iv&oru fapsAA

A SELECTIVE MICROFILM EDITION

PART III (1887-1898)

Thomas E. Jeffrey Microfilm Editor

Gregory Field Theresa M. Collins David W. Hutchings Lisa Gitelman Leonard DeGraaf Dennis D. Madden

Mary Ann Hellrigcl Paul B. Israel Robert A. Rosenberg Karen A. Detig Gregory Jankunls Douglas G. Tarr

Reese V. Jenkins Director and Editor

Sponsors

Rutgers, The State University of New Jersey National Park Service, Edison National Historic Site New Jersey Historical Commission Smithsonian Institution

University Publications of America He tiles da, Maryland

THOMAS A. EDISON PAPERS

Reese V. Jenkins Director and Editor

Thomas E. Jeffrey Associate Director and Microfilm Editor

Robert A. Rosenberg Managing Editor, Book Edition

Helen Endlck

Assistant Director for Administration

Associate Editor

Paul B. Israel

Research Associates Theresa M. Collins David W. Hutchings Karen A. Detig

Assistant Editors Keith A. Nier Gregory Field Lisa Gltelman Martha J. King

Secretary

Grace Kurkowski

Gregory Jankunls

Student Assistant Bethany Jankunls

BOARD OF SPONSORS

Rutgers, The State University of New Jersey

Francis L. Lawrence Joseph J. Seneca Richard F. Foley Rudolph M. Bell

New Jersey Historical Commission Howard L. Green

National Park Service John Maounis Maryanne Gerbauckas Nancy Waters George Tselos Smithsonian Institution Bernard Finn Arthur P. Molella

EDITORIAL ADVISORY BOARD

James Brittain, Georgia Institute of Technology Alfred D. Chandler, Jr., Harvard University Neil Harris, University of Chicago Thomas Parke Hughes, University of Pennsylvania Arthur Link, Princeton University Nathan Reingold, Smithsonian Institution Robert E. Schofield, Iowa State University

CORPORATE ASSOCIATES

William C. Hittinger (Chairman), RCA Corporation Edward J. Bloustein, Rutgers, The State University of New Jersey * Cees Bruynes, North American Philips Corporation Paul J. Christiansen, Charles Edison Fund Philip F. Dietz, Westinghouse Electric Corporation Roland W. Schmitt, General Electric Corporation Harold W. Sonn, Public Service Electric and Gas Company Morris Tanenbaum, AT&T

•Deceased.

FINANCIAL CONTRIBUTORS

PRIVATE FOUNDATIONS

The Alfred P. Sloan Foundation Charles Edison Fund The Hyde and Watson Foundation Geraldine R. Dodge Foundation

PUBLIC FOUNDATIONS

National Science Foundation National Endowment for the Humanities National Historical Publications and Records Commission

PRIVATE CORPORATIONS AND INDIVIDUALS

Alabama Power Company Amerada Hess Corporation Anonymous AT&T

Atlantic Electric

Association of Edison Illuminating Companies, Inc.

Battelle Memorial Institute The Boston Edison Foundation Cabot Corporation Foundation, Inc. Carolina Power & Light Company Consolidated Edison Company of New York, Inc.

Consumers Power Company Coming Glass Works Foundation Duke Power Company Entergy Corporation (Middle South Electric Systems)

Exxon Corporation Florida Power & Light Company General Electric Foundation Gould Inc. Foundation Gulf States Utilities Company Idaho Power Company International Brotherhood of Electrical Workers

Iowa Power and Light Company

Mr. and Mrs. Stanley H. Katz Matsushita Electric Industrial Co., Ltd. McGraw-Edison Company Minnesota Power New Jersey Bell New York State Electric & Gas Corporation

North American Philips Corporation Philadelphia Electric Company Philips International B.V.

Public Service Electric and Gas Company RCA Corporation Robert Bosch GmbH Rochester Gas and Electric Corporation

San Diego Gas & Electric Savannah Electric and Power Company Schering-Plough Foundation Texas Utilities Company Thomas & Betts Corporation Thomson Grand Public Transamerica Delaval Inc. Westinghouse Educational Foundation Wisconsin Public Service Corporation

A Note on the Sources

The pages which have been filmed are the best copies available. Every technical effort possible has been made to ensure legibility.

PUBLICATION AND MICROFILM COPYING RESTRICTIONS

Reel duplication of the whole or of any part of this film is prohibited. In lieu of transcripts, however, enlarged photocopies of selected' items contained on these reels may be made in order to facilitate research.

PUBLISHED WORKS AND OTHER WRITINGS

This series consists of articles and other published works by Edison, along with a few manuscripts that were probably intended for publication. A comprehensive bibliography of Edison’s works for the period 1862-1898 precedes the microfilmed documents. Those items that have not previously been published in the book or microfilm editions of The Papers of Thomas A. Edison have been filmed here. Included are nine articles describing Edison’s X-ray experiments of 1896, as well as other works dealing with a variety of electrical technologies and general topics. Some of Edison’s publications, particularly for the West Orange period, were based on research conducted under the direction of various associates. For example, his "Account of Some Experiments upon the Application of Electrical Endosmose to the Treatment of Gouty Concretion," published in 1890, was derived from a formal report by Arthur E. Kennelly (see Kennelly Notebook #2, Notebook Series).

