1. Charles Mott’s journal provides a detailed record of the variety of work that Edison and his staff performed throughout the late spring and summer to prepare for the commercial manufacture of electric lamps at Menlo Park. Mott Journals N-80-03-14 and N-80-07-10, passim., both Lab. (TAEM 33:683, 37:302; TAED N053, N117); for a discussion of these journals see headnote p. 671.

2. See Doc. 1939 n. 7; Jehl 1937–41, 787.

3. Wilson Howell’s reminiscence, “Howell, Wilson S.,” Pioneers Bio.

4. TAE to Vesey Butler, 28 Aug. 1880, Lbk. 6:354 (TAEM 80:368; TAED LB006354).

5. Mott Journal N-80-07-10:59, N-80-00-05, N-80-00-06, N-80-00-07, all Lab. (TAEM 37:330, 969, 38:2, 39:1064; TAED N117:29, N127, N128, N176).

6. See Mott Journals N-80-03-14 and N-80-07-10, both Lab. (TAEM 33:683, 37:302; TAED N053, N117); Docs. 2002, 2009, 2012, 2027 (see esp. n. 2); and Jehl 1937–41, 614–24.

7. N-80-06-02:21– 33, Mott Journal 80-07-10:21, both Lab. (TAEM 36:405 –11, 37:312; TAED N105:8 –14, N117:10).

8. U.S. Pat. 298, 679.

9. U.S. Pats. 239, 153, 239, 745, and 351, 855.

10. See Doc. 1988.

11. N-80-06-28:37, Mott Journal N-80-07-10:31, both Lab. (TAEM 36:90, 37:317; TAED N102:19, N117:15).

12. U.S. Pat. 239,372; N-80-06-28:39 – 43, N-80-06-02:35 – 37, both Lab. (TAEM 36:91– 93, 412 –13; TAED N102:20 – 22, N105:15 –16).

13. See Doc. 1973.

14. See Docs. 1961 and 1966. Several tools used in making lamps in the laboratory, including a plane, a finishing mould for bamboo fibers, Page 771and cutting dies, are at the Henry Ford Museum and Greenfield Village in Dearborn, Mich. (29.1980.269, 188.36908, 29.1980.270, 29.1980.271, 29.1980.267, MiDbEI[H]).

Staff at Edison’s first lamp factory in an undated photograph, probably taken in summer 1880. The men in the foreground are, from left, Philip Dyer, William Hammer, Francis Upton, and James Bradley.

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15. Work on the clamp-making machine began in May and at least one prototype was ready by late June (see Doc. 1939). On 28 June Charles Batchelor made sketches and notes on a “New clamp making machine” and on 20 July listed fourteen alterations to be made (N-80-06-28:1– 3, Lab. [TAEM 36:72 – 73; TAED N102:1– 2]). Batchelor made drawings related to the clamp machine throughout the summer (N-80-06-28:5 – 17, 23– 33, 67; N-80-06-02:89 – 95, 105 –117; N-80-03-29:265; all Lab. [TAEM 36:74 – 80, 83– 87, 105, 438 – 42, 446 – 52; 33:536; TAED N102: 3– 9, 12 –17, 67; N105:42 – 46, 50 – 56, N051:124]). Mott referred to work on this machine in nearly all of his weekly summaries of “work general” through mid-October (Mott Journal N-80-07-10, passim, Lab. [TAEM 37:302; TAED N117]).

16. See Doc. 1950; N-80-03-19:133, Mott Journal N-80-07-10:25, both Lab. (TAEM 34:671, 37:314; TAED N068:65, N117:12).

17. Albert Herrick sketched on 20 July the pump designed for the factory. The chain broke or caught on at least four occasions in September. On 22 September John Kruesi went to Philadelphia to see about ordering a new machine, and later that week drawings for a new screw pump were taken to a shop there. N-79-08-28:48; Mott Journal N-80-07-10:125, 131, 134 – 35, 137, 141– 42; both Lab. (TAEM 35:1080; 37: 364, 367, 369 – 70, 372 – 73; TAED N088:26; N117:62, 65, 67– 68, 70 – 71); see also Doc. 2010.

18. The mercury was received on 31 July. It was “exceedingly dirty” and was purified throughout the next month by William Hammer, George Hill, and unnamed “boys.” Mott Journal 1880 N-80-07-10:55, 59, 63, 100 –101, Lab. (TAEM 37:329, 331, 333, 352; TAED N117:27, 29, 31, 50). Page 772

19. N-79-07-25:256 – 59, Lab. (TAEM 33:954 – 55; TAED N056: 97– 98).

20. Mott Journal N-80-07-10:15, 80 – 81, 100, 115, 126, 129, 150, Lab. (TAEM 37:309, 342, 352, 359, 365 – 66, 377; TAED N117:7, 40, 50, 57, 63– 64, 75).

21. Mott Journal N-80-07-10:6, 117, Lab. (TAEM 37:305, 360; TAED N117:2, 58); Jehl 1937– 41, 789.

22. See Doc. 1996. Mott Journal N-80-07-10:125, 144 – 45, 149, 152, 161– 62, Lab. (TAEM 37:364, 374, 376, 378, 382 – 83; TAED N117:62, 72, 74, 76, 80 – 81); Jehl 1937– 41, 815. Durability was determined by operating lamps above their designated intensity, usually at 48 candlepower; records of the first two lots of factory lamps are in N-80-09-28, N-80-08-18, N-80-09-27, N-80-10-15.1, and N-80-10-12, all Lab. (TAEM 36:459, 706; 37:445, 646; 39:700; TAED N106, N111, N119, N121, N171).

23. Docs. 2002 n. 4, 2034 and 2061; Mott Journals N-80-07-10:271–83, PN-80-09-23, and PN-81-01-19; all Lab. ( TAEM 37:437– 43, 43:1100 –10, 1115 – 38; TAED N117:136 – 42 NP013:42 – 48, NP014:1–24); Electric Light—Edison Electric Lamp Co—General (D-81-23), DF (TAEM 57:756; TAED D8123).

24. Jehl 1937– 41, 812 –14; see Doc. 1971. The glassblowing department required a large amount of labor. An undated photograph shows William Holzer with thirty-two assistants (most of them young men), all but three of whom are identified in Jehl 1937– 41, 813; an original print of this photograph is in box 97, WJH.

25. See Doc. 2061; Jehl 1937– 41, 813–14.

1. See headnote above.

2. Frank Thomson began working for the Pennsylvania Railroad as a machinist’s apprentice and spent his entire career with that company except for a brief period of government service during the Civil War. Since 1874 he had been general manager of the system east of Pittsburgh. In this capacity he introduced major improvements in the Pennsylvania’s track maintenance and signal system, and planned its distinctively decorated passenger stations. He became president of the railroad in 1897 but died just two years later. DAB, s.v. “Thomson, Frank.”

3. Edison gave instructions on 3 July to “Have lamp put on sprengel Page 774exhausted to high point, and then exhaustion stopped allowing it to burn for 20 hours at 18 candles to ascertain if vacuum falls.” Mott reported that day that “One of the pumps was taken out and the connection between the Springle drop tube and the gauge tube was made longer and crooked (to prevent if possible the up flow of the fall mercury into the gauge tube and lamp).” This was the first of several more general experiments by Francis Upton and Francis Jehl on “testing for leakage or lowering from any cause of the vacuum.” In one of these, described by Mott on 7 July, an evacuated lamp was sealed onto the pump which was itself then sealed off from the fall tube. After a considerable period of operating the lamp “a small bubble of air was let or leaked in and vacuum dropped accordingly, but immediately began to improve again, without working the pump, showing that the air was either absorbed or used up in occidizing the carbon.” N-80-07-02:1; Mott Journal N-80-03-14: 277, 282 – 84; N-80-07-05:4 –11; all Lab. (TAEM 36:604; 33:822, 825 – 26; 36:269 – 72; TAED N108:2; N053:140, 143– 44; N104:4 – 7).

4. This was a redesign of the machine that Charles Dean made in June for cutting wooden loops (see Doc. 1930). It was completed on 9 July and Mott subsequently stated that it worked “very nicely, the knives only requiring a sharper and finer edge.” On 16 July Mott reported that Dean was using the device to cut “the loops of .010 diameter beautifully and calipering evenly all the way around and was preparing the saw for cutting them off when Mr. Edison, admitting the perfection of the machine, directed him to clean it up, take it apart and put away, as at present the fibers were an improvement on the wood and the machine would not be required unless at some future time.” In an uncharacteristic digression Mott noted that the machine was “so complete in all its 226 parts or pieces and so perfect in working that it should deserve a place amongst the archives rather than be destroyed or in all probability carried off piece by piece.” Mott Journal N-80-03-14:287, N-80-07-10:10, 17–18, both Lab. (TAEM 33:827, 37:307, 310 –11; TAED N053:145, N117:5, 8 – 9).

5. David Cunningham was a mechanic and machinist who began working for Edison sometime in the first half of 1879. In 1881 he assisted Charles Batchelor with Edison’s installation at the International Electrical Exhibition in Paris. Jehl 1937– 41, 680, 682; Time Sheets, NjWOE.

6. See Doc. 1939. Mott repeated this information in the next day’s journal entry, the last in which this subject is discussed. Mott Journal N-80-03-14:277, Lab. (TAEM 33:822; TAED N053:140).

7. On 26 July Edison executed a patent application for a large-scale electromagnetic ore separator. Designed on the principle discussed in Doc. 1921, it employed a series of magnets to give diverging trajectories to ferrous and non-ferrous matter in the ore falling from the top of the machine. This application issued in October 1881 as U.S. Pat. 248,432. The notebook entry to which Mott refers was made by John Kruesi and indicated that the separator was to be about 24 feet high and capable of handling 560 pounds of ore per minute. N-79-06-12:200 – 201, Lab. (TAEM 35:577; TAED N080:94).

8. Francis Upton wrote out a handful of experiments and variations to be tried. The platina wires were to be heated in a chamber as it was evacuated and then measured, presumably for changes in length. Other carbons were to be measured before and after being dipped in an unspecifiedPage 775 solution. A lamp was also to be left on a pump with a McLeod gauge and its vacuum periodically noted (see note 3). N-80-06-29:275 – 76, Lab. (TAEM 36:261– 62; TAED N103:139 – 40).

1. Edison did not address this letter but evidently sent it to Keene Valley, N.Y., known as a summertime home of scholars and landscape painters, where Henry Rowland spent much of the summer. Rowland, who had been at Menlo Park in March (see Doc. 1914), may have visited Edison on his way north from Baltimore. WGD, s.v. “Keene Valley”; Rowland to TAE, c. 6 July 1880, DF (TAEM 55:149; TAED D8036ZDI1).Page 776

While a student in 1868 Rowland designed a generator which he expected would run cooler than contemporary machines with long armatures. It employed an induction coil wound longitudinally on a cylinder, much like the design later adopted by Siemens. This revolved around a concentric cylinder wound longitudinally with iron wire. Both cylinders were placed circumferentially between the poles of a magnet, which induced complementary poles in the iron coil. Rowland hypothesized that this arrangement would eliminate the heating in machines where the iron coil revolved around stationary induction wires, which he attributed to the iron’s rapid magnetization and demagnetization. Hathaway 1886, 102; Rowland student notebook, folder 24, box 39, HAR; see also King 1962c, 369 – 74.

Henry Rowland’s September 1868 drawings of his dynamo machine with stationary iron coil; at left is detail of the induction coil winding on the rotating armature.

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2. See Doc. 1851.

3. Rowland replied that he was “Happy to accede to your offer. I have a perfect Siemen’s armature made about 1869, together with other parts of the machine and can prove the date by proper documents. The wire was wound longitudinally and revolved around a stationary iron core. It is about a foot long and three inches diameter”; he subsequently described the field magnets as “long like yours.” Edison drafted a response on the letter instructing Rowland to “send on the mach & we will put it together Prepare the app[licatio]n.” On 18 July Rowland responded that he had sent instructions to Baltimore to have the armature sent to Edison and also indicated that he still had other parts of the machine. In this letter, which included a drawing and description of the armature, Rowland told Edison that “I do not suppose they will give me a patent but you can at least prevent Siemens obtaining one and establish my priority.” Rowland to TAE, c. 6 and 18 July 1880, DF (TAEM 55:149, 142; TAED D8036ZDI1, D8036ZDK).

1. Charles Mott referred to Edison’s entry on the preceding page, dated 3 July, in his journal that same day. Mott did not return to work until 7 July, when he found this “list of applications to be made of the system for power, lighting, & c. both for land and submarine purposes.” Later that day Edison asked Julius Hornig to make working drawings of these devices but they have not been found. Mott Journal N-80-03-14: 277, 280 – 81, 283, Lab. (TAEM 33:822, 824 – 25; TAED N053:140, 142).

2. Mott noted on 7 July that John Kruesi had in his office sketches of “two systems of operating canals by Electricity” but these have not been found. One plan was to have each vessel draw current from conductors alongside the canal for a motor to drive a propeller. The other would use a “track lain along the tow path over which a motor with hand over hand clutch gear travels and by line or otherwise tows the boat or boats.” Mott Journal N-80-03-14:280 – 81, Lab. (TAEM 33:824; TAED N053:142).

3. This is the only extant reference to a rock drill prior to Edison’s statement of its development in Doc. 1957; nothing is known of the tamper.

4. The New York Herald reported that Edison built a “captive machine” for making preliminary experiments with heavier-than-air flight (“Ships of the Air,” New York Herald, 3 Aug. 1880, p. 4; for descriptions of other nineteenth-century efforts to build rotary wing flying machines see Liberatore 1998, chap. 2). On or about 7 July several sketches were Page 778made of this device, which consisted of fan blades mounted on a vertical shaft turned by a small electric motor. Charles Batchelor found that a blade of “two ordinary palm leaf fans” revolved at 200 r.p.m. produced a lift of twelve ounces per square foot. On 9 July Edison made a similar drawing of the “Electric Balloon” and that day Batchelor built and tested one with a tin fan wheel but found that it could not raise its own weight. Work continued intermittently on this device another ten days. Batchelor put in a more powerful motor on 12 July and, according to Mott, “the wheel revolved with fearful rapidity all standing well back expecting to see the wheel fly to pieces by centrifugal force”; it produced four ounces of lift. The next day he tried an arrangement of palm leaves which produced seventeen ounces of lift and “will give a fine motion to the air and make a neat and desirable apparatus to combine with electric light systems, for ventilation or keeping air in room in agitation.” An additional experiment was made on 19 July, after which no more were recorded, but Edison stated in the August Herald interview that he hoped to achieve 8,000 revolutions per minute with a three horsepower motor. N-80-06-28:11–17; N-80-07-02:84, 142 – 43, 55; Mott Journal N-80-03-14:287– 88; Mott Journal N-80-07-10:8 – 9, 22; all Lab. (TAEM 36:77– 80, 615, 624, 614; 33:827– 28; 37:306, 313; TAED N102:6 – 9; N108:13, 22, 12; N053:145 – 46; N117:4, 11).

