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 1« 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 by the varying pressure upon tho semi-conductor was found to bo exceedingly small, and it occurred to mo that ns so small a change in a circuit of largo resistance was only a small factor, in the primary circuit of an induction coil, where a slight chango of resistance would be an important factor, it would thus enable me to obtain decidedly better results at once. The experiment, however, failed, owing to the great resistance of tho semi-con¬ ductors then used.
After further experimenting in various directions, I was led to believe, if I could by any means reduce the normal resistance of the semi-conductor to a few ohms, and still effect a difference in its resistance by the pressuro due to the vibrating diaphragm, that I could use it in the primary circuit of an induction coil Having arrived at this conclusion, I constructed a .transmitter in which a button of some semi-conducting substance was placed between two platinum disks, in a kind of eup or small containing vessel. Electrical connection between the button and disks was maintained by the slight pressuro of a piece of rubber tubing, J inch in diameter and £ inch long, which was secured to tho dia¬ phragm, and also made to rest against the outside disk The vibrations of the dinphragm wero thus able to produce tho
THE CARBON TELEPHONE. OO
requisite pressuro on the 'platinuin disk, and thereby vary tli resistance of tho button included in the primary ciruuit of th induction coil.
At first a button of solid plumbago, such os is omplnyud b electrotypers, was used, and tho results obtained wore consilient excellent, everything transmitted coming out moderately di- tinot, but tho volumo of sound was no greater than that of th magneto telephone.
In onler, therefore, to obtain disks or buttons, which, with i low normal resistance, could also be made, by a slight pressure to vary greatly in this respect, I at oneo tried a gi;eat variety o substances, such os conducting oxides, sulphides and other par¬ tial conductor, among which was a small quantity of lamp, black that lmd been taken from n.smoking petroleum lamp and • preserved as a curiosity on account of its intensu black color.
A small disk made of this Bubstancc, when placed in the tele¬ phone, gave splendid results, the articulation being distinct, and the volumo of sound several times greater tlmn with telephones workod on tho magnoto principle. It was soon found upon investigation, that tho resistance of tho disk could ho varied from three hundred ohms to tho fractional part of a single ohm by pressuro alone, nnd that tho best results wero obtained when tho resistance of tho primary coil, in which the carbon disk was included, was of nn ohm, nnd tho normal resistance of the disk itself three ohms.
Mr. Henry Bentley, president of tho local Telegraph Com- pany, at Philadelphia, who 1ms mado nu exhaustive series of experiments with a complete set of this apparatus upon tho wires of the Western Union Telegraph Company, has actually succeeded in working with it over a wire of 720 miles in length, and lins found it a practicable instrument upon wires of 100 to i 200 miles in length, notwithstanding tho fact that tho latter wero plaecd upon poles with numerous other wires, which occasioned ; sufficiently powerful induced currents in them to entirely destroy \ tho articulation of tho magneto telephone. I also learn that ho • has found the instrument practicable, when included in a Morao 5
[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.]
22(1 THE SPEAKING TELEPHONE.
circuit, with a battery and eight or ten stations provided with i
die ordinary Morse apparatus j and that several way stations could exchange business tclephonically upon a wire which wns being worked qundruplex without disturbing the latter, and not¬ withstanding, also, the action of the powerful reversed currents of the quadruples on the diaphragms of the receiver. It would thus seem as though the volume of sound produced by the voice with this apparatus more than compensates for the noise caused by such actions.
While engaged in experimenting with my telephone for the pur¬ pose of ascertaining whether it might not be possible to dispense witli the rubber tube which connected tho diaphragm with the rheostatic disk, and was objectionable on account of its tendency to become flattened by continued vibrations, and thus necessitate tho readjustment of tho instrument, I discovered that my prin¬ ciple, unlike all other acoustical devices for tho transmission of speech, did not require any vibration of the diaphragm — thnt, in fact, tho sound waves could be transformed into electrical pul- ,f‘
sations without tho movement of any intervening mechanism.
The manner in which I arrived at this result was as follows: j,
I first substituted a spiral spring of about a quarter inch in ■
length, containing four turns of wire, for tho rubber tube which
connected the diapliragm with the disks. I found, however, thnt
this spring gave out n musical tone which interfered somewhat
with the effects produced by tho voice; but, in the hope of over- j
coming the defect, I kept on substituting spiral springs of thicker 1 •
wire, and as I did so I found that tho articulation became both
clearer and louder. At last I substituted a solid substance for ■ ,
the springs thnt had gradually been made more and more inelastic,
and then I obtained very marked improvements in the results. ^
It then occurred to mo that tho whole question was one of pres- ■.(
sure only, and that it was not necessary that the diaphragm should
vibrate at all. I consequently put in a heavy diaphragm, one
and three quarter inches in diameter and one sixteenth inch • ■[•
thick, nnd fastened tho enrbon disk and plate tightly together,
so that tho latter showed no vibration with the loudest tones, ]
Tns OAMiON TELEPHONE. 227
Upon testing it I found my surmises verified; tho articulation • was perfect and the volumo of sound so great that conversation carried on in n whisper three feet from tho telephone was clearly heard and understood at the other end of tho line.
This, therefore, is the arrangement I have adopted in my pres¬ ent form of apparatus, whioh I call tho enrbon telephone), to dis¬ tinguish it from others. It is fully described in nnothor part of this work.
Tho accessories and connections of this apparatus for long cir¬ cuits are shown in fig. 105. A is ah induction coil, who.su primary
, wire p, having a resistance of several ohms, is placed around tho secondary, instead of within it, ns in the usual manner of con¬ struction. Tho secondary coi) s, of finer wire, 1ms a rusistnuco of from 150 to 200 ohms, according to tho degreo of tension re- - quired ; nnd the receiving tolcpliono R consists simply of a mag- -pet, coil nnd diaphragm. One pole of tho magnet is commuted to tho outor edge of tho diapliragm, and tho other, which carries tho wire bobbin of about 76 ohms resistance, and is inoluded iu tho main line, is placed just opposite its contrc.
[PHOTOCOPY]
["Edison’s Telephonic Researches." In George B. Prescott, Speaking Telephone, Electric Light, and Other Recent Electrical Inventions (New York: D. Appleton & Co., 1879):
THE SPEAKING TELEPHONE.
TELEPHONE SIQNAW.INO APPARATUS. 2211
P It is the signalling relay, generally a Siemens' polarized in¬ strument, which has been given a bias towards one side, and con¬ sequently is capable of responding to currents of one definite direction only.
Pile lover of this relay, when actuated by the current from a distant station on the line in which the instrument is included, closes a local circuit containing the vibrating call hell B, and thus gives warning when speaking communication is desired.
Besides serving to operate the call boll, the local battery E is also used for sending the call signal. S is a switch, the lever of which, when placed at o, between m and n, disconnects the trans¬ mitter T and local battery E from tho coil A, and in this posi¬ tion leaves the polarized relay. P 11 free to respond to cur¬ rents from tho distant station. When this station is wanted, however, the lever S is turned to the left on n, and depressed sev¬ eral times in rapid succession. Tho current from tho local bat¬ tery, by this means, is made to pass through the primary coil of A, and thus for each make and break of the circuit induces powerful currents in tho secondary a, which pass into the lino and actuate tho distant call bell.
1Vhen tho call signals have been exchanged, both terminal stations place their switches to tho right on m, and thus intro¬ duce the carbon transmitter into their respective circuits. The changes of pressure, produced by speaking against the diaphragm of either transmitter, then serve, as already shown, to vary tho resistance of tho carbon, and thus produce corresponding varia¬ tions in tho induced currents, which, acting through the receiv¬ ing instrument, reproduce at tho distant' station wbatovor has been spoken into tho transmitting instrument • ■
For lines of moderato lengths, say from one to thirty miles, another arrangement, shown in fig. 100, may be used advantage¬ ously. Tho induction coil, key, battery, and receiving and trans¬ mitting telephones, aro lettered tho samo ns in tho previous figure, and are similar in overy respect to tho apparatus there shown; the switch S, however, differs somewhat in construction from the ono already described, but is mado to servo a similar purpose.
When a plug is inserted between 3 and 4, tho relay or sounder 11', battery E, and koy K only are included in tho main liuu circuit, and this is tho normal arrangement of tho uppurutus for signalling purposes. Tiie battery, usually about tlireu culls of tho Duniell form, serves also botli for a local and main battery. When a plug is inserted between 1, 2 and 4, tho apparatus is . available for telephonic communication.
I have also found, on linos of from ono to twenty miles in length, that the ordinary call can be dispensed with, und a sim¬ plified arrangement substituted. This lattor consists simply
of tho ordinnry receiving telephone, upon tho diaphragm of which a free lover, L, is mado to rest, as shown in fig. 107. When tho induced currents from tho distant station act upon the receiver It, the diaphragm of tho lattor is tlu-own into vibration, but by itself is capable of giving only n comparatively weak sound ; with tho lover resting upon its contro, however, a sharp, penetrating noise is produced by the constant and rapid rolmumls of tho lover, which thus answors very well for calling purposes at stations where there is comparatively but littlo noise.
[PHOTOCOPY]
["Edis°n»s Telephonic Researches." In George B. Prescott, Speaking Telephone, Electric 218 234] °thSr Recent Electrical Inventions (New York: D. Appleton & Co., 1879):
280 TIIE SPEAK IN a TELEPHONE.
Among the various otlier methods for signalling purposes which I liavo experimented with, I may mention tho sounding' of a note, by the voice, in a small Eeiss's telephone'; the employ¬ ment of a self-vibrating reed in the local circuit; and- a break wheel with many cogs, so arranged as to interrupt tho circuit when set in motion.
Fig. 107.
| I’LEOTOO-STATIO TELEPHONE. 281
* f* w'fe and to earth. When one of the forks is set in vibration by
I a starting key provided for tho purpose, tho currents produuud
by tho approach of ono of its magnetised prongs towards tho I . magnet, and its recession therefrom, pass into tho lino anil to tho • • further station, where their notion soon causes tho seeond fork
to vibrato with constantly increasing amplitude, until tho bull is i struck and the signal given.
d», - £ MS. - , rkj
, H TC-
I have also used direct and induced currents to release clock work, and thus operate a call, and in some of my earlier acoustic experiments tuning forks were used, whoso vibrations in front of magnets caused electrical currents to be generated in tho coils surrounding the latter.
By tho further action of these currents on similar forks nt n distant station, bells were caused to bo rung, and signals thus
given. Pig. 108 shows an arrangement of this kind. AandB
are two magnetized tuning forks, having the same rate of
vibration and placed at two terminal stations. Electro-magnets
m and 7»l nro placed opposite one of tho prongs of the forks at
each station, while a bell, C or D, stauds opposito to the other. V
The coils of tho magnet are connected respectively to tho lino
rig. m.
For telephonic calls the call bells nre so arranged that tho ono opposito to tho fork, which generates tho currents, i j thrown out' of tho way of tho latter's vibrations. *
Another call apparatus, which I have used, is represented in fig. 109. In this arrangement two small maguetio pendulums, whoso rates of vibration nro tho samo, nro placod in front of
separate eleotro-mngnets, tho helices of which join in tho main line circuit When ono of tho pendulums is put in motion, thu currents generated by its forward and backward swings in front of tho electro-magnet pnss into tho line, and at tho opposite ter¬ minal, acting through tho helix tliero, cause tho seeond pendulum to vibrato in unison with tho former.
Pig. 110 shows a fonn'of cloctrophorous telephone which acts
[PHOTOCOPY]
E'w SKSf fS^T; In Ge°rge B' Pres“«- SPe“kinS Telephone, Electric 218-234 ] ° h Recent Electncal Inventions (New York: D. Appleton & Co., 1879):
282 THE 31‘EAKINQ TELEPHONE,
by the approach o£ the diaphragm contained in A or B towards or its recession from a highly charged electrophorous. O orD. 'I'lte vibrations of the transmitting diaphragm cause a disturbance ul the obul't'° at ^oth ends of the lino, and thus give riso to faint Hounds. Perfect insulation, however, is necessary, and either apparatus can he used both for transmitting and receiving, hut tbo results are necessarily very weak Another form of electro-static telephone is shown in fig. 111. In this arrangement. Deluo piles of some 20,000 disks each are contained in glass tithes A and B, and conveniently mounted on glass, wood or metal stands. The diaphragms, which aro in electrical connection with the earth, are also placed opposite to ono polo of each of the piles, while the opposite poles are joined together by the line conductor. Any vibration of either dia¬
phragm is thus capable of disturbing the electrical condition of the neighboring disks, the same as in the electrophorous tele¬ phones; nnd consequently the vibrations, when produced by the voice in one instrument, will give rise to corresponding electrical changes in the other, and thereby reproduce in it what lias been spoken into the mouthpiece of the former.
With this arrangement fair results may be obtained, and it is not necessary that tho insulation should bo so perfect as for the electrophorous apparatus. Fig. 112 shows a form of electro- mechanical telephone, referrod to near the beginning of this communication, by means of which I attempted to transmit electrical impulses of variuhle strength, so ns to reproduce spoken words at a distance. Small resistance coils — 1, 2, 8, eta— were- so arranged with connecting springs near a platinum faced lever
- • . .
i j
j| TUEUMO-ELECTllIO TELEPHONE. 283
“• B, in connection with the diaphragm in A, that any movomunt
of the latter caused ono or more of tho coils to bo out in or out of the -primary circuit of an induction coil 0, tho number, of course, varying with tho amplitude of tho vibrating diaphragm. Induced ourrenta corresponding in strength with tho variations of resistance were thus sent into the line, and could then bo made to act upon au ordinary receiving telephone. By arranging tho
springs in a sunflower pattern about a circular lover, I have suc¬ ceeded in transmitting articulate sentences by this method, hut the results were very linrsh and disagreeabla Fig. 118 shows a form of tho water telephone previously re¬ ferred to, in wliich a double cell was used, so us to alford enii;. sidcrable variation of resistance for tho very slight movements
-ffy. 113.
of the diaphragm. ■ Tho action of tho apparatus will readily lie understood from tho figure, where a wire in tho form of tho letter tl is shown, with tho bend attached to tho diaphragm, and its ends dipping into tho separate celis, and thus made to form part of tho circuit when tho line is joined to tho instrument aL «
I am now conducting experiments with a thermo-electric tole-
[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.]
281 ' THE SPEAKING TELEPHONE.
phone, which gives some promiso of becoming serviceable. In this arrangement a sensitive thermo-pile is placed in front of a diaphragm of vulcanite at oach end of a lino wire, in the circuit of whivh lire included lowresistance receiving instruments. Tho principle upon which the apparatus works depends upon the change of temperature produced in tho vibrating diaphragm, which I have found is much lower us the latter moves forward, and is also correspondingly increased on the return movement.
Sound waves are thus converted into heat waves of similar \ characteristic variations, and I am in hopes that I may ultimately be able, by the use of more sensitive thermo-piles, to transform these heat waves into electrical curronts of sufficient strength to produce a practical telephone on this novel principle.
Before concluding, I must mention an interesting fact con¬ nected with telephonic transmission, which wns discovered during some of my experiments with tho magneto-telephone, and which is this, that a copper disk may bo substituted for :tlie iron dia¬ phragm now universally used. Tho same fact, I believe, has also been announced by Mr. W. It Preece, to the Physical Society, at London.
If a piece of copper, say ono sixteenth of an inch thick and three fourths of nn inch in diameter, is secured to the centre of a vulcanite diaphragm, the effect becomes quite marked, and tho apparatus is even inoro sensitive than when tho entire diaphragm is of copper. Tho ennse of the sound is due, no doubt, to the production of very weak electrical currents in the copper disk
[PHOTOCOPY]
["Telegraph." By Edison and others. Appleton’s Cyclopedia 2 (1880): 849-859.]
"oralnt^tho'^vaeum ^ t^ b P,°lnJ,of con.t:e,ltratJion l,|cse sirups nro passed through tlio charcoal
l«I»nnUUowa“if!ur\Ul11 Zfn,,'l’ ?'llUr0 ,‘l10 su«ar U M 10 ''4™ auUd
5 S . . *« •» «■»
\Vbrkt for Itcfmna.—' “Stnlcmiint of thn Sugar Cron nib In Louisiana " ri,n,nn„,ni„» r„„ 1
$ZlSST‘- Manual ,» Evan*, IsoSfon, S.
S^HuL"SSsLS3S?^Z^Ln&\5^^ g-«-.
°,f S,l““r'" K«rr. Lomlon, m.ll; “ Manufacture of Suuar and tl 0 Mu'S! ih !SWi J.u,?h' L",."lui'.' 18"u> Mlatnrjr of Sugar and Sugar-YInldlug Plant!!” Rood I 0 I
D0IS1 ibrimXn'du S*- „ j'“ l‘,,‘ do^Cldiulo a|i|iu!|!uia nu
^oaton' and " Manufacture of lluet-itoot'Suyar,'’ C
TALKING MACniNE. Son Piiomoiunt.
