1. In a telegraph exchange later in the day, Lowrey and Edison agreed on Friday, 6 December, as the date for the visit (DF [TAEM 18:98]). On 29 November, Rockwell Kent, Lowrey’s secretary, had written Edison about Lowrey’s “very pleasant conversation” with August Belmont during which Belmont had asked to meet Edison and said “that he desired to gain for you the benefit of the influence and support of his friends in Austria.” Kent told Edison that Lowrey thought “it very desirable that the meeting should take place and hopes that you will certainly come in town” (DF [TAEM 18:204]). Later on the 29th Lowrey attempted to arrange a meeting for the following day in New York, but he subsequently agreed to bring Belmont out to Menlo Park in order to accommodate Edison (telegrams between Lowrey and TAE, 29 Nov. 1878, DF [TAEM 18:93–94]).

2. Milton Latham served one term in the U.S. House of Representatives and was elected governor of California in 1859. Immediately after his inauguration he was appointed to fill an open seat in the U.S. Senate, where he became noted for his Southern sympathies. Latham amassed a fortune in railroading and as president of the London and San Francisco Bank from 1865 to 1878 but lost it in railroad investments before his death in 1882. George Bliss wrote Edison on this day that Latham had stopped in Chicago on the way from Paris to San Francisco. DAB, s.v. “Latham, Milton Slocum”; NCAB 4:108; Bliss to TAE, 2 Dec. 1878, DF (TAEM 18:356).

3. Rowland Hazard was a New York investor who in the 1880s became president of the Gramme Electrical Co., the American Electrical Manufacturing Co., and an electric railway in Cleveland. In 1884 he was elected treasurer of the new American Institute of Electrical Engineers. Passer 1972, 39, 225; Transactions of the American Institute of Electrical Engineers, 1:4.

4. Anthony Drexel (b. 1826) was the dominant partner in the Philadelphia banking firm of Drexel & Co., founded by his father in 1837. NCAB 2:273; Carosso 1987, 133–45.

5. That is, 9 December. A visit to Menlo Park by J. P. Morgan, Egisto Fabbri, and Anthony Drexel had been planned for the day of this letter, but Lowrey had to postpone the trip “on account of previous engagement with Drexel.” Lowrey to TAE, 30 Nov. 1878, DF (TAEM 18:210).

1. At the bottom of this cable Griffin noted that it “cost $43.32 gold & will be paid by DM & Co.” Edison sent this message instead of one that Grosvenor Lowrey drafted with Fabbri and Morgan and mailed to Edison on 30 November. That message read:

Think I can negotiate much better here and secure one strong combination to finance light and sell it. I must be entirely free however. If you leave it to me will secure for you such share in general profits as I think right under circumstances besides reimbursement your outlays and compensation for any future services My interest requires this and practical success may depend on it. Answer

2. Puskas wired back on 5 December, “Answer tomorrow” (see Doc. 1606). DF (TAEM 18:221).

1. Although the precise significance of the calculations and sketches in this document is uncertain, they concern characteristics of electric lighting systems with large numbers of lights spread over a considerable area.

2. This evidently refers to copper wire; contemporary references gave the resistance of 1 mile (5280 ft./1609.31 meters) of pure copper wire with a diameter of .22 inch (5.59 mm) as 1.1278 ohm. Adjusting for an increased diameter and half the length yields approximately the figure given here. Prescott 1877, 967; cf. Clark and Sabine 1871, 109.

3. This is the weight in pounds (equal to 85.7 kg) of 1,000 feet (305 m) of pure copper wire with a diameter of .25 inches (6.35 mm) (calculated by the editors from figures in Prescott 1877, 967; there is a similar table in “Directions for Setting up and Operating the Brush Dynamo–Electric Machine, for Electric Light,” DF [TAEM 17:1101]). Edison multiplies it by 2 (378) and then adds half again (94) to get the figure for 2,500 feet (approximately half a mile). He quadruples that figure three times to calculate the result of doubling the diameter successively to ½, 1, and 2 inches, and then doubles that number to get a rough figure for the weight of a mile of 2-inch copper wire (60,416 pounds). Finally he multiplies that by $0.20, the approximate price of a pound of copper (Ency. Brit. Supp., s.v. “Copper”), to get the cost for that mile of wire ($12,083.20).

4. I.e., 2,500 feet.

5. The figures below are a rough estimate of the price of a mile of 1-inch copper wire, using 7,500 pounds per half mile and $0.20 per pound (see note 3).

6. There are four other similar sheets from this day covered with related rough sketches, tables, and calculations. They show many variations on parallel, series, and combined circuits, switching arrangements, a few lamp designs, and some detail about junctions at branching points in circuits. Vol. 16:307, 310—11; Cat. 1146; both Lab. (TAEM 4:743, 745–46; 6:637).

Details from sketches of 3 December showing plans for wiring junctions in electric power distribution systems.

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1. The lamp drawing below shows the design principles that Edison claimed in a patent application executed on 9 December (Case No. 166) which was allowed in 1880 but subsequently abandoned (Patent Application Casebook E-2536, PS [TAEM 45:698]). Only the drawings and claims from that application are extant, but a full description is included in his British Patent 5,306 (1878), for which Edison executed the provisional specification on 28 December. Here Edison claimed that by using a “pyroinsulating coating” he could wind several layers “of very fine wire” in his lamp so that each burner would “have a resistance of several hundred ohms which permits of several hundred burners or lamps being connected quantitively in multiple arc, without requiring large main conductors.” This coating was “an oxide of metal, such as cerium, lime, magnesia, or other metal or material which will not be injured by a high degree of heat.” In his British patent, Edison described a method and device (fig. 5) for applying the pyroinsulation “by dissolving the oxide in an acid, coating the wire or strip with the solution, and then passing the wire or strip through heat from a flame or otherwise,” which decomposed the solution and deposited the oxide. The pyroinsulation made it more difficult for the metal wire or strip to fuse and prevented the current from passing between the metal coils after they were wound around “a spool or cylinder of lime or other infusible material.” Edison also suggested using the pyroinsulating material as a layer between the coils.

Drawings from Edison’s U.S. patent application for electric lights with coiled coated wire burners.

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Charles Batchelor’s 4 December drawing of a mechanism to fill spiral burners.

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2. In the following days, Batchelor sketched a “Machine for filling spirals with chalk or other insulator” and included directions for its construction and use (it was made by George Jackson) as well as an “Instrument for pressing spirals under heat.” The lamp design shown in Edison’s American and British patent applications (see note 1) also incorporated a new electromechanical regulator developed during December; on 5 December, Batchelor drew details of the center rod and the “Mode of fastening the ends of spiral into end pieces” for that regulator. He and Edison also sketched several variations of this lamp design through the middle of December. They considered pneumatic regulators as well lamps consisting of multiple bobbins; Edison included the latter in British Patent 5,306 (1878, fig. 3). At the end of the month, after extensive experiments with pyroinsulators, Edison listed the advantages of “coating wire with a non conductor of heat” as “solidity strength & capability of long service, cheapness, non liability to derangement, noiseless [and] compactness.” Vol. 16:307, 314, 319; N-78-11-22:5–7; N-78-12-04.2:1–13, 17–25; N-78-12-11:3; N-78-12-15.1:1; N-78-12-15.2:19; all Lab. ( TAEM 4:743, 747, 751; 29:155–56, 328–34, 336–40, 680, 942; 40:314).

11 December sketch by Edison of a multiple bobbin lamp.

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1. Blake had enclosed in this letter a reprint of his paper on the telephone which had been read in London. He explained to Edison “that I close the lecture with a tribute to Bell in which I think you will agree with me as I do with you in your remark that there are but two telephones, Edisons and Bells. As the experiments were made entirely to measure the excursions of the discs of the Bell telephone I had no occasion to refer to your experiments.” He also said he hoped to make more phonographic experiments with human ear membranes. Blake’s paper has not been found. Blake to TAE, 22 Nov. 1878, DF ( TAEM 16:468).

2. On 28 November, Blake had sent Edison part of a draft paper on the “Graphic and Photographic illustration of Sound waves.” He asked for additional information from Edison or Batchelor about the phonograph’s invention and “the train of thought or of experiment which led to the use of the present recording tin foil.” A docket notation on Blake’s letter indicates that Batchelor replied on 30 November (DF [TAEM 18:1063]). Blake’s draft attributed the invention to Edison’s electric pen experiments on indenting a yielding surface. The version published in the first number of the American Journal of Otology ascribed it to work on embossing telegraphs, in which Edison thought of “substituting for the magnet and lever a diaphragm and point, and thus reproducing speech; but at the time the due importance was not attached to the conception, from the supposition that the rapidity of the vibrations of the disk would not allow the needle-point to drop into the indentations with sufficient accuracy” (Blake 1879, 6). In February 1879 Blake sent a copy of the issue containing this article to Edison, who subsequently Page 757 subscribed to the journal. Blake to TAE, 28 Nov. 1878, 14 and 18 Feb. 1879, DF (TAEM 18:1063; 49:769, 774).