Edison’s captive balloon.

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At the end of November Edison received an inquiry from an engineer wondering if he intended to pursue his earlier investigations. Edison wrote a draft reply on the letter stating that he had “tried some experiments in the aerial navigation line & did intend to take the matter up but have been so attacked for my criminal efforts to devise a subdivided electric light I have given it up.” TAE marginalia on John Mackenzie to TAE, 22 Nov. 1880, DF (TAEM 53:333; TAED D8006Z).

5. See Edison’s U.S. Patent 248,435, which he executed on 11 August but did not file until October; it issued a year after being filed.

6. Edison made several sketches of this latter plan on 21 July. N-80-07-02:123, Lab. (TAEM 36:619; TAED N108:17).

Edison’s drawing of an electric locomotive for towing barges.

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7. Two months earlier Edison had conceived of another experimental project employing a high-speed electric motor: a “little Electromotor carrier that will run on a track in pipe track being composed of leafs for messenger service to take place of the telephone Central system. The Idea being to have a Central station with pipes leading to Customers 10 of Customers on a single line have permutation pins So a message put in a motor will be thrown out at the right customer.” Edison did nothing with this idea until 29 June when, according to Mott, he began “seriously discussing the putting of it in practical operation for six or eight Page 779miles as an experiment.” Two days later he instructed Hornig “to devise and make diagram of a motor geared expressly for speed and as light as practicable to be capable of 200 miles per hour for messenger.” During that week carpenters were at work on the superstructure for a test track but there is no record of the project after 3 July. N-79-06-12:119 –120; Mott Journal N-80-03-14:266 – 67, 272, 278 – 79; both Lab. (TAEM 35:540 – 41; 33:817, 820, 823; TAED N080:57– 58; N053:135, 138, 141).

Edison’s 6 May drawing of the “electromotor” messenger device.

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8. Edison devised one such mechanical arrangement in early August (see Doc. 1967 esp. n. 3).

1. This is one of the first extant references to experiments with bamboo lamp filaments. Lamp 1248 was made with a bamboo filament the previous day but it broke before testing. Lamp 1253 produced a cold resistance of 188 ohms and the equivalent of 8.6 lamps per horsepower. N-80-07-05:25, 28; Mott Journal 80-07-10:3, both Lab. (TAEM 36:279, 281; 37:303; TAED N104:14, 16; N117:1).

Edison’s impetus for trying bamboo is not certain. Charles Mott wrote in his journal on 7 July that “A collection of Bamboo Recd and choice Bast have been obtained and some loops cut out but none yet put in the lamps to test” (Mott Journal N-80-03-14:282, Lab. [TAEM 33:825; TAED N053:143]). Francis Jehl (1937– 41, 614 –15) recalled that:

We always had . . . palm leaf fans lying about on the tables upstairs; these fans were often used in the course of experiments, especially when we desired to evaporate some liquid in a shallow glass plate or dry some mixture. It thus happened sometime towards the latter part of April or May that Edison noticed, while doing some microscopic work with a filament of carbon, that one of these fans was lying near his instrument. In his stooping position he noticed that a part of the binding rim of the fan was detached and was away from the fan leaf. He received the impulse to take the fan up and examine the rim: on closer examination it was found to be made from some sort of cane. He cut a piece of it, planed it and put it under his microscope: its structural characteristics were the most ideal thus far obtained. Batchelor was called to prepare a few raw filaments from the rim of the fan and carbonize them. The results were that Edison was satisfied that he now had a better carbon than that produced from the paper cardboard.

2. This may be the lamp which Mott indicated this day was tested at 483 ohms cold, 300 ohms hot, and produced the equivalent of 9.6 lamps per horsepower. Mott Journal N-80-07-10:3, Lab. (TAEM 37:303; TAED N117:1).

3. The page that begins with this lamp record is marked to indicate that it was later entered as an exhibit for Edison in a patent interference, Edison v. Maxim v. Swan.

4. This lamp broke before it could be tested. N-80-07-05:30, Lab. (TAEM 36:282; TAED N104:17).

1. Bouverie expressed his wish that Edison might accept the company’s offer (see Doc. 1933 n. 6) but particularly asked him “not to decide, or to commit yourself to any absolute course , respecting the reversionary interest you have in the Edison Company, until you have seen Mr. Johnson.” The same day, Johnson wrote Edison asking him to comply “with Bouveries request ‘that you do nothing to alter the present status until the companys representative (ie me) has had the opportunity to personally present their case to you.’= I am in honour bound to use Every effort to induce you to withhold your signature from the Trust Deed of Gourauds until the Company has had an opportunity of stating their Case.” He went on to indicate his approval of the trust arrangement, which he hoped Edison would eventually adopt. Johnson did not immediately return to the United States, however, but accepted a leave of absence from the company from 1 July until the expiration of his contract two weeks later and took a vacation to the Continent. Bouverie to TAE, 1 July 1880; Johnson to TAE, 1 and 20 July 1880; all DF (TAEM 56:715, 707, 752; TAED D8049ZFK, D8049ZFJ, D8049ZGC).

2. Gouraud had sailed for New York on 3 July and visited Menlo Park on the date of this draft. Gouraud to TAE, 29 June 1880, DF (TAEM 55:737; TAED D8046ZBK); Mott Journal N-80-07-10:18, Lab. (TAEM 37:311; TAED N117:9).

3. Edison executed on this day the agreement designating Alfred Renshaw the trustee for his reversionary interest in the London telephone company. He subsequently arranged with Gouraud that the two of them would “together hold not less than the necessary two-thirds” interest needed to control the trust. Agreement with Renshaw, 16 July 1880; Agreement with Gouraud, 29 July 1880; both DF (TAEM 56:728, 755; TAED D8049ZFU1, D8049ZGE).

4. Two weeks later Edison and Gouraud jointly authorized Renshaw to accept in full payment of the reversion interest £20,000 in United company shares or “any larger amount if you find it possible to obtain it.” TAE and Gouraud to Renshaw, 29 July 1880, Lbk. 6:243 (TAEM 80:330; TAED LB006243).

1. This entry was dated 16 July (Friday) but was continued to the following Monday, 19 July.

2. The anticipated electrical load determined the number of wires in each line. Wires were dropped from the strand at intervals away from the generating station as the current decreased.

3. Francis Upton made his notes and calculations on this day’s tests in another book, from which this table is derived. The first column indicates resistance “wire to wire”; the other two give the resistance to the ground for each leg of the circuit, in this row the 25-wire Carman cable. There were several standard procedures for determining the resistance of cable insulation but how Upton conducted these tests is not known. In each instance he divided the measured resistance (such as 2800 ohms) by 200, presumably to compensate for a galvanometer shunt. From this he deducted the resistance of the “conducting wires from galvanometer” (6.3 ohms apiece). Upton erred in copying numbers to this row from his notes, in which he calculated the resistance to ground at 4.2 ohms where he measured 2100 ohms, and 8.2 ohms to ground where he measured 2900 ohms. N-80-06-29:145 – 55, Mott Journal N-80-07-10:16, both Lab. (TAEM 36:197– 202, 37:310; TAED N103:74 – 79, N117:8).

4. Upton remarked in the other notebook that “The weather has been raining for two weeks and the ground is thoroughly wet.” On 15 July Charles Mott had recorded in his journal that “The gang that have been at work on laying the conductors to the Street lamps since May 1, got Page 784them all down to day, but there is still a large amount of it to tar, cover and fill trenches. This job has taken Two & one half months—with an average I should judge of six men on the work” (N-80-06-29:155, Mott Journal N-80-07-10:14, both Lab. [TAEM 36:202, 37:309; TAED N103:79, N117:7]). After recording the disappointing results of the day’s first tests, Mott commented:

It will be seen that some of the circuits are very badly insulated and all more or less defective. Men have been set at work uncovering parts of the trench of 25 wire circuit and removing the dirt from around the lamp posts. after the boxes had been raised out of the ground at low wet points it was retested but with same results. It seems a little strange that unexperienced men should be permitted to put down nearly five miles of wire and cover it without being required to test a single circuit or wire until the entire work is finished, and it will now require considerable extra labor and delay in putting the circuits in working order. [Mott Journal N-80-07-10: 16 –17, Lab. (TAEM 37:310; TAED N117:8)]

5. Upton obtained similar results from three more tests on Carman’s line that afternoon. N-80-06-29:159, 165, Lab. (TAEM 36:204, 207; TAED N103:81, 84).

6. Mott reported on 17 July that workers spent much of the day removing soil from around the lamp posts and junction boxes “but late this after noon when tested by Mr Upton no improvement or change was found to have been effected, and Mr [Wilson] Howell to whom this work had been entrusted seems ready and more than willing to take advice, and listen to suggestions that if taken in time might have saved him the annoyance of having made a partial failure, and would surely have saved Mr. Edison the extra expense of redoing this work.” Mott Journal N-80-07-10:20 – 21, Lab. (TAEM 37:312; TAED N117:10).

7. Acting on the suspicion reported by Mott that the problems were partly attributable to the tar, Upton tested a bucket of it on Monday (19 July) but found the resistance “extremely high and could not easily measure” it. That day the exposed kerite wires on Carman’s line were “overlaid with rubber tape (‘piping’) and served with coal tar, then left exposed to the sun to harden” (Mott Journal N-80-07-10:23; N-80-06-29:183; N-80-07-16:7–15; all Lab. [TAEM 37:313, 36:216, 38:489 – 93; TAED N117:11, N103:93, N137:4 – 8]). Further experiments with tar and tar paper for insulating the electric railroad took place concurrently for several weeks (N-80-07-16:17– 53, 57– 79; Mott Journal N-80-07-10:16 – 34 passim; both Lab. [TAEM 38:491– 510, 513– 524; 37:310 –19; TAED N137:9 – 27, 29 – 40; N117:8 –17]; see also Doc. 1961).

1. Porter’s letter has not been found. It may have been prompted by Charles Clarke’s 16 July inspection trip to Philadelphia to see Edison’s engine under construction. Mott Journal N-80-07-10:18, Lab. (TAEM 37:311; TAED N117:9).

2. Clarke wrote to Porter the same day that this engine “is intended for the operation of a division of a railroad and not for electric lighting. The load to which it will be subjected will be very variable, resembling the duty of a rolling mill engine or working crushing machines; only the work in our case will be applied even more suddenly (instantaneously) and will vary with every variation in resistance on the line due to grades and curves &c.” Clarke also requested information about the relative economy and first cost of adapting a compound engine to this application. Edison sent Porter the patterns for the dynamo on 6 August. He asked to “have it cast in your foundry and planed to measurement. . . . It is desirable that the Iron is as soft as can be used to make a good casting,” presumably to avoid the magnetic retardation of the armature referred to in Doc. 1889. The engine was never built. Clarke to Porter, 20 July 1880; TAE to Porter, 6 Aug. 1880; Lbk. 6:219, 264 (TAEM 80:322, 336; TAED LB006219, LB006264).

1. Stockton Griffin prepared the letter based on this corrected draft on this date, and copied it into Edison’s letterbook. Edison instructed Griffin on the draft to address the envelope to “W. H. Patton Supt Union Consolidated, Virginia City Nevada.” Lbk. 6:222 (TAEM 80:324; TAED LB006222).

2. This letter answers Patton’s 7 July response to Doc. 1949. Patton explained that miners were “rapidly approaching a vertical depth in the Comstock Mines of 3000 feet—beyond which point it will be difficult to carry the necessary power to drive our pumps and do our hoisting.” He stated that compressed air and hydraulic power had been rejected as too inefficient but “Electricity generated by Dynamo-Electric machines would seem to be most likely to fill the bill—provided you can accomplish what you claim.” He added that an electric power system could only be tested by actual use in a mine and “If your company is disposed to take any steps towards such a test—the companies which I represent will do all in their power to assist— should you feel disposed to entertain any thing of the kind please send me a description of the machines necessary to use and any information you may give regarding them—and the matter will receive immediate attention at my hands.” Patton to TAE, 7 July 1880, DF (TAEM 54:399; TAED D8032R1).

3. Edison referred to a rock drill in Doc. 1952 but there are no extant Page 787records of work on such a machine before 25 July. On that day Charles Batchelor made notes on the “characteristics of a rock drill,” particularly its reciprocating action, and drew several forms of drills. Some would be driven through pulleys or gears and cams but according to Charles Mott, one driven directly by the armature shaft would be “capable of being run at 2000 or 3000 revolutions per minute and with lateral stroke of probably one half inch imparted to it by a lifting cam, and having a short stroke is capable of acting rapidly, and incessantly pecks rather than striking heavy blows.” A few days later Batchelor made another set of brief notes, after which there is no surviving evidence of this project. N-80-06-28:47– 59, 65; Mott Journal 80-07-10:39; both Lab. (TAEM 36:95 –101, 104; 37:321; TAED N102:24 – 30, 33; N117:19).

One of Charles Batchelor’s 25 July sketches of a direct-driven electric rock drill.

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1. About this time Edison requested the firm of Babcock & Wilcox to restate its April estimate for 1200 horsepower “Boilers with and without Economisers,” the original figures having been lost. On or about 13 July Francis Upton made a brief estimate, principally of operating costs, for a 600-light central station; also cf. Doc. 1897. TAE to Babcock & Wilcox, undated, DF (TAEM 53:812; TAED D8020ZGJ); N-80-06-29:117, Lab. (TAEM 36:183; TAED N103:60).

2. The consumption of one gas jet was assumed to be 9,000 cubic feet per year (see Doc. 1897). This calculation gives the number of “M” units produced by a 1250-horsepower central station, at six lights per horsepower. The two sets of logarithmic computations below, including the line “$1.85 at consumers,” are taken from the facing page.

3. The logarithm of 406,000 is 5.6085. The correct depreciation is 6.0 cents per M.

4. In this operation Upton used logarithms to divide the daily labor cost (1300 cents) by the 187.5 M units of electricity consumed in five hours.

5. In the calculation below Upton assumed that the engine would consume three pounds of coal per horsepower hour and that each lamp would operate an average of five hours per day. In the last step he used the logarithmic shortcut explained in Doc. 1795 n. 4.

1. Husbands enclosed the statement of his account with this letter (DF [TAEM 55:869; TAED D8047ZBC]). Two weeks earlier he remitted Page 793$1,000 and on this day paid $3,050.78 for telephones and supplies (Husbands to TAE, 10 July 1880, DF [TAEM 55:862; TAED D8047ZBB]).