In practice, the magnet of the recorder or register current upon the line, especially upon lines of considi York und Washington. Considerable power is rcquli
by the use of a very powerful battery. To dispense power to effect the Indentation of the paper, a magne the recording instrument in the line, and the latter is but a few feet of wire and one or two jars of battcrv, 'Jim Jlclny, Fig. 4088, is provided with n delientely. by uvo^crews, the one uiwhe right, 6, being tipped v
core ceases to attract the nrinuturc. The lever and p< register, and serve to stop und start the flmv of clceti ins key docs in the main circuit ns previously dcscrib
[PHOTOCOPY]
["Telegraph." By Edison and others. Appleton’s Cyclopedia 2 (1880): 849-859.]
mil receiving apparatus. 1
unison or swing. Connilctod to
™t!io fo!|UUTho 1 ptotinum poi*' ta*h f fr^lpioc'‘ljion until the
’is prevented from passing toto the platen, upon which is luid a
lar point is reciprocated ovul » F,UM;U, wmen as lum a sheet °ff the .circuit ihrough iho reciproculcd iioint ami moist.
lo th'o (Ittwr!1^ Bn t^win^to^tN^
1 3h»imi
at a speed of from 18
Tim dep rcs’sion of \ ^ t,IC ^,‘cntft0,J,e; J 'Hie Edison The paper is prepared at a speed of from 85 to 50* w
L
(+o o o
loo O O Cl
-o o o
tained by using a supplementary row of holes placet paper is carried forward by a tootlicd wheel engagin' fointed strip used in thc,\Vhcatstono system. The j:
represented by the smaller circles. ^lyUdr smitter. The slip is perforated for tlie’lcttcr
-j — ;• — “»o obtained by induction the other direction. The transmission of the currents
and” El{json’f‘I8-v j’pf tl,° tra»wniittcr consists of a dri
arranged so thatThcy wilt *Ml^ ,,,tt,5mnn- -v,lccI'
upper perforation is used in conjunction with one wh
\ O yooo
O
ooooo
[PHOTOCOPY]
["Telegraph." By Edison and others. Appleton’s Cyclopedia 2 (1880): 849-859.]
[PHOTOCOPY]
[’TIow to Succeed as an Inventor." In How to Succeed in Public Life: A Series of Essays if
ed. Lyman Abbott (New York: G.P. Putnam’s Sons, 1882): 95-104.] |
[PHOTOCOPY]
[PHOTOCOPY]
[''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.] ^
nK-ncincr at seven o'clock at »i ht and rh till eight or nine the next morning. 1 do not find this wearing on my health ; in fact, 1 do not believe that any thing is wearing-that you like.
There must be continuity of work. When you set out to do a certain thing never let any thing disturb you from doing that. This power of putting the thought on one particular thing, and keeping it there for hours at a time, comes from practice, and it takes a long while to get m the habit. I remember, a long while ago, I could only think ten minutes on a given sub¬ ject before something else would come to my mind. But, after long practice, I can now keep mv mind for hours on une topic without being distracted with thoughts of other matt ers. « When 1 was at Menlo Park, 1 was once working with my assistants a long time trying to connect a piece of carbon to a wire ; every time it would break. Then 'we would' spend several hours in making another, and that
would break. After working a day ami t wo nights in this way, we finally accomplished <£.ir purpose. One of my assistants wearily got up and said : “Well, 1 think Job got too much reputation on a small capita! ! "
The fact is. the inventor must have a tre¬ mendous amount of patience. There are proba¬ bly one hundred disappoint meats t o one success, and the things that are valuable seem to be very hard to do. Then, loo, hi: must have the quality of imagination largely de¬ veloped, or he will get into a rut, and that is the one thing above all others he must not do. In addition to these qualities, the inventor should have an analytical mind.
A man to lie an inventor need not be a great mathematician. 1 have had college-bred assist¬ ants who were “ ’way up,” as the saying is. in arithmetic and algebra, but who sometimes made the most outrageous mistakes in their calculations. With a thorough a'cqeaintance with the ordinary branches of arithmetic a man
[PHOTOCOPY]
['TIow 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.]
;j K
I i!
ro SVUCEK/J
Ca" maku calculations .accurate enough for -i]]
practical purposes. Faraday, the greatest of all experimentalists, has nothing about mathemat- >cs in Ins books. Such a knowledge is neees ”7 !" Pur" scit:n«=- but not in applied science.
It is not necessary that young man in or <ler to succeed should have a collegiate (duel f°n. If he has a natural taste for mechanics l-e will educate himself while carrying out his P ans , that is to say, educate himself in all that I3 7?^ to s“«*ss in his profession.
! r:,Ct' Sl,ch Poetical education is the only e u cation which is good for any thing. Learn¬ ing science and mathematics in college is one ‘Wig I learning them practically and expert
- “?• vi? <mrc,u ^ bm 1
J..ak too highly of the technical schools. Theft iey teach not alone from books, but allow the pupils to work at the bench. The Troy Poly¬ technic School, I think, turns out the best men. Then there are the Massachusetts In¬ stitute of Technology, the Stevens Institute of
■ IS AJf It! VENTOK. 99
Technology, and the Washburnc Institute,— all
Whether the would -he inventor goes to col¬ lege or gets his education practically in the shop, the proper way to make progress in his 1 c._rning is to set out to do a certain thing, and lo read, study, and experiment on that one sub¬ ject. In these days the domain of science is so broad that it is simply impossible for one man to acquire a universal knowledge of it. There¬ fore. let him lake one subdivision of it, and, paying no attention .0 the rest, let him devote his whole time to that. If he succeeds in mas¬ tering that subdivision he can go into some¬ thing else.
The student will learn a great deal by the way. To illustrate: in my carbon lamps 1 found I had to use bamboo. I set to work and tend Every thing I could find in the works on botany in regard to bamboo and the family of gigantic grasses ; experimented 'with the microscope. Now, I am no botanist; but I
SUCCEED
, !■< ■ * know enough about the science to answer my !
■ ;,;i purpose. Anc! 1 never read any thing about the
j§t. ' steam-engine until a year ago. The rule should
; > ke never to read any thing you are not inter- l
! IS estedin. ‘ .jj
! Rut the student, will find that experience is ]
; | the best teacher. The reason why 1 get along ' :|
«| with comparative ease how is because 1 know
* f!' h"om experience the enormous number of things
that • will not work. From the great number of experiments 1 • have made, and the vast i j .1n , amount of information 1 have stored up, 1 am
■ tji saved a great deal of time and trouble in not /
;Vt5i having to travel over barren ground.
‘•!«i There arc charlatans among scientific men, - ;
• ' as there are in all .professions. You will fijid
i»3 1 *n hooks, for instance, experiments described
|ji| tlwt could, in the nature of things, have been * \
made but once. 1 he results are accepted as jllS facts by some. Sometimes, with the increase
||| ; of knowledge, it is proved that the experiment
could not have been made at all ; the write simply been imposing on the public.
The reason why so many so-called “ ii tors" fail is because they have not the j of analysis, and they are not practical, instance, a man will devise a machine certain object He makes an enormously plicated affair and gets out his patent, he has obtained Ids patent lie finds there demand for such a thing; and, if there is rnand for it. Ids want of practicability lias the machine so complicated that it cann made a commercial success. The only It can apply to himself when he is workin order to see that he is on the right trn common-sense. Therefore, it would m well for him to be born with a silver spo Ids mouth. It will be a Help, instead of a drance, if he has had to knock around the \ and earn his own living, for he will ha better L-nimUm of . .1.. .-*1
[PHOTOCOPY]
["How to Succeed as an Inventor." In How to Succeed in Public Life: A Series of Essavs ed. Lyman Abbott (New York: G.P. Putnam’s Sons, 1882): 95-104.]
will know that the world does not pay for any thins; unless it absolutely wants it.
Another reason for failure is that inventors work well enough while ever)- thing goes smoothly, hut give up when thev get - stuck." That is just the time when one should not be discouraged ; at such a time the inventor should bring all his powers of patience and persever¬ ance to bear on the matter in hand.
Tor the young. man who has, as I said in the beginning, a natural taste for mechanics.— such a taste ns amounts to an enthusiasm, - the pros¬ pect for success as an inventor is good. He can take hold of almost any thing; the steam- engine, for instance. Probably a million men have already worked at it. That would not deter me in the least; because that which is knowi^lo what is possible to he known, stands, we will say, as one to ten millions. The best method of doing almost any thing you can mention in mechanics has not yet been' found out. Wc have not got the most perfect sewing-machine.
1-ifty years hence the sewing-machine wc have now will be laughed at. The mind of man if so almost infinite that the field is unlimited But the only proper wav is to take up one branch: make yourself a specialist.
Of course there is pecuniary reward for the successful inventor. If, by some, slight mechan¬ ical invention, you muld save one eighth of one per cent, in weaving a yard of cloth, o make the value of a spindle one tenth of out per cent, more, the amount saved all over the world would he enormous. They had an ore in Tngljjnd that contained so much phospho rus that they could not work it. Two men conceived the idea of lining the surface with fire-brick to absorb the phosphorus. And that slight change opens up an enormous tract of country containing this ore. They sav that the man who conceived' the idea of putting brass tips on children's shoes netted half a million dollars from his invention. That, vou see, was an invention that combined the two
[PHOTOCOPY]
^ U SUC<-EED JS si AT INVENTOR.
successful qualities: it was simple and it' was panted by the public. Men very often admire *e invents a complicated machine,
but they will not purchase his machine ; they buy the one that does the same work in a simpler way.
How To Succeed:
A N eminent physician, who had long mad . a stud>' o{ .the brain, its functions am diseases, once said to me that the partition be tween genius and insanity was as thin as tissue paper. Endowment with genius, therefore, ii by no means an unmixed blessing, as not a fev facts and experiences go to prove. I would no think, even for a moment, of writing a line o: suggestion to this gifted class.' If they have sufficient balance to. preserve intact that thin tissue- wall of safety, and ' sufficient common- sense to work, their genius will rise on men’s vision as surely as the star that appears above the eastern horizon, and the world will have
[PHOTOCOPY]
["Electricity Man’s Slave." Electrical Review (January 24, 1885): 8-9.]
Eloctrlclly Man's glare.
hail played a parlao raillcnl am ilriclly. Hardly a single ncrv complex body which wo cal [ society, that haa not thrilled and rlbralcd will alrcngthened tha bond
o f trade and lent ton fold pre- 1 clflon and celerity to the Innumerable agencies 'by which It worka; It haa breathed new tIUI- lty Into the arta and sciences; it haa eren warmed and alrcngthened the aoclal forces; and ln'a word one may Juatly claim for it I such a unlvcraal atlmulua.aa cannot be credit¬ 'd lo any other purely phyalcal agency In tho world'a hlatory.
It la not yet fifty yean alnce the Invention | of the electro magnetic telegraph, made by Profceaor B. P. n. Morac, waa first put Into operation between Washington and Halil- re. To-day there la hardly a hamlet ao ill and remale that a telegraph atatlon a not link Ha Inhahltanla wllh every point he civilized worliL Tho crude apparnlua i deed by Profeaaor Morae liaa been again again Improved on by subsequent In.
| vector* In tho eame field. ...
Only a few year* elapsed after the micccai of Profeaaor Morac before the drat auhmarlm cable operated in America waa laid betweer Cape Itay and the ahorea of New-Bruoawlck Thla achievement In 1852 euggeeted to Mr Cyrus W. Field, we believe, the connectloi of the New World with the Old, by mennao
Many Inver
iwycr. bail previously 1 | experimenting with a' view to making ur Inmpa giving llglitby menoa of Incandesce
on fnllacloua tbcorlea and- were fort-doc lo failure. The writer waa led lo the In Hon or the filament lamp by keeping In ml
the com - -
piled to
ip forming but one unit of : complete ayatem. Ilia object, therefore, wn not merely the device of an elcctrlo lamp; h aimed to Invent aayatrmof electrical illumln niton which could be operated on an extend edacalc In tho name manueraalathobualnca of gas Illumination; to find some means bj which the electrical energy could be turner into light, and that light lie used for house
a ayatem superior- to that ol o compete with It commercial ■eault of these experiments wa
nnd tho starting of a Contral Station In New j York, at 8 r.M. on September 4. 1888. Then : for the (lr*t time electricity for the produc- 1 lion of light waa supplied and sold o meter. Thla station has breo In operai I alnce. night and day, and haa been folios 'by the establishment of other stations t : In this country nod Europe.
In addition to the foregoing, electricity boon brought to tho aid of melal-workers the purposes of electro-plating end elec typlogilthas assumed a place Incur houses for ; the operation of cnll-bolls and sonuoclalora; , for protection agatost burglars; and for tbcl correction of our clocks and other purposes. | , Yet though ao much haa been already dooe In tbs last fifty years in the way of elei development, the writer I* confident tb
The efforta : snee telcpbon atlafaclory Id
ice telephoning havo already pr
now daily carried on between I York and Doston to a limited extent, great difficulty In long.dlstnnee tclcplx le tho loss of tho current by static Induction I | on the earth and wires In close proximity. If igle wire could be pltced sufficiently higb
>r If a wire could be siretchc be earth to the moon, the conncctlo I could also bo adequate. Perfect results wei I recently obtained on a Government line 1 Arizona, a distance of about a thousan mile*, the wire stretchlngoveratreeleM spec of country, more perfect far than can how be ! ■had between Now York nnd Hartford. Tbs I loss of the electrical energy by static absorp¬ tion nnd the running logtlbor of lbs elec- Irlcsl waves, Is the fact Dial utterly precludes the possibility of sub-marine telephoning is Hie ocean. One thing, however. Is now tin, that the lime Is closo at hand when | Otophone will be perfectly successful Id nbroken circuit for a distance of at least 1 nllcs; and that a subscriber will be ablo ; ommunlcato wllh 75,000 commercial i es. More tbau this, even, It Is probable Hint by means of repealing stationa, com. j itcallon can be had over all parts of the :
; United States.
b wrought by leicpnone wilt he equaled, hy tho transformation wrot trical lighting. Two years' bcronil a doubt I' household purpt sold in compollllc
legrapb and I rmnllon wrought through elec- j
[PHOTOCOPY]
[ Electricity Man’s Slave." Electrical Review (Januaiy 24, 1885): 8-9.]
great problem lo
A^TOihriKttlctaTTWB^ -
. . -*■ application anting Its trill. I
cal energy from coal. Tbs dream of w tranefonned directly from ihe aolar
i derived In aome simple and Inexpensive ay directly from coal, which la aolar heal id light stored up by nsm™ — n—
believes lo lie a certain ft...
of producing electricity
. Tbe present
labor lo operate It, the ultimate product la very costly. Once, however. Ihe secret of the direct production of Ihe electrical energy from coal Is discovered, a marvelous revolu- lion will take place. The coat lo the con. Burner Ihcn will bo very email. From one great central station In a city electricity will lie furnished lo giro light, heat and power to houses, stores, public buildings, factories and workshops, and at bo reduced a cost as
living will probably sec direct transformation of i would utilize 80 per c« process of turning the on heat, heat luto energy c
Electricity os
ichold oi
It has already been successfully used (forex* perl mental purposes) at Berlin, Paris, Port ! Rush (Ireland), and by the writer at Menlo Park as a motive power on a railroad. Theae.
various experiment *
id Indical
y of tho elect:
; Th“ of rebellions orw, Which
i for the want of an economical method of I working are to-day practically usdcre, will I probably at some data not far bcncc yield to man Iba predoua metal they contain by assistance of electricity. Though tbe ex¬ periments hsvo not been very successful, enough bes been done lo show that there will be eventual auccesa.
Such, briefly (old, are the marvels of elec- m'kMl *" “lre“dy “ccomP,l«hcd, or ns foresight. If the story could bare been tuld *s a prophecy flfly ycara ago it would Imvo dnred even the most adventurous mind. Yet the oilier half of Iba alory hidden behind Ihe veil will not be a Jot less wonder, ful. The writer, lo revlowlng what be believes from a long nnd absorbing aluily of Ilia problems of dcctrldly, has only lotirh- ed on thoao phases of development which experiment has shown lo bo within thograsp of tho scientific Inventor. To discuss Its possibilities would bring Into play a linn of
dreams of Ibo poet than to the aober Judg meat of Ihe practical worker. -if. T. Tribune, j
[PHOTOCOPY]
["The Air-Telegraph: System of Telegraphing to Trains and Ships." North American Review 142 (March 1886): 285-291.]
THE AIR-TELEGRAPH
Ststem op Telegraphing
Trains and Ships.
H
I have been asked to write something about my now system of • telegraphy by induction between moving railway trains and tbo usual fixed stations, which' makes it possible to send messages through tho air without attaching any wire to the 'cars or to the
The indnction coil has long been known to electricians and studied by them, bnt its enormous practical value does not seem to have been understood. Indeed, this has hardly been suspected by those who have used the coil simply in scientific experiments. A number of years ago an induction coil was made, which had the power of throwing sparks a distance of twenty-one inches and making them penctrato solid blocks of glass threo inches thick ; and this was considered so remarkable that it is recorded as among the most striking of experimental achievements. But I arrived at something much more startling than that, in tho course of some researches which I had undertaken for another purpose. For some years I have been at work looking for a new force, traces of which I havo often observed in my study of electrical and other action— a forco which is constantly present in many forms and places, but has never been measured, named or brought under con¬ trol. I have devised dozens of machines to test this unknown forco and ascertain its characteristics ; and I havo now planned a test which may, within a few months, givo me a clear proof of its existence and put me on the trail by which I can follow it up and capture it.
While I was carrying on investigations upon this line, I found that, by means of an apparatus whioh I had made, I could thrown very strong electric current fifty feel through the air, from one conductor to another, by means of a simple primary coil which
[PHOTOCOPY]
["The Air-Telegraph: System of Telegraphing to Trains and Ships." North American Review 142 (March 1886): 285-291.]