Most of the items in this series appeared as articles in technical and scientific journals, popular magazines, and newspapers. Included also are letters to the editor, papers presented to learned societies, and chapters and introductions in books. Many of the items are photocopies, and a few may be difficult to read. In addition to the published works, there is also a lengthy manuscript in Edison’s hand regarding American monetary policy and the federal regulation of business, which was probably composed in reaction to the Sherman Antitrust Act of 1890.

Chronological Bibliography of Published Works by Thomas A. Edison, 1862-1898

This bibliography includes articles, letters to the editor, and other published works from the period 1862-1898 that appeared with Edison’s byline or that have been attributed to Edison. Many of the early articles have been published in The Papers of Thomas A. Edison, Volumes 1-3 [cited below by volume and page numbers] or in Thomas A. Edison Papers: A Selective Microfilm Edition, Parts I-II [cited below by reel: frame]. They have not been refilmed here. Items that appear in Part III are so indicated. The documents have been filmed in chronological order according to the date of the journal or other publication in which they appeared.

Articles by Edison were often widely reprinted. Although some reprints are listed in this bibliography, the citations should not be regarded as comprehensive. No attempt has been made to document Edison’s involvement with in-house publications like the Phonogram.

[1862]

Weekly Herald. 12: 7.

[1868]

"Edison’s Double Transmitter.” Telegrapher 4 (April 11, 1868): 265. Vol. 1, p. 56. Filmed 9: 354.

"The Induction Relay: To the Editor." Telegrapher 4 (April 25, 1868): 282. Vol.

"Edison’s Combination Repeater." Telegrapher 4 (May 9, 1868): 298. Vol. 1, pp.

"To the Editor." Telegrapher 4 (June 2, 1868): 334. Vol. 1, pp. 66-67.

"Self-Adjusting Relays." Telegrapher 4 (August 8, 1868): 405. Vol. 1, pp. 76-77.

"The Manufacture of Electrical Apparatus in Boston." Telegrapher 4 (August 15, 1868): 413-414. Vol. 1, pp. 77-83.

"American Compound Telegraph Wire." Telegrapher 5 (October 17, 1868): 61. Vol. 1, pp. 86-89.

[1869]

"Queries: To the Editor." Telegrapher 6 (October 16, 1869): 58. Vol. 1, p. 139. [1874]

"Duplex Telegraphy." Part 1 of 3. Operator (September 1, 1874): 1. Vol. 2, pp. 288-290.

"To the Editor." Scientific American 31 (September 5, 1874): 145. Vol. 2, pp. 282-285. This item was reprinted widely.

"Platina Points: To the Editor." Operator, Supplement (September 15, 1874): 2. Vol. 2, pp. 302-304.

"Duplex - No. II." Part 2 of 3. Operator (October 1, 1874): 1. Vol. 2, pp. 315- 320. Filmed 26: 126.

"On a New Form of Relay." Telegraphic Journal and Electrical Review 2 (October 1, 1874): 319-320. Vol. 2, pp. 281-282.

"The Electro-Motograph." Telegraphic Journal and Electrical Review 2 (October 1, 1874): 321-322. Reprinted from Scientific American [see above, September 5, 1874].

"Cable Telegraphy: To the Editor." Scientific American 31 (November 7, 1874): 292. Vol. 2, p. 330.

"Duplex - No. III." Part 3 of 3. Operator (November 15, 1874): 1. Vol. 2, pp. 332-336.

"On a New Method of Working Polarised Relays." Telegraphic Journal and Electrical Review 2 (November 15, 1874): 361. Vol. 2, pp. 320-321.

"On a New Form of Relay." Operator (November 15, 1874): 2. Reprinted from Telegraphic Journal and Electrical Review [see above].

"To the Editor." Operator (December 1, 1874). Vol. 2, p. 336.

"Cable Telegraphy: To the Editor." Scientific American 31 (December 12, 1874): 372. Vol. 2, pp. 364-365.

"The Electromotograph, A New Discoveiy in Telegraphy." Journal of the Society of Telegraph Engineers & Electricians 3 (1874): 161-163. Reprinted from Scientific American [see above, September 5, 1874].

[1875]

"Electrical Problem: To the Editor." Telegraphic Journal and Electrical Review 3 (January 15, 1875): 23. Reprinted from Operator [see above, December 1, 1874].

"On the Imperfect Contacts Which Occur in Signalling with Rigid Contact- Points." Journal of the Society of Telegraph Engineers 4 (1875): 117-119. Vol. 2, pp. 433-435.

[1876]

"To the Editor." Scientific American 34 (January 1, 1876): 2. Vol. 2, pp. 680- 681.