1. The previous day, John Huddart Russell had lodged a protest against one of Edison’s British provisional patents, claiming that Edison was “not the true and first Inventor of the said Improvements or of some of them.” The provisional specification, which had been filed on 23 October and subsequently issued as British Patent 4,226 (1878), was for an electric light system including a tuning fork generator, central station regulator, self-regulating spiral lamps, and current meters. The London firm of Brewer and Jensen defended Edison’s application and subsequently reported to Lemuel Serrell that Russell had no invention of his own. Russell had apparently acted on behalf of A. Arnaud, whose British Patent 4,074 (1878)—for a system of electric lighting in which the lamps were placed in parallel circuits—had been filed in October. That patent was still unsealed and could therefore have been opposed by Edison (Brewer and Jensen to Serrell, 17 Dec. 1878, DF [TAEM 18:851]; Dredge 1882–85, 2:lii). A copy of Russell’s statement, made by Brewer and Jensen and sent to Lemuel Serrell on 4 December, is in DF (TAEM 18:828); an excerpt was also published in the 19 December New York Sun. “The Genie of Menlo Park,” Cat. 1241, item 1066, Batchelor (TAEM 94:436).

2. D. V. Lynch worked for the New York World, probably as a reporter. He had corresponded with Edison earlier in the year about possible stories for his paper. TAEM-Gi, s.v. “Lynch, D. V.”

3. The New York World quoted the last two sentences of this telegram Page 758 in a 5 December story about Edison’s electric light research. On the morning of 4 December, after learning of Russell’s objection, Edison had wired Serrell for clarification: “Can patent be opposed after obtaining great seal.” Serrell answered that it could not. Edison telegraphed back at 8 pm that he understood the patent was “ordered to be sealed immediately How is that.” “Content at Menlo Park,” Cat. 1241, item 1057, Batchelor (TAEM 94:434); TAE to Serrell and Serrell to TAE, both 4 Dec. 1878, DF (TAEM 18:829).

Serrell replied the next morning that “Notices to Seal have to be published three weeks to allow opposition to be entered.” He explained the situation more fully in a 6 December letter. The patent had been filed in October

and notice to proceed was given as soon as the same could be done, viz Nov. 12. when the certificate of Prov. prot. was delivered.— Opposition could be entered as the law provides before the expiration of three weeks viz before Deer. 3d. The case comes up before the “Law Officer,” and he hears and determines the question whether Edisons provisional has been obtained “in fraud of the true and first inventor”: That is the only allowable opposition: The opposition has to show that Russell was the first inventor of that which Edison has shown, and this opposition is made in ignorance of what Edisons spec, contains; The published title does not give any idea of the nature of your invention, hence Russell may claim some different device and will have his trouble for nothing, and have to pay the costs .

Serrell wired Edison on 20 December, “Brewer Telegraphs Russells objection defeated with costs.” Brewer and Jensen to Serrell, 4 Dec. 1878; Serrell to TAE, 5, 6 and 20 Dec. 1878; all DF ( TAEM 18:825, 831, 833, 855).

1. This is the complete text of Edison’s 3 December cable to Siemens. DF (TAEM 17:1070).

2. Siemens’s British Patent 3,134 (1878) covered a pattern of winding two separate wires around each armature coil. With one end of each Page 759 pair connected through a metal ring on the armature and the other ends placed at opposite sides of the commutator, the wires acted as a single circuit. Because this design increased the length of wire passing through the magnetic field with each revolution, the Siemens dynamo could produce more electricity per horsepower and weight than other machines. In early models the routing of wires to the commutator was asymmetric and complex, although simpler arrangements were adopted later. Edison recalled that “Upton, Batch, & myself worked three days & nights on Siemens’ patent to figure out how the devil he connected up his armature & we never succeeded in doing it from the patent.” Siemens does not appear to have received a U.S. patent for this design. Dredge 1882–85, 1:56, 77, 279–84, 2:xlvii; King 1962c, 393; TAE to Edward Johnson, 23 Nov. 1881, Lbk. 9:331 (TAEM 81:111).

1. Gouraud enclosed a clipping from the 5 December London Standard concerning the paper “On the Practical Application of Electricity to Lighting Purposes” read by James Schoolred before the Society of Arts. In the discussion that followed Schoolred’s paper, William Preece stated that he “did not believe” it would be possible to achieve a practical subdivision of the electric light as “the intensity of the light diminished according to the square of the number of lights into which it was divided.” He went on to call Edison ‘“an American of the Americans,’ who had taken out 269 patents, of which only three were being worked, so far as he knew. He believed that although Mr. Edison was a clever inventor he had in this instance ‘stumbled on a tremendous mare’s nest.’” DF (TAEM 18:214).

2. Edison had been issued 133 U.S. patents at this time, as well as a small number in other countries. Among the devices then being used commercially that incorporated at least one Edison patent were printing telegraphs, quadruplex and district telegraph systems, telephone Page 760 transmitters, the phonograph, and the electric pen. Any reply Edison made to Gouraud about Preece’s comments has not been found.

1. See Doc. 1494 nn. 4 and 5.

2. Unidentified, probably a clerk or secretary at Porter, Lowrey, Soren & Stone.

1. See Doc. 1494 n. 5. Lowrey had wired Edison on 4 December: “Have placed two hundred and fifty dollars to your credit with Drexel as return of British patent fees.” Griffin replied that Edison wanted to know “if the fees for the two British patents which have been sent over and for the one now ready to be sent are taken from the E Light fund and if so cannot the total amount be placed to his credit.” Lowrey to Page 762 TAE, 4 Dec. 1878, DF (TAEM 18:100); Griffin to Lowrey, 4 Dec. 1878, Lbk. 4:28 (TAEM 80:21).

2. In his 4 December letter, Griffin wrote that Edison “requests me to ask if he has signed the Drexel Co partnership as he has no recollection of so doing.”

3. Probably Joseph Mora (b. 1844), a Cuban exile who became a Wall Street banker. He was likely José De Navarro’s partner in the New York banking firm of Mora, De Navarro & Co. Obituary, New York Times, 14 Dec. 1904, 9; NCAB 15:246.

4. Robert Gallaway was a New York banker and associate of J. P. Morgan. He was an original investor in the Edison Electric Light Co. Obituary, New York Times, 14 Nov. 1917, 15; Articles of Incorporation, DF (TAEM 18:38).

5. On 5 November, Edison had sent an order to Johnson, Matthey & Co., a London firm that refined precious metals and manufactured various platinum devices. James Adams had contacted them in October and was advised that “Iridium in a state of purity cannot be supplied in the form of sheets and wires, as it is not malleable or ductile—but we make high alloys of platinum and Iridium in sheet and wire which may answer your purpose.” Johnson, Matthey & Co. to TAE, 7 Feb. 1879, DF (TAEM 50:21); Johnson, Matthey & Co. to Adams, 22 Oct. 1878, and Johnson, Matthey & Co.’s Paris Universal Exposition circular, both Cat. 30,102, Scraps. (TAEM 27:950–52); information from other chemical and metallurgical companies follows in Cat. 30,102; draft orders for this material are in DF (TAEM 18:510–12).

On 5 December, Johnson, Matthey & Co. responded to J. S. Morgan & Co.’s inquiry by explaining that “the highly alloyed iridium wires are causing us much trouble; the difficulty in preparing some of them being we fear insuperable.” Johnson, Matthey & Co. promised to keep trying and, “as Mr Edison seems to be pressing you, we will at once pack and send forward all the items of the order that are now ready and which form the bulk of it.” A copy of this letter was sent to Edison by Drexel, Morgan & Co. on 18 December. Johnson, Matthey & Co. to J. S. Morgan & Co., 5 Dec. 1878; Drexel, Morgan & Co. to TAE, 18 Dec. 1878; both DF (TAEM 17:1091, 1093).

Edison wired Lowrey on 6 December, “Please have J.S.M & Co send forward at once material that is ready.” The first shipment of material did not reach New York until about 18 December, the day that Drexel, Morgan & Co. wrote Edison that they had received Johnson, Matthey & Co.’s invoice. A second parcel, containing platinum alloy foil and wires, arrived on 23 December. Johnson, Matthey & Co. supplied most of the items remaining from Edison’s 5 November order in early 1879. TAE to Lowrey, 6 Dec. 1878; Drexel, Morgan & Co. to TAE, 18 and 26 Dec. 1878; Baldwin Bros. & Co. to TAE, 23 Dec. 1878; Johnson, Matthey & Co. invoice, 12 Dec. 1878; Johnson, Matthey & Co. to TAE, 4 Jan. and 7 Feb. 1879; all DF (TAEM 17:1073, 1091, 1111–12, 1116, 1117; 50:6, 21).

6. Not found.

1. Lowrey sent this telegram at 11:35 a.m., having telegraphed the previous day that “Mr Navarro and I will come down at eleven and Mr B will arrive about three.” At 11:55 he wired that neither Navarro nor Mora would visit that day, but telegraphed again at 12:45 to tell Edison that he and Belmont would arrive on the three o’clock train. DF (TAEM 18:102–3).

2. On Thursday, 5 December, Batchelor had drawn up a list of items “To be made immediately & shown on Friday afternoon—”

2 old style lamps double spiral square 1 Lamp (long spiral) about 10 6 springs 2 Lamps new pattern Get some platina wire pure for springs—

N-78-11-22:3, Lab. (TAEM 29:154).

3. Lowrey is apparently referring to a draft of the agreement between Edison and Drexel, Morgan & Co. (Doc. 1649). A draft with alterations, including one initialed by Lowrey and dated 6 December, is in DF ( TAEM 18:238).

1. Edison probably wrote this entry between 29 November, when he made related notes in a different notebook, and 15 December, when he dated subsequent material in this notebook. He made a similar table of lamp resistances on 3 December (Doc. 1597). Following this entry are two undated pages with similar tables indicating the resistance of circuits with a given number of lamps. N-78-11-28:13; N-78-12-15.2:15–19; both Lab. (TAEM 29:26, 40:312–14).