. 280 ' TOE NORTH AMERICAN REVIEW.
gavo spark in tho air, wliilo tlio secondary coil conncotod therewith, although giving sparks through tho air sovcral inches in longth, was powerless to transmit a wavo over this great distanco. This fact at onco oponod a wholo now field for tho practical uso of induced olcctrioity in telegraphing botwcon points at which a wire connection would not bo practicable. It was like finding suddonly a now volume of romanco in tho ond- tos library °f oleotrioal wondors. Aftorwards my friends, Mr William Wiloy Smith and Mr. E. T. Gilliland, came forward with an invention patented by thorn in 1881, for working tho telephone by means of induced currents to and fro botwcon railroad care and n special wire near tho track. Wo combined our resources, and I wont on osporimonting— having discarded tho tolopbono nod adopted Moiso oharactore — until, beginning with a lenp of tho cur¬ rent through fifty feet of air, I am now ablo to sond it fivo hun¬ dred aud oighty foot. Henco it appeared that no special wire uou d bo needed closo to tho track, becanso tho ourront generated on tlio car could jump ovor to tlio regular Morso wires ; and theso wires woro used by mo, through tho employmoufc of proper instm- merits, to convoy messages to their destination, without intorforin"- '"“‘l '10 ree“l“r trafflo. Tho result of work by Mr. Gilliland and myself, in inventing, perfecting and adnpting apparatus, is that a circuit can now bo established botweeu any train, cither moving or at a. stand-still on a railroad, and tho torminus of tho road : or bo- tween tho trains and any station on tho route. A circuit is also cstabhshcd botwcon any ouo train and all othor trains on tho sumo
It would bo out of plaeo, hero, to givo all tho dotails of tho apparatus by which this is accomplished. Tho ourront generated o. tho car proceeds from a small fivc-coll battery placed under a (ablo (or cabinet, as wo call it), about two feet square, which holds tlio instrument. Tho table affords room for a Morso key, an elec¬ tro-magnet and an mstrumont called a “vibrator," which, by means of a motal reed, gives a musioal ohnraolor to tho electrical impulses caused hy oponing nnd closing tho circuit. At tho ter¬ mini, or at any fired station, all that is heeded is a similar appara-
or four of H “ Wir° "ithXo
or four of tho regular telegraph- wires. On tho car tho wires from ho battery and instrument are grounded through tho axles nnd wheels. Anothor wire leads up to tho ordinary motal roof of tlio
THE AIR-TELEORAPH.
m
■ car and charges it with olcctrioity. • Tho roofs of tho Bovoral oars ■> composing a train may also bo connected by an insnlatod ooppor • wire. In this way tho roof aots ns ono sido of a condonsor, and •: -tho usual telegraph wires stretched on poles along tho odgo of tho • . ■ road-bed form tho other sido of tho condonser. Tho current from . tho car battery and tho roof of tho oar is of buoIi a nature that tlio , ; wavo of electricity sent from tho apparatus in tho car lasts only . about ono 600,000th of a second. During this short poriod tho nir seems to conduct electricity j but if tho current woro allowed to' remain any longer the air would ontor into such a state as to opposo any further transmission. If now an iutorval of timo is allowed to . . clapso tho air regains its normal condition nnd nnothor wavo enu bo transmitted. In Bonding a singlo Morso lottor, for instanco tho •letter E, which is a Biuglo dot, ovor fifty soparato waves with waits . . botwcon thorn havo to bo transmitted, at tho rnto of Bix hundred per second. Thoso separate, rapid waves form a musical Bound. .Along or short depression of tho koy of an organ imitntes tho . sound of' tho dots nnd dashes ns hoard in tho rocoiving instrument. Tho oporators, both on tho car and at tho fixed stutions, hear thoso notes through tolophouio soundors, so that tho rattlo of tho train nnd tho crackling noiso of othor messages rushing nlong tho wires do not disturb thorn in tho least. All that tlioy hoar from theso ' reccivora is a clear, crisp, humming noto which is perfectly dis¬ tinct in its short or long iterations. Tho oporator on tho car has tho tolephonic receivers fastened over his ears by a rubber strap, so that both hands rqinnin froo, ono to work tho key with and tho othor to writo out messages ns tlioy urrivo. Tho regular Morso waves traverso tho wires at tho rnto of about thirteen to a second. Mino go through tlio nir nnd nlong tho wires at tho rnto, ns I havo said, of six hundred a second. This docR not inako it possible to send a messngo nny more rapidly tliun on tho regular Morso cir¬ cuits; butit offsets ono result of tho highest importance— that is,
■ that ono ourront does not iuterforo with tho other. Tlio sounds whioh wo trausmit by inductivo olcctrioity cannot bo heard by operators nt ordinary Morso instruments ; but any nverngo opora¬ tor at a fixed station providod with our instrument can read our messages with oven greater onso than ho could rend from tho cus¬ tomary relay instrument.
• Honco it makes no difference how many wires there may bo along-sido tho railroad. No confusion is possible. Neither can
[PHOTOCOPY]
["The Air-Telegraph: System of Telegraphing to Trains and Ships." North American Review 142 (March 1886): 285-291.]
288 the Noitm American review.
car operators tnko messages oft thoso wires wlion sent by moans of
lrainn77 “‘"ra"18, ButmcS6aSC3 l>y our apparatus from one train to another, or from trains to stations, can travol ovor the usual circuits without difficulty. Dispatclios can bo 6ont to or- if,0"’ oa™ !n oithor direction, either forward or backward along the route. The ourrent leaps ovor to and runs along tho wires6 niidwhntovor train or station may bo called, that train or station will hoar tho call and answer it, but others which am not called will
ri°d win “f0 ? Two trllina P^ins each othor on tlio road uill not materially interrupt communication, because they pass within a few seconds, and tho telegraphing to and from each ouo can bo resumed immediately.
Tho orpenso of putting instruments in on cars or at station* w. l be small No. special wire will ever bo needed except in extreme leases whore regular wires diverge widely from tho road-bed The instruments on trains will occupy only a cornorin oither a baggage ova passenger car, and tl.oy can bo moved from ono car “?‘h0r ““d Bat e°;ne afi“in within a few minutes after tho transfer. Tho advantage of this systom ovor any which in-
tothoinT118 “ °?-ly Wir° bot'voon tho ™ils or close
to thorn is apparent in tho fact that, while a singlo speoial wiro could easily bo cut by miseliiovous poisons, nothing could break —T,11 tby °T Ey6tCm’ un]06S dI th0 r°gular telegraph tho tranV W m 1°™ F"rthoimoro, a wiro running along
the wv mom™t 1“’ Trod by “,,y ncoidont to 11 at
tho Tory moment whon it would bo essontial to talk to that train
sT“uoLmaVfho°tlnVOry sending reports to tho fixed
ment was nWr ? ’ ° ?“* °T°U “ thocari“ thoinstru-
onorat'nrs inTt , b° ovoltuTncA> » would not matter. The opoiators and tram dispatchers would at once suspect nn accidont and telegraph accordingly to othor trains.
This invention might well bo callod “tho air-toleeranh ”
tlmTres0 “Zt’ tl ^ “ *° C°n7C™ a“m& tbo at'"°sphora from tho wires, lint tho company to whioh it now bolongs calls it s.mplj tho railway telegraph.” I expect to apply it fn such a } that ships at sea, many miles apart, can exchange messages of
shmnSbaHoo k? f ."f"' Prabably,bo acfomplislmd by us. ng a biilloon-kito coated with tin-foil, soaring several hundred Sira, « W„°„ n°i aud eoiitro'lcd by a fine wiro. Tho song of tho Sneiis would liavo no charm for any marinor who could hear from
THE AIR-TELEORAPU.
homo and Bend word to his sweothoart by this method. Nows of • ■ I, 4't. '••;•••, . • wrecks, distress, mutinies, oto;, coiild bo rapidly forwarded from
, j;I t'!.. ship to ship within caoh other’s signalling uroa, aud merchants
> ■ could not only find out just where tho ships aro that carry valuablo
T,-’;-.- cargoes invoiced to them, but could oIbo, if they desired, tolograph •4 to altor the destination of their vossols, in accordance with changoB
>' ' of the market. In timo of war a lino of ships stationed along tho
j'- 1 const or botwcon tho scene of active hostilities and tho nearest tolo-
'I: . ’ graph offico, could bo of immense sorvico in convoying, by tlio
.. •■■■ j ■■■•■:. . “air-telegraph” uows of the enemy’s approaeh, or in transmitting
rr'-'.'.ttv. dispatches whoro communication by tho land routes was interrupted.
■ 1“ arohipclngos and whero small islands lio near tho coast, this i':v dovico would mako it possiblo to tolograph from island to island
or to tho main shore much more ohoaply than by laying submarine ] cables. Why should wo not also uso tho samo means for tolograph-
■J.r ’ ing from stations at long intervals, which might bo sot up inmoun-
v’Ss'i'V. tain or forest rogions, which tho wires do not commouly ponotrato ?
'■yii’i't'-'-'l -. . But it is not necessary to dwell on thoso and oilier uses to • .■ whioh tho invontiou may bo put in tho future. Tlioro is ono ap- ' ■ plication of it which at presont transcends all otliors and 1ms been
~y. j-i • . triod fully on tho Staten Island Kuilroad. Bcforo thoso pages aro " ' published -it' will also bo in oporation on tho Ohicago, Milwaukoo .to •«!*.'• y-.; ■ and St. Paul Kailroad, whero its valuo in train-dispatching will bo
1 •’ illustrated. I am not familiar with tho management of railroads,
;J.5. ■ but somo of thoso who aro so nssuro mo that tho “air-telegraph”
or railway telegraph will groatly facilitate railway Bervico in tho *■} • following ways :
fy. 1. On roads having a Inrgo trnfilo, it is moro economical to
dispatch freight trains (oxcopt in somo cases of lino and special ':J, ‘ freights) os soon as tlioy nro mado up, and to allow thorn to mako
i ■■■■ "■ • '• their run without being bound by a fixed sclicdulo. A special and
' important instance of this is tho way in which trains loaded with
.-. . : .. grain have to bo sent from tho West to tho Bast ns rapidly ns pos-
,i . ' : Bible. Auy method that enables tho train department to move
. .. bucIi trains safely without n fixed sclicdulo must bo iuYaluablo.
( • On a singlo-traok road, especially, with telegraph stations somo dis-
tnneo apart, it is essential that tlio train doimrtment should watch : aud control tho movements of trains so as to ltcop thorn clear from
(all dangors and collisions. As things aro now, tho chief train dis- • . patchor is liko a genorul trying to conduct a campaign and to move
[PHOTOCOPY]
["The Air-Telegraph: System of Telegraphing to Trains and Ships." North American Review 142 (March 1886): 285-291.]
290 the north American review.
aXrSo?t^
absolute command of thowholoL * 8yat°m ^ hi“
patdmf has to extend ^L^fsoHSmoXost'oloS un-‘ toward cvouta Among theso diffioultiGa nrn “wvnnb- » j 1,1
Hssasgii?
■giliPHssg
notice ’ h° S0lv0fl 1118 Problo'» “t the shortest
r|Sg«SSSS
, itift sr* ■“f.^scsrs:
JS&ZEZ I8-”01 COnfino‘1 *» train-dis-
fras a
i-TELXORAPII.
K'c
i^.v
which rcquiro that a traveling agent or partnor should bo notifled beforo ho roachos his station, may bo oiplaine.d to hirnby tho rail- way tclogrnph, whilo ho sits in tho car journeying along ntr tho rato of thirty or forty miles an hour. Similarly ho may send book to his ofllco in Now York, San Francisco or Ohicngo any information which ho happons to piok up, or business dooisions which ho was not able to make beforo starting.
Tho benefit to nowspapor correspondents is obvious. Thoy cau collect nowB at ono town, and on tboir way to another plnco they can writo their dispatches in tho train and sond them from it dirootly to tho editorial office, whorovor that office may bo, tboreby . saving a great deal of timo.
Police business will of course bo greatly oxpodited by this Bystom. . Tho polioo authorities of any town or city, if thoy lmvo reason to - suppose that a criminal or a civil offondcr — such as embezzlers nud confidonco mon — lias taken to flight by railroad, can at onco Bend : descriptions and inquiries to all traius on tho routes loading from . tlicir locality.'
Tho working of tho invention is not a matter of uncertainty. ■ It' is already dovclopod and porfoclcd, and can bo applied any¬ where. I liavo had it elaborately tested for sovcral mouths, uud it oporates equally well in all weathers. So completely is it undor control that, I think, by fastening motallio plates on houses near tho regular lines of tolograph wires, offices could bo oponodin tboso houses, and an opposition telegraph system bo started on tho snmo wires. It is possible that I may in timo find means of using tele¬ phones on trains, for oral conversation, which was tho origiuul idon of Mr. William Wiley Smith ; but that would bo a soparato dovclopmcut. Tho now rnilwny tologruph is comploto, as it stands to-day ; and, in its now utilization of inducod electricity, as woll as in its wido-spread, • practical bearings, it seoms to me— if I may speak of it for a moment without rogurd to my personal rolnliou ' to it — ono of tho most important among recent inventions, in tho results it is likoly to accomplish.
Thomas A. Edison.
[PHOTOCOPY]
["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.]
ii \r
F» p
PROCEEDINGS
THE AMERICAN ASSOCIATION
ADVANCEMENT OF SCIENCE,
thirty-sixth meeting,
'THOS. A. EPTSOMy
NEW YORK,
AUGUST, 1887.
[PHOTOCOPY]
["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.]
02 section n.
tho potential generally becomes steadily positive. Potential as high as • *18 many thousands of volts ore observed, accompanied by sparking in the ap* .' ’ ** parutus. It appears that, lu general, tho appcaranco of negative potential Is coincident with the appearance of rain, cither at the station or near by.
It cannot be said to precede the ralu with certaluty, although this some* iyigji times happens. *
On a magnetic nmnoK or balance foii measuring maonktio conduc¬ tivity. By Dr. Thomas A. Edison, Orange, Now Jersey.
practice, especially If we consider the various forms which It has assumed, '> than the device contrived by Christie and commonly known as Wheat* atofi°’a bridge. It was with the belief that a similar instrument could bo ' constructed which should perforin the same service for magnetic measure* \ merits, thut the experiments were made tho results of which I have tho , honor now to present to tho Seetlou.
The Wheatstone bridge Is based upon the fact that If two points ofdlf* • ferc at electric potentials arc united by two conducting paths the fall of potential along these paths Is absolutely the samo provided that theso .l* paths are absolutely alike electrically. Consequently, if two points cqul* * distant from the place of higher potential be connected together, no cur* .* rent will flow through tho connecting wire. So, by analogy, If two points ’ *. be fjiAlntttliicd at a constant difference of magnetic potential, the full of ;i potential from one to the othor through two or more paths will bu abso* 1 iuteiy uniform in all provided these paths be mngnotlcally Identical. II at any two points equidistant from a given termlual, tho magnetic pi UQ1 is the same and these poluts would bo without differential action upon
Th° magnetic brldgo may bo constructed In the form of a rhomb, the typical form of the Wheatstone brldgo. For this purpose tho four sides are made of tho purest Norway Iron as soft as possible and thoroughly annealed. To tho acuto angles of the rhomb are connected tho poles of a - *’
magnetic potential- difference at theso points. Connected to tho two ob* tuso angles, and projecting Inward, are two bars of Norway Iron similar la aoctlon to tlioso forming the sides. Their Inuor ouds, which aro hollov out» Approach to within about a half Inch of each othor. Between th
To tJl° 8tIrruP is attached either n pointer moving oi or getter a mirror by means of which tho deflection cc usua! way with a larapstond and scale.
In tho Instrument now In uso Jo my laboratory tho magnetic b id
P- ^ cnj8 °r p°ics °f «i«trom.gnej bsis
MH'-.. tlmmlddlc of the short sides, while tho bora which pass In-
' hi™ . h, "0'f an‘}°['Ka 10 11,0 ■"“«'• of tho longer .Idea. Tho four «oa. ond of ti S°.r COUBl,ll,tu ll'« Of tho brldgo. Tho two > i “ ' L. d f 1,10 rtct“"=lo are ilxod, tho two nt tho othor oud aro mova- form a se i j 1 1 cl r clo^t n'n ding *”JVar<j t0 1,10 ncedl0 Aro curved so us to
It will ho readily aeon that when ‘“hodoolromagnot la charged, a con-
wlU .be uo “u But If 0,,u or tho movable burs bo loosened, tho are e s u once deflected, mid in n dlrectlou depending upon the sldo
t max-
“f lr0,J1 or ,n •“/ other way which nlfects^ho mog- M,lc l f “ u'Vlty tl;ro"«1' th« bridge, tho dodectlon ahowa at onoo the
i^*Ttamiwin«Ue b*5d **'n* 010 r“"s“ °f tho “PPni“tus la maintained.
•, qoallty of tlm iron purchased forth! Ve"!y'grm
k 0b8,!rv,:d lra"» auppoacd commercially to ho of tlmflmo
r b I Ml |j°"!'M!U0“ y 11,0 Potential difference developed by a dynamo
& rsrjsx iai s
jjjP'* geuemfor tlum^ttccu at*?0*0*! 1*° *i<:tur,,,inei* a°d the constants of
% f^et thla bridge u'wHlit^aeem'wn'rhe^cquid^yuaeful for testing Iron and
l>!.l..y of l“nrjr„S;cmal!!.ri""t!rro0f"'y th° “"d
; . Cauatructcd wlth'auMu lentTre m,d dotaUaT'tho'^gS
c bridge may without doubt bu made a most valuable Instrument of precl- ■lea for the nirthcranoc ofsolontlllc rcaoarcli. Tho theory oflta action Is ' luieeUhrMgonconsanmt!d*for*IU ““'i c0““l®rP‘‘rl of on onllnnry Wheat-
« Wit water, alnco now whatever la true electrically of the ono la true mag-
bet thovarlallo ** 'T ‘,'l“ for *" dtam^ttabodlM
["The Perfected Phonograph." North American Review 146 (June 1888): 641-650.]