"Mr. Edison’s New Force: To the Editor." Scientific American 34 (February 5, 1876): 81. Vol. 2, pp. 753-754.

"Mr. Edison’s New Force: To the Editor." Scientific American 34 (February 12,

1876) : 101. Vol. 2, pp. 762-763.

"Laboratory Notes," nos. 1-7. American Chemist 7 (October 1876): 127. Vol. 3. [1877]

"Laboratory Notes," nos. 1-7. Scientific American Supplement 3 (February 10,

1877) : 913. Reprinted from American Chemist [see above].

"Laboratory Notes," nos. 8-11. American Chemist 7 (March 1877): 356. Vol. 3.

"Laboratory Notes," nos. 1-7. Chemical News 36 (September 21, 1877): 138. Reprinted from American Chemist [see above].

"Laboratory Notes," nos. 1-7. Scientific American 35 (November 7, 1877). Reprinted from American Chemist [see above]. Filmed 94: 82.

[1878]

"Clocks Which Will Talk: The Wonderful Possibilities of Edison’s Invention." New York Sun (April 28, 1878). Filmed 25: 173-174.

"The Phonograph and Its Future." Scientific American Supplement 124 (May 18, 1878): 1973. Filmed 25: 269.

"The Phonograph and Its Future." North American Review 126 (May-June 1878): 527-536. Reprinted widely. Filmed 25: 198-199.

"To the Editor." New York Tribune (June 8, 1878): 5. Filmed in Part III.

"The Phonograph and Its Future." Telegraphic Journal 6 (June 15, 1878): 250. Filmed 25: 265.

"To the Editor." New York Tribune (June 27, 1878): 5. Reprinted in Engineering [see below].

"Mr. Edison on the Microphone: To the Editor." Scientific American 39 (July 13, 1878): 20. Filmed in Part III.

"To the Editor." New York Tribune (July 15, 1878): 5. Filmed in Part III.

"Professor Hughes’s Microphone." Engineering 26 (July 19, 1878): 45. Reprinted from New York Tribune [see above]. Filmed in Part III.

"Telephonic Repeater: To the Editor." Chemical News 38 (July 26, 1878): 45. Filmed in Part III.

"On the Use of the Tasimeter for Measuring the Heat of the Stars and of the Sun’s Corona." Proceedings of the American Association for the Advancement of Science (August 1878; pub. 1879): 109-112. Paper

presented to the AAAS in St. Louis by Heniy Draper, leader of the Draper Eclipse Expedition. Reprinted elsewhere. Filmed 94: 438-440.

"The Sonorous Voltameter." Proceedings of the American Association for the Advancement of Science (August 1878; pub. 1879): 112. Filmed 94: 440.

"To the Editor." Scientific American 39 (September 28, 1878): 196. Filmed in Part III.

"Telephone Relay: To the Editor." Chemical News 38 (October 18, 1878): 198. Filmed in Part III.

"The Sonorous Voltameter." American Journal of Science and Arts Series 3, 16 (1878): 379. Reprint of paper presented to the American Association for the Advancement of Science [see above].

[1879]

"On the Use of the Tasimeter for Measuring the Heat of the Stars and the Sun’s Corona." American Journal of Science and Arts Ser. 3, 17 (January 1879): 52-55. Reprint of paper presented to the American Association for the Advancement of Science [see above].

"Clerac’s Tube: To the Editor." Telegraphic Journal and Electrical Review 7 (April 15, 1879): 131. Filmed in Part III.

"On the Phenomena of Heating Metals in Vacuo by Means of an Electric Current." Proceedings of the American Association for the Advancement of Science 28 (August 1879; pub. 1880): 173-178. Reprints of this paper have been filmed. See 26: 364-365 and 47: 905-908.

"On a Resonant Tuning Fork." Proceedings of the American Association for the Advancement of Science 28 (August 1879; pub. 1880): 178. Filmed in Part III.

"Mr. Edison’s Experiments: American Savants Instructed by the Menlo Park Inventor." New York Sun (September 3, 1879). Filmed 24: 667 and 94: 509.

"On the Phenomena of Heating Metal in Vacuo by Means of an Electric Current." ScientificAmerican Supplement 194 (September 20, 1879): 3089. Reprint of paper presented to the American Association for the Advancement of Science [see above].

"The Action of Heat in Vacuo on Metals." Chemical News 40 (September 26,

1879) : 152-154. Reprint of paper presented to the American Association for the Advancement of Science [see above].

"Heating Metals in Vacuo by the Electric Current." Telegraphic Journal 7 (October 1, 1879): 320-321. Reprint of paper presented to the American Association for the Advancement of Science [see above]. Filmed 26: 364-

"The Action of Heat in Vacuo on Metals." Nature 20 (October 2, 1879): 545- 546. Reprint of paper presented to the American Association for the Advancement of Science [see above].

"Edison’s Telephonic Researches." In George B. Prescott, Speaking Telephone, Electric Light, and Other Recent Electrical Inventions (New York: D. Appleton & Co., 1879): 218-234. This chapter was reprinted in subsequent editions of Prescott’s work, the titles of which vary. Filmed in Part III.