2. That is, the customs house.

3. On 17 June William Carman sent Husbands two letters, enclosing with them copies of a series of Edison’s and Sigmund Bergmann’s bills charged to his account. These show small charges for a number of items including washers, screws, fare to New York, and sundry expenses there. Husbands apparently did not receive these until mid-August. Carman to Husbands, both 17 June 1880, with copies of enclosed bills, Lbk.6:100 –109 (TAEM 80:307–11; TAED LB006100, LB006101, LB006102, LB006103, LB006103A, LB006104, LB006104A, LB006105, LB006105A, LB006106, LB006106A, LB006107, LB006108, LB006109); Husbands to TAE, 14 Aug. 1880, DF (TAEM 55:872; TAED D8047ZBF).

4. Husbands wrote on 21 May that another party had submitted an application for the government license for Edison’s lighting system. He protested that “you promised me the handling of it, provided I was successful with the Telephone. . . . This is all right, but for the fact, That I might have been spared anoyance and mortification from friends by your simply writing me that I could not have it. Then I would have known where I stood” (Husbands to TAE, 21 May 1880, DF [TAEM 55:855; TAED D8047ZAY]). Edison also received a report from Fabbri & Chauncey that their agent in Valparaiso had made this application and was afterward visited by Husbands, who claimed to have Edison’s authority for the light. Edison wrote to Husbands that it was

unfortunate that you so misunderstood matters. I told you before you left Menlo Park that I had already made contracts to parties and disposed of the whole of South America on the light. What I intended to do was (provided you were successful with the Telephone) to arrange it with the parties who hold the contracts to take care of you so that you could introduce it and have the science part of the exploitation. This I fully intended doing. I will consider it a special favor if you will just let matters take their course as I intended from the first that they should. [TAE to Husbands, 16 July 1880, Lbk. 6:184 (TAEM 80:318; TAED LB006184)]

The license was eventually awarded to Edward Kendall, who was Fabbri & Chauncey’s representative; nothing more is known of him (Sherburne Eaton to TAE, 20 Nov. 1882, DF [TAEM 62:192; TAED D8237ZAJ]).

5. Husbands enclosed with that letter the declaration by the president of Chile granting Edison an exclusive eight-year licence for telephones. He explained that this privilege would begin in April 1881; a week later he cabled that the term was for ten years. On 29 April Husbands and his associates “celebrated by connecting the offices in Santiago & Valparaiso & talked successfully over a line 180 miles long.” This was apparently the only long-distance line that Husbands constructed. President of the Republic of Chile to TAE, 26 Apr. 1880; Husbands to TAE, 1 and 6 May 1880; all DF (TAEM 55:843– 44, 846; TAED D8047ZAP1, D8047ZAP, D8047ZAR); Berthold 1924, 37– 38.Page 794

6. Husbands was backed financially by W. H. Brown, a New York metals dealer. See Doc. 1823 n. 7.

7. Cf. Doc. 1823.

8. See Doc. 2031 n. 2.

9. W. J. Clark, who replaced Walter Morgan (see Doc. 1886 n. 2). This was apparently against Edison’s recommendation but nothing more is known of Clark. Husbands to TAE, 10 July 1880, DF (TAEM 55:862; TAED D8047ZBB).

10. The enclosure from Husbands has not been found. Two weeks earlier he had written that “The steamer ‘Columbia’ created a sensation here, all parts working good here. In the next steamer I will ask for proposals to do the same thing in the coast company here.” The New York Herald reported at the end the month that the Columbia’s lights worked well all the way to Portland (but see Doc. 1976 n. 3). Husbands to TAE, 10 July 1880, DF (TAEM 55:862; TAED D8047ZBB); “Electric Light on Steamships,” New York Herald, 30 July 1880, Cat. 1241, item 1518, Batchelor (TAEM 94:610; TAED MBSB21518X).

11. As recently as mid-May Husbands believed it would be easy to devise a better way of properly moistening the receiver chalks but had concluded that “the crank movement is an nuisance one can not read off or receive & write at the same time—& must be done away with.” Husbands to TAE, 15 May 1880, DF (TAEM 55:850; TAED D8047ZAU).

1. Polyform was Edison’s name for a topical analgesic compound he devised in 1878 whose ingredients included alcohol, chloroform, ether, and morphine (see Doc. 1287). His application for a U.S. patent was unsuccessful but in August 1880 a London agent filed the final British specification on his behalf (Serial No. 2,206, 8 Sept. 1880, “Medicinal Preparation” in Abstract of Edison’s Abandoned Applications (1876 – 1885), p. 12, PS [TAEM 8:539; TAED PT004 (image 13)]; Brit. Pat. 599 [1880], Batchelor [TAEM 92:155; TAED MBP024]).

2. The term neuralgia historically applied to intermittent acute pains, particularly in the face and head. By this time, however, its Englishlanguage use had greatly expanded to encompass a variety of pains for which no direct physical cause could be found, including some arising from internal organs and those now attributed to overly strenuous or repetitive muscle exertion. Alam and Merskey 1994, 429 – 58.

3. Moore had cabled from Glasgow on 15 July: “Can I acquire your polyform rights for this country if so write terms” (DF [TAEM 53:181; TAED D8004ZDU]). Stockton Griffin noted on Moore’s letter that Edison replied on 9 August.

4. Edison instructed Lemuel Serrell in September 1879 to assign his U.S. rights to Charles Lewis and several partners, and in April told one correspondent that he had done so in order “to rid myself of the awful amount of correspondence & trouble which the newspaper publications caused I have no interest in it.” Lewis and his associates organized the Menlo Park Manufacturing Co. in New York in 1879. It promoted “Edison’s Polyform” as a treatment for neuralgia, rheumatism, and headaches, among other things, although Edison told another correspondent in 1880 that “The medicine is improperly advertised to cure Rheumatism but it will relieve facial neuralgia” (TAE to Serrell, 3 Sept. 1879, Lbk. 5:129 [TAEM 80:143; TAED LB005129]; marginalia on G. H. Kent to TAE, 16 Apr. 1880; marginalia on H. C. Guck to TAE, 29 June 1880; [TAEM 53:149, 175; TAED D8004ZCS, D8004ZDR]; Menlo Park Mfg. Co. label and advertisements in PPC [TAEM 96:596; TAED CA016A]). The company subsequently relocated to Boston and in 1884, with the U.S. application still pending, asked Edison’s permission to obtain Page 796 a copyright registration on its labels featuring his autograph and portrait. Edison refused (Menlo Park Mfg. Co. to TAE, 15 June 1883, 26 June and 25 Sept. 1884; all DF [TAEM 64:209; 71:185, 277; TAED D8303ZDW, D8403ZEC, D8403ZGZ]; TAE to Menlo Park Mfg. Co., 2 Oct. 1884, Lbk. 19:291 [TAEM 82:909; TAED LB019291B]). The firm was apparently never profitable and in 1890 Lewis offered him a controlling interest in the stock of a new company called the Edison Polyform Co., but Edison instructed his secretary to “Write Lewis that if any further attempts are made to bring the polyform out that I shall knock it in the head” (Lewis to TAE with TAE marginalia, 4 Oct. 1890, DF [TAEM 128:701; TAED D9004AER]).

5. Edison received a cable via New York from Moore in London dated 5 August (Thursday) stating that the “Glasgow company in paying additional five and accepting London terms lose about 2000 will you abate what may be required up to this so we make no loss.” In a letter the same day Moore proposed that the company should withhold enough from the £5,000 advance royalty still outstanding to recover their loss. Edison drafted a reply on Moore’s cable that he would “do as Gouraud says.” George Gouraud was still in the United States. Moore to TAE, both 5 Aug. 1880; TAE to Moore, 6 Aug. 1880; all DF (TAEM 56:762, 759; TAED D8049ZGI, D8049ZGH, D8049ZGI1).

1. This article was a follow-up to one in the New York Herald the day before, in which Edison reportedly claimed that applying his “electric engine” to the New York elevated trains would save $500,000 annually in direct costs. The later article, after noting that the company’s directors “would say nothing of importance, one way or the other, about the matter,” presented cautiously optimistic comments attributed to operating department officials. “The Electric Motor,” New York Herald, 24 July 1880, p. 3; a typed transcript of this article and typed extracts from the Herald’s 23 July article on “Electric Locomotion” are in Cat. 2174, Scraps. (TAEM 89:283, 279; TAED SB012:34, SB012AAS).

2. David Hickman worked on his uncle’s farm in nearby Metuchen before he applied to Edison for a job in 1880. Preparing the underground conductors was his first task at the laboratory. Hickman subsequently superintended the Pump Department of the Menlo Park lamp factory and remained associated with Edison until 1891. “Hickman, David Kelsey,” Pioneers Bio.

3. Six days later this line was wrapped with tarred twine. Francis Upton tested the insulation, finding 1,400 ohms resistance to ground and

4,000 between the wires. Insulation of this and the other lines continued until 28 August, when Charles Mott reported that Edison suspended the work. Insulation tests were conducted at intervals both on these lines and in the laboratory until September. Mott Journal N-80-07-10:52, 55, 81, 105; N-80-07-16:47– 51, 71– 76, 79 –101; N-80-07-05:72 – 75; all Lab. (TAEM 37:328 – 39, 342, 354; 38:508 –10, 520 – 33; 36:303– 04; Page 798 TAED N117:26 – 27, 40, 52; N137:24 – 26, 36 – 49; N104:38 – 39); see also Doc. 1985.

Chamber for passing a hydrocarbon atmosphere around a heated carbon.

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4. Mott reported on 20 July that Charles Dean was “making a pair of formers for cutting out fibers each one is designed only to cut one side or edge and intended to be secured to the bench and drawn and held together by a treadle leaving the operator both hands to adjust and use in cutting.” On 3 August Dean completed and tested one pair; Mott noted that they produced fibers of uniform dimensions and “are very convenient effective and work satisfactorily.” He noted in weekly summaries of work that Dean continued to work on the instrument and on 1 September one was sent to the lamp factory, “made very heavy to avoid all danger of springing and tempered to prevent scarrification by knife or hammer.” Mott Journal N-80-07-10:26, 61, 68, 93, 105, 108, Lab. (TAEM 37:315, 332, 336, 348, 354, 356; TAED N117:13, 30, 34, 46, 52, 54).

5. Two days later an arrangement in which the filament ends were secured was again tried. On 28 July Edison executed a patent application covering several similar devices to keep the filament “under strain during carbonization, with one or more points fixed against moving, and the contraction proceeds against the strain, which constantly keeps the filament against or in contact with a former, preserving its shape and obviating any risk of warping or twisting.” Such a device was particularly important with bamboo filaments, which shrank about 20% during carbonization. Mott Journal N-80-07-10:41, Lab. (TAEM 37:322; TAED N117:20); U.S. Pat. 263,139.

6. This is the first of a number of experiments in which filaments were heated in the presence of volatile hydrocarbons, particularly kerosene and gasoline, although paraffin, bituminous coal, and other substances were tried. The object seems to have been to deposit a uniform coating of carbon on the filament. In one series of tests, however, Batchelor deposited the carbon on thin platinum wires which he then instructed Alfred Haid to dissolve, leaving a narrow tubular conductor (see Doc. 2007 n. 1). Some hydrocarbons were placed in the carbonizing mould with the fiber but in most cases a carbonized filament was electrically heated in a chamber filled with a hydrocarbon. Mott recorded related experiments through the end of July and a number of lamps were made with carbons treated in this way before the experiments were suspended. Edison later returned to the subject but heating lamp filaments in a hydrocarbon atmosphere (called “flashing”) became an important manufacturing process for his competitors. N-80-03-06:181– 93; N-80-06-02:8 – 15; N-80-07-23:281; Mott Journal N-80-07-10:39 – 41, 44 – 45, 50 – 52, 54 – 55, 57; all Lab. (TAEM 33:1050 – 56; 36:401– 04, 981; 37:321– 22, 324, 327– 30; TAED N057:90 – 96; N105:4 – 7; N112:140; N117:19 – 20, 22, 25 – 28); Howell and Schroeder 1927, 79 – 81.

7. Beginning on 21 July Charles Clarke made numerous drawings and calculations pertaining to power transmission in the locomotive, especially reduction gearing and clutches for the wheels and modifications to the “climbers” for steep grades (see note 8). He did most of this work before the end of the month but continued it intermittently through mid- August. N-80-07-19:15 – 35, 45 –135, Lab. (TAEM 37:113– 25, 130 – 75; TAED N115:8 –18, 23– 68).

8. On June 15 Mott described Julius Hornig’s design for “a novel gear Page 799for attachment in front of motor to climb steep grades, its motion and action is very similar to hand over hand climbing, being composed of arms and clutches which grapple the rails one of each [side?] and by a cam movement the clutch is released arm raised up and extended, dropped down on and again clutched on the rail, the arms acting alternately.” Mott reported at intervals the progress of laboratory assistants in constructing and installing this equipment, which is described more fully in Doc. 1987. Mott Journal N-80-03-14:236, 249, 257, 263; Mott Journal N-80-07-10:4, 21, 30, 33; both Lab. ( TAEM 33:802, 808, 812, 815; 37:304, 312, 317–18; TAED N053:120, 126, 130, 133; N117:2, 10, 15 –16).

1. See Doc. 1878.

2. Biedermann had cabled in April that he needed to know the “name of each particular apparatus and when machines will arrive.” Edison replied that the “System consists Electric Generators, Electric pressure regulator, Electric meter, Lamp and System laying wires, also Electromotor for power; will cable when shipped, will send copies patent papers” (Biedermann to TAE, 26 Apr. 1880; TAE to Biedermann, 27 Apr. 1880; both DF [TAEM 54:232, 233; TAED D8026ZBN, D8026ZBO]). Biedermann then arranged for trademark protection on the condition of having sample apparatus by 1 June and suggested that drawings might be acceptable if the machines could not arrive in time. Edison cabled on 11 May that he was still “working on samples fear not reach in time have mailed papers.” He shipped the devices two weeks later (Biedermann to TAE, 4 May 1880; TAE to Biedermann, 11 and 25 May 1880; all DF [TAEM 54:236, 239, 246; TAED D8026ZBP, D8026ZBT, D8026ZCA]).

3. When Biedermann cabled that the generator and meter had arrived and asked what speed he should run the generator, Edison replied that the “Generator sent only small sample Lamps you have not suitable this size will send you lamps suitable.” Biedermann to TAE, 22 June 1880; TAE to Biedermann, 24 June 1880; both DF ( TAEM 54:251, 252; TAED D8026ZCE, D8026ZCF).

4. J. C. Young was connected with the Adams Express Co. in New York and acted as Biedermann’s intermediary. On 12 July Edison wired him that “Biederman has all necessary appliances except another lot lamps which I am making.” TAE to Young, 12 July 1880; letterhead of Young to TAE, 24 May 1880; both DF (TAEM 54:255, 245; TAED D8026ZCJ, D8026ZBZ).