THE PERFECTED PHONOGRAPH.
Ten years ago I contributed to tho Nortii American Review (May-Jnno, 1878), a paper on tlio “Phonograph and its Future,” in which I sketched tho solution of certain problonis accomplished by my invention, and predicted some of tho uses to which it would bo put. Other weighty mutters engaged much of my timo and attention after that nrticlo was published, but tho. future of which I then spoko has now arrived, and tho predictions which I made at that timo are now verified. For, when these words ap¬ pear in print, tho demonstration of tho phonograph’s practical adaptability to tho purposes mentioned by me will have bcon com¬ pleted, and the porfeoted instrument itsolf will be in tho hands of tho public, to bo tested and employed by thorn at will. Rumors, I understand, have boon circulated to tho effect that, subse¬ quently to my announcements mndo ten years ago, I allowed tho phonograph to go adrift, leaving its further development to clmnco and to tho tendor mercies of such disinterested porsonB, not con¬ nected with mo, os might coneoivo that tlioy woro doing mo a favor by claiming to have dovoloped my idea. Thoso who may liavo beon tnkon in by these rumors would do well to inform them¬ selves concerning tho prolonged luborinvolvcd in carrying out im¬ portant inventions. They nro also referred to my former state¬ ments in this Review, as proof that tho signor of thoso statements at least know clearly what ho was talking about and predicted only that which ho has now fulfilled.
Since tho timo of Lucrotins, tho movomonts of atoms have boon invested with an intonso interest for philosophers and soion- tific students, and tho wave-motions of light, lient and Bound liavo engaged, with a constantly increasing degreo of importance, tho attention of modem investigators. When we consider tho rela¬ tion of thoso motions to mutliematics and to music, tho concep¬ tion of Pythagoras that nnmbor and harmony constituted tho
The North American Review
June 1888
["The Perfected Phonograph." North American Review 146 (June 1888): 641-650.]
842 the NORTH AMERICAN REVIEW.
prinoiplo of tho Univorao does not scorn to bo very far out of tho way. In tho phonograph wo And an illustration of tho truth that human spoeoh is govornod by tho laws of number, harmony and rhythm. And by moans of those laws, wo aro now ablo to rogistor all sorts of sound and all articulate utterance— ovon to tho lightest shades and rariations of tho voice — in lines or dots which aro an absolute equivalent for tho emission of sound by tho lips ; so that, through this contrivance, wo can cause these lines and dots to givo forth again tho sound of tho voice, of music, and all other sounds recorded by thorn, whether audible or inaudible. For it is a very extraordinary fact that, wliilo tho deepest tone that our curs are capablo of recognizing is one containing 16 vibrations a second, the phonograph will record 10 vibrations or less, and can tlion raiso tho pitch until wo hear a reproduction from them. Similarly, vibrations above tho highest rate andiblo to tho car can bo recorded on tho phonograph mid then reproduced by lowering tho pitch, until wo actually hoar the record of those inaudible pulsations.
To make the general idea of the recording of sound more clear, lot mo remark ono or two points. Wo huvo all been struck by tho precision with which oven tho faintest sen-waves impress upon tho surface of a beach tho lino, sinuous lino which is formed by tho rippling edge of their advance. Almost ns familiar is thefact that grains of sand sprinkled on a smooth surface of glass or wood, on or near a piano, sift themselves into various lilies and curves according to tho vibrations of tho melody played on tho piano- koys. Those tilings indicate how easily tlio particles of solid matter may reccivo an imparted motion, or tako nn impression, from delicate liquid waves, air waves, or waves of sound. Yet, well known though these phenomena nro, tlioy apparently never suggested until within a few years that the sound-waves sot going by a human voice might bo so directed as to trace an impression upon somo solid substunco, with n nicety equal to that of the tide in recording its flow upon n sand beach.
My own discovery that this could bo done came to me almost accidentally wliilo I was busy with experiments having a different object in view. I was engaged upon a machine intended to repeat Morso characters, which wero recorded on paper by indentations that transferrod their message to another circuit automatically, when passed under a tracing-point connected with a circuit-clos-
THE PERFECTED PHONOGRAPH. 643
ing apparatus. In manipulating this mnehino I found that when the cylindor carrying the indontod paper was turnod with groat swiftness, it gavo off a humming noise from tho indentations— a musical, rhythmic sound resembling that of human talk heard indistinctly. Tbis led mo to try fitting a diaphragm to tho machine, which would receive tho vibrations or sound-waves inndo by my voico when I talked to it, mid rogistor tlieso vibra¬ tions upon an impressible material pluood on tho cylindor. Tho material soloctcd for immediate uso wns paraffined papor, and tho results obtained were excellent. The indentations on tho cyl¬ inder, when rapidly revolved, caused a repetition of tho originul vibrations to reaoli tho oar through a recorder, just as if tho machine itself wore speaking. I saw at oneo that tho prohlom of registering human speech, so that it could be repeated by mechani¬ cal menus us often S3 might bo desired, was solved.
Tho history of tho phonograph as it wns thou dovisod and manufactured in small quantity, merely for purposes of public ex¬ hibition and explanation, need not be ropcatcd here. Tho idea occurred to mo in tho spring of 1877, mid, according as I could got loistiro, I gavo my attention to preparing tho few exhibi¬ tion machines which were placed before tho public in 1878, and thon universally recognized by scientific mon and every ono elso as an nbsoluto novelty. Tlieso machines, of course, exemplified only a small part of the capacity of tho phonograph. I wns liurd at work describing and noting down the various parts of tho ina- chino as it would appear when porfootod, and making drawings of them in various forms.
As it was impossiblo to drop my work and sit down to toll tho public what I was doing every day, I noted briefly in my North American Review article of May-Jnno, 1878,somo of tho tilings which I proposed to accomplish. Tho details of tho olcctric light and othor inventions afterwards absorbed much of my timo and attention. My laboratory wns convortcd into a factory in order to supply the demand for tho electric light, and my progress in car¬ rying out my ideas about tho phonograph, though continuous, was necessarily retarded. For months pnst, liowovor, I linvo had a special factory in operation, producing tho component parts of tlio perfected phonograph, so us to bring the machino within tho reach of the publio in tho form which I originally designed it to take.
["The Perfected Phonograph." North American Review 146 (June 1888): 641-650.]
044 ' THE NORTH AMERICAN REVIEW.
It may bo of interest, hero, to contrast briefly the perfected phonograph with the more exhibition models shown, all over the world, in 1878. Those models woro largo, heavy machines which purposely sacrificed distinctness of nrtioulution, in order to sootiro a loud tone which oouhl be heard in a largo room whon omitted through a funnel-shaped transmitter. Tin-foil was used as the material on which tlio indentations woro to be made. The cylin¬ ders woro rovolvcd by hand, or by clock-work ; and thoro woro numerous otiiordotails of construction which differed from those of tho instrument us now completed. At that time I bad mndo various designs for a special kind of electric motor, differing from all otliors, to run tho macliino, in plaeo of clock-work ; and tho phonograph as wo now mannfuoturo it is provided with such n motor, which turns tho cylinder noisolessly, uniformly and easily. Instead of tin-foil, I now uso a cylinder of wax for receiving tho record of sound-pulsations, as in tho original experiment. One
THE PERFECTED PHONOGRAPH. may bo sot at that point on tho wax ns soon ns you w oil tho record. Another voty handy attachment suj for suspending tho reproduction of sounds whon it is j rapidly for tho copyist who is writing it out. A socon pressed down, will run tho reproducer back so ns to thing which line not boon clearly understood, and this i any desired numbor of times.
A sin do wax oylindor, or blank, may bo usod fo: twenty successive records boforo it is worn out. But if is to bo kopt, the wax blank must not bo talked upon a simply slipped off from tho motnl oylindor and filed awn' reference. It may bo fitted on to tho oylindor again a and will at onco nttor wlmtovor has boon registered < of thoso wax blanks will ropent its c with undiminished dearness. Further, wo uro nblo I
[ The Perfected Phonograph." North American Review 146 (June 1888): 641-650.]
TEE NORTE AMERICAN REVIEW.
intonations ! Wo nro in n position to obtain results of t, by tho present phonograph, from the wave-motions of so that it soeins to me wo realize hero tho “ poetry of • in u new sense, coinbinoil with tho science of motion, ly article ton years ago, I enumerated among tho uses to lio phonograph would bo applied : 1. Letter writing and s of dictation without the aid of a stenographer. 2. Pho¬ to books, which would speak to blind pcop'o without i thoir part. 3. Tho teaching of elocution. 1. Repro¬ of musio. 5. Tho “ Family Record ” — a registry of say- minisccnccs, etc., by members of a family, in their own md of tho last words of dying persons. 0. Musio boxes i. 7. Clocks that should announce in articuluto speech i for going homo, going to meals, etc. 8. Tho presorva- langungcs, by oxaet reproduction of tho mnnnor of pro- h. 0. Educational purposes ; such as preserving tho ox-
TEE PERFECTED PEONOORAPE. 0
form. In teaching tlio correct pronunciation of English, a especially of foreign languages, tho phonograph ns it stands see: to bo boyond comparison, for no system of phonetic spelling o convoy to tho pupil tho pronunciation of a good English, Prone Gorman or Spanish speakor so well us a nmchino that roprodm his utterance even more exactly than a human imitator could.
Tho speeches of orators, tho discourses of clorgymon, can had “ou tap,” in ovory liouso that owns a phonograph. It won not be vory surprising if, a few yours hence, phonographio nov paper bulletins should bo issued on wax cylinders. Even now, soon as tho phonograph comes into gonornl uso, uowspapor i porters and correspondents can talk their matter into tho phoii graph, cither in tho editorial oflico or at somo distant point, by telephone wire connected with a phonograph m tho coinposin room, so that tho communication may bo sot up in typo witho
["The Perfected Phonograph." North American Review 146 (June 1888): 641-650.]
in Now York way bo placed on anotlior maohino of tho samo pattern in China, and sponk oxactly ns it was spokon to on this continent. Enoh wax blank will roooiyo from 800 to 1,000 words; and of oourso several blanks may bo nsod for one documont, if needed. 'Dub uniform size and pattern make the thing perfectly practicable in ofliccs which have business connections ail over the globe. My private seorotary to-day speaks all letters into a phono¬ graph, from which they are taken off by a type-writer or ordinary long-hand writor, with an immense saving of timo and troublo. Porsons having a largo correspondence can talk all tlioir letters into tlio phonograph in a very short timo, and leave thorn to bo listoned to and copied by an assistant, without the delay involved in stenography or the trouble of going over and correcting tlio copyist’s work, which is almost inevitable under the conditions of dictation now prevailing.
Furthermore, two business men, conferring together, can talk into tlio rccordor by means of a donblo transmitting tube, with porfcct privacy, and yet obtain upon the oylindor an unimpeacha¬ ble transcript of their conversation ill their own voices, with every break nnd pause, ovory hesitation or confident affirmation, every partial suggestion or particular explanation, infallibly sot down in tlio wax.
They can tlion linvo this conversation written out or typed by a secretary, for future reference; or can, if tlioy prefor, linvo it multiple-copied by our mechanical process. In this way, many misunderstandings may boavoided. Interesting philosophic or literary discussions and dialogues may bo recorded in the samo way. In fact, tlio phonograph will do, nnd does at this momont accomplish, tlio samo thing in respect of conversation which in¬ stantaneous photography does for moving objects ; that is, it will present whatever it records with a minute accuracy unattained by
THE PERFECTED PHONOGRAPH. 04a
instantaneous photograph, what uttitudes nro takon by tho horse in motion.
Lottora of introduction may bo Bpokon on to a phonograph blank, without any of the formality of address and phraseology now customary, or tho troublo of folding, enveloping and address- nig a written communication. In fact all oorrospondonco will be greatly simplified and wisely abbreviated by tlio use of phono¬ grams. A telephone subscriber can plnco at his tolophono n pho¬ nogram which will announce to tho exchange, whenever lie is oallod up, that ho has loft tlio oillco and will return at a certain timo. Similarly, ouo man calling at tho office of anotlior nnd not finding him, will talk into tlio phonograph anything he wishes to say. This saves tho troublo of writing a note, nnd obviates tho uncertainty of giving to dork, offioo boy or sorvnnt an oral mes¬ sage that may bo forgotten or inoorrcotly delivered. Hotels and clubs will, naturally, find this function of tho phonograph ox- tremoly serviceable; nnd their guests, or patrons, will avail them¬ selves of phonograms constantly. Tho accuracy of interviews with nowspnpor reporters will also bo determined, no doubt, by phonographic record. And travelers in vestibule trains will bo glad to use phonograph blanks in place of letter paper and tele- graph blanks, owing to tho difficulty of writing while on a rapidly moving train. 1 J
It must bo borno in mind that I am not talking now of things which may bo ffiado possiblo in tho future. I did my predicting ton years ago ; and tho functions above mentioned are tlioso wiiioli Uio present perfected phonograph is nblo to fulfill at this moment To uso tho phonograph, n littlo instruction and practioo are needed, but much less tl.an tho type-writer requires and hardly more than tho training needed for tlio operation of nsowing- macluno. 6
Various other uses for which tho phonograph is now fully, ripe might bo mentioned ; but I do not want to give to these memo¬ randa tho character of a catalogue. Enough lias boon said, I
["The Perfected Phonograph." North American Review 146 (June 1888): 641-650.]
THE NORTH AMERICAN REVIEW.
them. It will become an important factor in education j and it mil teach ns to bo careful what wo say— for it impartB to us the gift of hearing oursolvcs as others hoar ns— exerting thus a deoid- cdly moral inAuonco by making mon brief, businesslike and i nrxvnv ms -1 — . find uniting distant
«M*MvuHugimprovea manners, nndur friends and associates by direct vocal communication.
Thomas A. Edison.
["Mr. Edison and His Phonograph: To the Editor." Washington Star (Januaiy 24, 1889).]
[PHOTOCOPY]
["The Dangers of Electric Lighting." North American Review 149 (November 1889): 625-634.]
THE DANGERS OF ELECTRIC LIGHTING.
1IY THOMAS A. EDISON.
So much 1ms of Into boon said nml written upon tbo subject of high-tension electric currents nnd their probttblo or possiblo • danger to human life, nnd so many dilloront opinions huvo boon advanced by men. whoso positious sorvo to surround their uttor- nucos with an ntmosphoro .of knowledge of the matter under dis¬ cussion, that tiio mind of an unscientific public 1ms been uimblo to conio to any dofmito conclusion upon the basis of *• oxport ” testimony. It is most uufortunnto that a practical demonstration in support of tho real fuclB of tiio caso could not have boon made •in n loss tmgio ninnnor than was wituessed a fow days ago in Mow York by soveral thousaud pooplo ; and yot if ttio martyrdom of this poor victim results in tho application of stringent measures for tiio protection of lifo in tho future, it tho lesson taught is ap¬ preciated to tiio fall oxtont of its fatal manning, tiio sacriGco will not lmvo been niado in vain. With the increase of olcctrio light¬ ing (which to-day is used only to a vary limited oxtont ns com¬ pared with its iuovitnblo futuro use) and the multiplication of wires, those dangera which oxist now in n thousand different parts of tho city will bo manifolded many times. In fact, the oppor¬ tunities for repetitions of tiio uccidont referred to abovo will be practically unlimited.
I can writo upon this subject only ns ono convinced. I can¬ not discuss it otherwise. Tiio public would scarcely be interested in tho details lending up to tho position taken by myself nml tho conclusions to which 1 lmvo come, for the reason that it would iuvolvo u moss of matter bucIi as they hnro been iiltonipting to digost during suvoral months past ; and, instead of explaining, I might succeed onlyin adding to tho prosonl confusion of popular idoas. But I may say that I hnro not fuiled to seek practical demonstration in support of bucIi facts as lmvo buou developed,
VOL. OXMX.— NO. 306. 40
[PHOTOCOPY]
["The Dangers of Electric Lighting." North American Review 149 (November 1889): 625-634.]
620 i ; THE NORTH AMERICAN REVIEW.
, 1 h“T®. takon life— not human lifo— in tho belief and full
' consciousness that tho oud justified tho means. ’ 1:
‘ The ourronts used for elcotrio lighting at tho presont timo may generally bo divided into four classes .-
First — Tlio low-tonsion continuous current, with a pressure not exceeding 200 volts, used for incandescont lighting.
Second— Tho high-tension continuous current, witli a press- nro of 2,000 volts and ovor.
Third— Tho high-tension somi-continuous current, with a pressuro of 2,000 volts and ovor.
. Fourth— Tho alternating curront, with a pressuro from 1,000 to 3,000 volts and ovor.
Tho first is harmless, and can bo passed through tho human body without producing uncomfortablo sonsations. Tho second is dangerous to lifo. Momontary contact with a conductor of tho third results in paralysis or death, ns lias frequently occurred ; and tho passage of tho fourth, or alternating, current through any living body means instantaneous death.
Those aro simplo facts which cannot bo disproved. Tboro is a record of nearly ono hundred deaths, which furnishes an unan¬ swerable argutnont in support of these statements. Discussion and controversy may sorvo tho questionable purposo of dolnying popular faith in them, but thoy cannot olmngo thorn ; and tho sooner thoy aro accopted and acted upon tho less liability will thoro bo of a rocurrcnco of tho late horror, which is still fresh in tho minds of all thoso who witnessed or reud of it.