"On a Resonant Tuning Fork American Journal of Science And Arts Ser. 3, 18 (1879): 395. Reprint of paper presented to the American Association for the Advancement of Science [see above],

[1880]

"The Success of the Electric Light." North American Review 131 (October

1880) : 295-300. Filmed 53: 380-386.

"Telegraph." By Edison and others. Appleton’s Cyclopedia 2 (1880): 849-859. Filmed in Part III.

[1882]

"Description of the Edison Steam Dynamo." Co-authored by Charles T. Porter. Journal of the Franklin Institute 114 (July 1882). Reprinted [see below].

"Description of the Edison Steam Dynamo." Co-authored by Charles T Porter Electrician 9 (July 15, 1882): 199-201. Paper presented to the American Society of Mechanical Engineers in Philadelphia, April 1882, and reprinted from the Journal of the Franklin Institute. Filmed 95: 196-199.

"How to Succeed as an Inventor." In How to Succeed in Public Life ...A Series of Essays, ed. Lyman Abbott (New York: G.P. Putnam’s Sons, 1882'): 95- 104. Filmed in Part III. ' '

[1885]

"Electricity Man’s Slave." New York Tribune (January 18, 1885): 10. Reprinted [see below],

"Electricity Man’s Slave." Electrical Review 6 (January 24, 1885): 8-9. Reprint [see above]. Filmed in Part III.

"Electricity Man’s Slave." Knowledge 7 (Februaiy 13, 1885): 127. Reprint [see

"Electricity Man’s Slave." Scientific American 54 (March 21, 1885): 185. Reprint [see above]. J

[1886]

"The Air-Telegraph: System of Telegraphing to Trains and Ships." North American Review 142 (March 1886): 285-291. Filmed in Part III.

[1887]

"On a Magnetic Bridge or Balance for Measuring Magnetic Conductivity." Proceedings of the American Association for the Advancement of Science 36 (August 1887; pub. 1888): 92-94. Filmed in Part III.

"On a Pyromagnetic Dynamo: A Machine for Producing Electricity Directly From Fuel." Proceedings of the American Association for the Advancement of Science 36 (August 1887; pub. 1888): 94-98. Reprinted [see below].

"On the Pyromagnetic Dynamo, A Machine for Producing Electricity Directly From Fuel." Telegraphic Journal and Electrical Review 21 (September 9, 1887): 257. Reprint of the paper presented to the American Association for the Advancement of Science [see above]. Filmed 25: 573-576.

[1888]

"The Perfected Phonograph." North American Review 146 (June 1888): 641-650. Filmed in Part III.

"The Perfected Phonograph." Public Opinion 5 (June 9, 1888): 202-203. Reprint [see above].

[1889]

"Mr. Edison and His Phonograph: To the Editor." New York Tribune (January

23, 1889): 7. Reprinted [see below].

"Mr. Edison and His Phonograph: To the Editor." Washington Star (January

24, 1889). Reprint [see above]. Filmed in Part III.

"The Dangers of Electric Lighting." North American Review 149 (November 1889): 625-634. Filmed in Part III.

"The Dangers of Electric Lighting." Public Opinion 8 (November 9, 1889): US- 114. Reprint [see above].

"The Dangers of Electric Lighting." Electrical Engineer 8 (December 1889): 518. Reprint [see above].

"The Concentration of Iron-Ore." Co-authored by John Birkinbine. Transactions of the American Institute of Mining Engineers 17 (February 1889; pub. 1889): 1-17. Paper presented to the American Institute of Mining Engineers in New York. Filmed in Part III.

[1890]

"An Account of Some Experiments upon the Application of Electrical Endosmose to the Treatment of Gouty Concretion." Telegraphic Journal and Electrical Review 27 (August 22, 1890): 213. Paper presented to the International Medical Congress in Berlin, Germany. Filmed in Part III.

[1891]

"Recollections of My Boyhood." New York Continent 20 (May 1891). Galley proof has been filmed in D-91-04 (Document File Series).

[1892]

"Insulation." Electrical Engineer 14 (July 13, 1892): 34-35. Filmed in Part III. [1896]

"Experiments with Roentgen Rays." Electrical Engineer 21 (March 25, 1896): 305. Filmed in Part III.

"Further Experiments in Fluorescence Under the Cathode Ray." Electrical Engineer 21 (April 1, 1896): 340. Filmed in Part III.

"Are Roentgen Ray Phenomena Due to Sound Waves?" Electrical Engineer 21 (April 8, 1896): 353-354. Filmed in Part III.

"Roentgen Ray Lamps and Other Experiments." Electrical Engineer 21 (April 15, 1896): 378. Filmed in Part III.

"A Card from Mr. Edison: To the Editor." New York Journal (April 18, 1896). Filmed in Part III.

"Influence of Temperature on X-Ray Effects.” Electrical Engineer 21 (April 22, 1896): 409-410. Filmed in Part III.