5. A. M. Cherbuliez identified himself as a commercial arbitrator. Agreement between Biedermann, Cherbuliez, Gaspard Zürlinden, et al., 8 Sept. 1880, Miller (TAEM 86:278; TAED HM800128).

6. Gaspard Zürlinden identified himself as a lawyer. Agreement between Biedermann, A. M. Cherbuliez, Zürlinden, et al., 8 Sept. 1880, Miller (TAEM 86:278; TAED HM800128).

7. The 8 September agreement between Biedermann, Cherbuliez, and Zürlinden refers to their intention to set up a manufactory for the elements of the lighting system “with the single exception of those machines whose manufacture they will turn over to the ‘Societé Genevoise pour la construction des Instruments Physique à Genève’” (Agreement between Biedermann, Cherbuliez, Zürlinden, et al., 8 Sept. 1880, Miller [ TAEM 86:278; TAED HM800128]). According to their 9 September 1880 agreement with Edison, Biedermann, Cherbuliez, and Zürlinden had arranged that this company would not manufacture similar instruments for anyone else (DF [TAEM 54:267; TAED D8026ZCR]).

8. On 14 August, two days after having visited Menlo Park, Young wrote Edison that he had “cabled Biedermann your acceptance of his proposal” and received an acknowledgment. Young to TAE, 14 Aug. 1880, DF ( TAEM 54:264; TAED D8026ZCO); see also Doc. 1985 n. 4.

1. See Doc. 1766.

2. On 21 July Pitt Edison wrote that having Edison’s proxy statement for his stock in the Port Huron Railway “would make me more secure in my position” at a future shareholders meeting. The next week William Wastell endorsed the idea of having Pitt formally represent Edison, promising that he and Pitt would cooperate in “the best interests of the road.” In reply Edison asked “how many shares I have got. you have 126. do we not controll if so let us at the next election put our own people in (Pitt Edison to TAE, 21 July 1880; Wastell to TAE, 28 July 1880; TAE to Wastell, 31 July 1880; all DF [TAEM 55:349, 351, 353; TAED D8040A, D8040C, D8040D]). However, nothing seems to have happened with this plan or towards paying off the mortgage. John Sanborn reported in December that he had declined Pitt’s offer to sell him Edison’s shares but had offered to trade stock in a narrow gauge line. The following November Pitt was still trying to secure a controlling interest in the company and suggested to Edison that “the way to catch these fellows is to be ready when they are sick as they have spells” (Sanborn to TAE, 21 Dec. 1880; Pitt Edison to TAE, 20 Nov. 1881; both DF [TAEM 55:355, 57:541; TAED D8040F, D8114F]).

3. At the end of August Pitt wrote that the railroad was “doing a good business” and promised that he would send reports the next week, but these have not been found. Pitt Edison to TAE, 30 Aug. 1880, DF ( TAEM 53:541; TAED D8015H).

1. William Carman dated this letter 31 July when he copied it into Edison’s letterbook. Lbk. 6:250 ( TAEM 80:332; TAED LB006250).

2. On 25 July Rowland wrote from Keene Valley “that you request me in your letter to make out an application for a patent but I have not the slightest idea how to do it as I never had anything to do with patents. There is nobody up here to consult on the matter and so I must ask you to advise me on the matter.” It is not clear to which letter Rowland was referring but see Doc. 1951 n. 3. Rowland to TAE, 25 July 1880, DF ( TAEM 55:144; TAED D8036ZDL).

3. On 1 August Rowland explained to Daniel Coit Gilman, president of Johns Hopkins University, that he did “not expect to succeed in getting a patent but may at least defeat Siemens and establish my claim to have invented the machine first. If I get the patent I may be able to build my own laboratory.” Rowland to Gilman, 1 Aug. 1880, DCG.

In late August Edison wrote to Rowland in Baltimore asking if he had received this letter because “We are ready to go ahead with the patent and are waiting for the necessary papers.” Rowland replied from Boston that he would soon gather all the remaining materials in Newark and bring them to Menlo Park, which he did on 6 September. Samuel Mott completed the patent drawings by 11 September. TAE to Rowland, 24 Aug. 1880, Lbk. 6:334 (TAEM 80:364; TAED LB006334); Rowland to TAE, 30 Aug. 1880, DF (TAEM 55:161; TAED D8036ZDX); Mott Journal N-80-07-10:116, 127, Lab. (TAEM 37:360, 365; TAED N117: 58, 63).

1. The following day Upton noted that this lamp had a “good carbon” and a resistance of 141.5 ohms. It was put on in the photometer room downstairs for twenty minutes and gave a light of 48 candles (N-80-07-23:151– 53, Lab. [TAEM 36:915 –16; TAED N112:75 – 76]). About this time a standard method of photometry was established at the Menlo Park laboratory. Each lamp was placed in a Bunsen photometer and measured against a spermaceti candle used for the British standard. The voltage and current required by the lamp were measured at the same time (Howell and Schroeder 1927, 193– 95; Jehl 1937– 41, 960 – 62).

2. The following day this was 68”. This probably represents the distance of the lamp from the standard candle on the bar of a horizontal photometer (Dibdin 1889, 16 –17, 29 – 30).

3. The purpose of this operation and the one adjacent are unclear.

4. Upton used similar calculations to determine the resistance of other lamps about this time. Those trials were made with a calorimeter and galvanometer, and the smaller of the quantities in the addition appears to represent the weight (in grams) of water. For reasons which are Page 806unclear, Upton divided this sum by 200 to get the resistance in ohms. N-80-07-23:95 –123, Lab. (TAEM 36:888 – 902; TAED N112:47– 61).

5. Charles T. Hughes (ca. 1847–1910) later claimed that he began working at the laboratory on 21 October 1879, the day the first successful carbon-filament lamp was tried. However, his letter of introduction from Horace Eldred is dated 25 October. At the time Hughes was working for the Commercial Telephone Co. of Albany, N.Y., and was being considered for the position of telephone expert in South America. It is not clear when Hughes actually began working at Menlo Park. According to his reminiscences he initially worked on experiments with the electromotograph telephones and also with Patrick Kenney on the autographic telegraph. Hughes’s name does not appear in notebooks related to those experiments and it appears that his main role was that of a buyer obtaining materials for the laboratory. Later, because he had railroad experience Edison had him work on the electric railway experiments. He also assisted with experiments on preserving food in a vacuum. After leaving the laboratory he worked as an agent for the Edison Electric Light Co. and subsequently was associated with General Electric. Eldred to TAE, 25 Oct. 1879; Laura Hughes to TAE, 25 June 1910; both DF (TAEM 52:216, 195:1092; TAED D7939ZAD, D1036); Hughes’s testimony, TI 1:398 – 99 (TAEM 11:176; TAED TI1029); Hughes’s reminiscences, 19 June 1907, Meadowcroft (TAEM 227:125; TAED MM010C); Jehl 1937– 41, 546 – 47.

6. Martin Force.

7. The same night they also bet on lamp 1348 (N-80-07-23:140 [TAEM 36:911; TAED N112:70]). Wilson Howell later recalled that

Life tests of lamps were made in the old days at Menlo Park generally in groups of about 100 lamps arranged on long laboratory tables. The lamps were burned above normal temperature so as to get quick results. These tests generally ran about twenty-four hours, being the occasion for all night work by Mr. Edison and some of his associates. Wagers on the life of individual lamps or upon which one would be the next to fail afforded us mild excitement. [Howell’s reminiscences, p. 2, Pioneers Bio.]

1. This furnace was designed in connection with a nickel mould so that carbonization took place in an atmosphere of hydrocarbon gases to prevent oxygen from affecting the filaments. Earlier in the year, probably in February, laboratory chemist Otto Moses had designed a carbonizing furnace for this purpose (it is pictured in Friedel and Israel 1986 [p. 164]). It is not clear if the Moses furnace was more generally used at the laboratory for carbonizing filaments. The new mould and furnace were designed by Charles Batchelor in late June and early July. According to Charles Mott the mould was a “nickel box of size sufficient in depth to hold 30 slotted plates, the bottom of one serving as a cover or lid for the one beneath, each entire plate in this way requiring about ⅛ of an inch. The plates are only large enough for one loop at a time and the box or mould filled with the plates is designed to be used in a gas furnace which will be devised expressly for the purpose.” The furnace was contracted out and arrived at Menlo Park on 20 July. During the following week the “gas and blast pipes and fixtures” were installed and the furnace was tested on 29 July; the following day another of these was apparently set up in the chemical laboratory. Edison executed a patent for this carbonizing apparatus on 30 July, which subsequently issued as U.S. Patent Page 808248,423 on 18 October 1881. On 3 August the furnace was “connected with blast [and] gas pipes in carbonizing room, the blower did not give sufficient air blast so one of the glass blowers tables and bellows were carried in and the furnace heated. One of the large moulds for 30 carbons was put in and on first trial it was found that the gas had gotten in around the jointed base and formed a sort of tar which held the carbon together. Mr. Batchelor then drilled a small hole in top of mould and used pipe clay around the base or lid and on the second trial with mould thus arranged the carbons came out first class.” The following day Charles Mott noted that “The gas furnace has been in use to day, and with five formers in the mould first class carbons were gotten out safely and the furnace gives perfect satisfaction so far”; it continued to work satisfactorily and was soon installed at the lamp factory. Batchelor continued to experiment with and redesign the furnace over the next several days and on 14 August Edison sent Mott to a firm in Woodbridge, New Jersey, to “order Three Gas furnaces for carbonizing to be made with the square holes for vent in the top of the lid instead of the side and to have two one inch bands one around the lid and one around the furnace.” These arrived on 6 September, bringing to five the total at the factory. N-80-01-28:19 – 20; Mott Journal N-80-03-14:270 – 71, 273, 279; Mott Journal N-80-07-10:26, 38, 49, 54, 58, 62, 64, 69, 81, 115; N-80-06-02:45 – 71; all Lab. (TAEM 33:839 – 40, 819 – 20; 37:315, 321, 326, 329, 331, 333–34, 336, 342, 359; 36:416 – 29; TAED N055:10; N053:137– 38, 141; N117:13, 19, 24, 27, 29, 31– 32, 34, 40, 57; N105:20 – 33).

1. William Carman noted on this draft that he copied the letter and Edison signed it on 9 August, but the letterbook copy made by Carman and signed by Edison is dated 7 August. TAE to Patton, 7 Aug. 1880, Lbk. 6:283 (TAEM 80:348; TAED LB006283).

2. This letter is in answer to Patton’s 27 July response to Doc. 1957. Patton wrote that the air in the shafts 3,000 feet below the surface was between 100 and 130 degrees Fahrenheit and “highly sprayed with moisture—would this affect the insulation and reduce the effectiveness of machines?” (Edison wrote in the margin next to this paragraph: “no we should take precautions.”) He also inquired about four other specific operating conditions: submerging the motor in water; reducing its speed for pumps working at six to twelve strokes per minute; operating under variable loads; and dividing the electric current among motors at several locations. He hoped to use electric motors below 3,000 feet, “conveying the power generated at the surface to the points required in such a way as to loose as little as possible in effectiveness—the power to be reliable and under perfect control— If you can get the 76% you claim and operate the machines under the conditions stated above the system will succeed— should you desire to go further in the matter please answer as soon as convenient.” Patton to TAE, with TAE marginalia, 27 July 1880, DF (TAEM 54:405; TAED D8032U).

3. Edison made two sketches of a “means for getting a slow movement to mechanism” on or about 5 August. In his only references to this apparatus Charles Mott noted that Julius Hornig was working on it on 6 and 9 August (N-80-07-30:18, 52; Mott Journal N-80-07-10:67, 70; both Lab. [TAEM 38:471– 72; 37:335, 337; TAED N135:10 –11; N117: 33, 35]). Edison filed a provisional British specification on 30 September for “Improvements in Dynamo-electric Machines” which included apparatus to reduce the speed of driven machinery “belts or gearing, in whose use there are inherent defects, such as the slip and stretch of belts, the rattle of gear, and so forth.” In this arrangement

The rotary motion of the armature is first converted into an oscillating motion, which is then converted into a continuous rotary motion in the following way:—

Upon the shaft of the armature is a balanced crank pin to which is attached a pitman or driving rod connected to an oscillating frictional pawl mechanism.

Upon the driving shaft is fixed a wheel having a frictional periphery. Loose upon the driving shaft is an arm extending a distance above the rim of the frictional wheel, and then bent over and fashioned into a frame, in which are pivoted two pawls connected together by a frame capable of being shifted, so that only one pawl can take at the time upon the wheel. . . .

The arm carrying the pawls is slotted, and the pitman or driving rod is connected thereto by a pin whose position is adjustable in the Page 813slot, so that the leverage may be adjusted and the speed communicated easily varied.

The arrangement described is used in duplicate; that is, two or more driving rods communicate motion from the armature shaft to as many frictional pawls and driving wheels on the driven shaft, the crank pins being so arranged relatively to each other that a continuous motion is imparted to the driven shaft, and mechanism connected therewith. [Brit. Pat. 3,964 (1880), Batchelor (TAEM 92:212; TAED MBP030)]

British patent specification drawing of Edison’s adjustable pawl mechanism for reducing the speed of the shaft driven by an electric motor.

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The final specification illustrated and particularly described the application of this mechanism to pumps.

On 1 October Edison also filed what was evidently a similar U.S. application (Case 249). It was forfeited and only the claims and drawings, as well as a later summary, are extant. Mott Journal 80-07-10:70 – 71, Lab. (TAEM 37:337; TAED N117:35); Patent Application Casebook E-2536:172; Serial No. 18,421, 1 Oct. 1880, “Motors” in Abstracts of Edison’s Abandoned Applications (1876 –1885), p. 2; both PS (TAEM 45:716, 8:529; TAED PT020172, PT004 [image 3]).

In an undated draft to an unknown correspondent, Edison discussed the general relationship between the dynamo and motor. If the two machines were of the same construction they would turn at nearly the same speed under no load. However,

If the Resistance of the Receiver [motor] is changed it may be made to revolve at 1200 Revolutions while the steam Dynamo is going but 600, and by adding work until it is brought down to a speed of 600 the maximum will be obtained. But the maximum work is not the most economical it is the same as a Steam Engine there is small economy in taking steam to the full stroke & getting the maximum power of the Engine but let it cut off early & we get the most economical work all of which you well know hence; we only work the Receiving Dynamo up to 20 or 25 pc of its capacity. [Undated Notes and Drawings (c.1879 –1881), Lab. (TAEM 45:132; TAED NSUN07:10)]

Edison incorporated this relationship into the 30 September provisional specification, explaining it in terms of the counter electro-motive force developed in the motor.