1. The Edison Speaking Phonograph Co. subsequently reported December sales of fifteen machines, five more than the previous month (see Doc. 1484 n. 1). Edison Speaking Phonograph Co. royalty statement for December 1878, DF (TAEM 19:204).

2. In January, Johnson recalled “the fine Brass Phono” he had given Edison. He explained that “In the fine Phonographs we introduced a new feature viz: using Tubeing for Cylinders—net result—’Magnificent failure.’ they all warp in at the slots—& cause the needle to skip ½ inch or more at the slot. We will have to replace Cylinders with the Old Style solid Brass.” Johnson asked that if Edison had received one of the hollow cylinders, he return it “at once to be altered at same time as others.” It is unclear how many brass instruments had actually been sold by this time. The only brass machine listed on the royalty reports was sold in November. Johnson to TAE, 18 Jan. 1879; Edison Speaking Phonograph Co. royalty statements for November 1878; both DF (TAEM 51:681; 19:201).

1. The Astor, a free library for adults, was one of the institutions from which the New York Public Library was formed in 1895. Lydenberg 1923, 1–12, 337–48; see also Doc. 1545 n. 1.

2. Upton’s list of sources is in his first literature search notebook. He had evidently consulted several of these sources already and noted that he had reviewed through 1858 Die Fortschritte der Physik (The Progress of Physics), an annual review published in Berlin. Literature Search Notebook #1, Upton (TAEM 95:375).

3. J. C. Poggendorff’s Annalen der Physik und Chemie, published since 1824 in Leipzig.

4. Nothing is known of this subject.

5. Instead of going to Boston, Upton prepared to move to Menlo Park. He wrote his father that “the first few weeks will be lonely enough for Menlo Park is such a dreary place. The work will of course keep my mind full, and away from home-sick thoughts.” Upton arrived at Menlo Park on 13 or 14 December. He reported to his brother at the end of the month that he was “getting along finely here enjoying myself very much indeed with my work. Just learning how to sleep daytimes.” Upton to Elijah Wood Upton, 12 Dec. 1878; Upton to Charles Upton, 29 Dec. 1878; both Upton (TAEM 95:502, 506).

1. Batchelor evidently made these notes to conceptualize the flow of current in the armature as the coils moved between the field magnets. There are several other diagrams of the flow of current through a ring armature and individual coils from mid–December in N-78-12-15.1:22–24, 27, Lab. ( TAEM 29:953–55).

2. The letters inside the bars are from left “S,” “N,” “N,” and “S.”

3. Cf. N-79-03-20:67, Lab. (TAEM 33:34). In another series of drawings, Upton compared magnetic lines of force with the internal currents of a battery, “Trying to establish a relation between the magnet and Zn & Cu with currents flowing in a fluid.” This line of thought became more important in early 1879. N-78-12-28:15; N-79-03-20:42–45, 57; all Lab. (TAEM 30:9; 33:23–24, 29).

Sketches likening a Gramme dynamo armature to multiple copper and zinc poles in a battery.

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1. See Doc. 1607.

2. The location of the offices of Drexel, Morgan & Co., Lowrey’s law firm, and the Edison Electric Light Co. Doc. 1494 n. 1; and see the Drexel, Morgan letterhead, TAEM-G1, s.v. “Drexel, Morgan & Co.”

3. Not found.

4. See Doc. 1532.

5. Cases 156 and 162 covered thermal regulators of the current for electric lamps. They were both allowed on 7 December and issued on 22 April 1879 as U.S. Patents 214,636 and 214,637, respectively.

1. James Gordon Bennett had become editor of the New York Herald in 1872 after the death of his father, the elder James Gordon Bennett, who had founded the paper in 1835. DAB, s.v. “Bennett, James Gordon.”

2. The next day the New York Herald printed “The Electric Light,” a one and a quarter column article describing lamps that Edison had demonstrated for Fox. The Herald reported that two of Edison’s electric light patents had just been allowed but that he had eleven applications pending and would not disclose details of his system. Cat. 1241, item 1048, Batchelor ( TAEM 94:431).

On 9 December, William Croffut of the New York Daily Graphic had wired Edison, “Will you give Graphic facilities for describing and illustrating electric light.” Edison replied the same day, “Yes when I am ready.” Edison provided an interview for the Graphic later in the month in which he described his lamp and dynamo research. DF (TAEM 17:264); “Two Hours at Menlo Park,” New York Daily Graphic, 28 Dec. 1878, Cat. 1241, item 1091, Batchelor (TAEM 94:444).

1. R. G. Dun & Co., established in 1841 as the Mercantile Agency, was by 1871 one of two major credit-reporting firms in the United States. See TAEB 1:469 n. 1.

2. This number refers to the agent making the report. The book containing the matched codes and names has been lost. The meaning of the numbers at the end of the document is unknown.

1. It is unclear why Edison wanted Wallace’s carbons for electric arc lights. He paid Wallace’s firm $60 for “Carbon Lt” on 21 December, the same day he sketched a lamp and listed next to it more than a dozen substances including “Carbon—Wallace.” Wallace’s arc light was unusual in that the carbons were “made in the form of plates, twelve inches long by two and a half wide, and half an inch thick.” The carbons were “so large that they will last for ten nights, of ten hours each, and the lamp requires no care except for their renewal,” owing to the simple electromagnetic regulator that kept them separated from each other in a large rectangular metal frame. There were, however, no “means for maintaining the light at a given point, so as to use it in connection with a reflector.” Electric Light Co. Statement Book, Accts. (TAEM 88:444); Vol. 16:315, Lab. (TAEM 4:748); Prescott 1878c, 412; Prescott 1879, 511–12.

2. Wallace had evidently offered Edison the use of this Siemens generator. Edison made sketches of its field magnets, armature, and commutator wiring on 17 December (Doc. 1627).

William Wallace’s arc light.

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1. On 2 December, Charles Edison had begun an extensive search for chemicals with which to make a more enduring electromotograph receiver. He undertook “Experiments with differant mixtures to find out differant or change in resistance of Button when left in crock with water.” By 12 December he had tested nearly two hundred compounds, most of which he noted either made fragile buttons or were poor conductors. He tested several dozen additional materials between 13 and 15 December. On 16 December, Charley drew a new form of receiver in which the button was a thin disk mounted on a base and turned on a vertical axis. The following day he continued “Experiments to determine conductivity of differant chemicals.” Between then and 22 December he tried more than six hundred substances, including various nuts, chewing tobacco, pussy willow bark, and “bitter orange peel.” Most were nonconductors, but on 22 December Charley recorded “Hair From a bat with Carbon” as a good conductor. On 24 and 26 Page 776 December he tested “paper soaked with differant oils for conductivity.” Charley continued experimenting with electromotograph buttons in January. Vol 18:100; N-78-12-02:3–227; both Lab. (TAEM 4:1132, 29:443–547).

Charles Edison’s 16 December telephone receiver design.

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2. That is, “number.”

1. This was presumably the wife of Major Thomas Thornburgh, who was stationed at Fort Steele. In September 1879, Thornburgh was killed while trying to put down a Ute rebellion at the White River (Colo.) Agency in Indian Territory near where Edison and Barker had gone hunting during the summer of 1878; see App. 1.A[4]. Knight 1960, 299–300; Dunn 1886, 698–701.

2. Barker attached two short clippings from an unidentified newspaper. These farcical items attributed a woman’s purported insanity to illfitting pantaloons and claimed that Edison was “at work on an invention to keep pantaloons from bagging.”

3. E. Carre of France was among the largest manufacturers of electric carbons. In 1876 he had patented a composition “consisting of powdered coke, calcined lamp black and a particular syrup formed of twelve parts of gum and thirty of cane sugar.” These were considered stronger than retort carbon and were better conductors but wasted more rapidly and produced small sparks and an irregular light. Prescott 1879, 431–32; Dredge 1882–85, 1:354–56.

Hiram Maxim’s 1877 platinum burner electric light.

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4. Hiram Maxim was chief engineer of the United States Electric Lighting Co. at this time. The company had been formed by the Equitable Life Assurance Co. and had its offices in Equitable’s building at 120 Broadway in New York. An accomplished inventor, Maxim had experimented with both incandescent and arc lighting and subsequently became a determined rival of Edison. He moved to England about 1882, where he invented an automatic machine gun and a form of smokeless powder; he was knighted in 1901. Passer 1972, 147–48; DNB, s.v. “Maxim, Sir Hiram Stevens”; Wilson 1879, 433.

5. Vertical text at center is “Plat, wires.” Maxim had invented this lamp in 1877 but never patented it, “because he found by experiment that it required a much greater expenditure of power to produce a given light with it than was required with the carbon points.” Prescott 1884, 233–35.

Fixture for Hiram Maxim’s arc lights in use in 1878.

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6. Maxim used two arc lights of his own recent design to illuminate a corridor of the Equitable building. His lamp had automatic feed mechanisms to advance each carbon at the rate it was consumed, thereby keeping the arc itself in the same place. The lamp had

a silvered reflector, of suitable shape to throw the beams that would be wasted above in a horizontal or downward direction, and from this reflector two rows of prisms are suspended. One half of the prisms are arranged with their flat side to the light, and the other half have their angular side toward the light. Below the focus is a bowl shaped glass, having a zone ground just wide enough to be always between the eye of a near observer and the luminous arc. The point from which the light is emitted appears from a distance diamond shaped and quite large. Thus modified, the light can be looked at with perfect ease, while its brilliancy does not seem to be at all impaired, the ground glass portion of the globe only being between the eye and the luminous point.

