [TAEM 37:432, 949–52, 958; 39:676–77; 43:1127; TAED N117:130; N125:67–70, 76; N168:2–3; NP014:13]). The copper was then fused to a short platinum wire sealed into the glass; another copper wire leading to the base was similarly attached to the other end of the platinum outside the globe. The enlarged filament ends were retained because they dissipated heat well, preventing the copper from melting. Edison applied for a patent covering the clamps for making such connections in April and in June he filed another application for the electroplated union itself (U.S. Pats. 266,447 and 251,544). The electroplated connections represented a significant saving in the materials and labor of commercial Page 982lamp manufacture and were used in Edison’s lamps until 1886 (Howell and Schroeder 1927, 77–78). The method described by Upton as “plating on the whole carbon and then plating the copper on the carbon off” probably refers to plating the entire length of a filament, then removing metal from all but the shanks by a reverse electrolytic process. Intermittent research continued for several months to determine the best form of clamps and fixtures, and also to try gold and silver. Silver proved prone to electrical carrying and copper remained the preferred metal (N-80-09-11:99, 107–11; Mott Journal N-80-07-10:276; both Lab. [ TAEM 39: 293, 297–99; 37:440; TAED N153:49, 53–55; N117:138]; TAE to F. C. Van Dyck, 14 Mar. 1881, Lbk. 8:70 [TAEM 80:867; TAED LB008070A]; a few related experimental notes from mid-January are in Box 13, EP&RI).

Photograph showing the plated union of filament and lead-in wires adopted in early 1881.

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2. This change was formally adopted by late May, when Upton wrote on letterhead of “The Edison Lamp Co.” Upton to TAE, 28 May 1881, DF (TAEM 57:895; TAED D8123ZCC).

1. See Doc 2001 n. 2.

2. See Doc. 2001 n. 3.

3. R. G. Dun wrote to Edison on 4 February that the agency had received “one or two inquiries as to the ‘Edison Electric Lamp Company’ Menlo Park” but could find no incorporation papers on file. Edison drafted a reply on the letter which is the basis for the formal answer prepared by Stockton Griffin, essentially summarized below. R. G. Dun to TAE, 4 Feb. 1881, DF (TAEM 57:768; TAED D8123E); TAE to R. G. Dun, 5 Feb. 1881, Lbk. 6:902 (TAEM 80:508; TAED LB006902).

4. This notation is unclear but Edison indicated in his 5 February letter (see note 3) that about $35,000 had been invested in the lamp company. He had charged about $26,600 to lamp factory accounts by the end of 1880. According to Samuel Insull’s recollection years later, “Edison’s scheme was to form a company of one hundred shares, each share being $2500., and as I recall it, no stock being transferable except on the personal permission of Thomas A. Edison. Edison had a controlling interest, Batchelor had a ten per cent interest; I think Upton had ten per cent and I think Johnson had five per cent.” Ledger #4:332, 361, Accts. (TAEM 87:350, 358; TAED AB002:141, 149); Insull Notes, pp. 21, Meadowcroft (TAEM 227:159; TAED MM010DAH); see also Doc. 2018.

5. At this time no court cases related to Edison’s electric light patents had been filed.

1. Johnson indicated at the top of the letter that he was writing from the “Ofs of The Edison Electric Light Company 65 5th Ave,” which was located between 13th and 14th Sts.

2. Sigmund Bergmann had patented in November a form of adjustable electromagnetic relay, which Johnson had been helping to refine and in which he also had some financial interest. Bergmann and Johnson gave Painter control of the patent for the purpose of selling it, which Painter evidently proposed to do to Jay Gould’s American Union Telegraph Co. In December, Johnson reproached Painter for his dilatory dealings with Gould and American Union vice-president David Bates:

Now what are you going to do? You gave us to understand you could sell to Gould—if it was endorsed by the management— It has been so endorsed to an extent unusual in a pending negotiation— You appear to be resting on your oars— Gould has shown no disposition to deal outside of [Thomas] Eckert & Bates— They Evince perfect consciousness of being the sole parties with whom a decision rests. Bergmann is naturally restive under this Condition of things—says by giving it to you we have simply tied our own hands— Thinks that if I had it now I could make more out of it for myself & him than you will be able to get Even if you sell it at all which he doubts.= I write thus fully & freely—because I am on the ground & see the situation—while you are not— What are you going to do? [Johnson to Painter, 16 Dec. 1880, Unbound Documents (1879–1882), UHP]

The next day Johnson informed Painter that Bates “told me today he wanted this Relay matter settled—said he wants to order 100 of them if they buy— Otherwise will give order for Old Style— In my opinion they are more in the mood to buy now than they will be a few weeks hence” (Johnson to Painter, 17 Dec. 1880, Unbound Documents (1879–1882), UHP). The outcome of this matter is not known.

3. Johnson was apparently playing on the name of the Consolidated Virgina Co., controlled by a partnership known as the “Bonanza firm,” Page 986which developed the so-called “Big Bonanza” in the Comstock Lode. TAEB 4:416 n. 1; Elliott 1973, 132–33.

1. According to its letterhead L. Prang & Co. was a Boston firm specializing in art and educational publishing. L. Prang & Co. to TAE, 8 Feb. 1881, DF (TAEM 57:605; TAED D8120ZAE).

2. L. Prang & Co. indicated in this letter that they were expanding their works and wanted to build into their new engine and boiler house sufficient space to add an electric lighting plant capable of supplying “10–12 lights, each one powerful enough to light up a steam lithographic press.” Edison’s 11 February draft reply on the letter is the basis for this document. L. Prang & Co. to TAE, DF (TAEM 57:605; TAED D8120ZAE1).

3. Hinds, Ketcham & Co. were lithographers and printers of colored labels and show cards. Their incandescent lighting plant was installed on 27 January 1881. Edison had his staff wind the dynamo for this plant “using much finer wire . . . the machine being intended to make its own field, hence the higher resistance of the coils around magnets.” This installation became a showcase for the Edison light, with Hinds, Ketcham & Co. boasting in its own advertising circulars that “We are the first manufacturers in the world to put into practical operation this great triumph of American genius” and encouraging “our friends . . . to call and see the operation of Prof. Edison’s wonderful subdivision of the electric current and the vacuum lamp.” They found it possible to match colors using the incandescent lamp, which they found “to be entirely free from all the faults and objectionable features of other artificial lights, and is the best substitute for daylight we have ever known and almost as cheap.” Mott Journals N-80-07-10:278, PN-80-09-23, and PN-81-01-19; N-80-10-23:44; all Lab. (TAEM 37:441; 43:1107, 1109, 1116–18, 1120; 35: 1036; TAED N117:139; NP013:44, 46; NP014:2–4, 6; N087:19); Hinds, Ketcham & Co., advertising brochure, box 25, WJH; Edison Electric Light Co., Bulletin 4:2–3, CR (TAEM 96:677; TAED CB004:2).