"Photographing the Unseen: A Symposium on the Roentgen Rays." Century Magazine 52 (May 1896): 120-131. [Edison’s contribution appears on p. 131.] Filmed in Part III.

"Recent Roentgen Ray Observations." Electrical Engineer 22 (November 18, 1896): 520. Filmed in Part III.

[1897]

"Fluorescing Salts." Electrical Engineer 23 (January 6, 1897): 17. Filmed in Part

"Electrical Boston Thirty Years Ago." Electrical Engineer 24 (November 18, 1897): 486. Reprinted from Telegrapher, 1868.

"Introduction." In George E. Tewksbury, A Complete Manual of the Edison Phonograph (Newark: United States Phonograph Co., 1897): 10-12. Filmed in Part III.

[1898]

"Edison on the Incandescent Lamp: To the Editor." Electrical Review 32 (January 5, 1898): 7. Filmed in Part III.

"To the Editor." New York Sun (January 12, 1898): 6. Reprinted [see below].

"Mr. Edison Protests Against Yellow Journalism: To the Editor." Electrical Review 32 (January 19, 1898): 43. Reprint [see above]. Filmed in Part III.

"Edison’s Views on Lightning Rods." Electrical Review 32 (June 29, 1898). Filmed in Part III.

[PHOTOCOPY]

["Mr. Edison on the Microphone: To the Editor." Scientific American 39 (July 13, 1878): 20.]

fifommanimHons. :

To the Cilitor of the Scientific American : <

In reply to ilio communication of Messrs Pitt nnil Dopp, wliicli nppcurci! In your Issue of Juno 20th, under the head- toe ot Tho Microphone,” I wish to sny Unit Imd the uhovo '"'"led gentlemen rend carefully what I have said In regard to tho variation iu tho cleotrio conductivity of carbon and . other semi-conductors when subjected to pressure, they would have saved themselves tho Iroublo of wrltiugyou. I stated, and proved, Hourly two yoarsago, that conductors of electric- lly when finely divided nud moulded iu dim form of but¬ tons varied their resistance by pressure, and subsequently that the whole elfect was due to surface contact, and not to Intcr-molcculur action. Mr. .M. Richards, ;of tho Colt s Arms

-explanation oilerod by Professor Hughes, 'which your corre¬ spondents referred to, is capable of being shown as nbsurd, and only tends to provo that ho did not gain his Information : by experimental research, hut simply by piracy.

,, i T. A. Edison,

Menlo Park, N. J., Juno 24, 1878. f

[PHOTOCOPY]

["Professor Hughes’s Microphone." Engineering 26 (July 19, 1878): 45. Reprinted from New York Tribune (June 27, 1878).]

[PHOTOCOPY]

["Telephonic Repeater: To the Editor." Chemical News 38 (July 26, 1878): 45.]

CORRESPONDENCE. telephonic repeater.

by me over a year ago. and one

IfiSKssasssfe*

Menlo P«,k, N.J., July «, i«,S.

[PHOTOCOPY]

["To the Editor." Scientific American 39 (September 28, 1878): 196.]

(Somsiimuleutt.

2b the Editor oftho Scientific American : I

week or so past, on tlio possibilities of Professor Edison’s

Granting that it can bo so sensitively made and adjusted as to detect a star by Invisible radiations, then I would pro- 1

seen advanced heretofore, namely, for the measurement of distances of heavenly bodies from tlio earth.

If it is not already known, it would bo a matter of com¬ paratively casyoxperlment to establish a ratio of Increnso orj

given temperature measured at regularly approaching or ro-j ceding instances. For Instanco, the heat of the dame of n| candle^ being, soy, 10’ at 13 feet dlstanco, will Indicate on!

will bo, say, 8K’j and so on regularly for .tho Increaso or decroaso of distance. So that if at the least dlstanco from the Instrument measurement is mado of a heated object (which, If at a greater temperature than that previously os-

measurement Is then mado at on Increased denown dlstanco from tlie Instrument, by the quantity Indicated on the scale,!

mathematical formuloMhe distance of tlm body from the

for e sample. Lot one obsorver observe at exactly the mid-day meridian passage, anil another, nt tlio same instant of timo.

of tho sun ns about 05,000,000 miles, such an instrument, to detect a difference In the loss of hent, coming from n source so fnr distant, while traversing 3,000 miles, or 3-05,000 of the whole, must be able to detect tho loss of heat for every inch of removal of a body distant half a mile from tho In¬ strument! Can it be dona?

’’It’s a big thought to think;” and yet. If it is possiblo for the spectrum to pick up and photograph upon tho oyo

Ascribing nl

why is no

tho inventor of this most won _ _

near, pulling new possibilities and grand thoughts 0 minds of men, I nm. Joint Thomson.

York, August 24. 1878.