4. Patton did not address all of these questions but in a subsequent letter he provided some details about the Comstock pumping and hoisting operations and enclosed drawings of a typical shaft, although these have not been found. He expressed particular concern that the hoists should be made to start and stop smoothly, and invited Edison to make a practical demonstration with a single 100 horsepower dynamo. Stockton Griffin informed Patton that Edison had prepared working drawings but preferred not to send them “until his test with the large Dynamo (120 h.p.) is made here which will be in 5 or 6 weeks—from these tests absolute calculations can be made as to cost, while now there is liability of an error of from 3 to 5%” (Patton to TAE, 20 Aug. 1880, DF [TAEM 54:416; TAED D8032W]; Griffin to Patton, 25 Oct. 1880, Lbk. 6:498 [TAEM 80:396; TAED LB006498]). Edison referred the matter to Julius Hornig but took no further action until Patton inquired again in Page 814December 1881, telling him that “the Brush Company are becoming very active on this coast—and have made propositions in regard to the same business.” Edison explained that he could not act because “The trouble as to the transmission of power by electricity is that the demand is so great for machines that our Directors do not feel inclined to send out any machines simply for an experiment at their expense” (TAE marginalia on Patton to TAE, 1 Nov. 1880 and 5 Dec. 1881, DF [TAEM 54: 429, 59:147; TAED D8032Z, D8138ZAJ]; TAE to Patton, 29 Dec. 1881, Lbk. 9:484 [TAEM 81:177; TAED LB009484]).

5. Edison’s intended meaning is unknown, and this phrase was omitted from the completed letter.

1. In June, just before the scheduled visit to Menlo Park of two Metropolitan Elevated railroad officials (see Doc. 1940 n. 3), Lowrey wrote that he wished to explain to Edison a plan for the electric railroad “which will perhaps put us on velvet (as the vulgar say) in respect to the light as well as the railroad.” A short while later he expressed his hope that the unspecified arrangement would “produce a sum of money sufficient to set up an Electric Lighting district in the city of New York” and shortly afterward arranged for José Navarro, a principal investor in the Metropolitan Elevated railroad, to visit Menlo Park. Lowrey to TAE, 9 and 19 June 1880; Zenas Wilber to TAE, 29 June 1880; all DF (TAEM 55: 311, 54:56, 55:134; TAED D8039H, D8023T, D8036ZDD).

On 5 August the New York Herald reported that electrician Stephen Field had received a patent on an electric locomotive intended for San Francisco’s streetcar system but which the inventor hoped to test on New York’s elevated lines. Field had not yet built a prototype and Edison, in a subsequent Herald interview, dismissed the design’s chance of success but Field went on to enjoy a successful career designing and building electric traction systems. “Electric Locomotion,” New York Herald, 5 Aug. 1880; “Field’s Electro-Motor,” ibid., 6 Aug. 1880; “Electric Inventions,” ibid., 10 Aug. 1880; Cat. 1241, items 1514, 1515, and 1519, Batchelor (TAEM 94:608, 610; TAED MBSB21514X, MBSB21515X, MBSB21519X); DAB, s.v. “Field, Stephen Dudley.”

2. In July 1880 the New York Elevated and Metropolitan Elevated companies, joint owners of the Manhattan Elevated railroad which operated all of New York’s elevated railroad lines, began contentious and ultimately unsuccessful merger negotiations. It is also possible that Lowrey was involved in resolving lawsuits, recently sanctioned by the courts, by property owners for damages caused by the elevated lines. Klein 1986, 283– 84.

3. Possibly a reference to Fabbri & Chauncey’s interest in Edison’s South American electric light patents.

4. Doc. 1649.

5. See Doc. 1979.

1. John S. Shapter was chief engineer for the steamboat service of the Central Railroad of New Jersey, which operated ferries to Manhattan from its Jersey City terminal. Calvin Goddard to TAE, 15 July 1880, DF ( TAEM 53:783; TAED D8020ZFO); Condit 1980, 65 – 66, 141– 42, 368.

2. Edison drafted this letter on or about 26 July (DF [TAEM 53: 786; TAED D8020ZFR (images 1– 4)]). Stockton Griffin transcribed it largely unchanged with a date of 26 July and also copied it into Edison’s letterbook; Edison subsequently made extensive emendations on the transcription which, with the exception of one paragraph (see note 7), were incorporated into this document (DF [TAEM 53:790; TAED D8020ZFR (images 5 – 7)]; Lbk. 6:235 [ TAEM 80:325; TAED LB006235]).

3. On 3 August, Thomas Connery wrote to Edison from the New York Herald office that publisher James Gordon Bennett “would like to know if your electric light could be applied successfully for the illumination of his new steam yacht Polynia. If yes, what would be the entire cost of the thing? I wish you would figure it out fully and write me at your earliest convenience.” Edison telegraphed the next day that “It can be applied with great success shall I take the order It will take six or seven weeks.” Connery wired back that he would need to know the expense, to which Edison replied that he assumed Bennett “would like seventy five lights this requires small engine and magneto machine combined. cannot give exact estimate as Engine builder has not sent price Engine but think it would not exceed twenty six hundred dollars, without he wants it extraordinarily fancy.” Connery to TAE, 3 and 5 Aug. 1880; TAE to Connery, 4 and 5 Aug. 1880; all DF (TAEM 53:797, 800, 799; TAED D8020ZFW, D8020ZFY, D8020ZFX, D8020ZFZ).

4. Presumably the cost of producing gas (cf. Doc. 1707 n. 9).

5. Edison’s original 26 July draft (see note 2) presented a difference of Page 818$42.60 “In favor of gas.” The advantage attributed here to electricity is based on a series of revisions made by Edison to the copy made by Griffin (see note 2), including reducing depreciation from 5% and interest from 8%, fuel from $4.20 per ton (with the stipulation of pea or dust coal), and charging leakage to gas. The earlier versions also contained a paragraph following this itemization indicating that “if the gas fixtures were added, the tanks and other apparatus upon the boat, breakage of globes, substitution of new burners at the jets etc, this gain would disappear.”

6. In his revision of Griffin’s 26 July draft copy (see note 2) Edison added two advantages to this list: a one-quarter decrease in insurance costs; and “This light will burn under water.”

7. Edison appended this paragraph to Griffin’s 26 July draft copy (see note 2). He also dictated a brief paragraph, evidently for insertion elsewhere and later canceled, about the economy to be gained from using existing gas fixtures for the electric light.

1. This is the date that Edison filed the application as Case 237; he probably executed it a few days earlier. The application was rejected in October by the Patent Office, which held that each of the claims was anticipated by other American and British patents. After Edison filed an additional affidavit (not found) in October 1882 it was again rejected and Page 821 subsequently abandoned. Patent Application Casebook E-2536:140, PS (TAEM 45:712; TAED PT020140).

2. Unidentified; possibly a clerk for Dyer and Wilber.

3. The text of the application, from the beginning of this paragraph to the claims, was incorporated into Edison’s provisional British specification for generators, machines, and motors filed on 30 September. Brit. Pat. 3,964 (1880), Batchelor (TAEM 92:212; TAED MBP030).

4. That is, the connecting rod.

1. The Corning Glass Works of Corning, N.Y., supplied “tubes & bulbs” to the Edison lamp factory, which “work[ed] them up into Electric Lamps by table blowing with gas” (TAE marginalia on U.S. Census Office to TAE, 27 Nov. 1880, DF [TAEM 54:25; TAED D8021R]). Discussions with the Corning Glass Works concerning a supply of glass for lamps probably began in June when a representative of “A Glass Manufacturer from Corning N.Y.” visited Menlo Park (Mott Journal N-80-03-14:250, Lab. [ TAEM 33:809; TAED N053:127]). According to Howell and Schroeder 1927 (p. 163), the Corning Glass Works supplied bulbs that were “hand made and free blown taken directly from the furnaces. These free blown bulbs were used by the Edison Lamp Works for about twelve years, although other lamp manufacturers adopted moulded bulbs much earlier. The hand made moulded bulbs were uniform in size and shape, while the free blown bulbs varied a great deal and had to be gauged and sized into groups of similar dimensions.”

2. There is a note of the same day addressed from Edison to the Corning Glass Works (possibly for a telegram) that reads “How soon will our glass come need it very bad.” There is no extant answer to either inquiry (DF [TAEM 53:802; TAED D8020ZGB]). On 18 August Charles Mott reported that “Two boxes of tubing from Corning N.Y. glass works received at Factory and upon test by Holzier pronounced very good glass for the purposes of the lamp” (Mott Journal N-80-07-10:87, Lab. [ TAEM 37:345; TAED N117:43]).

1. There is no extant record of 200 lamps being started on Friday, 13 August.

2. On 14 August Charles Mott reported “Men wrapping conductors with Muslin tarred and then wound with Marlin and again tarred.” Mott Journal N-80-07-10:81, Lab. (TAEM 37:342; TAED N117:40).

3. That is, for Edison’s house and for Sarah Jordan’s boarding house.

4. John R. Segredor was an out-of-work would-be inventor when he first contacted Edison in April 1879 to tell him some of his ideas and to ask for a job at the laboratory, indicating that “if I can get a position that will pay my board I will be satisfied.” Edison apparently offered to let him come to Menlo Park for a limited period in order to work up some of his ideas. He was at Menlo Park by the end of May when a time sheet shows him working on a “telephone order.” Another time sheet shows that he was working on electric light experiments in mid-October. The next indication of his presence at the laboratory is a note by Edison on a 10 March 1880 letter from a man who was having trouble getting an Edison dynamo, which he had built after reading the Scientific American article about it, to work properly. In response Edison told Segredor to make a diagram of the connections. Soon thereafter he left Menlo Park. This notebook entry indicates that he had returned to Menlo Park by sometime in the summer. In early September Edison sent him to Florida to gather plant samples for possible use as filaments (see Doc. 1984). Segredor to TAE, 22 April and 4 May 1879 and 3 May 1880; Clay McDill to TAE, 10 Mar. 1880; all DF ( TAEM 49:888; 49:894; 53:365, 301; TAED D7913S, D7913V, D8007U, D8006H); Time Sheets, NjWOE.

5. Albert B. Herrick (1860 –1938) began working at Menlo Park on 28 August 1879. He was primarily involved with lamp experiments in the laboratory and the lamp factory. He left Edison’s employ in January 1881 to study mechanical engineering and chemistry at the Stevens Institute. After leaving school in 1884 he worked briefly for the Baltimore & Ohio Railroad Co. and then for two years with the Brush-Swan Electric Co. In 1886 he established the manufacturing business of A. B. Herrick & Co. in New York City. Two years later he became chief electrician for Bergmann & Co. After the formation of Edison General Electric he became chief electrician of the Schenectady plant. When the company merged into General Electric he was made chief electrician of that company’s departments but soon left to form the engineering partnership of Herrick & Burke in New York City. “Albert B. Herrick,” Pioneers Bio.Page 824

6. Possibly William Mills, who joined the laboratory staff in 1880 but about whom nothing further is known. Jehl 1937– 41, 545.

7. William J. Hammer (1858 –1934) joined the Menlo Park laboratory staff in December 1879 after working for a year as an assistant to Edward Weston at the Weston Malleable Nickel Co. in Newark. At the laboratory Hammer helped with conducting tests and keeping records of experimental lamps and in 1880 Edison appointed him chief electrician of the lamp factory. In the fall of 1881 he went to London to assist Edward Johnson with the construction of the Holborn Viaduct central station (becoming its chief engineer) and the installation of the Edison exhibit at the Crystal Palace Exposition, where he designed the first electric sign spelling out Edison’s name in electric lights. In 1883 he became chief engineer of the German Edison Co. He returned to the United States in 1884 to work for the Edison Electric Light Co. and then served as chief engineer and general manager of the Boston Edison Electric Illuminating Co. He also had charge of several of Edison’s exhibits, including the 1889 Paris International Exposition. In 1890 he established himself as an independent construction and consulting engineer in New York City. Hammer did significant research on radium, including developing the first radium-luminous paint. Hammer was also noted for his pioneer work on electric signs and for the historic lamp collection he amassed. “Hammer, William J.,” Pioneers Bio.; ANB, s.v. “Hammer, William Joseph.”

8. Martin Force.

9. A boarding house kept by a Scotchman named Davis near the railroad tracks in Menlo Park. Jehl 1937– 41, 38.

10. Probably the Cornish grocery store, which was in the same building as the Menlo Park post office. Marshall c. 1931, 113.

11. The John Kruesi and Charles Batchelor families lived in a divided house across Christie Street from the Edison family home. Jehl 1837– 41, 220 (see map).

A map of Menlo Park showing several key buildings. Taken from Francis Jehl’s Menlo Park Reminiscences.

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1. On 4 August Charles Batchelor noted that “We are considerably bothered with the carbons bending over whilst they are on the pumpsPage 826

We think this must be due to to unequal heating so I have put up 2 fibres in moulds and heated up only one end of each in the preliminary heating.” He did not record results of this experiment. Two days later he theorized that if the carbons were “not heated sufficiently in carbonizing when they are put on the pump and heated a great deal higher the outside shrinks more than the inside; and the clamps being held tight it has to bend over to adjust itself.” He proposed on 8 August a number of experiments to see if any changes in the heating process would correct the problem, and it is to these trials that Batchelor refers in this document. N-80-06-02:49, 55– 65, Lab. (TAEM 36:418, 421–26; TAED N105: 22, 25 – 30).

2. In his journal entry of this day Charles Mott noted that “All the plates used in moulds as formers or shapers for carbons are being changed by Andrews so as to hold the widened ends so the thin edge of them will stand towards the faces in the lamp by which means the fiber will in every case be bent so that the inner or pith side of the fiber will come on the inside or outside of the loop instead of on the face as formerly.” On 17 August Cornelius Van Cleve “made the commencement at carbonizing in the Factory to day and from first mould of twelve carbons and formers got out eleven in nice order and from second mould of fifteen carbons got 13 out successfully.” It is unclear if these were the new moulds but the same day Batchelor noted that these were carbonized “edgeways.” Mott Journal N-80-07-10:79, 86; N-80-03-06:207; all Lab. (TAEM 37:341, 345; 33:1063; TAED N117:39, 43; N057:103).