It has ofton boon asked why tho numbor of accidonts of this nature is lnrgor in the city of Now York than in any othor city. Tho reason is that Now York has a groator numbor of wires to tho square milo than any othor city in tho United States. Tho ' percentage of deaths in other places will reach that of Now York itfhon wires aro strung in liko numbers ; but if olectrio lighting under its presont conditions oxtonds in tho lattor city proportion¬ ately, its death-rate will havo beon greatly multiplied by tho timo othor oitios reach its presont high porcontago.
Many suggestions linvo beon made ns to tho best way in whioh to remedy tho oxisting ovil, and tho popular ory seoms to bo,
‘‘ Put tho wires underground.” But, instead of diminishing, this will increase tho dnngor to life and proporty. Thoro is no known insulation which will coufluo thoso high-tcusion currents for more
THE DANGERS OF ELECTRIC LIGHTING. 627 than a limited period, and when thoy are placed beneath tho . ground, with tho present systora of conduits, tho result will bo a sorios of carth-contnots, tho fusion of wires, and tho formation of powerful electric arcs, whioh will oxtond to othor motallic con¬ ductors iu tho same conduit, and a wliolo mass of wires mndo to receive this dangorous curront and convoy it into houses, ofiices, stores, etc. It is thus ovidont that tho dangers of such circuits . arc not confined to tlio wires which oonvoy tho high-tension cur¬ rents, but other wires conducting harmless currents are liable to bo rendered ns deadly in effect ns tho former. It is ovidont, also, that a singlo wire carrying a current at high pressure would bo a constant momico to thosafotyof all other wires in tho same con- .duit. Even though thesodangorous wires bopluced iu soparato tubes in tho sumo conduit with othor tubes, tlio risk is not diminished.
Several instances aro on record, and ono I linvo particu¬ larly in mind, showing tho possibility of serious accident through tho crossing of wires. Near tho corner of William and Wall Streets, Now York, tho underground conductors of tho Edison Illuminating Compuny bocumo crossed, and tho current which was passing through thorn at a pressuro of only ouo hundred and : ton volts molted not only tho wires, but sovoral foot of iron tubing in which thoy wore incased, and reduced tho paving-stones within a nidius of threo or four foot to a moltou mass. This sys- .. tom is so arranged that consumers aro not affected by such ucci- „ donts ns this. Thoy may and do moan oxponso to tho company, but tho public aro ontiroly freo from any possibility of danger. Tho crossing of wires iu this way moans tlm concentration of ■ sovoral hundred horse-power of onorgy in u small space. What would linvo boon tho effect of such across ns I havo described had tho pressure boon two thousand instead of ono hundred and ton volts? and what also might bo tho effect were it to occur in a conduit in closo proximity to hundreds of telephone wires and thoso of othor oloctrio-lighting systoms ? Tlio risk, too, is greatly increased by tho fact that consumers who are supplied with curreiits from a low-tonsion systom are accustomed to handle their olootncal appliances freely, knowing them to bo harmless. If thoso are to bo rendered at nny moment dangorous to life, tho result will bo appalling. I sny nothing of tho injust¬ ice to vondors of harmless supplies of electricity.
So fur, tho deaths which havo occurred from this sourco lrnvo
[PHOTOCOPY]
["The Dangers of Electric Lighting." North American Review 149 (November 1889): 625-634.]
. ®'028 . . ^'THB'NORTIIAiiERICA^REVIEW.
^eotrii-ligh’tfng^na 'telo- giaph companies— moil whoso duties have required .them to work .m oloso proximity to tho oonduotors of those death-dealing cur- ronts. It is truo that a number of ' accidents, mimy of tliom at¬ tended with fatal results, haro occurred to pedestrians on tho streots of how York and othor cities through tho medium of fullon wires • but tho risk incurred by thogonornl public with tho proso'nt system is really loss tlmii it would ho if these dangerous conductors woro . P,nccl‘ >“ closer proximity to tho ground. As tho cartli is ap¬ proached tlm danger is multiplied. Tho connection and crossing '
. of tuo wires hyaline of moisturo or liquid contact aro just ns B V° “,3.th° ooutuot ?? ono wire with onothor when ovorhoatl.
!. mt ““s. error of judgment is uot' confined to tho public, but IS shared in by tlm officials of tho city of Now York, is mudo ap- parent by a resolution of the Mayor oilcrcd at a meeting of tlm Boaid of Electrical Control on .Monday, OotoherH, and which is reported in tho following form :
The logical info'ronco horods that tho lives if tho pcoplo will bo salons soon ns tho wires have been placed underground. If a jutro-glycorino factory wero being 'operated in tlm 'city of New York and tlm pcoplo desired to remove tlm dangor, no ono would suggest puttmg it underground. When it bccamo necessary for tho protection of employees and of tlm public to regulate boiler- pressures in tlm city, tho authorities proceeded on lines entirely different from those winch are being followed in connection with electrical pressures ; and yet tlm eases arc parallel, and the course • „f ?',S0""'S *'“oh 1,1 n perfect system for tho limitation
of steam-pressure and tho periodical inspection of boilers should be retraced, and tho principle applied to secure safety from a ' pressure which, uncontrolled as at present, is far more dangerous than tlm former was boforo steps were tuken to rondcr it harmless.
Iho insulation of a wiro carrying a high-tension current in tlm mos porfoct ninnnor known mny insuro temporary safety; but t mo is bound to dovolop defects as tlm result of tho action of tlm ourront upon tlm insulating material, of a change in tlm molecu¬ lar structure of tlm material itself, and for ether reasons. The •
THE DANGERS OF ELECTRIC iilOHTiNG. '029 'pulsation's 'or vibrations in' an oleotrio' conductor ‘eaiis'o corre¬ sponding vibrations in tho insulation. ' So pbworful is this offeot that tlm insulation givos off n sound corresponding to tho oscilla¬ tion of tho ourront. So long os tho insulation retains its originnl elasticity, tho ourront is confinod ; but tho influonce of the air, or of gas and othor ngonts, tends to cliango tho elasticity, and tho billions of vibrations to which it 1ms boon subjected finally render it vory suscoptiblo of being piorccd by a spark of static olectricity. jThusanavonuo for tlm ingress of moisturo is formed, not only in ono spot, but in many, through which tho ourront may bo communi¬ cated to any conductor of oloctrioity near onough to ninko physi¬ cal contact, or a oirouit mny bo coinplctod botwcon tho two by a '.lino of moisturo or tlm formation of an olootric arc, ivitlUts sub-. 1 soquont destructive action.
The numerous nccidonts which linvo occurred in tlm oity of Now York during tho past year show to a vory largo extent tho operation of timo upon tho insulating material which surrounds tlmso wires. Wlion first erected, tho current was to a certain ox- tput successfully confined ; but tho air is doing its work, abra¬ sions aro moro easily made, and, without tho adoption of genuiuo ‘ methods of control, " accidents” may bo looked for in lnrgor numbors ns timo goes on, duo not only to deterioration of insula- ( tion, but to tlm multiplying of electric circuits to supply tho populur domnnd for olcctric light.
Tlm public may rest absolutely assured that safety will not bo secured by burying tlmso wires. Tim condensation of moisturo, tlm ingress of water, tho dissolving infliionco of coal gas and air- oxidation upon tlm various insulating compounds will result only in tho transfer of deaths to man-holes, houses, stores, and offices, through tlm agency of tlm telephone, tho low-pressuro systems, and tho apparatus of tho liigh-tension current itself.
I linvo no intention, and I am suro nono will license me, of being an alarmist. When tho possibilities of tlm future nro viewed in tlio light of recont developments, it must bo nppnront to ovory ono that tho timo has como when tlioso in authority should adopt propor and adequate measures for the protection of lifo and property, and my familiarity with tlm subject enables mo to soo very clearly tho only trim romody which can bo nppliod — namely, tlio regulation of oleotrioal pressures. Once tlmso press¬ ures aro reduced to a point which is harmless, tho public may re-
[PHOTOCOPY]
["The Dangers of Electric Lighting." North American Review 149 (November 1889): 625-634.]
830 THE NORTH AMERICAN REVIEW. .
• tiro in security and ioavo electricians to discuss "tho* morits or' demerits o £ various mothods of insulating, tho defects of which will only concern those 'interested in the commorco of olcctricity.
• "Thoro is ho plea which will justify tho usoof high-tonsion and alternating currents, oither in a scientific or a commercial sense. Tlioy are employed solely to rcduco investment in coppor wire and real estate. For. instance, in aro-lighting it is customary to put forty lamps on oaoli circuit j each lamp requires a pressnro of fifty volts; therefore tho total pressure on tho circuit is two thousand volts.' Now, if, instead of using only oho wiro for all theso lamps, four circuits of ton lamps each wero to bo established, tho pressure oh each wiro would bo only five .hundred volts. Tho weight of coppor necessary for those four circuits of ton lamps each would bo two and a half times greater than for one circuit of forty lamps — a question, as I linvo said, simply of investment.
. Tho alternating current under high pressure and direct-cur¬ rent liigh-prossuro systoms are also employed, as I have intimated, to savo investment in real cstuto as well as copper. If a certain district is to bo supplied with electrio light, tho natural point from ' which tho current should bo distributed. is tho centre, with wires .. *, radiating toward tho circumforohco'of tho circlo of suppfy ;uand' ^ if, instead of including in any ono of theso districts an area so largo that resort must bo had to high pressure in order to reach . its limits, tho distributing power of a single station bo confined to •„ a capacity consistent with safety, and other contrcs Bought from’ ' ' which to furnish current to other areas, the necessity for high oloctrical pressure vanishes. But real cstato in sucli centres as theso is oxponsivo, and tho promoters of olcctric-lighting enter¬ prises which spring into existence with tho growth and stability of tho mushroom, cannot aftord to considor permanency, the security of tho public, tho requirements of small consumers, or any such questions, which would incidentally involvo tho invest¬ ment of latgor sums of money ; but, scoking the outskirts of a dis¬ trict, whore land is cheap, or some abandoned building nva'ilable for sheltering a few dynamo machines, tlioy run small wires to tho area of supply, enormous pressure boing necessary to forco the current through theso small conductors over such long distances.
In tho last issue of The Electrical World, page 254, is recorded a series of oxporimonts conducted by M. d'Arsonval, a niomber of tho French Academy of Sciences, showing “tho effects of
THE DANGERS OF ELECTRIO LIGHTING. 681
continuous and alternating currents on animals.” Ho says': “A living boing is, abovo all, sonsiblo to a variablo state of tho cur¬ rent, from which it follows that at a moan equal pressure altor- noting currents are more dangerous than continuous currents”; and “with abattory of four hundred and twenty volts (continuous current) death is only caused by long-repeated interruptions of the ourrent.” In othor words, tho continuous current of tho abovo pressure could not bo mndo to cause death until it was interrupted or mado discontinuous— or perhaps a hotter expression would bo semi-continuous. By a variable stato of tho current is meant a fluctuation of pressure botwoen different extremes of voltago. Tho human norvo-systom, up to a certain limit of pressure, cannot dotoct tho flow of a continuous current if tho voltago bo 'porfcotly constant. This constancy iB obtained by multiplying tho number of commutator bnrs on tho dynamo. The brushes which aro sot upon tho revolving commutator, and conduct tho current from tho machine to tho outside systom, rest alternately upon tho different bars of tho commutator. Tho greater tho number of bnrs, tho loss will bo tho fluctution of tho ourront, which maybe likened to a wave-motion, rising and falling, and producing that variablo stato referred to by tho French scientist.
Nearly all dynamo machines used for arc-lighting nre con¬ structed with nu insufficient number of commutator bars to pro¬ duce a steady continuous current. Tho ranges of variablo pressure are not, however, nearly as groat as in tho alternating Bystem. With respect to tho latter, SI. d’Arsonval says: “An alternating Granuno machine caused death when abovo one hundred and twenty volts mean potential.” This is a small unit to contomplato after tho glib manner in which it has beourcccntly stated that this current is harmless at a pressure of ono thousand volts. I liavo inysolf seen a largo healthy dog killed instantly by tho alternating current at a pressnro of ono hundred and sixty- eight volts. It is a simple matter to calculate tho ranges of vari¬ able pressure in this system. Tho dynamo mnehino has no com¬ mutator. Tho armature or “ bobbin” is wound in such a way that tho wholo of tho current under a pressure, say, of two thousand volts, is Bout out on tho wiro first in ono direction, then is reversed and sont out at tho same pressure in tho othor direction, or passes through tho wiro in tho opposito direction; and theso
[PHOTOCOPY]
["The Dangers of Electric Lighting." North American Review 149 (November 1889): 625-634.]
,682 TflE NORTH AMERICAN REVIEW.
fovorsals tiro generally mado abouta hundred timos in oaoh sec-
OIl<K ,t . „:-i. . y
li > Bt“to of a continuous curront at a pressure of two
thousand volts means ordinarily a risofrom zero point up to two thousand, aftorwhioh, owing to the action of tho commutator; it varies botwoon, say, sovontoon hundred and two thousand, while tho variable stato of tho alternating current means a fluctuation from two thousand volts abovo tho zero point to two thousand bolow it, or a difforotico of four thousand volts. Tho dan¬ ger to lifo is probably proportionate to tho fluctuation of press- . .
nros. When an altoruuting current of fifteen volts is applied to a human being in tho. most effeotivo manner, tho offoot upon tho norvo system is so violont and tho pain produced so great that
it is absolutely impossible for any ono to stand it. . . •
As I have said before, tho only way in which safety can bo Bccurcd is to restrict electrical pressures. Tho continuous oitr- ront should bo limited to six hundred or sevon hundred volts, with a variable rango not exceeding a few volts. As for tho alternating current, it is difficult for mo to namo a safo pressure Its effect upon muscular action is so great that oven at oxceod- lngly low voltago tho hand, which grasps a conductor cannot freo itself, and it is quito possiblo that in this way tho sensitive nervous system of a human being could bo shocked for a suffii ciont length of timo to produco death. Tho olootric-lightiiig company with which I. am connected purchased some time n-o tho patents for a complete alternating system, and my protest against this notion can bo found upon its minute-book. Up to the present timo I linvo succeedod in inducing thorn not to offor this system to tho public, nor will they over do so with my consent. My personal dcsiro would bo to prohibit entirely tho uso of alternating currents. Thoy are ns unnecessary as they are dangerous. In tho city of Now York there are many miles of conductors beneath tho streets cduvoying a harmless continuous electric current to thousands of consumers, tho maximum pressure on this vast systom never oxcccding two hundred and twenty volts, which will forco so weak a current through tho human body that it can barely bo dotootod. Furthermore, it is found to bo commercially successful, and I enu thoroforo seo no justiflca tion for tho introduction of a system which has no olomont of • porm anonoy and ovory olomont of danger to lifo and property.
im,-
THE DANGERS OF ELECTRIC EIQBTINO. (533 This is no argument in favor of monopoly; If ovor tboi*j«{bbo a monopoly of oleotrio lighting in the United States, it will bo moithor dolayod,. provonted, nor circumnavigated by suoh subter¬ fuges as thoso alternating systoms, and their uso cannot bo justi¬ fied on that sooro. I havo always consistently opposed high-ten- .sion and alternating systems of olootrio lighting (although per¬ fectly freo to uso thorn), not only on account of dangor, but becauso of tlioir gonoral unreliability and unsuitability for anv genornl systom of distribution.
• 1,1 contemplating tho efforts of tho officials of tho city of Now lork to remedy tho evils connected with olcctric lighting, I havo boon impressed in a way which must havo impressed other on¬ lookers.' I refer to tho apparent difficulty of determining whoro tho authority to tnko action rests. Tho hands of thoso who wish to act appear to bo tied, which is unfortunate, considering tho exigencies and urgency of tho case. In England thoy handlo those matters bettor. Tho Eloctrio-Lighting Act of 18S2 pro¬ vides in section 0
This snmo section also provides that
Iluis to a responsible body is givou discretionary power for tho protection of tho public, and local authorities (by which is meant any municipality) havo tho right to apply to this board for reliof from any danger which thoy boliovo to exist in connection with electric-lighting systoms. Certainly tho responsibility for tho protection of tho pooplo of our city should bo as definitely placed, and thoso to whom such authority is given should adopt rigid rules for tho restriction of oloctricnl pressures. Perhaps polico
[PHOTOCOPY]
["The Dangers of Electric Lighting." North American Review 149 (November 1889): 625-634.]
031 ^ ' THE NORTH AMERICAN REVIEW. ; ' -
opnlvoi would bo oven nioro adoquato ’than tho‘ 'English system. , T‘
I nm not altogothor familiar with tho details of tlio systoin of ■ ■ ' •
boiler inspection which provuils in Now York, but I believe it is . - very oirieiont and would servo ns an oxoollont model for tho caso undor discussion. * ' '• - • ••* • a;..
When tho authorities require electrical pressures to be kopt i ; .. . within tho limits of snfoty, and when thoro is an efficient corps of inspectors, ns in the cnso of boilors, toseo that the rules adopt- °d nro carriod out, the security which tho public demand will ’ ;
bo attained; but until then nothing hotter can bo looked for than T a multiplication of the pnsunltios of tho past fow months. 1 '» '
I"-.' .- V, f i. t I^J f 1
[PHOTOCOPY]
["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. Presented to the American Institute of Mining Engineers in New York.]
lf[CEl(TRATiOI(;OF
JOHN B IRK- 1 N BIN !e| THOMAS A. EDISON,
THE COECEETJIATION OF
IT IUIiKINWNE, I'HII.ADKr.l’tllA, I
The Tranmdions already contain many subject of ore-concentration, but with refer merit of other ores than tliose of iron.
In this country much money, labor and voted to the enrichment of iron-ores by roas and carbonic acid, eliminate water, or mal and by washing and screening to remove earthy ores. In concentrating magnetites been done than is generally believed ; but, i up to tlie present time have not been eneoui so many attempts have proved unsatisfuc concentration, is now unjustly looked. up problem presented to individual ininesmiusl with caution.