2b the Editor oftho Scientific American :

Referring to the communication from Mr. John Thor which you kindly sent me, I havo overy reason to bc„„,u that the tasimetor will do all that he proposes. It certainly Is infinitely delicate, and Its only limit seems to bo in dej tority of manipulation. Last evening, while using tho Thon son galvanometer, tho spot of light went oil of tho seal when my hand was placed in line with tho tasimeter stand Ing at a dlstanco of fifty feet away froi I Menlo Park, N. J.. Sept 4, 1878.

[PHOTOCOPY]

["Telephone Relay: To the Editor." Chemical News 38 (October 18, 1878): 198.]

•■ ^CORRESPONDENCE. . --

' *■ TELEPHONE ^ RELAY.V £ '

To the Editor of: the Chemical Hetos.r&r. rl . StR,— In the Chemical News, vol. xxxviii., nJ ;j'38#.I . notice a counter-statement from Mr. E. j. ' Houston,' oil Philadelphia, regarding tny assertion that the telephone 1 relay which he haa brought out was devised by me over a year ago. He .aye:- . ag* : ;•.<!« .•

Now it would appear from a detcription' of thie in. etrument in the Telegraphic Journal of July i. iSjr, that Mr. Edison called his invention a pressure relay, and states that it is intended to be used in connexion with ,

telegraph i/not an articulating t el eph one*5 bu t a* spe'deso/ |

city are employed in a manner somewhat similar to the system of Gray. Nowhere in this article, or indeed elsewhere that I can find, does Mr. Edison claim that an be applied to relaying of rapidly varying articulating telephone.” .*!%*; ' ;*?. * ••

I quote from the article in the TiltgrHphie Journal of I July l, 1877, 10 which hc refers— f . j ? 1

" . . For instance, if a weak current circuiates~tipon the line in which the relay magnet is inserted the attrac* tion for the armature will be small ; consequently^ weak

the contrary, if the current In the firtt circuit bVstroiijj

and in .’proportion will ' the current in the sec Jhd circuit be Increased, no adjustment is ever required. * It'ls pro- . bablythe only device yet invented which will allow'oitlie trahsjation of signals' ^of variable ^streuglhi from| one

manner. ( The apparatus was 'tic signed by Mrl'Ediion'for .repeating acoustical vibrations o( variable striugfhs'in his speaking telephone.” ^

. This appaiaius is used r.ow.and was. used at, the date

[PHOTOCOPY]

["Clerac’s Tube: To the Editor." Telegraphic Journal and Electrical Review 7 [April 15, 1879): 131.]

[PHOTOCOPY]

[ On a Resonant Tuning Fork." Proceedings of the American Association for Advancement of Science 28 (August 1879; pub. 1880): 178.]

For the purpose of rendering audible the sounds produced by tuning forks, they are generally mounted upon resonant boxes containing a column of air whose vibrating period is the same as that of the fork. I have devised a modidcation of this plan, by

which the box is dispensed with, the resonant chamber, as is ' !bo.Wn *" ‘bo, cut> bcin6 formed by the prongs themselves. To make the fork, a thick tube of bell-metal, one end. of which is closed, has a slit sawed longitudinally through its center, the s’*1 .nearly to the closed end. This slit divides the tube equally and gives two vibrating prongs, analogous to those of a fork. To bring the prongs into unison with the column of air between them, the tube is put in a lathe and turned thinner until the desired point Is reached and the two are in unison. There- upon the sound of the fork is powerfully reinforced.

[PHOTOCOPY]

['Sr W n/lepho niC ?^earChe,SV In Ge°rge B- Prescott- Speaking Telephone, Electric 218-234] ReC6nt E ectncal Inventions (New York: D. Appleton & Co., 1879):

CHAPTER VI

EDISON'S TELEPHONIC RESEARCHES.

The following communication from Mr. Thomas A. Edison gives a detailed account of his researches in telephony, and is a valuable contribution to tho history of tho development of the speaking telephone.

Some time in or about tho month of July, 1876, I began experimenting with a system of multiple telegraphy, which had for its basis tho transmission of aeoustio vibrations. Being fur¬ nished, at tho same time, by Hon. William Orton, President of tho Western Union Telegraph Company, with a translated description from a foreign scientific journal of Reiss's1 telephone, I also began a series of experiments, with tho view of producing an articulating telephone, carrying on both scries simultaneously, by tho aid of my two assistants, Messrs. Batchelor nnd Adams.

With regard to tho multiple telegraph I will say that inany methods were devised, among which may bo mentioned tho transfer system. This consisted in combining a largo tuning fork with multiple forks, so arranged at two tcnninal stations, with contact springs leading to different Morso instruments, that the synchronous vibrations of the forks would change tho main lino wires from one set of instruments to other sets at both sta¬ tions, at a rate of 120 times per second. With this rate of vibra¬ tion tho wire would bo simultaneously disconnected at both ter¬ minal stations from ono set of Morsu signalling apparatus, and momentarily placed in alternate connection with three other similar sets of apparatus, nnd then again returned to tho first sot, without causing tho apparatus to mark tho absence of tho current otherwise than by it perceptible weakening of the same.

l Znll.ul.ria ilu. Dout.oli-OuHturrololil.cl.im Toli)gra|ilnm-Vorcln., liomu.gogulion It. tln.cn AuUnigu vun tlnr Kuiilglli)li JTitu..l.itliim Tologniplum-Dlructliiii. Ruill- glrlvnn Dr. I*. Wllliulin llrlt. Vnl.lx., lBdS, lingo JS5. (For ndoiwljrtlonofltiil..'.