1. In his journal entry of this date Charles Mott noted that “Mr. Edison wrote descriptions and made sketches of several new forms of electric meters in Book No. 132 page 1 &c.” The pages are those encompassing this notebook entry. Three days later Mott wrote “Mr. Edison made sketches of several different forms of meters and means connected to lamp for measuring the electric current which were given to [Samuel] Mott from which to make Patent Office drawings for caveat.” Nothing further is known of the caveat or the meter designs described in this notebook entry. An entirely different meter design became the subject of a patent application executed by Edison on 20 August. In this design the plates of the meter cell were suspended from a balance arm so that as copper was deposited on one plate it would tip the balance. As the balance arm moved it would cause a registering apparatus to record a mark and also reverse the current so that the copper was deposited on the other plate, thus moving the balance in the other direction. Edison explained in the application that because “the amount of current needed to cause the deposition of metal enough to cause the tipping is known, and Page 828as it is a definite percentage of the entire current, the registration may indicate the total amount of current; or, as the ratio existing between current and feet of gas for illuminating effect has been determined, the registration may indicate the equivalency in light of feet of gas.” Mott Journal N-80-07-10:79, 82, 138 – 39, Lab. (TAEM 37:341, 343, 371; TAED N117:39, 41, 69); U.S. Pat. 240,678.

The balance meter shown in Edison’s U.S. Patent

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2. Edison is probably referring to the current meter patented by Amos Dolbear on 15 June 1880. Dolbear’s device consisted of a slender iron core suspended by a spring directly over a cylindrical coil that was hollow along its axis. As electricity passed through the circuit, the coil attracted the rod against the spring’s tension into the central hole, in proportion to the strength of the current. A pencil was attached to the rod to record this motion on a strip of paper wound continually from one drum to another by a clockwork mechanism. U.S. Pat. 228,807.

1. Chester Pond was in the process of securing U.S. patents for visual electric signaling devices. On 7 September he received a patent for an annunciator in which the line number of an incoming signal was displayed by a vertical indicator slide. Two weeks later he obtained a patent for a similar device in which a wheel rotated into position to display the appropriate number (U.S. Pat. 231, 970 and 232,415). For reasons which are not clear but presumably were related to the impending issue of Pond’s patents, Edison requested him to come to Menlo Park “immediately” on 4 August. Pond came the following day (TAE to Pond, 4 Aug. 1880; Pond to TAE, 5 Aug. 1880; both DF [TAEM 55:569 – 70; TAED D8042ZBD, D8042ZBE]). On 10 August Edison tested whether the instrument could indicate the subscriber number desired by callers to a switchboard. The next day he executed an agreement by which he took a two-thirds interest in it for telephonic applications only. In return he promised to pay for further experiments and the expense of foreign patents. Edison later gave George Gouraud one-half his own interest in certain European countries and authority to sell the patents in those countries; Pond also drafted a power of attorney to Gouraud for that purpose (Mott Journal N-80-07-10:72, Lab. [TAEM 37:338; TAED N117:36]; TAE agreement with Chester Pond, 11 Aug. 1880, DF [ TAEM 55:645; TAED D8043ZAP]; TAE agreement with George Gouraud, 24 Aug. 1880; TAE draft agreement with Gouraud, Aug. 1880; Pond draft power of attorney to Gouraud, Aug. 1880; all Miller [TAEM 86:267, 271, 274; TAED HM800124, HM800125, HM800126]).

According to an undated draft of Edison’s agreement with Pond, the “Fire Alarm Indicator” consisted of “disks or wheels bearing numbers or characters in their peripheries, combined with all motive power, releasing devices and stopping devices, so that upon a signal being sent in from a numbered signal box, The disks are released and then stopped so that the number or symbol of the signalling box is displayed by the disks or wheels through a proper aperature” (TAE draft agreement with Pond, Aug. 1880, DF [ TAEM 55:653; TAED D8043ZAS]). ImmediatelyPage 830 after Edison signed the Pond agreement, John Ott (evidently assisted by James MacKenzie) began work on what Mott described as a

call box for the Pond indicator. In the Indicator the figures are thrown in position to read, by . . . telegraphic characters and to simplify the operation so that any person unacquainted with telegraphy may signal. the box is an arrangement of three indicator slides on each of which the necessary contacts for the characters representing the different numbers are formed by raised blocks and after each slide is adjusted to the numeral desired the contact is rapidly made by a spring with a platina point which is drawn across the raised characters by a clock work.

A more complete version of the call box was finished and “working very satisfactory” on 31 August (Mott Journal N-80-07-10:77, 96, 106, Lab. [TAEM 37:340, 350, 355; TAED N117:38, 48, 53]).

2. Chester Pond was the inventor of telegraphic signaling and relay devices and electric clocks, and was president of the Pond Electric Signal Co. in New York. NCAB 15:160 – 61; Letterhead of Pond to TAE, 24 Oct. 1881, DF (TAEM 57:243; TAED D8104ZEB).

3. These countries were specifically excluded from the 11 August agreement (see note 1) but incorporated into it by an amendment dated 14 August.

4. James MacKenzie had facilitated the 11 August agreement (see note 1), for which Edison assigned him an interest equal to one-twelfth of the whole (TAE agreement with James MacKenzie, 11 Aug. 1880, DF [ TAEM 55:650; TAED D8043ZAQ]). Edison had pulled MacKenzie’s young son from the path of a moving freight car in 1862, in gratitude for which MacKenzie taught him railroad telegraphy. MacKenzie subsequently became a manager of the American District Telegraph Co. Although his exact relationship with Edison at this time is not known he seems to have been involved with Pond’s indicator for more than a year (TAEB 4:23 n. 12; Pond to TAE, 6 Aug. 1878; MacKenzie to Union Fire Alarm Co., 14 May 1879; both DF [TAEM 19:538, 49:228; TAED D7836ZBS, D7903ZDT]).

1. Stockton Griffin made this draft the basis of the letter dated 17 August that he sent to Biedermann and copied into Edison’s letterbook. TAE to Biedermann, Lbk. 6:311 (TAEM 80:361; TAED LB006311).

2. This letter is a reply to Doc. 1962. Edison also had seen the text of Biedermann’s cable directing J. C. Young to “tell Edison important his man knows all dimensions and understand whole manufacture— Cable immediately when he departs.” On 22 August Biedermann requested Edison to “cable when your man leaves important to have one full sized generator and 60 ordinary lamps quickly Please send immediately cable when they will leave.” Edison answered that “It is impossible and useless to do what you request Have written in full.” Young to TAE, 14 Aug. 1880; Biedermann to TAE, 22 Aug. 1880; TAE to Biedermann, 23 Aug. 1880; all DF (TAEM 54:264 – 66; TAED D8026ZCO, D8026ZCP, D8026ZCQ).

3. See headnote p. 767.

4. Stockton Griffin copied this in the letter (see note 1) as 60 strokes per minute.

1. Possibly William Mead, identified in Wilson 1880 (1031), as a Brooklyn artist having an office or studio in Manhattan.

2. George Hopkins was editor of Scientific American. Hopkins testimony, p. 18, Böhm v. Edison, (TAED W100DEF018).

3. No article on the lamp factory appeared in Scientific American at this time. However, a more general article on electric lighting published in November did observe that “Mr. Edison has reduced the manufacture of his lamps to what may fairly be called a commercial basis, judging by the scale of the manufacture, the simplicity of the processes involved, and the uniformity and cheapness of the resulting product. He has erected a large factory for lamp making, and trained a numerous corps of glass blowers and other workmen for the work in hand.” Sci. Am. 43: (1880), 336.

4. The reference to 880 feet is not clear but probably refers to the change in elevation over the entire length of track. The traction mechanism for pulling the locomotive up steep grades (see Doc. 1961 nn. 7 and 8) evidently took several weeks to fabricate and install. Charles Mott reported that on 21 August “The new gear of the electric locomotive was run some little time this afternoon to grind down and wear smooth” before one of the generators gave out. When tried again two days later “the creepers did not work entirely satisfactorily but the dificulty was easily detected and can be readily remedied.” There was a separate problem with the friction wheel, however, which “would not hold sufficiently to carry the motor up the grade beyond the Pond,” but no suggestions were made to correct this. Mott Journal N-80-07-10:68, 70, 81, 93– 95, Lab. (TAEM 37:336 – 37, 342, 348 – 49; TAED N117:34 – 35, 40, 46 – 47).

1. On this day Edison executed a number of agreements regarding the disposition of foreign patents for telephones, electric light and power, and electric railways. Three of these were with George Newington of London, trustee for the prospective Edison’s Foreign Telephone Supply and Maintenance Co., Edison’s Foreign Electric Light and Power Co., and Edison’s Foreign Electric Railway Construction Co., each of which was to operate in extensive and somewhat overlapping regions of the world outside of Britain and the major Continental nations. These provided for Edison to take a large majority of each company’s stock in return for the rights to pertinent patents. Miller (TAEM 86:231, 233, 235; TAED HM800106, HM800107, HM800108).

The same day Edison executed three contracts giving George Gouraud one-half his profits from the Newington agreements in payment for helping to organize those companies, for which purpose he also granted Gouraud separate powers of attorney. He executed two similar contracts and powers of attorney to Gouraud for telephones in Mexico, and in India and British colonies other than Australia and Canada. He also signed one contract each for electric lighting and railways in portions of Africa and the Caribbean; the accompanying powers of attorney were dated 18 August but not signed until 24 August. On that date he executed an eighth power, for which no accompanying contract was completed, for electric light and power in unspecified British colonies. TAE agreements with Gouraud, 18 Aug. 1880; TAE powers of attorney to Gouraud, 18 and 24 Aug. 1880; all Miller (TAEM 86:239, 245, 251, 253, 255, 259, 241, 247, 237, 243, 249, 265, 257, 261, 263; TAED HM800110, HM800113, HM800116, HM800117, HM800118, HM800121, HM800111, HM800114, HM800109, HM800112, HM800115, HM800123, HM800119, HM800121A, HM800122); Gouraud to TAE, 24 Aug. 1880, both DF (TAEM 55:337– 38; TAED D8039ZAF, D8039ZAG).

1. See Doc. 1978.

2. The Electric Railway Co. of the United States was not incorporated until 1883. It controlled all of Edison’s pertinent United States patents.

1. In his journal entry for this day Charles Mott noted that “Mr. Batchelor devised and sketched several forms or styles of sockets for lamps which may be found Book No 105 pge 97 &c.” Two other, less detailed, drawings follow in the same book. On 2 September Mott reported that “John Ott completed one of the lamp holders devised by Mr. Batchelor and sketched in Book No. 105 pge 99. The thumb screw or circuit completer in this case admits of turning one way only and the contact is made by the pin connected to the thumb piece, which by a spring is thrown in against a metallic ring fitted to inside of socket. A tooth on the thumb piece drops into a notch in the sleeve of the shaft or pin thus letting the pin come suddenly in contact with the ring to complete the circuit and the tooth and notch are so formed that the thumb piece can be turned one way only and in so doing the circuit is suddenly and completely broken.” The next day “Ott finished a somewhat different lamp socket . . . in the former one the inside cup or socket was secured in the outer one by a screw on the bottom, in the one today the inner socket has projecting pin on lower end which finds under a single screw thread or incline thus making the contact for one line and holding the inner cup in position.” Page 99 of this notebook is missing. Mott Journal N-80-07-10:99, 109 –11, N-80-06-02:101, 103; both Lab. (TAEM 37:351, 356 – 57, 36:444 – 45; TAED N117:49, 54 – 55, N105:49, 48 – 49).

1. William H. Merrick was president and treasurer of the Southwark Foundry and Machine Co., recently organized to manufacture the Porter-Allen engine in the Philadelphia shop formerly operated by Merrick’s family. Letterhead of Merrick to TAE, 28 Oct. 1880, DF (TAEM 53:920; TAED D8020ZIJ); Porter 1908, 276 – 96.

2. Armature short circuits had hindered the laboratory generating station for more than a week. Charles Mott noted on 19 August that an Page 836armature “misteriously gave out this morning and no internal examination or test would reveal the point or cause.” The problem recurred in the same generator on two successive days and again on 23 August. Mott surmised then that “so many armatures giving out in this one machine would seem to indicate that the magnets in some way might be the cause or partial cause of it but that theory or suggestion does not seem to be entertained by those most familiar with the machines. one fact is observed in this machine that I have never known of in others, and have not been able to get an explanation of it and that is that a shock may be had by contact between the base of the magnet and the commutator brush or holder” (Mott Journal N-80-07-10:89, 91, 93, 95 – 96, Lab. [TAEM 37:346 – 50; TAED N117:44 – 48]). In fact, Mott reported on 2 September that

The magnet in which four or five consecutive successive armatures were burned out, was to day unwound and prepared for rewinding. The suggestion at the time, that there might or must be some defect in the magnet that was the cause of destroying so many armatures, made by a non collegiate , was promptly set down on, as presumptious, but now after a couple weeks have passed, the magnet is discovered to have a cross with its base and that rewinding is necessary. [Mott Journal 80-07-10:109, Lab. (TAEM 37:356; TAED N117:54)]

3. It is not known what changes, if any, may ultimately have been ordered. Charles Clarke was redesigning the armature, and especially the commutator connections, even before the late August generator problems. Mott referred to this project as a “new form of armature adapted for large machines.” Clarke worked on this (evidently with some assistance by Charles Batchelor) until mid-September (Mott Journal N-80-07-10:105, N-80-07-27:23– 79, N-80-06-02:87, all Lab. [TAEM 37:354, 194 – 222; 36:437; TAED N117:52, N116:12 – 41, N105:41]). At the end of the month Edison filed in London a British provisional patent specification incorporating Clarke’s design, which he stated would be easier and faster to repair in case of a short circuit between the coils:

This is accomplished by making of wire only that portion of the coil which is upon the operative face, the wires of a coil being connected at the ends by metallic plates fastened to an insulating base and insulated from each other. These plates are made so as to project at the proper points above the general surface of the core, at which points the wires are secured to them by soldering, brazing, or clamping devices. At one end each plate is suitably connected to the proper commutator block.

In case of necessity of removal of any coils it is unloosed from its plates at each end without disturbance of other coils. In fact, by such construction it is possible to remove, repair, and replace any coil without taking the armature out of the machine and with but a slight stoppage of the machine.

The plates upon the end are made as concentric almost semicircles insulated from each other with the projections for receiving the wires nearly at right angles thereto.

These plates offer less resistance than the wire, and consequently the internal resistance of the generator is proportionately reduced. [Brit. Pat. 3,964 (1880), Batchelor (TAEM 92:212; TAED MBP030)]

British patent specification drawing of new armature design using metal plates to complete the circuit through the inactive portion of each coil so as to reduce internal resistance.

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Page 837

The final specification incorporated the further modifications discussed in Doc. 1992. Edison also executed a U.S. application for this armature design on 11 December (Case 266); it issued in June 1881 as U.S. Pat. 242,898.