1. On 10 February Michels sent Carman a statement of accounts for the two previous weeks and asked him to “send me the balances Saturday,” amounting to $191.47, and to give the statement to Edison “before he leaves in the morning, and I will call on him later at the N.Y. office.” Michels to Carman, 10 Feb. 1881, DF (TAEM 59:465; TAED D8144G).

2. Michels replied on 14 February, “I will endeavor to carry out his wishes as soon as possible it will of course take a little time but I will be as prompt as possible.” On 18 March he sent Edison a “prospectus to form a Company to carry it on. I would suggest your asking a few of your friends to co-operate, as half the capital I mention would be sufficient to subscribe at once, which should make it a small matter to arrange.” This prospectus has not been found. Edison continued to fund the journal for several months but on 25 October 1881 wrote that he would stop doing so in sixty days, and on 23 February 1882 he gave Michels a final payment of $254.53 (Michels to Carman, 14 Feb. 1881; Michels to TAE, 18 Mar. 1881 and 23 Feb. 1882; all DF [TAEM 59:468, 481; 63:664; TAED D8144H, D8144N, D8251B1]; TAE to Michels, 25 Oct. 1881, Lbk. 9:219 [TAEM 81:80; TAED LB009219]). Michels found temporary support from Frederic Shonnard and some of his associates but in April 1882 he again asked Edison to take stock in a company to run the journal and also to provide some working capital. Edison, however, refused to “have anything further to do with the publication of ‘Science.’” Among those Michels attempted to interest in the journal was Alexander Graham Bell, who finally consented. After suspending publication in mid-1882, Science resumed on 9 February 1883 with Samuel Scudder replacing Michels as editor (Michels to Insull, 16 Dec. 1881; Michels to TAE, 28 Apr. 1882; both DF [TAEM 59:595, 63:665; TAED D8144ZBD, D8251E]; Insull to Michels, 9 May 1882, Lbk. 12:255 [TAEM 81:639; TAED LB012255]). Other correspondence and accounts regarding Edison’s involvement are in Science (D-81-44 and D-82-51), DF ( TAEM 59:451, 63:661; TAED D8144, D8251; for Bell’s involvement see Bruce 1973, 376–77.

1. In fact, Edison did not raise the money for this shop from the names found on this list; instead, he wrote a note on the outside of the envelope directing Otto Moses to “file this away unopened.” According to Samuel Insull, “The capital for the Edison Machine Works was provided ninety per cent by Edison and 10 per cent by Batchelor.” Edison organized the Machine Works to construct dynamos and other equipment for his electric light and power system. Insull Notes, p. 22, Meadowcroft (TAEM 227:160; TAED MM010DAH).

2. Unidentified.

3. Possibly Henry Bedlow, a member of a prominent New York family and a former member of the diplomatic corps who had also served three terms as mayor of Newport, R.I. Obituary, New York Times, 31 May 1914, 5.

4. Rufus Hatch (1832–1893) was a New York banker and stockbroker. DAB, s.v. “Hatch, Rufus.”

5. Unidentified.

1. Gouraud, Joshua Bailey, and Theodore Puskas to TAE, 5 Feb. 1881, DF (TAEM 59:770; TAED D8148X).

2. James Banker owned the Russian telephone patents of Edison, Joshua Bailey, and Elisha Gray. By two separate contracts with the Edison Telephone Co. of Europe he agreed to hold these patents in trust for the company. Banker agreements with Edison Telephone Co. of Europe, 31 Jan. 1881 (copy) and 1 Feb. 1881, DF (TAEM 59:763, 767; TAED D8148S1, D8148V).

3. Not found.

4. In the message to be transmitted to Gouraud, Stockton Griffin wrote “know” instead of “allow.” TAE to Gouraud, 8 Feb. 1881, DF (TAEM 59:780; TAED D8148ZAC).

5. Not found.

6. TAE to Gouraud, 11 Feb. 1881, DF (TAEM 59:783; TAED D8148ZAF).

7. This cable has not been found but on 4 February Gouraud wrote Edison that before the letter reached Menlo Park “we shall have brought out the Oriental Telephone Company (Bell and Edison,) for which a strong board has been secured. The last great achievement having been the acquisition of Sir William Thompson as consulting Electrician I shall also secure him for the Electric Light” (Gouraud to TAE, 4 Feb. 1881, DF [ TAEM 59:1002; TAED D8150E]). An agreement between Edison, Alexander Graham Bell, the Oriental Bell Telephone Co., and the Anglo-Indian Telephone Co. to form the company on the terms outlined below was executed on 25 January 1881; Samuel Insull also signed as trustee for the prospective firm. A 17 February agreement between these same parties (except Insull) ratified the terms of the January contract. According to this second agreement, the Oriental Telephone Co. had been incorporated on 4 February and was to operate in India, Ceylon, Java, Japan, China, South Africa, the Australian colonies, New Zealand, Egypt, Turkey, Greece, Malta, and the Hawaiian Islands. Edison’s interests in Australia and Japan were excluded (DF [TAEM 59: 991, 995; TAED D8150B, D8150C]).

8. Gouraud reported to Edison a few weeks earlier the liquidation of the Edison Telephone Co. of Glasgow: “You will be gratified to learn Page 991that I have at length brought this thing to a final settlement, and received a further payment of £5,000 subject to deductions. They have tried every conceivable way to do us out of this. I have shown myself as possessed of a large capacity for waiting, when I know what I am waiting for.” Gouraud to TAE, 4 Feb. 1881, DF ( TAEM 59:921; TAED D8149E).

9. Edison’s cable has not been found. About a week later Gouraud sent copies of the company’s prospectus and reported having received “very considerable applications amounting to more than £100,000 shewing that no doubt matters will go all right.” Gouraud to TAE, 19 Feb. 1881, DF (TAEM 59:1004; TAED D8150F).