TELEPHONIC RECEIVERS. 211)

By this means, therefore, four perfectly independent wires were practically orented, upon which signalling could bo carried on with any system which was worked no faster than thu ordi¬ nary Morso system. Each of those wires was ulso duplexed and found to work perfectly upon a lino of artificial resistance, thus allowing, with tho ordinary apparatus, of tho simultaneous trans¬ mission of eight different messages.

Notwithstanding the perfect success of tho system upon nn artificial lino, however, which possessed littlo or no electrostatic capacity, I liavo never, in practice, beun able to produce a snll'i- ciently perfect compensation for tho effects of the static charge

to allow of the successful uso of tho system on a lino of over forty miles in length, although I lmvo put tho linu to earth nt both stations after it leaves ono sot of instruments and befuro it is placed in contact with another sot; liavo sent reversed currents into it, nnd have also used magnetic and condenser coiiipensalinn in various wnyB, known to oxperts in static compensation, hut all without avail By 'vibrating tho lino wire between two sols of apparatus, however, good satisfaction has been obtained nirr lines of about 200 miles in length.

In my system of aeoustio transmission, which was devised in September, 1876, and is Bliown in fig. 108, two tuning forks, A

[PHOTOCOPY]

["Edison’s Telephonic Researches." In George B. Prescott, Speaking Telephone, Electric 21&22A] °ther ReCent Electncal Inventions (New York: D. Appleton & Co., 1879):

220 THE SPEAKING TELEPHONE.

mill B, vibrating from 100 to 500 times per second, were kept in continuous motion by a local magnet nnd battery, and the abort circuiting was controlled by the signalling keys K, anil Ka.

As will bo seen on reference to the figure, this system, like that shown in my patent of 1878,. is dependent upon the vary¬ ing resistance occasioned by employing a movable electrode in water, and which thus produces corresponding variations of the battery current in the line.

The receivers Ilt nnd Its, fig. 104, were formed of telescopic tubes of metal, by lengthening or shortening of which the column of air in either coukl bo adjusted to vibrato in unison with the

proper tone of the fork, whoso signals were to bo received by each particular instrument An iron diaphragm was soldered to one end of these tubes, nnd the latter placed in such a manner as to bring the diaphragm of each respectively just in front of an electro-magnet, which, in action, would cause them to vibrato. When the column of air in either receiver was properly adjusted to a given tone, the signals duo to stopping nnd starting the vibrations by the distant key were very loud, ns compnrcd to other tones not in harmony with the column of air. Flexible rubber tubes, with ear pieces, were connected to the receivers, so

MAiTmtMriuMNii muiriion*. S*l

that, in using the iiutnuucuU, the head of the o|icriitnr wan not required to held lit an unnatural or •trained |H»iihiik This system worked very well; hut one dulcet in it was apparent (rum the linit, und that was its continual tcmhiuuy to givu the n|>cnitor what is termed the back-alroke, even hum the •lightest cause, such us the opening of a door or the moving of the head, and also occurred on the slightest inattention wlmtovur.

With a Morse sounder, ns is well known, every dot is made apparent to thu ear by two sounds, the first being produced when tho lover strikes tho anvil, and the other when it strikes the upper or buck contact A dash, lilcu thu dot, is also uomposed of two sounds, but the interval of time between tho production of tho first, tho downward stroke or sound ami the upward stroke, is what determines its character. It frequently happens, how¬ ever, when a sounder is so adjusted that tho sound produced by the down stroke is of the same volume or loudness us tho one given by the up stroke, that tho order of reading becomes re¬ versed on the slightest disturbance or lnuttcution and thu ear mistakes the up sound for tho down sound, nnd vice versa. The signals consequently become unintelligible, anil tho operator can only restore tho proper order by closing both ears and watching the motion of the sounder lever, or by deudoning the back sound by placing tho finger on the lever until tho ear again catches a word or two. '

Similarly with the musical signals, the dots nnd dashes ure formed by tho relative short or long duration of a continuous tone, but in this case tho pitch is always tho same, and this con¬ stitutes an element of confusion that'is quite ns bad ns the bank stroke of tho sounder abovo referred to. I therefore arranged my keys so ns to transmit two short tones closo together to form a doty and two tones separated by an interval to form a dash ; lint there wns still so little distinctive difference between one and the other that I was led to defer further experiment with the appa¬ ratus for a time. It is probablu that somu means will he found for producing a greater degree of difference between thu two ele¬ ments of tho signals, such, for instance, us thu employment of two

IBEST AVAILABLE COPYI

[PHOTOCOPY]

["Edison’s Telephonic Researches." In George B. Prescott, Speaking Telephone, Electric Light, and Other Recent Electrical Inventions (New York: D. Appleton & Co., 1879):

222 .the speaking telephone.

forks of slightly different 'pitch, which, at least, promises well. When this is dono the system will be of some value.