1. This position had been held by Andrew Cone since 1878. Cone was a publisher connected with the Pennsylvania oil industry who had been U.S. Consul at Para, Brazil, from 1876. He left Pernambuco on 10 September 1880 for a medical leave in the United States, where he died soon thereafter. Henry Lee Atherton, who was in the insurance business in New York City, was named to succeed Cone in November. Cone 1903, 405 – 407; Cone to Second Assistant Secretary of State, 10 Sept. 1880; Atherton to Second Assistant Secretary of State, 18 Nov. 1880; both in Despatches from the United States Consuls in Pernambuco, 1817– 1906, vol. 11, U.S. National Archives and Records Administration microfilm T-344, reel 11; Wilson 1881, 54.

2. It is not clear when or how Edison came to seek especially Japanese bamboo, or from what source he obtained samples. On 18 August Charles Mott observed that “Four bundles of common Bamboo were recd. this morning and cable prepared to send to Japan for a quantity of Page 838large Japanese bamboo.” Mott Journal N-80-07-10:87, Lab. (TAEM 37:345; TAED N117:43).

3. This document precedes in the letterbook nearly identical letters of the same date to U.S. consuls in Puerto Rico; Para, Brazil; Port au Prince, Haiti; Kingston, Jamaica; and Panama. There are no extant replies (Lbk. 6:357– 59 [TAEM 80:370 – 72; TAED LB006357A, LB006358, LB006358A, LB006359, LB006359A]). Edison had sent a similar inquiry two days earlier to Vesey Butler in Havana stating that he needed “many tons” of the cane or bamboo for which he would “pay a good price if can get the right quality.” In October Butler forwarded samples of dried cane and also described other types of fibers found on Cuba, including one “as fine as silk & very white & strong.” Butler later promised that “we can supply you with all the cane you require from here as it exists in large quantities in the marshy districts. paying a trifle to the owners of the land we could cut all we require” (TAE to Vesey Butler, 28 Aug. 1880, Lbk. 6:354 [TAEM 80:368; TAED LB006354]; Butler to TAE, 6 Oct. 1880 and 20 Nov. 1880, both DF [TAEM 53:879, 956; TAED D8020ZHO, D8020ZIZ1]).

1. Edison received the cable quoted below at 7:45 p.m. on 18 August. The agreement combining the interests in the French patents was dated 16 –17 August; it designated the company to be formed as the Société Générale des Téléphones (Système Edison, Gower & autres). Harjes to TAE, 18 Aug. 1880; Harjes agreement with Constant Rousseau, Georges Lebey, and Jules Lair, 16 –17 Aug. 1880; both DF (TAEM 56:244, 235; TAED D8048ZFM, D8048ZFK1).

2. In the enclosed letter Henry Harrisse explained that French law required that

all the contributions, patents, privileges, and devices, called in French “apports,” which form the basis of a society and that are brought into the same for a certain price, shall be approved by a vote of stockholders not interested in the said “apports” either directly or indirectly. Now, the stockholders of the “Edison” [Telephone Co.] were all apparently actual owners of the patents; and, as such precluded from voting. The Banque Franco Egyptienne said that they could not raise a subscription for new stock, out of the general public and thus obtain the required number of disinterested stockholders to vote on the “apports.” [Harrisse to Harjes, 9 Aug. 1880, DF ( TAEM 56:253; TAED D8048ZFW)]

3. Joshua Bailey wrote Edison at the beginning of October that the Banque Franco Egyptienne wished to reduce the shares that patent holders would have in the new company, and in any case did not intend to issue shares until the number of subscribers increased. Near the end of the month, however, Harjes reported that the amalgamation was progressing smoothly and would receive final approval by all shareholder in a few days. Bailey to TAE, 1 Oct. 1880; Harjes to TAE, 27 Oct. 1880; both DF (TAEM 56:263, 270; TAED D8048ZGC, D8048ZGE).

1. John Segredor left Menlo Park on 27 August. There is no record of when these samples reached Edison but earlier shipments arrived on 2 and 6 September (Mott Journal N-80-07-10:104, 109, 116, Lab. [TAEM 37:354, 356, 360; TAED N117:52, 54, 58]). A record of samples sent by Segredor was kept by William Carman in a laboratory notebook which has not been reproduced on microfilm (N-80-06-01, Lab., NjWOE [see TAED N151]).

2. Stockton Griffin noted below Edison’s reply that the message was sent on 8 September.

3. An island group in the Gulf of Mexico off the coast of Florida’s peninsula. WGD, s.v. “Cedar Keys.”

4. Segredor replied on 8 September, “Yes will write today full details information received.” The same day he sent a lengthy description of his largely fruitless search through Georgia and Florida. He sent another long report on 15 September, telling Edison that “so far I have seen no cane that near equals the cane you are using in density. All I have come across is full of pores,” but the following day he mailed 128 samples collected in Georgia and Florida. Segredor wired again from Cedar Keys at the end of September that he could reach Havana “quicker cheap more certain” from the north. Edison replied “All right” and Segredor returned to Menlo Park on 5 October. Segredor to TAE, 8, 15, 16, and 28 Sept. 1880; TAE to Segredor, 28 Sept. 1880; all DF (TAEM 53:815, 828, 835, 868, 869; TAED D8020ZGN, D8020ZGR, D8020ZGS, D8020ZHD, D8020ZHE); Mott Journal N-80-07-10:155, Lab. (TAEM 37:379; TAED N117:77).

1. Wilson S. Howell (1855 –1943) began working at Menlo Park in December 1879. He worked initially on exhausting lamps. From 1881 to 1885 he worked for the Edison Co. for Isolated Lighting and then organized and managed the New Brunswick, N.J., Edison Electric Illuminating Co. Between 1887 and 1891 he was a consulting engineer. He then took charge of the Lamp Testing Bureau of the Association of Edison Illuminating Companies, which became the Electrical Testing Laboratories.

Shortly before Mott made this journal entry Edison gave Howell the task of developing an insulating compound for the underground cables. In his reminiscences Howell recalled that

Mr. Edison sent me to his library and instructed me to read up on the subject of insulation, offering the services of Dr. Moses to translate any French or German authorities which I wished to consult. After two weeks search, I came out of the library with a list of materials which we might try. I was given carte blanche to order these materials from McKesson & Robins and, within ten days, I had Dr. Moses’ laboratory entirely taken up with small kettles in which I boiled up a variety of insulating compounds. The smoke Page 843and stench drove Dr. Moses out of his laboratory. The results of this stew were used to impregnate cloth strips, which were wound spirally upon No. 10 wires one hundred feet in length. Each experimental cable was coiled into a barrel of salt water and tested continually for leaks. Of course, there were many failures, the partial successes pointing the direction for better trials. These experiments resulted in our adopting refined Trinidad asphaltum boiled in oxidized linseed oil with paraffin and a little beeswax as the insulating compound with which to cover the bare wire cables, which had been previously laid along side of trenches throughout the streets of this little Jersey village. Through the pot in which this compound was boiled, we passed strips of muslin about 2 inches wide. These strips were wound up into balls and wrapped upon the cables. After the man who served these tapes upon the cables had progressed about six feet, he was followed by another man serving another tape in the opposite direction, and he in turn by a third man serving a third tape upon the cable in the direction of the first winding. After the cables were all covered with this compound and buried, the resistance to earth was found to be sufficiently high for a working system. [Howell reminiscences, pp. 4 – 5, Pioneers Bio.]

2. Not found.

3. Francis Jehl.

4. Francis Jehl’s notebook entries regarding these experiments began on 31 August. Mott took the results from Jehl’s notes. Four days earlier Mott had noted that Jehl was “making some experiments for insulation of wires underground. the materials tried mixtures of tar paraphine and kindred substances and gums in various mixtures and combinations.” Experiments with insulation compounds continued through 21 September; beginning on the 14th they began experimenting with insulated cables No. 15 – 21. A summary of the compounds used on cables No. 1–7 and 15 – 20 was recorded by Mott on 18 September. On 22 September Mott recorded that the laboratory had “received during my absence a portable furnace (or stove) and boiler or kettle for boiling and preparing the insulating composition for the lamp lines.” The next day “Men commenced uncovering again (third time) the conductor trenches of street lamps. others preparing Muslin with compound of Oxidized Linseed oil, Pine tar, Asphaltum and Paraphine (No. 7.) with which to rewind the cables.” On the 24th Mott noted that “Fifteen men and boys were today set at work on insulating the Street Lamp conductors” with this compound (see note 1) using two thicknesses of muslin. N-80-07-16:100 – 23; Mott Journal N-80-07-10:103, 107, 112, 114, 134 – 37, 140 – 41; both Lab. (TAEM 38:533– 42; 37:353, 355, 358 – 59, 369 – 70, 372; TAED N137:49 – 58, N117:51, 53, 56 – 57, 67– 68, 70).

5. Mott apparently made two copies of the agreement between Edison, Ernest Biedermann, A. M. Cherbuliez, and Gaspard Zürlinden granting them exclusive rights to Edison’s electric light and power system in Switzerland (see Docs. 1878, 1962, and 1976). Edison executed this agreement the following day. Both copies were probably sent to Switzerland to be signed by the other parties and one of these was returned to Edison. Mott subsequently made a copy of the signed agreement along with notarizations by Stockton Griffin dated 9 September, Page 844the Swiss Consul at Philadelphia dated 11 September, and the American Consul in Geneva dated 30 September; all of these notarizations are found with the original signed agreement. The copy also contains a notarization by the American Consul in Geneva certifying that it is a true copy of the original; the notarization is dated 21 June 1880 but was most likely made in 1881 (DF [TAEM 54:267; TAED D8026ZCR]; Miller [TAEM 86:291; TAED HM800129]). On 8 September, Biedermann, Cherbuliez, and Zürlinden signed an agreement with several others in Geneva to form a company to exploit the Edison system in Switzerland. It is unclear if this arrangement was carried out, as a week later Biedermann, Cherbuliez, and Zürlinden transferred their rights to the Compagnie Genevoise l’Industrie du Gaz, which in turn agreed to form the Société Suisse d’Électricité to exploit the Edison system (agreement between Biedermann, Cherbuliez, Zürlinden, et al., 8 Sept. 1880; agreement between Biedermann, Cherbuliez, Zürlinden, and the Compagnie Genevoise l’Industrie du Gaz, 15 Sept. 1880; both Miller [TAEM 86: 278, 300; TAED HM800128, HM800130]; TAE to Biedermann, Nov. 1880, DF [TAEM 54:309; TAED D8026ZDX]).

6. The previous day one of “the regular dynamoes being the third machine was taken to Factory to replace the one crossed and to be used as pump motor.” On 9 September it was replaced by another motor with a .55 ohm armature, which was used “part of the afternoon supplying the carbon testers and one tier of (about forty) vacuum pumps, and being of the same resistance of the blower motor no preceptable fall in speed or power was observed in the blower machine when the other was put in the circuit.” The next day the motor seemed to be working fine. Mott Journal N-80-07-10:117, 12 – 25, 125, Lab. (TAEM 37:360, 363– 64; TAED N117:58, 61– 62).

7. Samuel Dimmock Mott (1852 –1930) was Charles’s brother. He studied for two years at Lehigh University but left in 1873 to promote his first patent, a guiding attachment for a boy’s sled. For the next several years he studied engineering and invention. In spring 1879 he enrolled in mechanical drawing and physics classes at Princeton. He joined the Menlo Park laboratory staff following the end of classes. He primarily worked as a draftsman for Edison. During his life Mott obtained thirty-six patents in a variety of fields. “Mott, Samuel,” Pioneers Bio.

8. On 18 August Edison had sketched a device that reversed the direction of the current through the lamp each time it was turned on or off. This was apparently a variation of Francis Jehl’s “Circuit changer” to prevent electrical carrying (see Doc. 1944 n. 7). Samuel Mott took Edison’s sketches to make drawings for a caveat. Mott presumably made some further variation that he hoped to patent himself. There is no record of either Edison’s caveat or Mott’s patent application. Mott Journal N-80-07-10:88, Lab. (TAEM 37:346; TAED N117:44).

1. Between 16 and 24 August 1880 Edison and Ludwig Böhm undertook a series of experiments to determine whether fruit could be preserved by placing it in a vacuum. In the first attempts “the fruit was injured by the heat but one pear was enclosed with slight injury and after exhaustion was hermetically sealed.” When George Gouraud came to the laboratory on 18 August he brought “some choice selected fruits to be sealed in vacuum,” which was done the next day. On 24 August Gouraud sent more peaches. These were also sealed and he took them to England. On 16 and 24 August Böhm made drawings of apparatus used for the fruit preservation experiments. Nothing further was done in regard to these experiments until the following April. Mott Journal Page 846N-80-07-10:83, 88, 90, 97; N-80-03-19:190, 217; N-81-04-30:1– 77; all Lab. (TAEM 37:343,346 – 47, 350; 34:700, 713; 41:1156 – 94; TAED N117:41, 44 – 45, 48; N068:94, 107; N306:1– 39); TAE to Gouraud, 17 and 22 April 1881, Cable Book (1881–1883), Misc. Lbk. 1:9 –10 (TAEM 83:876 – 77; TAED LM001009F, LM001010D).

2. This is the text of Gouraud’s cable to TAE, 9 Sept. 1880, DF (TAEM 53:213; TAED D8004ZFB).

3. Edison executed such a patent application on 11 Dec. 1880 and filed it three days later; it issued in October 1881 as U.S. Patent 248,431.

1. This specification was filed in London on 25 September 1880. Edison would have had to draft it about this date in order to allow a day or two for copying and at least ten more days for it to reach London by the 25th, since the cost of cabling a document this long would have been prohibitive.

2. London patent solicitor Peter Jensen filed this specification as a communication from Edison; he filed the final specification on 25 March 1881, taking British Patent 3,894 (1880), Batchelor (TAEM 92:194; TAED MBP029) in his own name on Edison’s behalf. The document is an omnibus specification combining elements from several U.S. applications that Edison completed during the summer, as discussed below. There is extant a portion of Edison’s undated draft of a broad specification for electric railways but it bears no clear relation to this document or his prior U.S. applications. There are also several pages of Edison’s sketches and notes dated 3 August pertaining to electric railway applications. Undated draft, DF (TAEM 55:243; TAED D8036ZGL); N-80-07-30:12 –17, Lab. (TAEM 38:468 – 70; TAED N135:7– 9).

3. This paragraph and the fourteen which follow concerning the operation of the electric locomotive and general operation of the railway were evidently similar to a U.S. application that Edison filed on 3 June 1880 (Case 218). That application was rejected, amended, placed in interference, and eventually abandoned. Its fifteen extant figures and Page 854eighteen extant claims were included in the thirty-six figures and thirtyfour claims of the final British specification. Patent Application Casebook E-2536:90 – 92, PS (TAEM 45:707– 9; TAED PT020090); see also Edison v. Siemens v. Field, passim, Lit. (TAEM 46:5 –114; TAED QD001).