10. Stockton Griffin transcribed this message and left it at Grosvenor Lowrey’s office for either Edison or Lowrey. Gouraud to TAE, with marginalia by Richard O’Brien, DF (TAEM 59:788; TAED D8148ZAK).

11. DF (TAEM 59:789; TAED D8148ZAL).

12. Neither of the following messages has been found.

1. Edison first ran the direct-connected Porter-Allen dynamo with an electrical load on the evening of 24 February. Charles Mott indicated that it ran “all the lamps at 535 Revo”; William Hammer reported between 600 and 700 lamps in this first test. Francis Jehl wrote in his diary that afterwards Edison and his assistants “all went down to have a drink for the dynamo.” When it was completed on 12 February, the armature of this machine was found to have an unacceptably high resistance of .18 ohm. Charles Dean then soldered the connections with an electric arc and it gave a resistance of .014 ohm. Jehl 1937–41, 873–78; Mott Journal PN-81-01-19, Lab. (TAEM 43:1127–28, 1132; TAED NP014: 12–13, 17); box 14, WJH; Jehl Diary, 12 and 24 Feb. 1881).

The 22 January Scientific American illustrated and described the completed dynamo, which was

designed to replace sixteen of the largest machines of this kind previously made. The dynamo and the driving engine are both mounted on a massive cast iron bed, 8½ by 7 feet and 2 feet deep, very heavy and strongly ribbed, the entire machine weighing 8 tons. Page 992Near the middle of the bed is mounted the dynamo-electric machine, which, we believe, is the largest ever constructed. Its field magnets, three in number, are 6½ feet long. The armature is 21 inches in diameter and 28 inches long, and weighs 1½ tons. The engine is 100 horse power. . . . Its stroke is 10 inches. The internal diameter of its cylinder is 9 inches. . . . The working pressure of the dynamo is 140 volts; the resistance of the armature is one two-hundredth of an ohm. [“Edison’s New Dynamo-Electric Machine,” Sci. Am. (44:47), Cat. 1241, item 1569, Batchelor ( TAEM 94:626; TAED MBSB21569X)]

Scientific American illustration of Edison’s large direct-connected dynamo (incorrectly drawn with armature coils of wire instead of solid bars) and Porter-Allen engine.

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See Doc. 1970 for Edison’s rationale for the use of multiple adjacent field magnets and, more generally, the design principles of the large direct-connected dynamo.

2. The eccentric gear was part of the steam cut-off mechanism.

3. This book contains records dated 28 February of loops numbered 3–9, which Edward Acheson made from pressed plumbago. These loops apparently operated at much lower resistance and voltage than ordinary fiber filaments. According to a 22 February laboratory summary that Charles Mott prepared for Edison, one such lamp produced 16 candlepower at 5 ohms and 21 volts, consuming an estimated 4,133 foot-pounds of power, the equivalent of eight lamps per horsepower (N-81-02-18:174–80, Lab. [TAEM 41:788–91; TAED N244:89–92]; Mott to TAE, 22 Feb. 1881, DF [TAEM 59:62; TAED D8137B]). According to Acheson’s later recollection, Edison instructed him to use a hydraulic press to “make for me a small graphite loop like this (making a sketch like a horseshoe). I want the loop one inch outside diameter, the filament to be twenty-five thousandths of an inch wide and two thousandths of an inch thick. I will have steel plates made for you to press sheets between and a die made for punching out the filaments. When you make one capable of mounting in a lamp, I will give you a prize of one hundred dollars.” Acheson began pressing the plumbago on 7 February. On 10 February Page 993he succeeded in cutting out one loop; the next day he managed several more which were placed in lamps and he claimed the bounty. With at least one plumbago lamp burning on 16 February, Mott reported that Edison was “well pleased with prospects.” Acheson entered into a piecework agreement to make 30,000 graphite loops. He recalled that they “produced a magnificent light, but they did not last long in use, disintegrating rapidly. I had made sixteen thousand of them and then went to Mr. Upton and told him that I was not happy in making an inefficient article. . . . I considered it a waste of money and would much prefer to throw up my contract,” to which Edison consented in April (Acheson 1965, 19–20; Mott Journal PN-81-01-19, Lab. [TAEM 43: 1125–28; TAED NP014:10–13]; Upton to TAE, 18 Apr. 1881, DF [TAEM 57:853; TAED D8123ZAZ]). For earlier efforts to form plumbago filaments, see Doc. 1914.

1. This document was filed and the company incorporated on 4 March 1881.

2. John Kruesi, who managed the Electric Tube Co. and also served as its treasurer, had left Menlo Park on 14 February to set up the company’s factory at 65 Washington St. in New York City. Jehl 1937–41, 848; Israel 1998; 199, 206, 223.

3. Anthony J. Thomas and Robert K. White were both members of Drexel, Morgan and Co. Thomas later became a director of the Edison Electric Light Co. and the Edison Co. for Isolated Lighting. Thomas to Insull, 10 May 1881, DF (TAEM 58:356; TAED D8130I); Edison Electric Light Co., Annual Report, 1885; Edison Co. for Isolated Lighting, Annual Report, 1884; both CR (TAEM 96:5, 266; TAED CA001A, CA002D).

4. Samuel Insull later recalled that the company’s shares were “owned one fifth by Edison, one fifth by Kruesi, one fifth by Batchelor and the other two fifths were owned by E. P. Fabbri and Mr. J. Hood Wright, who were partners of Mr. J. P. Morgan in the firm of Drexel, Morgan & Company.” Wright and Morgan each owned 30 of the 250 total shares of the company’s stock. In order to serve as trustees of the company, Thomas and White received nominal shares from Wright’s account. Insull Notes, p. 22, Meadowcroft ( TAEM 227:160; TAED MM010DAH); James Hood Wright to Samuel Insull, 28 April 1881; Thomas to Insull, 10 May 1881; both DF (TAEM 58:353, 58:356; TAED D8130F, D8130I).