Powered by the Wallace–Farmer generator, these lamps reportedly provided more light than the gas jets they replaced at less than one-third the operating cost. Prescott 1879, 479–81, 512.

7. The Wallace–Farmer machine was similar to other contemporary generators in using a duplex armature; that is, one having two independent circuits. In the Wallace–Farmer design a series of coils was placed around opposing faces of an iron disk. The coils on each side were wired into a single circuit but were not connected to those on the other side. These separate circuits constituted “a double machine, each series of coils, with its commutator, being capable of use quite independently of the other; but in practice the electrical connections are so made, that the currents generated in the two series of armature coils pass through the field magnet coils, and are joined in one external circuit.” The Wallace–Farmer generator collected the current through a single commutator, although duplex machines in general could have a separate commutator for each armature circuit. Prescott 1879, 445–56; Thompson 1905, 83.

8. On 18 November, Asahel Eaton had filed a patent application for a transmitter button of metallic powder in an elastic matrix. The patent issued on 29 July 1879 as U.S. Patent 217,930.

1. See Doc. 1499 n. 4. On 13 December, Roosevelt had asked Edison’s permission to amend this release by substituting “the word ‘apparatus’ for ‘toys’ as it so reads in the original contract.” Edison’s marginal notation on that letter reads, “Copy to UHP What about it E.” Roosevelt to TAE, DF (TAEM 19:163).

2. Painter wrote Edison again on 22 December, charging “that the recent concession was given by you to him [Roosevelt] for the Co’ in order that the whole interest might be in one concern— That in violation of this he immediately assigned it to Russell & then refused to sell to the Phono Co anything but a privelge to spend money.” He also claimed that “Roosevelt has threatened to make Phonographs under the Toy contract & is acting very badly.” Edison replied in the margin, “will not do anything with R.” DF (TAEM 19:168).

1. This is one of several experiments and analyses devoted to clarifying which motions, arrangements, and parts of generators do not contribute to, or in some way inhibit, the generation of current (see, e.g., Docs. 1628 and 1641).

2. Poles are labeled “N” above “fine wire” and “S” below.

1. For earlier work on the tuning-fork dynamo see Docs. 1427 and 1547. In the patent application Edison had executed on 3 December (Pat. App. 218,166), he stated that “this vibrating bar or fork may be two metres long more or less, and heavy in proportion, it has its regular rate of vibration, like a tuning fork, and the mechanism that keeps it in vibration is to move in harmony; a crank and revolving shaft or other suitable mechanism may be employed, but I prefer a small air, gas, or water engine, applied to each end of the fork.” In the patent drawing of the engine, the regulating valve is moved mechanically by the fork. On 11 December, Batchelor had sketched what appears to be a detail of this linkage and drew the entire engine with the valve actuated by battery current. He also listed possible modifications to the engine and its connection to the fork. N-78-11-22:13–17, Lab. (TAEM 29:159–61).

2. Edison drew a similar fork the same day with a different wiring arrangement, but labeled it “no good.” Another fork and Batchelor’s sketch of commutator switches follow. N-78-11-28:25–29, Lab. (TAEM 29:32–34).

1. In these drawings Edison considered a variety of armature configurations and their relationships with field magnets. They mark the beginning of his first sustained effort at designing generators. Most of the sketches involve ring armatures combined with multipolar field magnet arrangements similar to those used in large Gramme generators and to designs by De Meritens. King 1962c, 380–89; Dredge 1882–85, 1:197–201.

Dynamo design of 30 November.

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2. The shape and proportions of the first machine below resemble one shown in a dynamo design drawn by Edison on 30 November. The armature appears to be tubular in form, like a design later employed in a Maxim generator. Several of the later sketches show pole armatures surrounded by multiple-pole field magnets, similar in some ways to the arrangement of the Weston generator Edison had purchased. Vol. 16:305, Lab. ( TAEM 4:742); Dredge 1882–85, 1:224–5; Prescott 1884, 659–9; cf. Doc. 1508 n. 2.

1. In interference testimony, Edison claimed that he had conceived this meter design in October and had it constructed in October and November, but this notebook entry marks the first extant evidence of such a design. He recalled that

The apparatus consisted of a cell with a fixed copper cylinder in the cell. This cell was filled with sulphate of copper. The other electrode was a plate of copper suspended by a spring. A lever connected to the plate came in contact with electrical stops at the extremity of the movement of the plate, in either direction. When the plate had become heavy by decomposition of copper it moved down into the liquid until the lever touched one of the contact points closing an electric circuit, which actuated a reversing apparatus for reversing the direction of the current through the electrode of the cell. The plate then became lightened from copper taken off of it by electrolysis, which continued until the lever came in contact with the upward point. When the current became again reversed, and so on. A ratchet wheel and magnet actuating a counter recorded the number of reciprocations of the plate. [Edison’s testimony, p. 6, Sprague v. Edison (TAEM 46:324)]

The drawing of the electromagnet apparently represents a polar relay with some kind of recording point to act as a counter. Each time the current reversed it would presumably make a mark.

2. Charles Batchelor recalled that

It seemed to be a favorite idea with Mr. Edison to measure electricity by means of depositing the metal and making the weighted plate tell, first, by weighing and afterwards by recording the amount of electricity that passed. The first experiments of this Page 792 kind that I remember were simply electrolytic cells in which the metal was taken off one plate and deposited on the other, one of which plates was weighed in order to tell how much current has passed. Mr. Edison also made experiments with a similar cell, in which the plate to be weighed was provided with a pointer, which, as the metal got heavier would indicate the amount of current that was passed. This plate was suspended by a spring in some cases, and in other cases was mounted on a counter-balance arm so that the plate fell and rose in the liquid as the current was reversed. He also made meters on the electrolytic principle that were automatic in their action, inasmuch as the weighted plate would pull down a scale beam, and at a certain point would reverse the current so that the other plate could receive a larger portion of metal, and so pull the scale beam in the opposite direction. On such devices recording arrangements were placed which would keep a record of the current that had passed by counting the number of oscillations that the lever had made. [Batchelor’s testimony, pp. 12–13, Sprague v. Edison (TAEM 46:327)]

3. Polarization, the accumulation of ions on electrodes in an electrolyte, increasingly impedes the flow of current. In the drawings below [Nos. 1–3), as one electrode gains weight through deposition it pulls down a lever connected to a dial gauge. In meter drawings of 20 December, Francis Upton showed a linear “scale for measuring” the amount of deposition. N-78-12-16:17, 19, Lab. (TAEM 29:1085–86).

4. In the drawing of the lamp circuit (following meter design No. 3) the shunt with the decomposing cell is shown at the top; the figure label is “100.” In the final drawing the figure label is “revrsr register.”

1. Andrews and James Gamble, general superintendent of the American District Telegraph Co., had tried at least five times since September to make an appointment with Edison in Menlo Park. Edison agreed to meetings on 4 and 24 October but broke both engagements to go to New York on other matters. Andrews to TAE, 6 Sept., 3 and 14 Oct. 1878; Gamble to TAE, 10 and 23 Oct. 1878; TAE to Andrews, 3 Oct. 1878; TAE to Gamble, 23 Oct. 1878; all DF (TAEM 19:545, 552, 555–66, 563).

2. Docs. 92 and 755.

3. See Docs. 1328 n. 3 and 1388 n. 6.

4. At this time, Elisha Andrews was president of the American District Telegraph Co. and a director of the American Speaking Telephone Co. Reid 1879, 632; see also TAEB 1:153 n. 2.

1. See Doc. 1559. In a letter of 29 November, Bliss had reported to Edison that after going first to Carthage, Ill., he “travelled day and night by rail and team and tracked Huffman through Illinois, Missouri and Kansas” before finding him “on the state line between Kansas and the Indian territory 60 miles from the nearest railroad.” Because “other parties” were also chasing Huffman, he “had to resort to every artifice to throw them off the track and conceal my movements.” Bliss succeeded with the help of “a friend who is a dealer in patents and who took along a patent steam cooker which we pretended to be selling to farmers.” DF (TAEM 18:355).

1. This apparently refers to Doc. 1150 rather than the Scientific American article discussed in Doc. 1388 n. 12; the French reprint has not been found. On 11 November, Serrell had notified Edison of opposition to his patent based on the claim that a description of the phonograph Page 795 had been published in Germany in January or February, before the application was filed there. DF (TAEM 18:799).

2. Presumably patent attorneys; the firm was located in Dresden. Thode and Knoop to Serrell, 18 Sept. 1878, DF (TAEM 18:761).

3. Edison gave this letter to the New York Sun as justification for withholding details of the electric light. According to the Sun, a reporter suggested that he might get the desired information at the Patent Office, to which Edison replied, “You can’t get the specifications at the Patent Office. They are kept secret until the patent is taken out. Several patents on the light have been granted, but I am not compelled to take them out inside of six months. The publication of these specifications at this time would prevent my getting my patents in Europe. Otherwise, I would gladly give you the specifications.” The Sun also printed an edited version of Serrell’s letter followed by Edison’s comment that “I know that none of the newspaper boys would willingly injure me; yet that speaks for itself” “The Genie of Menlo Park,” New York Sun, 19 Dec. 1878, Cat. 1241, item 1066, Batchelor ( TAEM 94:436).

1. A rough undated sketch showing the location of dead points on a Gramme armature is in N-78-11-22:23, Lab. (TAEM 29:164).

2. Batchelor is apparently referring to the fact that each “spring contact” touches at least two commutator bars at all times. The armature will always be polarized because the commutator’s rotation will not interrupt the flow of current.