For many years the magnetites of the Adirondack region of New York State have been roasted, reduced to proper size by means of
[PHOTOCOPY]
[•'The Concentration of Iron-Ore." Co-authored by John Birkinbine. American Institiite of Mining Engineers 17 (Februaiy 1889; pub. 1889V American Institute of Mining Engineers in New York.]
Transactions of the 1-17. Presented to the
l
1 THE CONCENTRATION OP IRON-ORE.
proved unsuccessful, but the parties who constructed it are reported to luive lost little money, owing to the fuct tliut otliors stood ready to pay them a good bonus for the privilege of hnnd-piokiug the dump-pile at a fixed into per ton of ore won. This dump-pile, which is now being hand-sorted, is estimated to contain 2,000,000 tons of ora and rook. There wore separated from this mass in 1888 some 21,000 Ions of merchantable ore, which, after paying 30 cents roy¬ alty and 51.86 freight, netted tlio operators a profit of 60 cents a ton. The Bessemer ore ns shipped yielded 62 per cent, of iron. About two-thirds of it was specular, and one-third magnetic. The contractors expeot to ship >10,000 tons from this pilo in 1889, and it is estimated that an equal quantity can be obtained for ten years to come. A similar plan of cobbing the dump-piles iB in operation in other, Marquette mines also. Nearly 30,000 tons of hand-picked ore have been shipped in the last three years by one company formed for tlmt purpose.
These statements and others which immediately follow are offered to indicate that the importance of re-working dump-piles is becom- ing appreciated. By reason either of imperfections in the earlier operation, or ol the impracticability of careful sorting underground, the percentage of merchantable ore in the dump-piles in mnny mines represents a very serious loss to the operator.
At the Champion mine, in the Marquette region, hand separation bus been carried on lor some time, but within the lust eighteen months a complete ojatein has been adopted which is giving very satisfactory results.* The ore us raised from the mine is either No. 1, No. 2, dump, rock, or waste. The No. 1 ore is mine-sorted, and must be absolutely clean, usually carrying 06.6 per cent, or more of. iron. No. 2 ore varies from 63.6 to 66.6 per cent, of iron. The remainder ol the ore is carried to sorting-floors, and dumped into a series ol stalls, the rock and waste going directly to the rock- and waste-piles. In each of these stalls two men and a/ boy have two wrought-iron cars, into which the ore is carefully spread by n shovel, and the various grades are picked out by hand. Some of this ore sorted from the stalls is No. 1 “ Champion,’’ some is No. 2 « Chelsen,” and two inferior grades are also produced : No. 3, “ Suffolk,” car¬ rying 60.00 to 63.6 per cent, of iron, and. No. 4, “ Norfolk,” yield¬ ing 57.0 to 60.0 per cent. To indicate how closo this hand-sepnrution
' THE CONCENTRATION OF IRON-ORE. 3
maybe made, wo may oite two cargoes, sold as “Norfolk ”, grado,
, to yield 57 .per cent, of iron. . The actual sampling of the ore after delivery showed for the two cargoes 67.09 and 67.12 re¬ spectively.
In six months, July 1st to December 31st, 1888, about 43,000 tons of material were thus hand-sorted, tlio percentages of the vurious grades being as follows i No. 1, 17 per cent.; No. 2, ,11 per cent.; No. 3, 31 per cent, j No. 4, 16 per cent, j rook, which Includes everything below tlio “ Norfolk ” grado, 26 per cent. The quantity of material handled per man per day is approximately seven gross tons, from wlffcli about five gross tons of ore are selected at an aver¬ age cost of 38.6 cents per ton for lubor. The price paid per ton of selected ore varies according to grade. The averago rate of wages paid per day during tlio time above mentioned was $1.76.
The perfection of the system of hand-sorting is due to the plan of .organization, and also to the thorough inspection by skilled assist¬ ants, whose compensation is made up by assessing the various con¬ tractors in proportion to the amounts of ore they deliver. An ex¬ periment in magnetic separation is about being tried at this mine.
At the Iron Mountain, Missouri, wot concentration is now in use, but up to the present time no reduction in the size of the ore is mudo by crushers or other means, the practice being lo hydraulic the dump-piles or wash the earthy material from the ore, size it in soreons, and pass it through jigs arranged for each size of mate¬ rial. A detailed description of the method pursued appears in the Journal of the United Slates Association of Charcoal Iron. Workers, . vol. viii. p. 38.
At the magnetite mines in Putnam county, New York, there are two concentrating plants, one consisting of crushers, rolls aiul plunger-jigs,* which is now being altered so as to separate the ore by magnetism, and a new plant in which tlio ore is reduced by Bull stamps, washed, and passed through rotary-jigs. It is understood that a magnetic separator also will bo added to this plant.
At present tlio largest producer of separated ore is the Chateaugay Ore and Iron Company, which at its mines in Clinton county, New York, crushes the leaner material obtained in mining, and treats if by water-jigs, tlio produot being a regular portion of the ore mix¬ ture of some of our prominent eastern blast-furnaces making Bes¬ semer pig. That the material produced is satisfactory has been
« Described by Mr. A. I'\ 'Wendt, JW, xiii., 36.
[PHOTOCOPY]
[.The. Concentration of Iron-Ore." Co-authored by John Birkinbine. Transactions of the American Institute of Mining Engineers 17 (Februaiy 1889; pub. 1889): 1-17 Presented to the
American Institute of Mining Engineers in New York] ' Presented to the
1 VliJS CON (JENTU ATI ON 01-' IUON-OUK,
deinonstridcd by Mr. E. S, Moffat," who 1ms used M high uaB0 ,)or cent, of his ore burden of Chntcaugay separated oro, and each year ■ Ims increased the consumption. lie kindly supplies the following figures as the amount of separated oro used at the furnaces of the Lackawanna Irou unci Coni’ Company, at Scranton, ]»a.
“ 1888, .
Mr. A. L. Tnman, general manager of the Chatcaugay Oro and J ron Company, supplies the following data :
“ Prior to 1886 wo made separated ore in a comparatively small way, which was used in the production of blooms, but in 1886 we .™...n.(.„chl its production with more vigor, making, in 1886, 23 885 tons; in 1887, 47,32*1 tons; and in 1888, 54,048 tons.”
These figures indicate that a market is being found lor (his finely comminuted ore. The holes in the screens at the separating plant ol tliu Chatcaugay Ore mid Iron Company, at Lyon Mountain, New l ork, are/irof an inch in diameter, but necessarily a largo portion ol the material is much Ilnur. A hund-trial of the crushed ore before it passed to the jigs showed the average to be 30 mesh; of thu total amount only 14 per cent, by weight remained on a 4-inesh sieve, and leas than onc-lmlf of the entire material -was hold in a screen of 16 meshes to the inch, while 8.3 per cent, passed through 100 or tiller mesh screens.
It may naturally be expected that as a rule blast-furnace managers will object to the lino material, but it is questionable whether many
. . . . iJ successfully in thu blast-furnace are not ns finely
i. -the softer hematites, which may be
. . . “I undoubtedly uro speedily converted into
sand by drying out in the shaft of the blast-furnace.
These soil ores are much esteemed by the bhist-furiiaeu managers of tbo Northwest, and where the desire is to drive a furnace, the lump
11 11 liscnrded for this fine tc I heroforo, indepen-
tjpnt ly oi thu character of the ore, we may question whether its finely divided state should not commend rather than condemn it for blasl- lurnacu use.
In crushing any ore a considerable amount of lines is invariably "Hide which pass into the furnace. As to the cllect of the separated ore III thu blast-furnace, Mr. Moffat wrote on September 1st, 1888:
divided as separated o
TUB CONOENTHATION OF IRON-OIIU, g
' rr ‘‘,Myra°XPer,ien^ h“ be0" olliefly "’ith concentrated Chatcaugay (Lake Champlain) ore, and wo have had so little trouble with it that I feel almost justified in saying that I do not know of any dillieul- ties ni its use up to say 50 per cent, of the ore mixture, which is tl.o most I have tried. 1' or tho past two months (Juno and July) wo liuvo boon running tl.e four Scranton blastfurnaces, whioh are in opera '0" o„ * concentrated Chatcaugay ore. They have woilcd just as well as when we ware using ordinary furnace ores, no increase of pressure, no1 irregularities, and no trouble of any kind. A few {lays since the quantity of concentrated oro in use on our No T fur mice (73 feet high X 20 feet bosh), was doubled, running it up to 5-of the ore ohargo. , The only other change made was a slight . decrease of limestone; the speed of the blowing-engines and all other conditions being kept the same as before. I rather expected some increase of pressure at the tuyeres, but such has not been tl.e case ,ll,e furnace was working well before the change was made, and luui worked just as well since. The fuel used is \ coke' and l Lackawanna anthracite coal. ■
“During 1887 we ran our No. 5 furnace (70 feet X 19 feet) for several weeks on a ‘burden/ of which 50 per cent, was concentrated Cl ateaugay ore. When we made this trial I anticipated a consider¬ able increase in pressure of blast, and in order to meet this increased the proportion of coke to one-third. 1 altorwards concluded that tins "loreaso of coke was unnecessary, as the pressure of the blast went down considerably. The furnace worked well on 50 per cent, concentrated ore and showed no peculiarities.
“None of the concentrated Ohatcaugay oro is coarser than wlmt will pass through a quartor-inoh hole, and most of it very niiioh liner. As diderent blast-furnaces work differently, I would n mend parties commencing the use of concentrated magnetitu to tr a Small proportion at first, say ^ and then gradually increase.”* Interesting data concerning the operation of the plant at Lyoi mountain, ..hero this oro was prepared, analyses, etc., arc found in a carefully written and valuable paper by Messrs. Maynard and JCunhurdt m tho School of Mines Quarterly, vol. ix., No. 2 ; and a full description of tho plant was presented in a paper by Mr. Fred S. •lluttinan, “Concentrating Magnetite will, the Conkling Jig at Lyon Mountain, New York” (7 hint., xvi., 609).
[PHOTOCOPY]
[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 Presented to the American Institute of Mining Engineers in New York.] ' Presented to the
T,!E CONCENTRATION OP IRON-OItE.
,, 0™“h(inS 8^“ ;» described in a paper upon the
m, Syst0ln °f 1,11,0 Crushing ” ('JYdns., xvi., 763). by Mr. Theodore A. Blake, who gives the cost of crushing and sizing tlni oio at J4 cents per toil of crude material.
In nil systems of concentration the co.mniin.tion and sizing of hu material to lie treated aro of primary importance; and although the various methods will not be discussed in this paper, it may ho remarked that tlio degree oftineness to which an orowill booruslicd tor separation, and the special machinery employed, is affected,
1st. By tlie she of the grains or crystals in the crude ore.
2d. By the f eg alter vl el s to bo cl tinted, and Is physical condition.
3d By tlie purpose for which the concentrate is to ho used ■Jtli. By tlie condition of tlie ore and the method employed for -separation. *
If the ore to bo treated is a magnetite with large crystuls, or if the object of separation is to romovosilicoous material only, a censor Si/.".g can be employed than in other cases ; fur practically, complete elimination of silica is not at present essential, and in some ores a system ol mechanical sorting or cobbing, treating pieces from fist to walnut size, may be practicable. It; however, the ore is dense and the crystallisation or granulation fine, or if apatite is to be removed, tile reduction ol size must be carried further, so' as to sopamte, as fi.r as practicable, each particle of magnetite from ti.e other materials. Ill dophosphorizntion by mechanical means a few hundredths of one 1 0‘ I .oallllol'll» 'Vl11 determine whether the ore will bo
c " . “"‘“jjj0 ui the Bessemer limit, ami lienee influence its
The extent to which an ore is to bo crushed will also ho influenced uj t lie ilomaiKl tor certain sizes or by the objection to others.
1 he condition of tlie crude ore will materially inlhionce tlie machinery to bo employed, a dry or a thoroughly wet oro being hmistmc tllU" °110 'vhi°h is dnl,1I’ or partially saturated with
siicImim ovimT'^' '8| n|lj0,,t/0 !;° 1D,U,U ,B emailing ore, heated' to such an extent IIS is believed will cause ti.e minerals composing it to weaken on their cleavage planes, thus facilitating the granulation.
J lie problem, therefore, is to bo determined specially for each oro 1111 1 fl 0 tly tl ; t ul f f or |
whether jaw, rotative or centrifugal, or the combination of crushes,
! stamps or rolls, and the system of sizing must lie suoli us to meet the particular case under consideration.*
In a test made at tlie Edison Laboratory of Snmson (Humboldt, Hinli.) inagnetio ore wluoh had passed through shuking screens of 20 meshes to the me!., tlie quantities stated below were refused uy sieves ot the v o cle gve PI s ore was reduced bv the Gates crusher and Cornish rolls. ^
A test made by Mr. W. II. Hotrman at Bayonne, New Joi on Croton magnet, o oro reduced by a Sturtevant mill, gave the lowing proportions of sizing:
ogniph on ll,o “DrcsshigorNon-IicssemorOres" by Messrs M,
th0 a,,l,ject "* 1,r“o,u ***£ 1 iJing Iho course sizing this nmlerinl opproxinmloil m, evemgo
[PHOTOCOPY]
[The Concentration of Iron-Ore." Co-authored by John Birkinbine. American Institute of Mining Engineers 17 (February 1889; pub. 1889): American Institute of Mining Engineers in New York.]
Transactions of the 1-17. Presented to the
thr concentration op iron-ore.
Magnetic Concentration.
At present, much attention is' devoted to the concentration of iron-ores by means pf magnetism, a method which, in view of the dates and nnmbern.of patents already issued, cannot lay claim to. novelty, j |,o patents issued by the United Stales Patent Office appear to cover nearly every form of apparatus, hut new designs are being rapidly added. b
Tlie earlier inventions were adapted for separating iron from brass a id other (.lings in mach.no-worhs, clo., and also for the removal v. A ttC 11)1 ‘ hC| r 10 80,110 of ‘ho magnetites
New i ork and New Jersey were also made upwards of twenty years ago, an 1 ex, eume t 1 vo It was done in separating the mag- notio i ron-sands of the St. Lawrence river and Long Island Sound.
1 ho. various inventions for separating iron-ores by magnetism may bo grouped „„der two general heads, viz. : those which have permanent magnets and those which have a fixed or an alternating current of electricity passed through magnets from a dynamo. These groups may again he classified into such as receive the ore on tallies or belts "’Inch pass under or over, or which are traversed by mag¬ nets j those which consist of magnetic rolls or drums cither receiving „ '"'e 0,1 ‘ll011' surface revolving over the ore; and those which >) magnetic influence draw the magnetic portion from a falling mass, a (Cling its trajectory so as to separate it from the gang.io material, limy may be further subdivided into those which treat the ore dry and those which immerse the material for concentration in water.
While in some ores a concentration answering most economical purposes may be readily made, the physical structure of the ore prevents a more perfect separation. In one Now York magnetite, a microscopic examination, which Mr. E. IC. Landis made, of the ore alter it passed the crushers, rolls and screens, proved tlint, how¬ ever fine the gram, it in many cases consisted of pieces about rJ, of an me, m dinmetor, showing, under the microscope, magnetite, ' magnetic pyrites, quartz, and sometimes hornblende.
J)r. JCugono Ilussuk, in his monograph on “The Determination ' ol Lock-1' orming Minerals,’' says: “If several ferriferous mineral species occur m i the rook to be examined, c.y., magnetite, il.nenito, b motile, olivine, etc., they can be separated from each other by varying the 8l.,-.,gth of the ourrcnl passing through the electro¬ magnet. At first, two elements are used, then four, six, eight, and "a y t011’ D00'10*’ shown that the minerals can bo arranged
THR CONCENTRATION OP inON-ORE. 9
in a series according to their different powers of being attracted.” He gives thirty-three minerals and indicates their order of attrnot- ability by magnets.
Dana suites that magnetite is strongly magnetio and sometimes pos¬ sesses polarity, and that from the normal proportions of one part of lfeO to one FoaOs there is occasionally a wide variation, and thus a gradual passage to the sesquioxido Fa,0,. Ho instances analyses ' from Bengal, India, in wliioli the proportion of FcaOa to FeO was nearly three to ono, in an ore wliioli was strongly magnetio and columnar, while another ore from llm same locality, in wliioli tho proportion of Fe.,0, to FeO was throe and a quarter to ono, was granular and not polar magnetic. Ho also says that hematite is sometimes attracted by a magnet and, occasionally, even magneti- polur. Martito, wliioli is supposed to be a psoudoinorph, mostly alter magnetite, is reported ns lion-magnetio or only feebly so, and nioiiiiccanite as slightly intlueiioing the magnetio needle,
The presence, therefore, of certain of tlieso minerals will mate¬ rially afi'ect the results obtained, as we naturally look for a bettor ‘ separation when tlie material in tho gaiiguo is but slightly attracted by tlie magnet or practically insensible to its influence.
Mr. JCllis Clurk, Jr. {Trims., ix., 451), describes a magnetic sepa¬ rator in use at Pribram, Bohemia, in which zinc-blende is separated from spathic iron-ore, previously roasted to make it magnetic, and reduced to grains less limn one mm. (probably 25-mcsh).
The writer knows of at least ten forms of magnetic ore-soparntore witli which experiments are now being made, and five of these may be considered us having been operated on a commercial scale.
In view of the experimental state of some of the apparatus and the fact tliut the patents for certain features are now ponding, it is impossible at this time to attempt a description of any, except such as have been operated on a scale approximating commercial utiliza¬ tion. Hence, but four general forms will be considered.