4. At the end of September Edison filed a provisional specification covering the governor and transmission arrangements for maintaining a constant armature speed. Brit. Pat. 3,964 (1880), Batchelor (TAEM 92:212; TAED MBP030).

5. These figures from the final specification show loose wheel H secured to sprocket (or rag wheel) I, and revolved by friction wheel Z. An axle connects sprocket K to grooved wheel L, which can be pressed against the rail by screw S.

In the undated patent draft (see note 2), Edison suggested that severe grades could also be surmounted by “the use of swinging Extensions connected to the [motor] field magnets, which Extensions may be thrown downward so as to nearly touch the track and thus produce a powerful traction.” This arrangement was included in the claims of Case 218 (see note 3).

British patent specification drawing of grooved wheel engaged against the rail head, for drawing loads up a steep grade.

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6. This portion of the specification concerning track insulation is similar to a U.S. application that Edison executed on 6 August 1880 (Case 238) which issued as U.S. Pat. 293,433 in February 1884.

7. On 3 July 1880 Edison executed a U.S. application (Case 223) specifically for “grippers” or “creepers” for drawing a load up a steep grade; it did not include the clutch mechanism and reduction gearing described in this document. The application issued in October 1882 as U.S. Pat. 265,778.

8. The final specification showed the entire mechanism for carrying motion from the motor armature to the creeper and, in detail, the locking creeper S, within which “and upon each side of the rail, wheels s are mounted, eccentrically pivoted as shown, the opening between them at the widest point being just enough more than the width of the rail to permit its passage therethrough. . . . [I]f a body the width of a rail be slid between them in the direction of the arrow . . . it will push them apart, Page 855but that if the motion be in the opposite direction it will cause the rollers s, s, to approach each other, gripping the body between them.”

Illustration and detail from the British patent of “creepers” for drawing the electric locomotive up a steep grade.

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9. This portion of the specification concerning the electromagnetic brake is similar to a U.S. application that Edison executed on 2 July 1880 (Case 222) that issued in 1881 as U.S. Pat. 248,430.

10. This paragraph and the remainder of the specification are similar to a U.S. application that Edison executed on 14 August 1880 (Case 246) that issued two years later as U.S. Pat. 263,132.

1. In his journal entry of this date Charles Mott wrote “Johnson sketched a new socket which is designated as ‘Boss socket’ in Book No. 153 pge 18 etc which is now being made by one of the new men in Shop.” Edward Johnson had arrived back in New York at the end of August and first came to the laboratory on the 31st. On 6 September he was again at the laboratory when Edison “made sketches of a number of styles and ways of running and concealing wires on gas chandeliers Some devices being fitted to permit of the use of either Electric or Gas Light without interference with each other”; these sketches have not been found. On the 10th “Johnson produced a six light chandelier on which to experiment in artistically fitting with connections, wires &c for substituting the electric lamp and to arrange for use of both or either without as little change or disfiguring as possible” (Mott Journal N-80-07-10:130, 107, 116, 125, Lab. [TAEM 37:367, 355, 360, 364; TAED N117: 65, 53, 58, 62]; Josiah Reiff to TAE, 28 Aug. 1880, DF [TAEM 53:207; TAED D8004ZET]). Johnson seems to have headed the development work on sockets and other fixtures, which were subsequently manufactured by Bergmann & Co., in which both Johnson and Edison were partners with Sigmund Bergmann (see their agreement dated April 1880, DF [TAEM 57:7; TAED D8101C] and Bergmann & Co. catalog, n.d., PPC [TAEM 96:185; TAED CA002C]). For the subsequent work on sockets and fixtures see the notebook kept by Johnson (N-80-09-11, Lab. [TAEM 39:245; TAED N153]; see also Mott Journal N-80-07-10:174, 188, 208, 223, 249, 255, 276 – 77; N-80-10-25:33– 35; both Lab. [TAEM 37:389, 396, 406, 414, 427, 430, 440 – 41; 34:168 – 70; TAED N117:87, 94, 104, 112, 125, 128, 138 – 39, N060:33– 35]; Johnson to Mitchell & Vance, 20 Sept. 1880; Charles Batchelor to George Merril, 19 Oct. 1880, Lbk. 6:415, 475 [TAEM 80:308, 393; TAED LB006415, LB006475]). Edison filed four patent applications on sockets and fixtures in March 1881 and Johnson filed one for a socket in May 1881 and for a chandelier the following September (U.S. Pats. 248,420, 248,424, 251,553, 251,554, 251,596, 256,701).

Edward Johnson’s drawing of a chandelier design. 1 and 2 are square tubing, 3 is round tubing, 4 is a flat scalloped ornamental band, and 5 is a hook on which the shade would rest.

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2. This drawing and the one on the preceding page are the first extant evidence for a screw socket. In his reminiscences Wilson Howell describes its origins:

Mr. Edison and a number of his helpers were grouped under a hanging lamp in the laboratory one evening. Edison was talking of the introduction of his light into homes, factories, stores, and of the necessity of making the system “fool proof.” Pointing to the lamp overhead hanging by its two wires from the open conductors, he explained to us how dangerous such a method of attachment would prove in the hands of the public. He explained that it was necessary to devise an attachment which would be secure, “fool proof,” insulated and quick. He described what was needed in such vivid language that one who listened attentively to Mr. Edison was given a picture of the device needed. The “picture” was that of another and older lamp attached to its source of supply—a kerosene lamp “burner” attached to its fount by a screw thread. A sketch was hastily made of this “socket” and, when shown to Mr. Edison was pronounced by him to be exactly the device he (Mr. Edison) had in mind. [Wilson Howell reminiscences, pp. 6 – 7, Pioneers Bio.]

1. Renshaw was in New York on this date on his way to Colorado. He visited Menlo Park on 28 September and asked to do so again on his return in November. Gouraud to TAE, 10 Sept. 1880; Renshaw to TAE, 23 Sept. and 15 Nov. 1880; all DF (TAEM 56:792, 791, 797; TAED D8049ZHD, D8049ZHC, D8049ZHG); Mott Journal N-80-07-10:147, Lab. (TAEM 37:375; TAED N117:73).

2. Gouraud apparently did not send this memorandum until 20 November. The transmittal letter is somewhat confusing. In it he stated that “I have just come across a document that will satisfy you and Johnson Page 859very fully as to the wily ways of EPB[ouverie] and A.W[hite]. as shown by a memorandum of which I send you a copy.” The enclosed memorandum called for the stockholders of the Edison Telephone Co. to sell their shares to the United Telephone Co. White asserted that the transaction would be “between the United Company and each individual Edison shareholder and not between the two companies.” According to Gouraud, Theodore Waterhouse, the Edison company’s attorney, told Bouverie that the proposed transaction would not be legal. Gouraud to White, 20 Nov. 1880, enclosing undated White memorandum, DF (TAEM 56:798, 800; TAED D8049ZHH, D8049ZHI).

1. James Russell returned the first completed notebook of his survey of gas usage in the projected New York central station district on 22 September (see Doc. 1995). The next day, according to Charles Mott, “Messrs Edison, Upton and Frances [Jehl] went to New York at 3:20 I hear to visit some gas works.” Mott reported that they returned “late in afternoon” of 24 September, having “found the ordinary burner at usual burning, to give about 7 to 7½ candles but from one burner in Bergmann’s got 27 candle power. Notes measurements ect Book No. 160 pge 5 etc.” Edison presumably made these tests to establish a basis for estimating the amount of light produced by gas lamps under actual operating conditions in New York. Mott Journal N-80-07-10:138, 140 – 41, Lab. (TAEM 37:371– 72; TAED N117:69 – 70).

2. S. Bergmann & Co.’s shop at 106 –114 Wooster St. in New York. Letterhead of Bergmann to TAE, 30 Aug. 1880, DF (TAEM 53:14; TAED D8001J1).

3. A standard instrument for measuring commercial gas pressure consisted of a U-shaped glass tube, with one end connected to the gas line and the other open to the air. A small amount of water was placed in the tube so that the difference in the water level in each side provided a visual indication of the pressure in the line. The water’s highest level was read against a vertical scale ruled in tenths of an inch. Because gas is less dense than air its pressure increases with height above the source. U.S. Department of Commerce 1914, 140.

4. William W. Goodwin & Co., at 142 Chambers St. in New York, manufactured gas and water meters. Edison wrote the name and address of this firm and another one, as well as references to several gas-related publications, on the first numbered page of this notebook. On the facing page was pasted the published results of routine tests of gas conducted by the New York Department of Public Works on 5 June, showing considerable variation in illuminating power at different times of day and among the various gas companies. A printed advertisement from a New York book seller of items pertaining to the gas industry was pasted to the third page. Wilson’s Business Directory of New York 1879, 290; N-80-06-16.2:1– 3, Lab. ( TAEM 39:488 – 90; TAED N160:1– 3).

5. This was evidently one of a number of standard burners used in photometry tests of municipal gas. One of the most common of these burners was the Brays No. 7 slit-union (see below). The Bray burners were of the open flame type (as opposed to the annular Argand) and were considered to operate relatively uniformly with different types of gas Page 864and at different pressures. Nothing is known of the “special Lava tip.” U.S. Bureau of Standards 1914, 91.

6. As indicated by the above measurement of flame size, these experiments were probably conducted using the techniques of jet photometry. A jet photometer was not properly a photometer, but rather a carefully-calibrated standard burner whose flame height at a given pressure provided an indirect measure of candlepower. This approach invited several sources of error and fell into disuse by the end of the century. However, Edison appears to have used it as a benchmark for the intensity of light consumers would expect to obtain at this pressure from a clean and adjusted burner, that is, sixteen candlepower. The phrase “15 @ 16” presumably represents a photometer measurement of fifteen candles in practice under conditions where sixteen candles would be expected. U.S. Department of Commerce 1914, 104; see also Doc. 1991.

7. Francis Jehl.

8. The Manhattan Gas Light Co., one of four New York gas suppliers, served the area south of 42nd St. as far as Grand and Canal Sts., a few blocks south of the Bergmann shop. Stotz 1938, 40, 45, 53.

1. The reference at the end of this document to a lower candlepower incandescent lamp providing more effective light in comparison to a gas Page 867lamp of greater candlepower suggests that this was probably written soon after the 23– 24 September gas candlepower tests at Bergmann & Co. See Doc. 1990.

2. That is, 10,000 plus one-eighth more.

3. It is unclear where Upton gets this figure for additional receipts from using 9 lamps per horsepower.

4. That is, .35 multiplied by 11.

5. That is, according to the indication of a jet photometer; see Doc. 1990 n. 6.

1. Charles Clarke and Edison continued these tests the next day, when they made three more trials. Clarke recorded that “No appreciable rise in temperature was found to have taken place by revolving rods of copper in the magnetic field therefore no injurious local currents and it was Page 868decided to adopt rods of large size instead of wires across face of armature.” On 30 September Clarke began to make sketches and notes for redesigning the large armature, calculating in particular the increased surface area of the induction coils to be gained from substituting trapezoidal bars for insulated round wire. N-80-07-27:89 –113, Lab. (TAEM 37:227– 39; TAED N116:46 – 58).

In the U.S. patent application Edison signed on 11 December (Case 266) he stated that

The construction of revolving armatures as ordinarily practiced, especially in the case of very large machines, requires the use of a large amount of insulated wire. This is expensive, and besides takes up room and allows of the accumulation of heat, owing to the nonconductor forming the insulation, to remedy which . . . I use rigid naked bars or wires of proper material, which are so disposed about the armature that each is separated from the others, there being between them an insulation partly of mica and partly of air, which suffices in practice for insulation, and in addition allows such access of air to all the active parts of the armature that danger of heating thereof by accumulation is greatly lessened. [U.S. Pat. 242,898]

This was essentially the form of armature built during the fall and winter for the Porter-Allen direct-connected dynamo, though it differed in a few particulars so as to be “more easily and cheaply constructed.” Edison also added the bar armature to a final British specification filed on March 30, 1881 (Mott Journal N-80-07-10:281, Lab. [TAEM 37:443; TAED N117:141]; Brit. Pat. 3,964 [1880], Batchelor [TAEM 92:212; TAED MBP030]).

1. There are no extant drafts of this article, which appeared in the North American Review for October. That issue was available by 17 September, when Sherburne Eaton wrote Edison that he had seen the published article and thought it “excellent—most excellent—both in tone, matter & style.” Eaton sent copies to George Gouraud and Charles Porter. Eaton to TAE, 17 Sept. 1880, DF ( TAEM 54:72; TAED D8023ZAF).

2. It is not clear exactly what type of bamboo Edison had available to him at this time. By the end of the year he was using a species cultivated in Kyoto known as Madake, which remained the standard for his commercial lamps until 1893 or 1894. Howell and Schroeder 1927, 76 – 77; Israel 1998, 202 – 3; see also Doc. 2002.

3. The most recent “authorized” account was probably that published Page 874in the 21 December 1879 New York Herald (see Doc. 1868 n. 3). This paragraph conflates two changes in Edison’s central station design: substitution of a few large generators directly connected to the steam engine in place of many small ones connected by shafts and belts, and the exclusive use of self-exciting dynamos instead of separately-excited magneto machines. Although there is no reason why Edison could not have built and operated very large magneto machines, once he began to conceptualize the commercial generator and steam engine as two integrated parts of a single self-contained machine (see Doc. 1936) he was obliged to adopt both changes simultaneously.

4. See Doc. 1995.

5. The article was evidently written by Francis Upton, not the first instance in which Edison delegated the task of composing something published in his name (see Doc. 1283). It evolved from an effort by the North American Review in 1878 to prepare and attribute to Edison an article about electric lighting generally based on information supplied by him; that project was assigned to Upton (see Doc. 1588). The magazine made a few inquiries about it in early 1879 and then let the matter drop until reports of the impending Menlo Park exhibition prompted editor John Barron to contact Edison again in December. In notes for a reply to Barron, Edison promised that “Mr Upton can prepare the article for him so it will be ready before public exhibition.” Barron wrote almost two weeks later that he would be “very glad” for this arrangement but Edison indicated that he would “have to see Mr Upton about preparing it as I have said nothing about it to him yet.” Then in January 1880, when the editor expressed disappointment “in receiving from Mr. Upton yesterday a postal card in which he stated that he could not promise your article by the 1st of Feby next,” Edison instructed Stockton Griffin to “write him nice letter say that we are absolutely driven to death with work & find it impossible to do anything.” There is no further correspondence about the article until its publication. North American Review to TAE, 27 Feb. 1879, 24 Mar. 1879, TAE marginalia on North American Review to TAE, 4 and 15 Dec. 1879, and 23 Jan. 1880, all DF ( TAEM 49:136, 688, 747– 48; 53:349; TAED D7903ZBH, D7906ZAA, D7906ZBR, D7906ZBT, D8007H).