1. The relation of this label to the drawings is uncertain. Edison’s work on understanding and designing generators during the latter part of 1878 roughly followed the general pattern of the historical development of the field. Such work was necessary to attain competence, since Page 803 “to those who have not served an apprenticeship to the technicalities ... the action of these machines is almost an unknown mystery” (Dredge 1882–85, 1:37). Several sketches here and in other entries reflect the prior practice that Edison was tracing and elaborating upon in an approximately chronological sequence. Having already considered disk armature designs related to the earliest of all generators—Faraday’s—and having worked with Wallace’s generator (a leading contemporary disk armature design), Edison explored designs with ring armatures (notably employed in designs by De Meritens and Gramme) and pole armatures (such as used by Lontin and Weston), and took up shuttle and drum armature types (identified with the work of Siemens and von Hefner–Alteneck) as well. He also reviewed a similar range of field-magnet configurations and considered many modifications. (On dynamo development generally, see Dredge 1882–85, King 1962c, and Prescott 1884.)

Neither the machine shown here nor the next designs (which show field magnets of the form used in many Siemens generators) have any clear resemblance to the various De Meritens generators, some of which had been introduced recently in France. Those were not dynamos, as they used permanent magnets for their fields. Moreover, they used ring armatures consisting of a number of segments. The drawing above has electromagnets providing the field and apparently a pole armature, with coils projecting radially from the armature’s axis. In one widely discussed De Meritens design, each segment was made of fifty thin iron plates pressed together and capped with iron at both ends. These were then wound with insulated copper wire and mounted on a bronze wheel, with strips of copper between them to magnetically insulate them from each other. As the bronze wheel revolved each segment passed under one of the poles of a series of horseshoe magnets. According to contemporary reports, the machine could light three Jablochkoff candles for each horsepower used; other generators required one horsepower per lamp. Some Edison designs in Doc. 1621, with ring armatures and multipolar field magnets, are similar to major aspects of the De Meritens generators.

A De Meritens dynamo, and detail of its construction.

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The label here probably indicates that the design shown had no commutator and thus would produce alternating current. The De Meritens high output was attributed to its armature design and to its having no commutator. According to an article clipped from the 18 October English Mechanic by Charles Batchelor, current was drawn instead through two springs placed against insulated rings on the armature shaft, which were themselves in contact with the windings. The resulting alternating currents could thus pass directly into the line without loss due to sparking in the commutator (see note 4). Also, pole armatures like that shown here were mostly associated at this time with generators that produced alternating current. Edison did not have access to a De Meritens dynamo but he had already borrowed a small Gramme from Princeton and had probably received the Siemens machine from William Wallace (see Doc. 1615). Dredge 1882–85, 1:185–204; Prescott 1879, 495–98; Sprague 1878a.

2. During his testimony in Sawyer & Man v. Edison (U.S.) (p. 3067 [TAEM 48:40]), Edison described a shop lamp as “one in which the current only had to be subdivided in a shop, and not over a large area, Page 804 where a high resistance was not absolutely essential.” He claimed that in January 1879 they experimented with carbon paper in a shop lamp similar to that shown in Fig. 2 of his U.S. Patent 224,329; the shop lamp sketch shown here resembles the design in Fig. 1 of the patent (see Doc. 1567 n. 1). Details of shop lamp designs from 9 January 1879 are in N-79-01-01:95–99 (TAEM 30:305–7).

3. This appears to be a design for dispensing with battery current in the Edison telephone set. The electromotograph receiver crank would also turn a small Gramme generator. A similar design is in N-79-03-20: 122, Lab. (TAEM 33:62).

4. The commutator of a generator is the contact point between the armature, where the current is created, and the outside circuit (which, in a dynamo, includes the field magnets). It automatically switches connections on the armature so the alternating current that is generated gets distributed as direct current. Commutators at this time were generally stationary wire brushes that picked up the current by pressing against the outside of a segmented copper circle on a rotating armature, where each segment was attached to a section of the armature wiring. They added to the expense of operating a dynamo, because sparking as each brush broke contact with each segment wasted electricity, inefficient contact wasted energy as heat, and brushes rubbing against the rotating commutator caused friction and wear. Excessive sparking quickly burned the commutator’s parts, leading to costly, time-consuming repairs. Carefully adjusting pickup brushes relative to the armature’s rotation could temporarily reduce or eliminate sparking, but each change in the dynamo’s load altered the optimum position of the brushes. Alternating-current generators do not require commutators, which was one of the principal reasons generator designers in the 1870s had given considerable attention to alternating-current arc lighting systems (Thompson 1902, 78–84). However, because there was no motor that ran on alternating current, Edison did not consider it for his system.

Sketch labelled “Attempt at non-communtator The suggestion for a new telephone receiver.”

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Edison first drew a non-commutation device on 13 December. Other drawings of designs without commutators are in N-78-12-28:13, 19–29; N-78-12-20. 1:3, 24–34, 37–45. 56–59, 64, 68; N-78-12-11:9; N-78-11-22:41–47; N-79-03-20:50–51, 77–82, 122; all Lab. (TAEM 30:8, 11–16, 117, 128–33, 134–39, 143–44, 147–48; 29:173–77, 683; 33:27, 39–42, 62).

5. It is the field magnet rather than the armature in the following drawing that follows the form typical of Siemens machines.

6. The relation of this label to the drawings is unclear; the designs share little if anything with Gramme’s.

7. The wires shown could represent an earlier type of Siemens armature, the shuttle, but the multiple commutator bars at the hub indicate they are just a segment of a set of such loops that would form a cylinder. Siemens generators used the design of von Hefner–Alteneck, in which the wire of the armature was wrapped around the outside of a rotating drum and connected at each turn to contacts on the commutator, so the coil was continuous but each segment was individually connected to the commutator. It resembled the Gramme ring in this feature but it had no return segments inside the circumference of the armature, and had comparatively smaller diameter and greater rigidity, allowing a smaller gap between the armature and the field magnet poles. These machines were the first to produce so much current that the resulting heating became an operational problem. King 1962c, 370–74.

8. There are several sketches of this distinctive shape from the same day, and another on 21 December. It closely resembles a shuttle armature but the complete magnetic shielding of the wire coil dictates that this is a magnet design (rather than any kind of armature) either for a rotating central field magnet or for a magnetic core for an armature that would revolve around it. Edison adopted such a design for more extensive trial at the end of the year (see Doc. 1646 nn. 3–4). N-78-12-11:21, 47, 53–59, Lab. (TAEM 29:689, 702, 705–8).

Edison’s first attempt at a non-commutator design.

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1. Hand-powered Gramme generators for table-top demonstrations commonly had permanent instead of electromagnets. A compound magnet designed by the French physical scientist Jules Jamin, consisting of several thin magnetized steel strips laminated together and with its poles a little closer than in simple horseshoe magnets, was frequently employed. Dredge 1882–85, 1:156–57; King 1962c, 383.

2. Batchelor copied these observations from the laboratory notebook in which he had recorded them the same day. There he stated that the “Small Gramme Machine from Princeton heats a Platinum wire to dull red (only just see it).” The original entry includes his measurement of the platinum wire’s resistance at 2.3 ohms. Batchelor also noted that 11 Condit & Hanson cells that were weak and “pretty well played out” had the same heating effect as the Gramme, but when refreshed would heat a 35¹/2 inch wire with a resistance of 3.47 ohms. N-78-12-16:101, Lab. ( TAEM 29:1126).

3. Batchelor meant those portions of the armature winding which cut the field magnets’ lines of force at any given moment.

4. A similar provision was a significant feature of the Brush dynamo. See Doc. 1489 n. 4.

5. Short-circuiting of a portion of the coil is not the same as Edison’s suggestion of opening the circuit for those portions.

1. Edison apparently dictated this reply to a 6 December letter in which Bliss had complained about press reports that Edison was “adapting the Typewriter for the preparation of stencils so as to supercede the use of the electric pen. It is also stated that the business has been placed in the hands of Mr McKenzie. I can scarcely believe this to be possible and shall be glad to have you advise me what the facts are.” DF (TAEM 18:359).

2. Edison is referring to an article in the New York Sun of 25 November which included a discussion of his efforts and those of James MacKenzie to develop a stencil typewriter. Although Edison had conceived such an idea in 1875, including it in his electric pen patents in England and other foreign countries (e.g., British Patent 3,762 [1875]), he had never perfected it, but instead

chucked it into a dark closet, after getting into the telephone business, and there it remained until the other day, when my old friend J. U. Mackenzie came in with a similar idea in his head. I yanked the thing out of the closet, turned it over to him, and said: You want something to do. Work that up. He took it and cleared out. To-day he came back, and instead of dropping the thing, as I expected, he seems to have made a perfect success of it.

MacKenzie’s instrument perforated a stencil using chisel point type “placed in a type-writer worked with the fingers like a pianoforte. Each written page may be placed upon a Gordon press or an electric pen press and as many copies worked off as wanted.” The Sun reported that MacKenzie “regards the success of the stencil type writer as assured, and there is undoubtedly a fortune in store for its inventors.” “The New Electric Lights,” Cat. 1241, item 1021, Batchelor (TAEM 94:416).