About eight years ago attention was drawn to magnetio separation by the treatment of some of the sea-sands upon our consts, by pass¬ ing the material between rolls, the adjacent portions of which woro in n magnetic field, while the opposite parts were without this field. The iron rolls revolved on journals carried on insulated standards wound with copper wire. By connecting these wires witli a battery (latterly with dynamos) tlie standards 'became olectro-inngnctio of opposite polarity and tlie rolls were ohnrgcd thereby', making a magnetio field between tho rolls. Tho ore being fed on tlie rolls wliioli revolved toward each other, was carried around the magnetio
[PHOTOCOPY]
on ?5- * ? co-authored by John Birkinbine. Transactions of the
American Institute of Mining Engineers 17 (Februaiy 1889; pub. 1889): 1-17 Presented to the American Institute of Mining Engineers in New York.] ' ntCd t0 the
]0 the concentration op iron-ore.
I rlo nil er g t.l it | ispc! beyond tl o magnetic' influence, wlule tho non-mngnetio purtieles dropped between the rolls.
II, o iluclmimn separator, which consisted or suoli n pair of rolls and n largo liorsc-slioe magnet properly wound, as shown in outline, ? Ifc'- t; wnf °">l>Ioyed in soiwrating magnetite from the lino sea-sand . rom the shores of Long Island Sound, and an extensive plant wns sont to Now Zealand, where the Son-Band carries a remarkable amount ol finely comminuted magnetite. ■
A pair of these rolls lias lately boon oporntod at the Croton mag¬ netite mines, near Brewster, N. Y, by tho Messrs. Chccver, to preparo concentrates from the wusto-pilcs of loan ore. The ore a
dense magnetite, is reduced by jaw-crushers and Cornish rolls so as to pass through lG-mcsh soroens. Average analyses, made by E. 1C. Landis, of the lean ore left on the waste-piles, show the general composition of the crude' ore, and tho concentrates and tailings obtained from tins ore ns follows :
Concentration of Croton (T/icat) Che, N. K, by Buchanan Magnetic
THE CONCENTRATION OF IRON-ORE. 1 1
The inorcascd amount of sulphur in tho eonccnlmlos, is probably duo to tho pyrile boing mngnotie.
Somo years ago, tho rcduoiiig-plnnl was operated to prepare ore for plunger-jigs, and the results obtained were ns follows:
Concentration of Croton {Thai) ore by Plunger .Tigs.
Crude Ore : Pino Jigs. Con re o .IIr*.
Metallic Iron . . . .......30.48 30.48
mcuuuc iron . . . 14.31 22.10
Another maohino consists of a single roll witli alternate strips of mngnotie and non-mngnctic material forming its periphery.
The Wenstrom magnetic separator, which is of Swedish origin,* lias a stationary field magnet and nil armature barrel consisting of a number of soli, iron bare, separated from one another by n non¬ magnetic material — in this case strips of wood. Tho whole is bound together by non-magnetio end-rings. The bins are cutaway nllur-
natciy on the inside to mako one bar project only towards the north poles of the magnet and tho next only to the south poles. This gives each succeeding bar opposite magnetism. On each of the four sections of the mngnet are wound fifteen pounds of copper wire. An Ellison dynamo furnishes a ourront of ten amperes and thirty- three volts. Tho ore is fed lo-tho barrel by means of a hopper, ns
or," at pngQ 609 of llte present y
[PHOTOCOPY]
[The: Concentration of Iron-Ore." Co-authored by John Birkinbine. American Institute of Mining Engineers 17 (February 1889; pub. 18891: American Institute of Mining Engineers in New York.]
Transactions of the 1-17. Presented to the
12 THE CONCENTRATION OF IRON-ORE.
shown in outline, Fig. 2, tlio cylinder turning in the direction of (lie nrrow. Tlio magnetite adheres to the bam of the barrel and is carried downward past tlio first delivory siiuto. Below tlio machine tlio bars, departing from tlio influence of the eleolro-ningnot, which is placed eccentrically, lose their power to hold tlio partiolos of mag¬ netic iron-ore and they drop oif. The particles of rock ill the ore being non-mngiiotio, drop from tlio barrel almost immediately and fall on tlio first sliutc shown in the engraving. Experimental tests on tlio WeiiBtrom innohine with various ores gave results ns follows:
Concentrations by the U'cnslrom Magnolia Separator.
Bench Ctlomi, Now Jersey,
Phosphorus,
Chntcnugny Ore & Iron Co., N.Y.,
PortHenry, Now York, Now lied, lyithorbces, Sherninn & Co.,
PortHenry, New York, Old Red, Witlierhecs, Shcrninn & Co.,
The Con It ling magnetic separator is a belt-machine of the general tnrm indicated by 1' ig. 3. which merely shows the principle and
Cniikting Separator.
not the detail. Tlio ore is fed on a belt and carried along under a series of belts, running nt right angles to the first. These cross- bells pnsB between the magnets and tlio ore lying on tlio distributing- belt, and may bo plnced at vnrying distances from the latter. As tlio ore, reduced to tlio proper size, posses along cpil tlio distributing- belt, the mngnetic-bclts, which may be influenced by magnets of different powers, pick up nnd carry to one sido the magnetic particles of tlie ore, while the non-raagnetio portion of the gangue is carried
THE CONCENTRATION OF IRON-ORE. 13
off ns tailings. The results obtained by treating some ores by this maaliino are reported ns follows:
Concentrations by the Conkling Magnetic Separator.
I. Port nonry, N. Y., Now Hod, Wlthorhecs, Bhermnn & Co.
II. Plait Mlno.N.J.
III. Mt. Hope Mine, N. .1., Thomas Iron Co.
IV. Lehigh Mountain, Pa.
Another machine wliioli has been operated experimentally on a commercial scale is called the “Monarch.” In this the ore is fed on one belt, from which tlio magnetic particles arc picked by a second belt placed above tlio first, but carrying the ore in the same direction; this belt is equipped with magnets or alternate polarity, to obtain, if possible, more perfect separation of the material as it passes the vnrying poles.
Analyses of results reported from this machine arc ns follows:
Concentrations by the Monarch Magnetic Separator.
I. Chnlcaugny Oro and Iron Co., N. Y. II. Llllto Hirer, N. Y. ’ -
ill. rorcstol Doan, N. Y.
IV. Wlthcrbccfl, Sherman & Co., N. Y., Now Bod. V. Wilhcrbccs, Sherman & Co., N. Y, Old Bed.
[PHOTOCOPY]
[''The Concentration of Iron-Ore." Co-authored by John Birkinbine. Transactions of the American Institute of Mining Engineers 17 (Februaiy 1889; pub. 1889): 1-17. Presented to the American Institute of Mining Engineers in New York.]
TUB CONCENTRATION OP IRON-ORE.
|
THE CONCENTRATION OP IRON-ORE.
15
Tlio Edison unipolar non-contact oloctrio separator dilPera fro in the forms described in that it lias no moving parts. Except such facilities for altering the relative position of the pai ls ns are essen¬ tial for adjustment in treating different ores, or are required to soonre certain results, all parts of the apparatus are fixed. The separator, which is illustrated by Fig. 4, consists simply of a hopper, a magnet and a partition to separate the concentrates and tailings into dilforont roccptnolos. Tlio illustration shows but one hopper, but in praotico tlio ore can pass on onoli side of the magnet, thus doub¬ ling the enpaoity. Tlio simplicity of tlio construction, which is the
result of patient and thorough investigation of many diflerent de¬ signs and methods, will commend itself.
Tlio oro after being properly cruised and sized is placed in hop¬ pers, from which its disolmrgo is controlled by bars closing slots which extend tlio iongtli of tlio hopper. These slots are made adjustable so ns to suit tlio size to wliioli tlio oro lias been reduced. Tlio hoppers are adjusted to appropriate heights abovo the inngnet. The magnet in tlio apparatus exhibited nt tlio Edison Laboratory, Llewellyn, N. J., is n moss of soft iron 0 feet long by 30 inches wide and 10 inches thick, weighing 3400 pounds, and wound with . 450 po is of copper wire, tiio coil being conneoted with a dynamo
r
consuming 2J horse-power and requiring a current of electricity of 10 amperes and an electromotive foroo of 116.5 volts.
Tlie material falling from the hopper passes the fuce of the mag¬ net, but docs not touch it. The distance of tlio magnet from the vertical plane of the falling material is so chosen lliat its attrac¬ tion causes tlio magnolia to separate from tlio non-magnetio particles Htillioionlly to alter their direction. By renson of tlio force uf gravity, this deflection of the trajectory, while sufficient to draw the mag¬ netic particles- away from the non-piagnotic, docs not draw llioiii against the magnet, but should any ore accumulate on the magnet it can be instantly dropped by breaking the current. The exact distance, liowover, is maintained so that none can stick to the magnet. Owing to the altered trajectory the magnetic ore falls upon one sido of the partition, which is so adjusted ns to secure the best result while the gauguc material drops upon tile opposite side.
In many ores there are particles of magnetite attached to sonic non-magnetio ninlerial which prevent them being carried ovor with thcconccntrntes, lint cause them to be drawn sufficiently from tlio verti¬ cal to separate them from tlio tailings, or when tlio stream of material permits several layers to pass the .magnet simultaneously, parti¬ cles of non-mtignetio material may retard the movements of magnetic portions so that they do not pass into the concentrates. In such cases an intermediate grade is collected called tlio 11 mugwump,” because it is neither concentrates nor tailings. 'This mugwump may be returned to tlio hoppers or passed before a second magnet. A scries of magnets may be arranged so that tlio concentrates, mugwumps or tails aro each subjected, os ill other machines herein described, to repeated magnetic influence, thus insuring more per¬ fect separation, and maintaining tlio capncity which isaslrong point 1 of the Edison apparatus. Tlio hopper in the apparatus exhibited to tlio Institute nt Llewellyn is 6 feet wide, and the quantity of ore which can be treated per day will depend upon the degree of fineness to which the material is crushed, and tlio widtli to which the slot in the liopper is opened. Arranging tlio slot to pass readily Ilia lean ore from Withcrbces, Sherman &-Co.’s Now Bed nt Fort Henry, N. Y., when crushed to pass.a 10-mesh sorccn; each sideof tlio magnet will separate conveniently about 150 tons of material daily, mak¬ ing the capacity of the two-fuco machine 300 tons per day.
The most systematical experimenting upon any one ore lias been made by Messrs. Withcrbces, Sliorman & Co., at Fort Hoary , N. Y., using various machines, and by Messrs. Clicovor with tile Buoli-
[PHOTOCOPY]
[''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. Presented to the American Institute of Mining Engineers in New York.]
16 TilB CONCENTRATION OF IRON-ORB.
nimn mngnctio rolls, treating the ores from the Croton mines, but a greater variety of ores imvo been concentrated by the Edison uni¬ polar machine, among which may be mentioned, Wilhorbccs, Shop¬ man it Co.’s Now Bed ore (to separate the magnetite from the siliceous gnuguo) and Old Bed oro at Port Henry, N. Y. (to rcduco the amount of phosphorus liy separating tlio npntitc from tlio mngno- tito) ; tlio Clmtcaugay ^rc & Iron Co.’s ore, at Lyon Mountain, N. Y. (to separate the magnetite from siliceous ganguo) j Messrs. Chccver’s Croton mines, Brewster, N. Y. (to separato tlio mng- netitofrom tlio gangiie and reduce tlio phosphorus and sulphur); the Cornwall Oro Bank Company’s ore, Lebanon, Pa. (to separate magnetite from silica mid reduce Btilphur) ; Mont Alto, Pa. (to separate small crystals of mngnetito from a lean ferruginous sand-rook); and the Phcenix Iron Co.’s ore, Jones mine, Berks Co., Pa. (to separate tlio gangue from tlio magnetite and reduce the sulphur). Various kinds of waste material from iron and steel works have also boon treated to extrnot the metal. With a modification, the apparatus ha? been used in treating gold-ore.
I ho concentrating plant lately erected at Humboldt, M ichigan, consists of n largo Gates rock-breaker, into which the lean magnetite from tlio dump-pile, yielding 40 to 45 per cent, of iron, is fed. Tlio material from the crusher passes over a shaking screen into a pair of 16 x 30 Cornish rolls, and from these the crushed ore is sized in screens to 20 mesh, the dust blown out of it, and tlio product from these soreens passes an Edison magnetic separator, whore the oro is conccutratcd. .The result is a concentrate carrying from G2 to 68 per cent, of iron, and within the Bessemer limit ns to phosphorus. As the plant has but lately been put in operation, the details of its workings cannot bo given. Tlio mugwump mado is returned by elevators to tlio feeding bin.
The following are some of the results obtained in treating iron- ores by tiie Edison separator :
Concentration oj New Bed Lean Ore, Port Henry, N. Y., by the Edison Machine.
20 mcali| !° } l^hoaphoriis B. Crushed to 1 Iron, .
lOmesli, . i Phosphorus 0. Abovo 101 Iron, . mesh, , . / Phosphorus
TUB CONCENTRATION OB' IRON-ORE. 17
Concentration of Old Bed Ore, Port Henry, N. K., by the Edison Machine.
Iron, . 60.5 00.16
Phosphorus, . ... '1.77 0.41
Iron, . . . . . 02.0 70.00
Phosphorus,. ... 1.40 0.18
Iroji . 04.20 71.20
Phosphors . llSO ’ 0.31
For 'the purpose of testing the apparatus, ora was selected with a maximum of apatite, and the phosphorus therefore shows largely in excess of tlio average contents in Port Henry Old Bod oro ns mined.
It will be observed tlmt while a considerable portion of tlio phos¬ phorus lias been eliminated it is still above the Bessemer limit. When it is considered how quickly a few stray crystals of npatilo will affect the result, or how easily particles of apatite may ho embraced ns it wore by particles of magnetite as they puss the magnet, tlio delicacy of tlio operation of removing the phosphorus will bo appreciated. ■Experiments now in progress indicate that a more thorough dephosphorizution than given above will be ob¬ tained.
Concentration of Croton Ore, N. Y., by the Edison Machine.
Concentration of " Jones Ore ” of Phocnir. Iron Co., by Edison Machine.
This analysis is by Voudy, those of Port Henry ores arc liy Woodbridge, and those of Croton ores by Landis.
[PHOTOCOPY]
["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. Presented to the International Medical Congress in Berlin, Germany.]
gAN ACCOUNT OF SOME EXPERIMENTS UPON THE APPLICATION OF ELECTRICALENDOS- iS'.'MOSE TO THE TREATMENT OF GOUTY CON- fc ' CRETION.
THOMAS A. EDISON, ol
Shaving ascertained that gouty concretions are in many f'casos medically treated with the aid of lithinm salts ^ taken internally, with the object of causing urato of |llthium to he formed, dissolved, and excreted from the fbody ; and being also informed that the difficulty met | with in the treatment was in ensuring that the salts so if administered should ho absorbed into the syBtem, it [ioccnrred to me that perhaps more rapid success might jibe obtained if the application were made externally, fc employing the well known principle of electrical endos- gmose to carry the lithinm into the tisanes. This method |fof operation appeared to offer considerable hope of tfsuccess, because the lithinm would be brought directly Kinto the neighbourhood of the concretions and would Jjthns be more likely to act promptly and effectively. m Electrical endosmose, as tho name implies, is that §. property of an electrical onrrent passing through a |P°i!mB aiaph[a®m b8tween two solutions, in virtue of
of common salt with the negative electrode. The current passed through him was i milliampCres, which was as mnoh as he conld conveniently stand. This treatment was continued for about two hours daily (luring one week-, the total time of application amount¬ ing to II hours. His nrino was collected during f week, and tests were then applied to it. Using a pi
cular spectroscope and method”, it waa found^hat^a solution containing TIrJB,,tU part by weight of LiCl in water was just dectectahlo by a faint red band in the spectrum. No such band could under theso circum¬ stances be discerned from the urine itself, hut a con¬ densation of all tho week’s urine reduced to the form of chloride gave a distinct band. An evaporation of . jths of the total quantity of this liquid yielded on analysis 0 22 gramme of lithinm chloride, and it waa therefore presumed’ that tho whole amount of salt ^creted wasO'SS gratqnae, corresponding to 0 09 gramme
of metallio lithium, or equivalent to the removal of 2 '-13 grammes of urlo acid.
I next tried the application of the method to a patient suffering from an acute and typical form of the malady, in December, 1889. This perBon volunteered to try the effeot of the method. He was 73 years of age, and had llved.au active healthy life until ten years previously, at whioh time, according to his own statement, he con¬ tracted the disease through sleeping in damp sheets. Concretions commencing continued to increaso slowly until they assumed large proportions. All the joints, except the knees, were mnoh enlarged by atheromatouB
[PHOTOCOPY]
["Insulation." Electrical Engineer 14 (July 13, 1892): 34-35.]
NSULATION.i
THOMAS A. EDISON.
illation of the circuits is bo vital a matter K liislorv repeat itself, and of recounting aj)ur on the subject may lie tolerated, lie l>eKt insulators ; next liquids, and sol- !lt,°n of gases is so good that no deter- have been made of any leakage through p to make an experiment, at or near the to be beyond the reach of gravitational might be left for hours in a gas without •ort.and observations then made to deler- chargo took place through surrounding :i rcu instances, the loss, of clinrgo which on electrified bodies, cannot readily be 'JSbttbe suspension or support that holds
icous vapor. Professor’ Boys exhibited ety of London m April, 1889, a pair of upended in moist air by a short hook of jo appeared to be about 25 per cent, in , under the same conditions, would have tppenr, It was said, within one minute, ur fa ce°l( a I- a°'1( ^Ctfraphisls
mi^e° * & S* wirc 18 221 8<lunro feet!
ch takes place con vectivcly Into the air i electrified body, is a phenomenon of a he layer of atmosphere over the point is ' magnitude of tho forces brought and the particles of moving air carry o a very high insulation, notably most l vegetable oils are by no means so good,
■ mil cully in obtaining them in a highly li e p u *est f| 1 \ ^t i Mod1 >re ' i ‘ ! lnK, 1101 ' on G* ia .•r cubic centimetre have been recorded;
°y°r in the far north. Sea water has a resistance of about
! 30 ohniR per cubic centimetre at 6‘ C. It would appear prob.