1. The following day George Soren wrote Edison about Fabbri’s interest in buying some of Edison’s shares in the Edison Electric Light Co. of Europe and the need to complete assignments to the company. On 1 March Edison assigned his Italian, French, and Danish electric light patents to the company and a month later he, Theodore Puskas, Joshua Bailey, and James Banker assigned the rights embodied in Doc. 1736. In his letter Soren noted that he had told Fabbri “that the stock was good for nothing at present, for the simple reason that the Company had no capital.” The company’s New York tax statement of 28 April 1881 indicated that it “was not fully incorporated till December 1880. Its capital is issued for European patents which have not yet any money value whatever.” Soren to TAE, 3 Mar. 1881; TAE agreements with Edison Electric Light Co. of Europe, all 1 Mar. 1881; TAE, Puskas, Bailey, and Banker agreement with Edison Electric Light Co. of Europe (copy), 1 Apr. 1881; statement of Edison Electric Light Co. of Europe, 28 Apr. 1881; all DF (TAEM 58:87, 72, 77, 81, 88, 113; TAED D8127A, D8127111, D8127222, D8127333, D8127A1, D8127H).

2. On 19 January 1881, Edison had extended for a month an option he had previously discussed with Ernest Biedermann regarding the sale to Biedermann and the New York banking firm Baltzer & Lichtenstein of 10,001 of Edison’s shares in the Edison Electric Light Co. of Europe for $750,000 and one quarter of the net profits. On 20 February, Edison made notes for a reply concerning a similar offer, possibly from another party, involving 10,500 shares. It appears that on 2 March Biedermann offered $400,000 cash and “350,000 of General Societe stock,” which Edison declined. At the end of March Edison wrote Baltzer & Lichtenstein that “in consequence of some arrangements which have yet to be made I shall be unable to give any reply to your offer . . . until April 15th 1881.” TAE to Baltzer & Lichtenstein and Biederman, 19 Jan. 1881; Page 996TAE memorandum, 20 Feb. 1881; TAE marginalia on Biedermann to TAE, 2 Mar. 1881; TAE to Drexel, Morgan & Co., 17 Feb. 1881; Drexel, Morgan & Co. to TAE, 19 Apr. 1881; all DF (TAEM 58:425, 429, 436, 109, 108; TAED D8132J, D8132N, D8132Q, D8127D, D8127C); TAE to Baltzer & Lichtenstein, 30 Mar. 1881, Lbk. 8:120 (TAEM 80:881; TAED LB008120); Wilson 1881, 69.

3. On 17 February Edison offered to sell to Drexel, Morgan & Co. one-quarter of his 51% interest in the European light company. The transaction was not to be completed until after the central station in New York had operated two weeks to the satisfaction of Edison, Fabbri, and James Hood Wright; in the meantime the stock shares of both parties would be held in a trust managed by the firm. Edison extended this offer to 2 March and again to 20 April. Drexel, Morgan & Co. accepted the proposition on 19 April but withdrew eight days later in deference to Edison’s prior interests in the electric light business for Paris. Fabbri subsequently bought 1,690 shares from Edison with an option for 1,690 more within three months after the New York central station began to operate. TAE to Drexel, Morgan & Co., 17 Feb. 1881; Drexel, Morgan & Co. to TAE, 19 and 27 Apr. 1881; all DF (TAEM 58:109, 108, 111; TAED D8127D, D8127C, D8127F); Insull memorandum, 6 July 1881; John Tomlinson memorandum, 6 July 1881; Fabbri to TAE, 7 July 1881; TAE to Fabbri, 8 July 1881; TAE agreement with Fabbri, 8 July 1881; all Miller (TAEM 86:404, 406–9; TAED HM810149, HM810149A, HM810150, HM810151, HM810152).

4. Edison’s answer has not been found.

1. John Roach was the preeminent builder of iron ships in the United States at this time, principally at his works in Chester, Penn. The Aetna Iron Co. had been located at 104 Goerck St. on the east side of Manhattan. On 1 March, Charles Mott reported that Edison had acquired the shop for the Edison Machine Works. DAB, s.v. “Roach, John”; Wilson’s Business Directory 1879, 380; Mott Journal PN-81-01-19, Lab. (TAEM 43:1134; TAED NP014:19).Page 998

2. That is, the price of United Telephone Co. shares stipulated in the settlement of Edison’s reversionary interest; see Doc. 2046 n. 2.

3. Samuel Insull arrived in New York on 28 February and was met at the dock by Edward Johnson, who promptly took him to meet Edison. Insull later recalled

that Edison wanted to spend the evening discussing matters in connection with his European affairs. It was assumed, inasmuch as I had just arrived from London, that I would be able to give more or less information on this subject. As Johnson was to sail the next morning at five o’clock, Edison explained to me that it would be necessary for him to have an understanding of European matters from him, and he, Edison, started out by drawing from his desk a check book and stating how much money he had in the bank and he wanted to know what European telephone securities were most salable, as he wanted to raise the necessary funds to put on the incandescent lamp factory, the Electric Tube Works, and the necessary shops to build dynamos. [Insull Notes, pp. 3–4, Meadowcroft (TAEM 227:141–42; TAED MM010DAH)]

Edison reportedly told him that his available cash amounted to $78,000 (McDonald 1962, 21). Insull also recalled that his summons to New York came in January in the form of a cable from Johnson, to whom he had been sending weekly reports of the British and Continental telephone business (Insull Notes, p. 24, Meadowcroft [TAEM 227:162; TAED MM010D]). Insull took the place of Stockton Griffin, who resigned for unknown reasons.

4. Gouraud cabled on 24 March: “Badly about six weeks badness about two months wickedness almost immediately.” Gouraud to TAE, 24 Mar. 1881, DF (TAEM 59:662; TAED D8146F).

5. Edison’s new offices at 65 Fifth Ave.

1. According to Howell and Schroeder 1927 (194–95), “Every lamp made was measured to determine the voltage at which it gave 16 candle power. This voltage was measured by means of a reflecting electrodynamometer made for the purpose. . . . All lamps at that time were measured at 16 candles and curves drawn on cross section paper made it possible to determine the candles per horse power which the lamp gave with the known voltage on the lamp and the resistance in series with it on a 150-volt circuit.”