3. In fact, Edison had acted to secure a U.S. patent. He made two sketches related to a “Perforating Type Writer” on 29 November, and John Ott’s timesheet indicates that he spent the entire next day making “Type Wrighter Models.” On 2 December, Lemuel Serrell received a model and draft patent specification for the typewriter; Edison executed the application two days later. The application was rejected and modified repeatedly, finally issuing in 1884 as U.S. Patent 295,990. NS- Page 80878-001, Lab. (TAEM 7:736); Ott’s timesheet, Serrell to TAE, both DF (TAEM 17:824, 18:822).

Edison’s design for a stencil typewriter in his December 1878 patent application (U.S. Patent 295,990) structurally resembles designs included in his foreign patents for the electric pen a few years earlier.

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In reply to Edison’s assurance that he was not developing such a device, Bliss stated “I am glad you are not disposed to press the type writer adaptation for stencil work on the market, as it seems to me this could not be done without seriously interfering with the legitimate pen business. It is hard work to make a success of the pen trade with the least possible hindrance in the way.” A year earlier, Bliss had looked forward to Edison developing just this combination. Bliss to TAE, 23 Dec. 1878, DF (TAEM 18:374); Doc. 1138.

1. Edison had written Gouraud on 18 November that he wanted “to do a little more work on the new receivers, they must be perfect when they leave my hands. I expect to send my nephew (Chas Edison) with them as he thoroughly understands the mechanical details. I cannot say definitely when he will go but it will be soon.” Gouraud replied on 5 December that he hoped the receiver would arrive in time for William Barrett to use in a 30 December lecture in London and urged Edison to “Spare no means to this end. It will be a grand opportunity to bring the thing out.” Lbk. 4:7 (TAEM 80:19); DF (TAEM 18:218).

1. This distortion results from the interaction between the poles created in an armature by the field magnets and those induced by electric current flowing through it. In a notebook entry the next day, Batchelor considered the relationship between this phenomenon and commutation: “In gramme armature the pole is carried round in direction of revolution. So it ought to [be] made as in sketch with shoes to help it round.” There is also a rough, undated notebook drawing of the axes formed by the poles when the armature is at rest and in motion. Thompson 1896, 71–77; N-78-11-22:19, 23, Lab. ( TAEM 29:162, 164).

Charles Batchelor’s 20 December sketch.

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1. The previous day, Batchelor had made several drawings of this instrument. Using a Wheatstone automatic telegraph receiver as a motor, he moved a vertical piece of smoked glass past the pointer attached to the platinum wire. N-78-11-28:39–43, Lab. (TAEM 29:39–41).

1. These experiments are concerned with the problem of frictional energy loss in dynamos. Similar concerns were discussed by Edwin Houston and Elihu Thomson in their paper on the “Circumstances Influencing the Efficiency of Dynamo–Electric Machines” read before the 1 November meeting of the American Philosophical Society (Houston and Thomson 1879). They noted that mechanical energy was “expended in two ways, viz., 1st, In overcoming friction and the resistance of the air; and, 2nd, In moving the armature of the machine through the magentic field.” In another set of notes from the same day Francis Upton explored the second problem. He also sketched what appear to be a commutator and a design “To prevent friction” similar to this one (N-78-12-16:121–22, 124–25, Lab. [TAEM 29:1136–38]; see also Doc. 1651 n. 16).

2. That is, center screws, which have a concave tip to hold the pointed end of a shaft, as in the diagram.

3. Batchelor was trying to find a way to reduce mechanical friction by placing “a magnet over the top of a shaft to lift it up and take the weight,” hoping that this would allow it to “run longer with given amount of energy.” He made ten trials of this experiment and the one above, recording the results the same day in a separate notebook. The values he reported there for the remaining experiments differ somewhat from those given here. He tried different magnets at different distances from the shaft. When he oiled the bearings and placed the magnet “¹/16 Page 812 inch away where you can push shaft to top or bottom,” the wheel ran for “20 seconds or 2½ times the length of itself without magnet.” N-78-12-20.1:5–9, Lab. (TAEM 30:118–20).

4. Based on their Franklin Institute tests (see note 1), Houston and Thomson had calculated average frictional losses at seventeen percent of the mechanical power required to drive a dynamo and considered this equivalent to thirty-three percent loss of electrical output. They noted that the Gramme dynamo was much more efficient, with mechanical loss of only seven percent.

1. This undated entry precedes Francis Upton’s notes on “magneto multiplier” machines and non-commutating generators, which were subjects of laboratory research from the end of November to late December (see Docs. 1627 and 1579). On 20 December, Batchelor experimented extensively with ways to reduce the loss of power in dynamos by the two causes identified here: mechanical friction and electrical resistance (Doc. 1633; see also Doc. 1628). The first notebook entry from these experiments contains a calculation showing one-half of the horsepower required to drive a dynamo being lost to mechanical and electrical friction. Upton labeled this “Horse power for magneto proportion of” (N-78-12-20.1:1, Lab. [TAEM 30:115]).

This entry follows two pages of Edison’s calculations of the proportions of internal and external resistances for Wallace, Gramme, and Siemens Page 813 dynamos. Edison also began, but did not finish, a note on the effects of doubling dynamo speeds. In another notebook from around this time, Upton made an extensive set of notes and calculations regarding the relationships between internal and external resistance, useful and uselesss work, and horsepower and dynamo speed, with comparisons between these different dynamos. N-79-03-20:4–6, N-78-12-04.1:11–37, both Lab. (TAEM 33:4–5; 29:568–81).

2. Edison probably meant “only.”

3. In his other notebook (see note 1), Upton described the effect of doubling the horsepower on a Gramme dynamo: “2 Horse power put on a Gramme machine will give 1000 revolution the total resistance being 20 ohms, 10 in & 10 out. If the Horse Power is doubled i.e.—4 H.P and the total resistance is doubled i.e. 30 out 10 in = 40, the speed of the machine will increase to 3000 revolutions and double the work will be obtained.” He concluded that in a “Perfect Gramme If the speed is doubled the electromotive force is doubled. If the internal resistance is halfed the E. F. is halfed, at the same time external increased half, total the same. If both at same time Elec–Force remains constant.” N-78-12-04.1:21–25, Lab. (TAEM 29:573–75).

1. Edison had wired Barker on 19 December, “Can you send me your small Gramme machine with permanent Jamin magnet for ten or 15 days.” At the time Batchelor was conducting experiments with one they had borrowed from Princeton University (see Doc. 1628 n. 1). After receiving Barker’s reply, Edison made a similar request of Henry Morton. This letter has not been found, but Morton answered that he would “gladly lend you any apparatus I had but unfortunately we have no Page 814 Gramme machine of any sort. I ordered one long ago through Barker but it was never sent.” TAE to Barker, 19 Dec. 1878; Morton to TAE, 26 Dec. 1878; both DF ( TAEM 17:1094, 1115).

2. Barker had borrowed a phonograph in November. On 16 December he asked Edison why William Carman had requested him to return it, since he had expected to have it for his lecture classes in January. Edison replied the following day (Tuesday), “Carman shipped you the wrong box. The instrument you have is a borrowed one and yours is here will ship tomorrow.” DF (TAEM 18:1065, 16:523).

3. Barker thanked Edison on 19 January 1879 for sending him another phonograph, “not as elegant as the other, but it works quite as well.” He also reminded Edison that he had not received the promised chalk cylinders. DF (TAEM 49:71).

1. Wallace enclosed part of “The Genie of Menlo Park,” a New York Sun article about Edison’s recent electric light research. The Sun quoted Edison as saying that he was satisfied with his lamp and had turned his attention to developing a suitable power supply:

My point now is the generator. The Wallace machine gives me three lights, each equal to a gas light, to a one-horse power. I feel sure that I can get six with an improved machine. Probably I can get more. Now, to make my grand practical experiment here in lighting Menlo Park, I should have to use twenty or thirty Wallace Page 815 machines. They would cost me from $30,000 to $40,000. They would be useless afterward, for I know that I can make a generator of double their power. So I shall postpone the experiment until I find the machine that will give the greatest amount of electricity per horse power. I am making many little generators of different forms. I propose to run them with weights, figured down to the fractions of a horse power, and shall take the machine that generates the most electricity.

The weight-powered “Test machine for driving magnetos.”

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The Sun clipping follows Wallace’s letter in DF; the entire article is Cat. 1241, item 1066, Batchelor (TAEM 94:436).

On 17 December, the same day that the Sun article appeared, Charles Batchelor sketched a weight-drive for generators on which he wrote “Train of Gears Generator to run 600 Weight to fall 10 feet Size of drum about 3.85 in order to make 10 feet drop in 10 turns Pin on drum to connect circuit and on turning ten times opens again Large handle for winding Weight up again” (N-78-11-28:35, Lab. [TAEM 29:37]). Three days later he drew a “Test machine for driving magneto’s” and gave it to George Jackson to build it (N-78-12-20.2:13, Lab. [TAEM 29:805]; Jackson’s timesheet, DF [TAEM 17:856]). Related sketches from about this time are in N-78-12-15.1:37, N-78-12-16:102–3, and N-78-12-15.2:15, all Lab. ( TAEM 29:960, 1127; 40:312).

2. Unidentified.

1. Edison apparently made some arrangement with his nephew Charley, who was the principal experimenter on the new receiver. An account book entry that begins on 5 December is labeled “Chas Edison Contract.” Ledger #3:335, Accts. (TAEM 87:146).

2. That is, Edison’s 31 May 1878 agreement with Western Union which required Edison to assign to the company any patents for new telephone inventions made by him before 1 January 1879. Miller (TAEM 28:1105).