I a jhimds cannot conduct without electrolytic decom¬
position. A microscope will show that one microampere decoin-.. | poses the drop of water it traverses.
j One of the most important and promising modemUheorics of i cnuwwtry is based upon the assumption, in accordance with a ; considerable array of facts, that solutions only conduct bv the i transfer of atoms or ions to the electrodes, each* carrying an elec¬ tric charge, and the conductivity of a liquid measures on this hy¬ pothesis the number of uncomliined or dissociated ions permeating its mass. These free ions are the porters carrying the qlrnrge, and the conductivity of the liquid depends upon the number available and the sneed with which they can migrate.
Liquids, too, have, as a class, tho quality of elastic insulation to high tensions, which is an important feature to the electrical engineer. Air for the first few centimetres will break and allow “ ,sc,h,in;e t0 occur when tho pressure reaches from 10.0Q0
to .*0,000 volts per centimetre (23,41)0 io 127.000 volts pur inch) ac¬ cording to the shape and condition of the electrodes, but rosin oil wil^o it°rtan< t1' )0Ut ^ l,UleS *,re85W,e°f a*r Pcr centimetre The following is a list of actually observed resistance in conf- mcrcml samples of well-known insulating substances. The ic- pults are given in megohms per cubic centimetre at or near 18 ‘ C.:
All transparent solids are insulators, but of course the opposite statement is not true that all opaque solids ate good conductors. •There is now good evidence for believing that the procers bv which light is propagated, the mechanism by which it is trails- muted through space, is purely clectromagiieliy, and the mag¬ netic vibrations passing through a conductor would generate electrical currents and be absorbed in the substance as heat, that energy5*’ * W0U d be optul,,B 10 the Hght, failing to transmit the The difficulty with solids is not so much to find insulators, for the great majority of solid substances freed from ir - -
poor conductors, but to find an insulation of suitable mechanical qualities. Glass, porcelain and mica seem to be almost the onlv practically available insulators that will '* * **
stresses and these for many structural pi
practically available insulators that wili support considerable ses and these for many structural purposes arc* fur weaker is <1 cm red. In American telegraphy, glass is almost the urn-
west, the ntmosphe
insulators except in dry weather. Porcelain or vitrifieif .
ware insulators are used instead, and in quite a variety of forms. Practically speaking, the insulation of a line is never that of tin* material forming the insulators, but always that of their surfaces and the films of dust and moisture that may have become en¬ crusted thereon. The most perfect insulators are those which have underneath tho hood a cup filled with oil in such a man¬ ner that, the current leaking from the wire to the ground has to pass over the oil, or else through the substance of the insulator itsoir. I hose insulators are certainly more expensive, and rcuuiro to be refilled with oil at intervals, but they will defv weather and keep the insulation nearly ns high in fog as in sunshine.
when a long, leaky wire is opened at the distant end, and tested tor insulation, the insulation per mile alwavs appears to b/ somewhat more Ilian it is for. any actual mile, since the more di$>. tant portions of the line are tested with a reduced pressure owing to the leakage over the nearer portion. When the wire is grounded at the far end, and its conductor resistance measured, the leakage will on tin* other hand make the apparent resistance per mile too low. But if the conductor resistance is reduced in a given ratio, say as 100 to 97, the insulation will be over indicated in the exact inverse ratio of 9.3 to 100, provided that the insulation of the line is uniform. So that if a wire’s conductor resistance at its temperature of observation is known to ho 10 ohms per mile, mil appears by leakage over the whole length to be 9 ohms, then i if the insulation per mile apparently measures 100,000 ohms, it will be really 300,000, and each mile taken separately might be expected to measure 300,000. As is well known, telegraph lines' work belter up to a certain point if the insulation is rather low. A wire has to be emptied of its charge between the impulses of flic key sufficiently far to keep the relays from sticking. If the Ration is perfect, this quantity luuyo^bc cleared through the readily at all points! 1 * C*,n
r'l the more essential goud insulation nerosa.
[PHOTOCOPY]
["Further Experiments in Fluorescence Under the Cathode Ray." Electrical Engineer 21 (April 1, 1896): 340.]
FURTHER EXPERIMENTS IN FLUORESCENCE UNDER .
• THE CATHODE RAY..
l^UHTHRH experiments with the fluorescence of different chemicals under the influence of the X*rny lmvc nddod n few more to the list already published. The following fluoresce: Cndlnin tungstate, tungstate of slue* llthlu benzoate, launatu lend, carbonate lead, salicylate potassium, carbonate silver, sodium salicylate, sodium ctu'bonnte, sodium tungstate, zinc acetate, ziuc chloride, zinc carbonate, molybdate zinc, benzole acid, malic acid, diplicuylnmiuc, rutligallic acid, pyiidiu ni-
I have so far found no salt iu the following metals to fluo¬ resce: Aluminum, antimony, arsenic, boron, beryllium, bismuth, cerium, chromium, cobalt, copper, gold, iridium, magnesium, manganese, nickel, tin, titanium.
[PHOTOCOPY]
["Are Roentgen Ray Phenomena Due 1896): 353-354.]
to Sound Waves?" Electrical Engineer 21 (April 8,
nil ratios they worn protected from Injury, wlmn within tint geometrical shadow, mid wore shivered when outside of- the siime. The some resells took placo whether the bottles wore lined with water or with air.
The breaking of a class by a sudden shock counnunlenlod by
means of wnter Is a fact lone known . 1 Is Illustrated by the
old familiar class experiment of exploding a ‘Trlnco ltnport dritii," while Its bulb Is'plnngod Into an ordinary apothecary’s phial tilled with water.
"I-lx pertinents with Stout Glass Tubes."— The cylindrical class tubes employed were ahnut six feet lone and l.ti iuehes In diam¬ eter, the class belnc about, an of an Inch In thickness. They were eovered by pnsllne cartrldce paper over them, so as to prevent the loss of fracments when brenknee oeeurred.
The tubes were adjusted to a framework of wood so arranged
at'lhey could be plunged In a horizontal noslltnn br.no,, in in..
that'lhey could bo plunced In a horizontal position beneath the surface of the water behind the pile, the axis of the tube being at right angles to the plane of Its shadow, and held there (the
[PHOTOCOPY]
["Roentgen Ray Lamps and Other Experiments." Electrical Engineer 21 (April 15, 1896): 378.]
[ A Card from Mr. Edison: To the Editor." New York Journal (April 18, 1896).]
I'crlmcnt Again, wltll ,flno..i;esiOIS._rJt.i«_V>j I'lipln wo o'vo tlie plioto-lluoroscopo, naj not to merer. THOMAS A^EDlSOXj
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["Influence of Temperature on X-Ray Effects." Electrical Engineer 21 (April 22, 1896): 409-410.]
INFLUENCE OF TEMPERATURE ON X-RAY EFFECTS.
|
nl Ihmroseopo, under the now conditions, the steel w
ami permits *t he short'
These experiments j
From continued work in tiiis field I find that bullis which arc spherical at tlto point where the maximum fluorescence appears are Tory liable to be pierced, not by the spark, but by a focus of bombardment, resulting, in the heating to the nielli ng point of an extremely small part of the glass.
In most cases, if the center of fluorescence is watched, a
lion-fluorescent portion will appear: if now the power of the : coil is Increased there will appear in (Ids nmi-llunrcsrciit area ■» ■ an extremely fine point which will grow red hot and be forced -inward by the atmospheric pressure. 1 have seen these spots eoinc and perforate the bulb within' two seconds. 1 find ilia I it occurs ‘when the electrodes are perfectly fiat, and ttial it proceeds nsV thin concent ruled pencil from the exact center coll Is iucivnsed there will appear in this lion-fluorescent, area . of tills concentrated bomba rdiiiout Is Increased ‘and the tube can be worked at a ’higher power before heating. Tile best remedy Is to permit the central rn.v to strike Hie glash at a low angle; Ibis. greatly Increases the area, and prevents the
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A SymP°sium °" the Roen,een my*-* Century Magazine
PHOTOGRAPHING THE UNSEEN.
A SYMPOSIUM ON THE ROENTGEN RAYS.
THE most nota- of its flesh-clad anatomy. It is even more re- J- ble event in markable that, outside of the work done by a scientific history few investigators (some of it recorded in this last year was the issue of The Century), the vast mass of effort isolation, by two has been mere tiresome repetition of a very physicists of Eng- limited number of Professor Roentgen’s ex¬ land, of anew ele- periments.
ment in the atmo- The detection and utilization of the X ray sphere. That dis- was in a sense evolutionary, although the covery of argon, actual occurrence was quite by accident. Dat- the. .unsuspected ing, perhaps, from Hauksbee’s Royal Society P5, existence of which work in obtaining phosphorescent light by for so long was rubbing briskly a glass globe exhausted of hardly to the air, it was a fashionable amusement through- credit of modern out the whole of the last century to witness science, is now electrical discharges in , . i . , „ matched by the vacuo . The reader can
beautiful work of 'Professor W. C. Roentgen test the thing for him- ln photographing the unseen by electric rays self by taking any in- from vacuum-tubes. It cannot be said that candescent lamp into a either of these advances was eagerly awaited dark comer, and chaf- as a sequential development. On the contrary, ing it briskly with a bit the individuality of argon was very strenu- of cloth or silk, when he ously denied by expert philosophers, and the will see a gleam of blu- first announcement of the « X rays,»'with their ish lightwithin the curious Paul-Pry capacity for photographing bulb. Of lateyears through a brick wall, was also met with out- thefavoritemeans spoken incredulity. Prom such incidents as of studying such these one may fairly infer that, while patient effects has been a investigation will always count for much in Geissler tube of science, happy chance is an important factor, glass, into which,
Innumerable eyes are strained in their gaze littlewiresofplat- upon the gloom, and just at what moment and inum being sealed at which point the veil of fog may casually lift at each end, high- is forever uncertain. tension currents
This countryis proverbially alert in matters can be passed, with of discovery, yet it was several days before the help of an in- any one repeated the Roentgen experiments, duction-coil. The news of which had been cabled in graphic discharge in the detail by European correspondents. As if to tube across the compensate for the delay and inertness, the space from wire to other extreme has since been rushed to, and wire creates beau- no school or college has considered the day tiful effects of col- well spent in which, with endless iteration, it ored light, depen- hap not taken « cathodographs » of hands and dent on the nature - coins. The sheep-like tendency of human be- of the rarefied * mgs is once more exemplified in the fact that, gases within the while a large proportion of the inhabitants tube. Professor of the United States have had their hands Crookes followed p taken, » only a single foot, so far as the writer up this lineof work Z is aware, has been made to reveal the secrets by improving such •
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["Photographing the Unseen: A Symposium 52 (May 1896): 120-131.]
on the Roentgen Rays." Century Magazine
PHOTOGRAPHING THE UNSEEN. 121
tubes, and by his brilliant demonstrations in fluence, but they refuse to be reflected, and state off Which Pnri!h.v0aUnrtt’ °r- “^adlant'” 60 through various prisms without any sort of state, of which Faraday spoke eighty years apparent refraction. They persist in follow- ^6°- from these experiments by Crookes ing absolutely straight lines, starting from dated new phenomena of phosphorescence the point on the glass bulb that is seen to be faintly fluorescing with a blue-green light, under the action of the invisible rays from the cathode to the glass. While they present analogies with the ultra-violet rays of the spectrum, their close identity with light is still regarded as doubtful. Light is attributed to transverse vibrations of the ether, but Pro¬ fessor Roentgen has suggested that his rays may be longitudinal vibrations, like sound- pulses in the air. They do at least throw shadows, cause chemical action, and set up fluorescence, while the last fact would ob¬ viously suggest that they may engender heat. Some trustworthy experimenters find the rays peculiarly irritating to the eye, and others
si
cuum-tube which has wires or disks sealed of the spectrum, 10 wmcr into each end or side walls, the glow, starting is not usually applied, trom the Positive, or anode, tip, fades out as The electrical conditions involved are of in-
utterly'cp0 oftwhjoh ‘he,df P ra’d,?ationo is ™at annrancefby Professor J? J. Thra?
region, seems uncertain, but the subject has stance upon which they fall, no matter how Wfl Z„yvmVe-^ i'gated.andProfessorRoent- the body may be protected against discharge, gen s discovery is one fruit of exploration in From this the writer would infer that the T SsT •ar,ra' Roentgen rays are those which, on emerging
It was first pointed out by the late Profes- from their prison of glass or aluminium have sor Hertz of Germany that these ultra-violet lost their own electric charge Derhaisen! rays from the cathode could penetrate opaque tirely. Professor Thomson statesP moreover bodies such as aluminium in a vacuum. This that the nature of the charge, whether posi- was interesting, but Dr. Philip Lenard further P
showed that such rays would also pass hut into the air and through any substance lying be- \ yond the vacuum. They would travel a con- i:; siderable distance, would cause phosphores- rii cence, and would act on photographic plates. Si From this to the discovery of Roentgen, who &j| has caused the permeable substances inter- posed in the lines of these rays to register their shadows on a photographic plate, is but a step, though a long and memorable one. "3 At this moment discussion is rife as to the nature of the Roentgen ray, and many old theories as to light, electricity, and the ether are threatened with change. The obedience of the ordinary cathode rays to a magnet is one of their characteristics; but the X rays are still Bezonians whose king is unknown, for they not only do not respond to magnetic in-
122 THE CENTURY MAGAZINE.
tive or negative, is immaterial. The corollary drawn by him from this is that all bodies under the influence of these rays become con¬ ductors. One such fact indicates many pos¬ sibilities in the electrical arts and sciences.
There is no need now to dwell upon the value of the Roentgen rays in surgery and dentistry, for the newspaper press of Europe and America has been full of their use in re¬ vealing the condition of the bony structure of the body. Their employment in the testing of metals, the inspection of objects in closed or concealed packages, and the detection of differences in various substances, is obvious. One immediate and important application al¬ ready made on both sides of the Atlantic is to the study of moving objects projected on a fluorescent screen, while yet another inven¬ tion is aimed at seeing and photographing objects hidden by darkness.
It will conduce much to the utility of these rays, however, to determine, first of all, their nature; that is, whether they are simply streams of matter under electrical impulse, or light of short wave-length, or some new phenomenon of vibration in the ether itself.
Thomas Commerford Marlin.
ing the high-tension electricity necessary for its excitation. At the start the bulb is full of air, and as soon as the coil is set in action crooked blue sparks pass freely between the aluminium plates within. The pump is now used, the silvery fluid alternately rising and falling within its tubes, and driving out the air before it. With its first stroke we observe a change in the bulb. The blue sparks cease, and in their place appears a waving purple flame, which, as the air becomes rarer, broadens, and finally breaks up into stratifications. The room is now darkened. Little disks of bluish- white light fill the tube, resembling somewhat a pile of saucers. The spaces between them widen, and finally a dark space appears about one of the electrodes. The discharge is now approaching the form described by Crookes as « radiant,® the light becomes fainter, and the dark space widens out until it touches the glass wall, which instantly glows with its characteristic green phosphorescence. A few more strokes of the pump and the vacuum is practically perfect. The resistance to the passage of the current is now so great, and the potential on the wires rises to such a point, that purple fringes of electric fire spring forth into the air. Sparks occasionally leap about the outside of the bulb, preferring the
On entering the room in which are arranged the elaborate paraphernalia necessary for the production of the Roentgen phenomena, the self-acting mercurial air-pump, with its laby¬ rinth of tubes and bulbs, is the first object that attracts notice. Connected with this'by a slender tube is the small glass bulb, with its two electrodes of aluminium, which is the source of the new energy; while just below it is the huge Ruhmkorff induction-coil, furnish-
long air-gap to the shorter but vacuous one within. The entire inner surface shines with a pale emerald light, while directly in front of one of the disks is a very bright spot of a yellowish color, where the full force of the cathode rays falls. This spot is the source of the mysterious «X rays,» which, though un¬ seen, radiate from it in all directions like light.
The bulb is now covered with a thick black
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and we see a shadow of the plate with its stenciled word. A wooden box of lead-pencils shows only tho shadows of the leads as a num¬ ber of narrow parallel lines. And now comes the most startling experiment of all. Wehold our hand behind the screen, and, closely ob¬ serving the luminous surface, perceive within
perfect, even tho cartilaginous spaces tween being discernible. It is impossibli describe the feeling of awe that one exp ences on actually seeing the image of his . skeleton within the enshrouding flesh.
_ Wonderful as are these phosphorest pictures, oven more so are tho photograi
52 (May' T896)?120e-13r.f e": A SymPosium on the R°e"'Sen Rays." Certur, Magaz
phosphorescent entire surface of the screen shines with a with the obser- bluish-green light. Placing a few coins in tho ad the room be- center of a thick book, we hold it between the . large wooden screen and the apparatus. The coins instantly as been painted appear as circular black shadows on the lumi- is set up before nous background. A brass stencil-plato is i toward us. The placed in an aluminium cigarette-case and th the board, ex- held against the screen. Tho litrht metal is
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["Photographing