It will bo noticed that the receiving instrument shown in fig. 1 04 contains the diaphragm magnet and chamber of the magneto- speaking telephone ; and I may say here that I believe I was the first to devise apparatus of this kind, which I intended for use in connection with acoustic telegraphs. I can, however, lny no claim to having discovered that conversation could bo carried on be¬ tween one recoivcr and the other upon the magneto principle by causing the voice to vibrate the diaphragm.

Another system of multiple transmission consisted, partly, in the use of reeds for receivers, and has been exceedingly well de¬ veloped in the hands of Mr. Elisha Gray, but I forbear explain¬ ing it here, owing to its complexity and lack of practical merit

My first attempt at constructing an articulating telephone was made with the Reiss transmitter mid one of my resonant receivers described above, and my experiments in this direction, which continued until the production of my present carbon telephone, cover many thousand pages of manuscript. I shall, however, describe hero only a tow of the more important ones.

In one of the ilrst experiments I included a simplified Reiss transmitter, having a platinum screw facing the diaphragm, in a circuit containing twenty cells of battery and the resonant re¬ ceiver, and then placed a drop of water between the points ; the results, however, when the apparatus was in action, were unsatis- factoiy— rapid decomposition of the water took place and a de¬ posit of sediment was left on the platinum. I afterwards used disks attached both to tho diaphragm and to the scrow, with sev¬ eral drops of water placed between and held there by capillary attraction, but rapid decomposition of the water, which was im¬ pure, continued, mid tho words came out at the receiver very much confused. Various acidulated solutions were then tried, but tho confused sounds and decompositions were the only results obtained.

With distilled water I could get nothing, probably because, at that time, I used very thick iron diaphragms, ns I linvo since

THE CA11B0N TELEPHONE. 223

frequently obtained good results ; or, possibly, it was bcenusu tho car was not yet eduented for this duty, and therefore I did not know what to look for. If this was tho case, it furnishes a good i illustration of tho fact obsurved by Professor Mayer, that wc

j often fail to distinguish weak sounds in certain oases when we

do not know wliut to expect

' Sponge, paper and felting, saturated with various solutions,

wero also used between the disks, and lcnifo edges wore stibsli- 1 tuted for tho latter with no better results. Points immersed in

1 electrolytic cells were also tried, and tho experiments with vari-

j ous solutions, devices, etc., continued until February, 1873, when

I abandoned tho decomposable fluids and endeavored to vary tho : resistance of tho circuit proportionately with tho amplitude of

vibration of tho diaphragm by the use of a multiplicity of pint- \ inum points, springs and resistance coils all of which wore do-

] signed to be controlled by tho movements of tho diaphragm, but

none of tho devices were successful.

In the spring of 1876, and during the ensuing summer, I en¬ deavored to utilise tho great resistance of thin films of plumbago and white Arkansas oil stone, on ground glass, mid it was hero that I first succeeded in conveying over wit~- many articulated seutenecs. Springs attached to the diaphragm and numerous other devices wore made to cut in and out of circuit more or less of the plumbago film, but the disturbances which tho devices themselves caused in the true vibrations of tho diaphragm pre¬ vented the realisation of any practical results. One of my as¬ sistants, liowover, continued tho experiments without interrup¬ tion until January, 1877, when I applied tho peculiar properly which semi-conductors have of varying their resistance with ' pressure, a fact discovered by myself in 1873, while constructing Bomo rheostats for artificial cables, in which wero employed powdered carbon, plumbago and other materials, in glass tubes.

For tho purpose of making this application, I constructed an apparatus provided with a diaphragm carrying at its centra a yielding spring, which wns faced with platinum, and in front of this I placed, iu a cup secured to an adjusting screw, sticks of

[PHOTOCOPY]

["Edison’s Telephonic Researches." In George B. Prescott, Speaking Telephone, Electric Light, and Other Recent Electrical Inventions (New York: D. Appleton & Co., 1879): 218-234.1

224 ' THE SPEAKING TELEPHONE.

crude plumbago, combined in various proportions with drypow- dera, resins, cto. By this meuns I succeeded in producing a telephone which gave great volume of sound, but its articulation was rather poor ; when oneo familiar with its peculiar sound, however, one experienced but little difficulty in understanding ordinary conversation.

After conducting a long series of experiments with solid ma¬ terials, I finally abandoned them all and substituted therefor tufts of conducting fibre, consisting of floss silk coated with plumbago and other semi-conductors. The results were then / very much better, but while the volume of sound was still great, •/ the articulation was not so clear as that of tho magneto tele¬ phone of Prof. Bell. Tho instrument, besides, required very frequent adjustment, which constituted an objectionablo feature.

Upon investigation, tho difference of resistance produced