1. Patrick Kenny was apparently at the laboratory by 28 December. Timesheet, DF (TAEM 17:870).

2. Twombly replied the same day that he had discussed with Green

the employment of Kinney, and he states that he is firmly of the opinion that until Mr Andrews has given up the contract which he has seen, he Mr A will prefer a claim upon any invention covered by said contract. He therefore would not be in favor of adding (25) twenty five dollars per week for the employment of Kinney until you have retired the contract, although he would not have any objection Page 818 to a portion of the regular weekly allowance being applied for that purpose.

The President I know has not any understanding with Mr Andrews, but has discussed the matter with him, and Andrews has signified that he would not be unreasonable regarding the matter.

[DF (TAEM 19:575)]

1. Tracy Edson, James Banker, and Calvin Goddard had arranged to visit the laboratory on Friday, 20 December. Timesheets of two Menlo Park workers indicate that they had begun moving shop equipment to the new main building the preceding Saturday. Moving continued into the following week. Edson to TAE, 18 Dec. 1878; Charles Dean and Charles Flammer timesheets; both DF (TAEM 18:119; 17:841, 854).

2. See Doc. 1562.

1. Doc. 1637.

2. Not found (see Doc. 1585).

1. In this drawing the armature turns on a horizontal shaft (right) within the C-shaped pole of an electromagnet. This design is also found in Francis Upton’s sketches of Gramme ring arrangements from around this time, including one with multiple armatures. Edison and Batchelor appear to have experimented on 28 and 30 December with other unipolar designs which failed to produce a current. N-79-03-20:106–9; N-78-12-16:171–73, 192, 194, 195, 203, both Lab. (TAEM 33:54–55; 29:1151, 1152, 1161, 1162, 1164).

Design for Charles Batchelor’s 26 December ring armature experiment.

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2. The next day Batchelor tried an armature that was “wound in the shape of figure 8 and the ends brought each to a copper ring on the hub.” He noted that “no current could be detected except the current due to induction on passing it in front of the poles.” Three days later Upton recorded similar results and drew several sketches of the direction Page 822 in which he thought current might be induced in such a winding. On 27 December, Batchelor used the three-layer and figure eight windings in another generator design but once again “no current could be detected.” Cat. 1304:20–21, Batchelor ( TAEM 91:22–23); N-78-12-16:183, Lab. (TAEM 29:1156).

1. The theater was located at 56 E. 14th Street in New York. Wilson 1879, 1481.

2. The Union Square Theatre presented The Banker’s Daughter, a romantic melodrama by Bronson Howard. The play had been staged under a different name in 1873 but premiered under the present title at the Union Square on 30 November 1878. An advertisement claimed that it was “produced with the finest scenery and appointments ever seen in New York in a modern play.” The show became a hit and played until April. Edison and his wife probably saw the Saturday, 28 December, performance with Charles and Rosa Batchelor. New York Herald, 28 Dec. 1878, 1; Howard and Halline 1941, 84–85.

3. Edward Gouge was the theater’s treasurer. Wilson 1879, 557.

1. Doc. 1637.

2. Doc. 1638.

1. This list appears to be Upton’s effort to determine how the energy put into a generator is expended. The marginal letters following each numbered item seem to characterize the type of expenditure. Their meaning is uncertain, though “C” is probably current, “H” is probably heat, “M” is probably magnetism, “R” is probably resistance, and “W” is probably work. The entry is one of several made the same day in this notebook. It is preceded by two pages concerning electricity and heat and six pages of armature and field magnet designs. It is followed by a page of calculations of battery current.

1. On 1 December, Barrett had written Edison that the London Stereoscopic & Photographic Co. “have as yet supplied no phonographs to the public and though I have long since ordered one, I fear there is little chance of one being ready for my use” in lectures scheduled for 30 December and early January. He enclosed two letters that the Stereoscopic Co. “sent to a friend of mine, which will show that they are trying to secure the Exhibition at high rates as long as possible & hence no doubt their reluctance to sell the instrument.” Barrett also stated that the Stereoscopic Co. had objected to his efforts to buy a French-made phonograph and he asked Edison if it would be possible to ship an instrument from the United States instead. Barrett to TAE, 1 Dec. 1878; London Stereoscopic & Photographic Co. to Rev. C. J. Ludenbill, 18 Oct. 1878; both DF (TAEM 19:323–27).

2. On 28 January, Edison wrote Puskas to ask if he would have any objection to giving Gouraud a power of attorney, but three days later he wrote again to acknowledge receipt of Puskas’s £200 check in regard to the British phonograph, adding that this “materially alters the question regarding a power of Atty for Gouraud to look after the Stereoscopic Co. It does not now appear to be necessary.” TAE to Puskas, 28 and 31 Jan. 1879, TP. Page 827

3. Thomas Butler was Gouraud’s secretary for two years until the end of 1878 or early 1879. He subsequently became an officer in several Edison companies. Butler to TAE, 22 Dec. 1884, DF (TAEM 71:59); McDonald 1962, 15–16; TAEM-G3, s.v. “Butler, Thomas.”

4. What may be one of these machines is pictured in Chew 1981, 6.

5. Neither Blakey nor the British Telegraph Co. has been identified; he may have been connected with the firm Blakey and Emmott (see Doc. 1511).

6. Elliott Bros., an instrument shop on the Strand in London. “1873 Catalogue of Electrical Test Instruments,” Catalogues, Electrical and Telegraph Instruments, Library, NjWOE.

1. The initial drawings in this entry show polar armature generators rather like those of Lontin, but apparently with cores of rectangular rather than circular cross-section for the poles. Dredge 1882–85, 1: 173–78.

2. Nothing further is known of this design. It is a small experimental generator whose field magnets are similar to those used by Henry Wilde, Charles Wheatstone, and Werner Siemens in the mid-1860s. King 1962c, 375–79.

3. The following four points specify the internal arrangement of a generator related to a machine under construction as the new year began. George Jackson and Thomas Logan recorded work on a new dynamo in their timesheets for 30 December (DF [TAEM 17:869, 872]). On 2 January 1879, Batchelor noted that they had “begun to make a Page 831 practical working machine after a few weeks hard study on magneto electric principles” and the design he sketched corresponds in several ways to the one here (Cat. 1304:25, Batchelor [TAEM 91:27]). This design, however, calls for an external field magnet as well as a magnetic core inside the armature, while the machine Batchelor discussed was encased in an iron shell without external magnets. Edison’s sketch in a 29 December notebook entry labeled “Edison dynamo” presumably represents a generator with the same internal structure but shows the iron shell arrangement instead of external field magnets (N-78-12-11:61, Lab. [TAEM 29:709]).

4. The arrangement specified here is a drum armature with a stationary magnet core as mentioned earlier in the entry. Soon after the introduction of von Hefner–Alteneck’s drum armature principle, Siemens dynamos were built with hollow instead of solid drums and a stationary iron core, but not an electromagnet as Edison specified. King 1962c, 374.

Charles Batchelor’s 2 January 1879 drawing of Edison’s new magneto design.

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1. Little is known of C. C. Soulages. Puskas identified him as Cornelius Herz’s partner and warned Edison to “beware” and to give him no information about Edison’s light. On 27 December, Lowrey wired Edison that “If Doctor Soulage calls about Gramme machine refer him to Fabbri. Dont let him see light.” At about this time Herz proposed that he and Edison “overlook past unpleasantness” and form an electric light Page 832 partnership with Milton Latham and Soulages. Puskas to TAE, 29 Oct. 1878; Lowrey to TAE, 27 Dec. 1878; Herz to TAE, 25 Dec. 1878, all DF (TAEM 18:175, 126, 246).

2. Gramme alternating current dynamos had a separate direct current generator for the field magnets. Prescott 1879, 482.

3. Stockton Griffin indicated on the back of this letter that a reply was sent the same day stating that Edison “Didnt want one of small machines if couldnt get it as proposed by Mr L.” Edison borrowed a Gramme dynamo anyway and paid duties of 40 dollars on a machine that was shipped to him on 7 January. Soulages asked for it back the following May, noting that Edison had kept it an unexpectedly long time. Edison then offered to buy the generator but apparently was obliged to return it. Goddard to TAE, 7 Jan. and 5 May 1879; Soulages to TAE and Soulages to Goddard, 4 May 1879; TAE to Goddard, 5 May 1879; all DF (TAEM 50:206–7, 255–57).

1. Edison wrote Puskas on 3 January 1879 that he was

sorry we cannot carry out the negotiations with Drexel Morgan & Co as foreshadowed in my Cable telegram of the 3d Ult. [Doc. 1596.] If you still feel disinclined to enter into such negotiations you must without delay make preparations to have parties there furnish some money for experimental purposes. The fund I have here is being rapidly exhausted, as it is very expensive experimenting. I bought last week $3000 worth of Copper rods alone, and it will require $18 000 worth of Copper to light the whole of Menlo Park ½ mile radius. It is also essential that Serrell should have at least $3000 in hand. A second set of patents on the Continent ought to have been taken out over a month ago but which has been neglected owing to a lack of funds.

Please write me immediately if you can arrange so that your parties shall contribute some aid in experimenting and how much. [TP]

1. The agreement may not have been signed on 31 December 1878. It was not notarized until 22 July 1879, at which time Fabbri and Lowrey swore before Daniel Seymour, a New York notary, that they had indeed signed the agreement as trustees and Fabbri indicated that he had also signed as copartner of Drexel, Morgan & Co. A 6 December draft of this document is in DF (TAEM 18:238).

2. Edison’s first British electric light patent (No. 4,226 [1878]) had been filed on 23 October.

3. Although this marginal addition was not initialed, it was included in later documents such as the power of attorney mentioned in note 4.