2. Edison executed a patent application on 11 December 1880 in which he described techniques for improving lamp vacuum by passing a current through the filament in order to drive out occluded gases in the filament and clamps while still on the pump. After the filament was kept “for some time at a medium incandescence” it was “then raised to a much higher incandescence by the cutting out of more resistance, until the air and gas and aqueous vapor have been driven from the enlarged ends of the filament and the clamps, which can be readily determined by the disappearance of a blue or violet color which is seen at the clamps while the gas and vapor are being driven off. This high incandescence is considerably higher than that at which the lamp is designed to be used, it being from thirty candle-power upward in a lamp designed to give sixteen candle-power.” This application issued in October 1882 as U.S. Pat. 265,777.

3. This refers to the fact that the “copper plated filament connections and carbon paste connections liberated a good deal of gas when heated. Before the vacuum became good there came a stage in which it was conductive. In this condition, when the filament was burned at high temperature, this cross current, passing through the partial vacuum and creating a blue glow in the bulb, heated the filament connections red hot and drove the gas out.” Howell and Schroeder 1927, 125.Page 1001

4. On 14 December Charles Mott had noted that “all the lamps are now heated quite hot before placing them on the pumps by which it is found that vacuum may be gotten much quicker.” Mott Journal N-80-07-10:248, Lab. (TAEM 37:426; TAED N117:124).

5. Henry Alexander Campbell (1853–1938), who did a variety of carpentry jobs at the laboratory, started working at the Menlo Park laboratory on 24 October 1878. He had been in charge of making alterations to the lamp factory building and then “became the master carpenter of the lamp works.” Jehl 1937–41, 222–23, 373, 582, 686–87; “Campbell, Henry Alexander,” Pioneers Bio.

6. Alexander Welsh began working at the lamp factory in the fall of 1880. There are several experimental notes by him between mid-November and the beginning of February, at which time he was given charge of carbonizing filaments. He was discharged in February 1882 because, according to Francis Upton, “When he was placed in charge of the carbonizing it was expressly mentioned that he should report experiments truthfully. We were satisfied he was not doing so; this lack of truthfulness had become a by-word in our factory.” Upton’s testimony, 5:3255–56, Edison Electric Light Co. v. U.S. Electric Lighting Co., Lit. (TAEM 48:134–35; TAED QD012F:132–33); N-80-09-28, Lab. ( TAEM 36:459; TAED N106).

7. Unidentified.

8. John Lawson used the corks in the process of electroplating lamp filaments (see Doc. 2050 n. 1).

9. This refers to wooden lamp sockets. The “Newark parties” are unidentified.

10. Nothing further is known of this offer.

11. Upton informed Edison on 17 February that he had “proposed to [William] Holzer this morning that the working day be nine hours instead of ten so as to save money and bring all the men to their work on time. He says that it might make some dissatisfaction. If we could do so all those working could commence at once. I sent you the time of arrival of the men.” Upton to TAE, 17 Feb. 1881, DF (TAEM 57:774; TAED D8123J).

1. Edison appointed Thomas Logan (d. 1887) foreman of the Menlo Park machine shop on 14 February 1881, replacing John Kruesi (Jehl Diary, 14 Feb. 1881; Jehl 1937– 41; 680, 872). Although Jehl claimed that Logan began working as a machinist at Menlo Park sometime in 1877, the first evidence of his presence at the laboratory is a time sheet for the first week of June 1878 (Logan time sheet, 8 June 1878, DF [ TAEM 17:625; TAED D7817AA:4]). While Edison was in New York, Logan sent him frequent, sometimes daily, updates in April 1881 on the progress made by the Menlo Park staff in getting the Porter-Allen engine to run properly (see Menlo Park Laboratory—Reports [D-81-037], DF [ TAEM 59:59; TAED D8137]).

2. The Menlo Park staff disassembled the large dynamo on 10 March to improve the bearings. This machine was used until late May when the armature short-circuited and was not repaired. The shafting and “engines,” by which Edison may have meant dynamos, were needed for the lamp factory, where a boiler and engine had been installed for a generating station. Jehl Diary, 10 Mar. 1881; Jehl 1937– 41, 882 – 84, 887.

3. Each of the standard .14 ohm machines, used for the Menlo Park demonstration plant, could operate about fifty 16-candlepower lamps (N-81-02-20:67, Lab. [TAEM 40:979; TAED N214:34]). According to Jehl 1937– 41 (884), in March “Edison required a couple of dynamos for the Edison headquarters in New York City. Thus, March, 1881, was the time when the electric power room behind the engine room, with its eleven ‘A’ type Edison dynamos, was dismantled.” Charles Mott reported that the dynamos arrived in New York on 18 March. During February Edison contracted with Edward Hampson, a New York steam engine and equipment dealer, for three complete eight horsepower steam engines, each to operate at 410 r.p.m. They were to be delivered to New York by 29 March and used for lighting purposes (Mott Journal PN-81-01-19, Lab. [TAEM 43:1138; TAED NP014:24]; TAE agreement with Hampson, Feb. 1881, DF [TAEM 58:220; TAED D8129S]).

4. The shop received this engine from Edward Hampson on 18 February. Nothing is known of its design or construction except its rating for 10 horsepower and 1150 rpm. Edison’s assistants discovered on 22 February that they could not bolt it to the floor because it vibrated excessively but they managed to test it the next day and on 4, 5, 8, and 10 March. On 4 and 5 March the engine ran at 435 rpm and powered an unspecified dynamo which lit 60 lamps; however, on 8 March it powered a dynamo with an armature resistance of 0.55 ohms, which was unable to “do the necessary work.” On 10 March several men “worked all night on bearings” and then ran it for a while at 480 rpm with “all lamps on.” Four days later they succeeded in running it for 10 hours at 425 rpm with 60 lamps on the circuit. Mott Journal PN-81-01-19, Lab. ( TAEM 43: 1128, 1130, 1134 – 37; TAED NP014:14, 16, 20 – 3); Charles Mott to TAE, 22 and 23 Feb. 1881, DF (TAEM 59:62, 64; TAED D8137B, Page 1003D8137C); Samuel Insull to Edward P. Hampson, 14 March 1881, Lbk. 8:72 (TAEM 80:868; TAED LB008072).

5. That is, a dynamo used to provide field excitation current for other dynamos which were directly connected to the mains.