4. Photocopies of the following legal documents, all dated 1 March 1881, are in DF, Supp. IV; a typed copy of Edison’s power of attorney to Drexel, Morgan & Co. is in Miller (TAEM 86:373).

1. Text is “water roller” in the first drawing below and “water” in the second drawing. On 26 December, Charles Edison had sketched a means of supplying moisture to the electromotograph cylinder using what appears to be absorbent batting and an adjustable trough (N-78-12-02:229, Lab. [ TAEM 29:548]). Similar drawings from around this time are in N-79-03-20:135–37, Lab. (TAEM 33:62–63).

1. Upton signed and dated the first page of this notebook on 20 December. He compiled much of the material from notes he made in another notebook from the time he arrived at the laboratory (around 15 December) through the end of December. Edison signed and dated Upton’s original notes. The problems recorded here indicate something of the direction of research at the laboratory during the last half of the month. Several entries also record Edison’s comments regarding a variety of scientific and technological questions. N-78-12-16:1–229, Lab. (TAEM 29:1076–1178).

2. The drawing on the left represents one hundred lamps and one Page 851 ohm resistance and the drawing on the right represents the other case. In this and examples 2, 7, and 8 Upton is using Joule’s law. Upton’s undated notes and calculations for this problem are in N-78-12-16:3–9, Lab. (TAEM 29:1078–81).

3. Upton made undated calculations in N-78-12-16:10–15, Lab. (TAEM 29:1082–84).

4. Upton’s undated calculations are in N-78-12-16:27–34, Lab. (TAEM 29:1090–94).

5. This example is substantially the same as a 17 December notebook entry in which Batchelor stated that 1,300 pounds of coal would yield enough gas to produce the equivalent of 30,000 candles of light. He then calculated that Jablochkoff lamps would produce “13 times more than gas” for the same amount of coal. Including the cost of carbon, this light “would be 4¹/3 cheaper than gas.” Batchelor stated that “We get 6 lights per HP if 90 can. per HP we should have 58,500 candles” from 650 horsepower. Upton worked through this example on 18 December, using the same figures as Batchelor. N-78-12-11:17–21, N-78-12-16:65–66, both Lab. (TAEM 29:687–89, 1109–10); cf. Doc. 1577 n. 2 and Bowers 1982, 105–7.

6. One horsepower equals 33,000 foot-pounds per minute, and 772 foot-pounds will heat one pound of water 1°F.

7. Upton’s notes for this problem from 18 December are in N-78-12-16:71–75, Lab. (TAEM 29:1112–14).

8. The meaning of “force” in the physical sciences and philosophy was a matter of some controversy during this period; that magnetism and gravitation were both significantly different from other commonly discussed physical forces had been suggested several times by Michael Faraday. Spencer 1966, 265–69; Spencer 1898; Tait 1876, 338–63; Faraday 1859, 443–63; Faraday 1965, 3:566–74.

9. This is the first of Edison’s comments, as opposed to specific problems, that Upton recorded in this summary and in his other notebooks. Many of these ideas were entered by Upton on the left hand page of the notebook containing the summary, while he recorded the problems on the right. The original, dated 18 December, is in N-78-12-16:95, Lab. (TAEM 29:1123).

10. See Doc. 1636 n. 1.

11. Text is “10 in all” and “¹/100 ohm” in first drawing below and “10 in all” and “100 ohms” in second drawing. Related calculations, dated 20 December, are in N-78-12-16:109–11, Lab. (TAEM 29:1130–31).

12. The following discussion of etheric force is apparently Upton’s record of Edison’s thoughts on the matter and is substantially the same as notes Upton made on 20 December. They are not the only instance of Edison’s concern with etheric force at this time. The 28 December New York Daily Graphic included an interview with Edison in which he stated that “while we were experimenting last night with the electric light I got some more indications of the presence of some subtle, evasive force that I could not call electricity or anything else with which we are acquainted.” Asked if it resembled the etheric force Edison claimed to have discovered several years before, he replied “Yes, it is the same—if that was anything, and I rather think it is something—a new radiant force, lying somewhere between light and heat on one hand and magnetism and electricity on the other.” He remarked that it did “not respond Page 852 to any of the physical tests of electricity, except the spark.” N-78-12-16:113–16, Lab. (TAEM 29:1132–34); “Two Hours at Menlo Park,” Cat. 1241, item 1091, Batchelor (TAEM 94:444).

13. This point roughly follows Michael Faraday’s general conceptual approach, which regards the space and air around magnets as being in an altered physical condition, one that contains energy and force. Faraday, however, reported that the atmosphere is paramagnetic, not diamagnetic, and that this is primarily due to oxygen. Faraday 1965, 3:sections 3464–81, 2770–96, 2853–63.

14. No experiment was recorded here or in Upton’s other notebook (see note 1).

15. Edison had experimented extensively with short- and long-core electromagnets for telegraphy. See, for example, Docs. 363, 375, 386, 392, 477, and 878; TAEB 2:139 n. 16, 245 n. 8, 353 n. 3.

16. In another notebook entry, dated 20 December, Upton had written, “Useless friction, as in the commutators, is much worse in a tension machine quantity machine than in a tension machine Owing to diff % of loss.” He also noted that if a dynamo’s field magnets vary in strength “the friction will be increased to run the machine at a higher rate.” N-78-12-16:121–22, Lab. (TAEM 29:1136–37).

17. That is, if money can be invested at ten percent interest, spending more than $292 to save one horsepower is wasteful. See similar calculations dated 20 December in N-78-12-16:116, Lab. (TAEM 29:1134).

18. Similar sketches that may be related to this one were dated 27 December. N-78-12-16:133, Lab. ( TAEM 29:1142).

19. On 20 December, Upton noted: “Wire brush commutators used to prevent largely vibrations. This could be effected with rod combined with rubber.” N-78-12-16:122, Lab. (TAEM 29:1137).

20. Here and in the preceding and following paragraphs Upton appears to be recording Edison’s thoughts. It is not certain what “carbon” means here, but it may refer to lamps such as are the subject of Docs. 1565 or 1568. In that case, “polarizing” could indicate a surface reaction at the point of contact between the different incandescing substances in the lamp. A “polarizing” phenomenon in arc lights was described in a November article by the English electrician John Sprague (Sprague 1878b).

21. Upton had written “Ex. 13 1000 cells 1000 local action” at the top of the next page. He crossed out the phrase in order to use the page for this paragraph and the one following.

22. Use of the last name of Johann Poggendorff (1796–1877) to indicate a publication in the nineteenth century generally referred, even after his death, to the Annalen der Physik und Chemie, (also known as “Poggendorff’s Annalen”) which he had edited since 1824, while in the twentieth century this generally refers to the Biographisch–Literarische Handwörterbuch zür Geschichte der exakten Wissenschaften, which he began in 1863. Poggendorff’s Annalen was one of the most respected journals in the physical sciences. DSB, s.v. “Poggendorff, Johann Christian.”

23. Chemical effects of light were not identified until the later eighteenth century. The existence of distinguishable heat and chemical rays (i.e. infrared and ultraviolet radiation) beyond the ends of the spectrum of visible light was demonstrated by William Herschel in 1800 and by Page 853 Johann Ritter in 1801, respectively. DSB, s.w. “Herschel, William” and “Ritter, Johann Wilhelm.”

This paragraph and the next one are substantially the same as Upton’s notebook entry dated 28 December. N-78-12-16:162–63, Lab. (TAEM 29:1146).

24. In one of his literature search notebooks Upton noted that Danish chemist and physicist H. P. J. Julius Thomsen had estimated in his 1865 paper “On the Mechanical Equivalent of Light” ( Phil. Mag. 4^th ser. V. 30: 246–49) “that the heat given out... in gas flame [is] 1000 times more than the light” (Literature Search Notebook #2:11, Upton [TAEM 95:403]). Later measurements are in line with the estimate (see e.g. Thompson 1910, 313, 364–65).

25. A related experiment using a soft iron ring is in N-78-12-04.1:36, Lab. (TAEM 29:581).

26. Upton more fully described this phenomenon on 29 December: “When on Bell telephone a motion is given to one diaphragm the other in answering will give a return current when it returns and so an echo as it were, will be made and a humming sound will result.” N-78-12-16:181, Lab. (TAEM 29:1155).

27. Upton noted on 29 December: “In clocks the pendulum will pick up earth currents and thus they will change their rates of movement if their direction is changed.” Earth currents are caused by differences in the electrical potential of the earth. N-78-12-16:181, Lab. (TAEM 29:1155).

28. See Doc. 1641 n. 2.

29. Upton made similar notes of Edison’s remarks about spectroscopy on 29 December. N-78-12-16:184–86, Lab. (TAEM 29:1157–58).

30. On 30 December, Upton again sketched this arrangement and noted “Coil revolved and no current as it ought to be.” N-78-12-16:194, Lab. (TAEM 29:1162).

31. Upton made substantially the same notes in N-78-12-16:196–97, Lab. (TAEM 29:1163).

32. In another, undated entry probably made on 30 December, Upton wrote that “The electromotive force is dependent on the chemical force existing between the substance and its exciting liquid or solid. The current depends on the number of molecules changing condition.” N-78-12-16:197, Lab. (TAEM 29:1163).

33. This refers to a paper by Oliver Heaviside, “On the Extra Current,” concerning electrical oscillations in a wire caused by induction, to which Heaviside attributed the effects observed in “Mr. Edison’s ‘aetheric-force’ experiments.” Heaviside 1876.