1. At the end of November 1880, Samuel Mott “made a bracket and small light socket from rubber scrap small and airy, and was requested by Mr. Edison to work it up in economical commercial form.” On 5 January “John Ott finished a pair of sockets for B. lamps with key at the bottom acting on a spring which forms the contact same style and principle of one made by Mott Nov. 26 except in the Mott socket the [key?] acted and formed the connection direct without intermediate spring” (Mott Journal N-80-07-10:223, 276 – 77, Lab. [TAEM 37:414, 440 – 41; TAED N117:112, 138 – 39]). Mott continued to work on the design through the end of the month (N-80-09-11:112 – 31; Unbound Notes and Drawings [1881]; both Lab. [TAEM 39:300 – 9; 44:1012 –14; TAED N153:56 – 65, NS81:2 – 4]). A patent application executed by Edison on 8 March 1881 includes the spring contact (U.S. Pat. 248,424).

John Ott’s drawing of the small socket design with spring contacts.

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1. In a 5 March letter to Edison, Horatio Nelson Powers identified himself as George Gouraud’s brother-in-law and the rector of Christ Church in Bridgeport, Conn. Powers to TAE, 5 Mar. 1881, DF ( TAEM 57:610; TAED D8120ZAI).

2. In his 5 March letter (see note 1) Powers wrote that he had “got into a little squabble with an editor” regarding Edison’s work in electric lighting and asked for the information supplied by Insull. Powers replied on 15 March with an enclosure, presumably a clipping from the Bridgeport Standard ; neither the letter nor the enclosure has been found. Insull replied the following day thanking him for the “enclosure which Mr Edison has perused with great pleasure. Should this not end the controversy, and should you require further information, I shall with Mr Edison’s permission be most happy to give it.” There is no further correspondence about this matter. Insull to Powers, 16 Mar. 1881, Lbk. 8:85 ( TAEM 80:869; TAED LB008085).

3. Unidentified.

1. This notebook entry was the first evidence of concern over the effect of temperature variation on the performance of the chemical meter, particularly preventing the solution from freezing and compensating for decreasing resistance as temperature increased. Research continued on these problems over the next several months. In May 1881 Edison applied for a patent on a meter with a winding in the shunt circuit whose resistance would increase with temperature, thereby compensating for the increased conductivity (or lower resistance) of the solution. At about the same time he filed an application for using the heat from a thermostatically controlled resistance circuit to keep the meter solution from freezing; in September he filed another application for obtaining heat for this purpose from a chemical reaction. U.S. Pats. 251,557, 251,558 and 265,774 and Jehl 1882, 16 –17; see also Israel 1998, 205, and Jehl 1937–41, 637– 69.

2. Nichols mistakenly wrote Cn for Cu throughout this document and later changed it except for this and one other occurrence.

3. No reference has been found to the saturation points of this solution in Watts 1872 – 75, a standard chemistry reference.

4. Nichols here cited a table in a standard German physics text (Wüllner 1874 – 75, 491). This table reproduced results obtained by the German physicist Gustav Heinrich Wiedemann (1826 –1899), who investigated the relationship between the thermal and electrical conductivities of solutions and metals ( DSB, s.v. “Wiedemann, Gustav Heinrich”). Nichols did not take the values for resistance directly from Wiedemann’s Page 1008table, but extrapolated and interpolated the values in order to obtain results for temperatures at 20° intervals. In this and the following table, Nichols also normalized his results; that is, he divided the results which Wiedemann had obtained by the value of the resistance at 0°. Thus the values he obtained for the resistances in both tables are not absolute values but are values relative to the resistance at 0° Centigrade.

5. Matthiessen and M. von Bose 1862 and Matthiessen and C. Vogt 1864 reported the effects of temperature on the conductivity of pure metals and alloys.

6. This term should be t ².

7. Edward Leamington Nichols (1854 –1937) was a chemist and physicist who received his Bachelor of Science degree from Cornell University in 1875 and a Ph.D. from Göttingen University in Germany in 1879. He worked for Edison at Menlo Park from October 1880 to June 1881, concentrating on experimental work for automatic chemical meters, studies of the behavior of Sprengel pumps, and the design and installation of equipment for measuring the voltage and current of incandescent lamps. After leaving Edison’s employ he held professorships in physics, chemistry, and astronomy at Central University in Richmond, Ky., the University of Kansas, and Cornell University. ANB, s.v. “Nichols, Edward Leamington”; “Nichols, Edward Leamington,” Pioneers Bio.; Jehl 1937– 41; 552 – 53, 815.

1. This cable was transcribed below a brief message of transmittal from the Direct United States Cable Co., and mailed from New York on this date. William Thomson lived and worked in Glasgow but evidently cabled this from London.

2. On 18 March Thomson wrote Gouraud that Joseph Swan had exhibited his lamps on 14 March at the private residence of Royal Society president William Spottiswoode, a mathematician and physicist, and that John Pender and John Hopkinson “were greatly pleased” with them. On 16 March Swan read a paper and exhibited his lamps at the Glasgow Philosophical Society, and on 17 March he brought his lamps to Thomson’s laboratory. Thomson’s measurements of them “perfectly Page 1009confirmed the statements in his paper. . . . Altogether the Swan light is much more perfect and its economy is much better assured than I knew when I saw you and Mr. Johnson in London last Friday.” Thomson to Gouraud, 18 March 1881, DF (TAEM 58:602; TAED D8133G); DNB, s.v. “Spottiswoode, William.”

3. According to the docket Edison replied on the same day. Although the reply has not been found, Edison directed Francis Upton to ship Thomson 50 lamps, including 20 B lamps of 8 candles, 10 C lamps of 8 candles, 10 B lamps of 16 candles, and 10 A lamps; the standard for A lamps was 16 candles and for B lamps it was 8 candles. He also directed Upton to “See that each set is of the same electro motive force and of the best economy, best bamboo, and of very high vacuum so that they will not lose their vacuum and economy” (TAE to Upton, 12 March 1881, Lbk. 8:59 [TAEM 80:863; TAED LB008059]). On 14 April Philip Dyer, secretary of the Edison Electric Lamp Co., informed Edison that he had shipped 20 A lamps and 20 B lamps, “with volts ohms and foot lbs. marked on each Lamp. As we have been to considerable trouble about picking these out, we ought to charge more than .35¢ each.” Two days later Dyer wrote Edison that he had decided to charge $1.50 per lamp, “as the Lamps cost us fully that on account of testing picking out &c.” The Lamp Co. charged them to the account of Drexel, Morgan and Co., which owned the rights to Edison’s British lighting patents (Dyer to TAE, 14 and 16 Apr. 1881, both DF [TAEM 57:849, 852; TAED D8123ZAV, D8123ZAY]).

Thomson received the lamps and began testing them by the end of April. His incomplete preliminary tests at the end of the month led him to conclude that

I do not expect to find any difference, which it is possible for me to test, between [Swan’s] and Mr. Edison’s with respect to economy. Either may be pushed to a very high degree of economy by working at sufficiently great intensities. It will be impossible for me or for anyone without months of experience to tell what is the highest intensity to which either lamp may be worked, without counterbalancing the value of high economy of light by wearing out the lamp in too short a time. [Thomson to Gouraud, 30 April 1881, DF (TAEM 58:613; TAED D8133O)]

Although no record of these or subsequent tests has been located, David Graham, a British entrepreneur interested in becoming an agent for Edison’s electric light, wrote Edison, “Sir William Thomson has shown me your lamp & from the tests he has made & appearance of it I am of opinion that it is of more practical use than Swans & I do not hesitate to state that we could do as well if not better with yours.” Thomson to Batchelor, 1 May 1881; David Graham to TAE, 25 June 1881; both DF (TAEM 58:614, 624; TAED D8133P, D8133X).

4. Gouraud was eager to have Thomson identified with Edison’s companies (see Doc. 2056 n. 7). On 25 March, with Edison’s approval, he offered Thomson the position of “Consulting Electrician to the Edison Electric Light Companies” of Europe. Thomson declined and later in the spring became a consultant to the Swan Electric Light Co., Ltd. Gouraud to TAE, 4 Feb. 1881; Gouraud to Thomson, 25 March 1881; Page 1010both DF (TAEM 59:1002, 58:604; TAED D8150E, D8133H); Thompson 1976 [1910], 764.

1. Charles Clarke, Edison, and Francis Jehl conducted these tests overnight. Jehl noted that “Mr. Edison came about ten. We fixed the large dynamo machine up and made a test of the curve of the magnet. Stayed up all night—did not get any sleep.” The laboratory staff continued making tests on 17 March. Jehl Diary, 15 Mar. 1881; N-81-03-04: 274 – 77, Lab. (TAEM 41:696 – 697; TAED N240:3– 4).

2. The curve of magnetism of a dynamo, also known as its characteristic curve, graphically represented the armature voltage as a function of field excitation. The data for the curve was typically taken with generator speed held constant and with no load on the generator. This curve changed when the magnetic field was increasing or decreasing because of residual magnetism in the field coil core, a phenomenon known as hysteresis. The purpose of this curve was to compare the performance of various dynamo designs. In this particular case, Clarke used these measurements to compare the performance of two field magnet designs, and he compared the data taken here with results from 10 December 1880 (N-81-03-15:19, Lab. [ TAEM 41:853; TAED N245:10]). In February and March Clarke performed similar measurements and calculations to determine construction details for various dynamo designs, including the South American portable dynamos, central station machines, and dynamos of various sizes for isolated lighting (N-81-02-20: 1– 213, Lab. [TAEM 40:946 –1035; TAED N214:1– 90]).

3. Clarke did not measure the armature deflection at 1000 rpm. Although the Porter-Allen steam engine could be run at speeds over 700 rpm, Edison determined that it was unsafe to run the engine at speeds over 400 rpm when connected to his dynamo. The standard operating speed was 350 rpm. Since armature voltage was proportional to generator speed, he calculated it by multiplying the measured armature deflection by the ratio of generator speeds. His purpose in scaling the measurements in this way was to obtain a convenient measure to compare the performance of several dynamo designs. Furthermore, on 29 March Clarke performed a series of calculations to redesign the armature and commutator so that the Porter-Allen dynamo would generate the same voltage at 350 rpm as it did at 600 rpm. N-81-02-20:111–13, Lab. (TAEM 40:994 – 95; TAED N214:39 – 40); Jehl 1937– 41, 868; Edison and Porter 1882, 218.

1. Not found.

2. On preceding pages of this notebook Upton wrote, “The fall in E.M.F. will be inversely proportional to the amount of copper in the conductor. There will be the same proportional fall for 10 lamps 180′ apart as for 30 if there is ⅓ the amount of copper in the conductor. . . . The amount of copper required varies as the square of the distance that the lamps are apart or as the square of the distance of the furthest removed lamp.” He gave an equation which related the voltage drop on the main conductor, the distance to the extreme lamp, the number of lamps, and the amount of copper in the conductor. This equation appeared earlier in an undated notebook entry from late 1880 in which Upton calculated the drop of 13.64 volts given here (N-81-03-22:155 – 57; N-81-00-01:71, 77; both Lab. [TAEM 39:469 – 70, 549, 552; TAED N158:78 – 79, N165:36, 39]). For prior calculations of the relationship between the number of lamps, distance, and cost of copper conductors, see Doc. 1889.Page 1013

3. Upton obtained the figure of 146.9 in an undated notebook entry from late 1880 in which he determined that “30 lamps at equal distances along a conductor each having 10 ohms in the conductor will have a fall of E.M.F. from 100 to 87.6 volts. The conductor will weigh 440.7 lbs. 10 lamps will have the same fall and conductors will weigh 440.7 ÷ 3 = 146.9 lbs.” The calculation “440.7 ÷ 3 = 146.9 lbs.” also appears on page 155 of this notebook. N-81-00-01:71, N-81-03-22:155, both Lab. (TAEM 39:548, 469; TAED N165:36, N158:78).

4. In this computation Upton used the same logarithmic shortcut explained in Doc. 1795 n. 4.

5. The logarithm of 1.165 is .0664, above. Upton obtained an identical result in an earlier undated notebook entry from late 1880 (N-81-00-01:186, Lab. [TAEM 39:606; TAED N165:94]). He used this proportion throughout much of the rest of this notebook to calculate on a block-byblock basis how much additional copper would be required to install uniform instead of tapered conductors in the central station district. Edison had included the principle of tapered mains in an 1879 caveat (Doc. 1789, see esp. n. 1) and an August 1880 patent application.

1. Unidentified.

2. Edward Goodrich Acheson (1856 –1931) came to work as a draftsman for Edison in September 1880. He was soon assisting with lamp experiments in the laboratory and, according to his recollection, declined the assignment as Charles Batchelor’s successor in charge of the lamp factory, and continued experimenting in the laboratory. He went to Paris in July 1881 to assist Batchelor with Edison’s exhibit at the International Electrical Exhibition. He spent the next three years in Europe installing electric lighting plants. Upon his return Acheson worked for a number of electrical companies. In 1891, he developed an artificial abrasive known as Carborundum, which became an indispensable industrial Page 1014abrasive. He later developed improved methods for manufacturing and using graphite. ANB, s.v. “Acheson, Edward Goodrich”; Acheson 1965, 15 –19; Szymanowitz 1971.

3. Alfrid Swanson was the night watchman. He began working for Edison in December 1876 and later also ran the steam engine and helped out in the machine shop. Jehl 1937– 41, 128; Cat. 1213:7, Accts. (TAEM 20:8; TAED A202:3); Time Sheets D-78-17, DF (TAEM 17:621; TAED D7817); Time Sheets, NjWOE.

1. James Bradley had apparently gotten this quote from the Celluloid Manufacturing Co. Writing from Newark he indicated that he had “stoped at Hyatt Place,” presumably referring to John and Isaiah Hyatt who had established the Celluloid Co. in Newark in 1871 (see TAEB 2:498 n. 1). They offered to make the sockets for five cents each out of “boneslate” but indicated that in order to try it they would have to make a $25 mould. Bradley to TAE, 24 Mar. 1881, DF (TAEM 57:833; TAED D8123ZAL).

2. Bradley had asked Hyatt about a cement to stick the sockets to glass and was shown a cement made of litharge and glycerine that cost twentyfive cents a pound. At this time Bradley was designing a mold for making sockets out of plaster of Paris. On 29 March he reported that he had tried litharge and glycerine and found it to be better than plaster of Paris but could only get 20 from a pound of material, which he thought too expensive. He suggested mixing sawdust or some other cheap material to reduce the cost. Bradley to TAE, 24 and 29 Mar. 1881; Upton to TAE, 25 Mar. 1881; DF (TAEM 57: 833, 837, 835; TAED D8123ZAL, D8123ZAN, D8123ZAM).

1. Italian physicist Antonio Pacinotti, 1841–1912 (DSB, s.v. “Pacinotti, Antonio”), developed a generator with a ring armature and commutator with brushes, the first design to produce a continuous and steady current. He published a description of his dynamo in the June 1864 issue of the Italian science journal Il Nuovo Cimento; for an English translation, see “Description of Dr. A. Paccinotti’s Electro-Magnetic Machine,” n.d., DF (TAEM 57:690 – 701; TAED D8120ZCH). Pacinotti exhibited the machine at the 1881 Paris Exposition, where it gained widespread attention for the first time and earned him a diplome d’honneur, one of the Exposition’s highest awards (Heap 1884, 28 – 32; Thompson 1902, 13–15). In 1870 the French engineer Zénobe Gramme independently invented a similar armature and commutator and took out broad patents on this design in the United States and Great Britain (see TAEB 4:585 n. 6; Dredge 1882 – 85, cxxix; U.S. Pat. 120,057). Edison referred to Schellen 1879 on electric motors and generators; the 1884 English edition provided an extensive description of Pacinotti’s machine, including a translation of the 1864 article (Schellen 1884, 204 – 19). Before the end of March, Edison asked Puskas to inquire about obtaining rights to Gramme’s patent in the United States (TAE to Puskas, 30 Mar. 1881, TP [TAED Z400BZ]).

2. Edison was probably referring to Jacques-Eugène Armengaud, who, like his younger brother Charles, was a respected consulting engineer and an authority on the patent laws of France and other countries, including the United States. Jacques-Eugène, who won design prizes at the international expositions in London in 1851 and Paris in 1867 and was also a member of the Legion of Honor, seems to have been somewhat better known than Charles. DBF, s.vv. “Armengaud, Jacques-Eugène” and “Armengaud, Charles.”

3. On 12 February Theodore Puskas ordered from Edison through his American agent Edward Saportas “an electric lighting machine capable Page 1016of demonstrating the system practically at the Palais Royal, Paris.” They specified that the dynamo was to be capable of powering 1,000 sixteen-candlepower lamps, was to cost about $8,000, and needed to be installed and operating by 30 May. On 14 February Saportas confirmed that James Banker was “authorized to act in the matter of machine for palais royal,” and that he had asked him to meet with Lemuel Serrell “in regard to obtaining necessary protection for invention upon introduction to France.” On 16 February Saportas wrote that Banker was prepared to give Edison the order for him to send the dynamo to Paris, but that Banker needed a cost estimate beforehand. Saportas also informed Edison that Puskas had cabled from Paris: “See whether Edison authorizes securing space in ‘exposition electrique’ for his inventions generally and for light in connection with palais royal answer quick.” Puskas & Saportas to TAE, 12 Feb. 1881; Saportas to TAE, 14 Feb. 1881; Saportas to TAE, 16 Feb. 1881; all DF (TAEM 58:838, 840, 841; TAED D8134C, D8134D, D8134E).

4. On 30 March Puskas cabled Edison that he had been “officially asked whether you exhibit other inventions beside light.” Edison replied “yes.” Puskas to TAE and TAE to Puskas, both 30 Mar. 1881, Cable Book 1:7 ( TAEM 83:875; TAED LM001007B, LM001007C); see also Doc. 2045.

1. A. M. Leslie was a medical instrument company based in St. Louis. Dacus and Buel 1878, 321– 23; Edmonson 1997, 206.

2. Not found.

3. A month later the Edison Electric Light Co. decided to form a Bureau for Isolated Lighting and placed Miller F. Moore in charge. In November this became the Edison Co. for Isolated Lighting. Edison Electric Light Co. circular, 11 Nov. 1881; Edison Electric Light Co. agreement with Moore, 30 Apr. 1881; both DF ( TAEM 57:712, 227:513; TAED D8121E, D8126X1).

1. Not found.

2. For Edison’s accounts with the Edison Electric Light Co., see the two Electric Light Co. Statement Books, Accts. (TAEM 88:412, 512; TAED AB031, AB032). Detailed accounts of money spent on various experiments can also be found in Edison’s Personal and Laboratory Accounts, Ledgers 3, 4, and 5, Accts. (TAEM 87:5, 209, 403; TAED AB001, AB002, AB003).

3. Not found.

4. Not found.